PROFILES OF THE FUTURE

by

ARTHUR C. CLARKE

      An inquiry into the Limits of the Possible

             Revised edition

                                  4

      POPULAR LIBRARY - TORONTO
 Published by Popular Library, CBS Publications, CBS Consumer Publishing, a
 Division of CBS Inc., by arrangement with Harper & Row, Publishers, Inc.

 September, 1977

 Revised Edition. Copyright @ 1958, 1959, 1960, 1962, 1973 by A.rthur C.
 Clarke. Copyright Q 1960, 1961, 1962 by H. M. H. Publishing Co. Copyright
 Q 1960 by Popular Mechanics Co.

 Library of Congress Catalog Card Number: 72-6714

 ISBN: 0-445-04061-0

 Portions of this book were first published in D. A. C. News, Holiday,
 Horizon, Playboy, Rotarian and Science Digest.

To my colleagues in the Institute of Twenty-First
Century Studies, and especially to
HUGO GERNSBACK
who thought of everything

 Printed In Ca

 All rights reserved. No part of this book may be used or reproduced in any
 manner whatsoever without written permission except in the case of brief
 quotations embodied in critical articles and reviews. For information
 address Harper & Row, Publishers, Inc., 10 East 53rd Stree4 New York, N.Y.
 10022
             CONTENTS

    preface . . . . . . . . . . . 7
    Introduction  . . . . . . . .11

 1. Hazards of Prophecy: The Failure of Nerve ... ... 19

  2. Hazards of Prophecy: The Failure
  of Imagination  . . . . . . . .30
  3. The Future of Transport  . . 40
  4. Riding on Air  . . . . . . .55
  5. Beyond Gravity . . . . . . .64
  6. The Quest for Speed  . . . . 79
  7. World without Distance . . . 88
  8. Rocket to the Renaissance  .100
  9. You Can't Get There from Here  115

  10. . Spitce, the Unconquerable   - 130
  11. About Time  . . . . . . .  140

  12.         . . . . . . . . . .Ages ofPlenty.........................158
  13. Aladdin's Lamp  . . . . . ...........173

 14. Invisible Men and Other Prodigies . . ... ... ... . . 180

  15. The Road to Lilliput  . .     192
  16. Voices from the Sky . . .     203
  17. Brain and Body  . . . . .  217
  18. The Obsolescence of Man .     232
  19. The Long Twilight . . . .     .....248
  Chart of the Future
 Preface to the Second Edition

 This book originally appeared in 1962 and was based npon essays written
 during the period 1959-1961. Since it was concerned largely with ultimate
 possibilities, and not with achievements to be expected in the near future,
 even the remarkable events of the last decade have dated it very little. The
 chapter "Rocket to the Renaissance," for example, now appears even more
 timely than when it was written, in 1960, nine years before the first men
 walked on the Moon.
  What has changed-and in ways that no one could possibly have predicted-is
  our entire attitude toward the future, and especially toward technology as
  a whole. Profiles was one of the first samples of a deluge of books about
  the future; today, there are societies, foundations, journals devoted to
  the study of "futuristics." The bibliog~-raphy is getting quite out of
  hand, and the best way of keeping track of it is through the World Future
  Society,' and its excellent magazine, The Futurist.

  I P.O. Box 19285, Twentieth Street Station, Washington, D.C. 20036.
                7
  Why has the future suddenly become respectable? There is certainly no
  simple or single explanation. It may be because most educated men have at
  last begun to understand the imperatives of change, and the urgent need to
  prepare for the inevitable revolutions in almost every field of human
  activity. Having lived through several revolutions in half a lifetime, I
  find it easier to accept the possibility that others are still to come.
  And yet-this fascination with the future has generated its own antithesis,
  particularly in the so-called affluent or developed societies. There is a
  growing disenchantment with "progress" (however this may be defined) and
  even a feeling that, in many directions, we have already gone too far.
  Part of this attitude, especially among the young, reflects the general
  malaise of the 1960's-the byproduct of traumatic assassinations, disastrous
  wars, and the other evils of that unhappy decade. Faced with these horrors,
  it was understandable that many should have decided it was all the fault of
  the scientific-technological approach-just as, forty years earlier, their
  equally sincere and intelligent precursors often blamed everything on
  capitalism. In each case, there was a lot of truth in the accusations; but
  it was not the whole truth, and the suggested cures were often worse than
  the disease.
  By the end of the 1960's, the revulsion against the industrial society's
  excesses had led to a revulsion against reason itself. The drug culture,
  the "yippies," the revival of interest in witchcraft, astrology, and
  eccentric religions, the tendency to adopt sandals and beads and to
  hitchhike to Katmandu-all these were part of the same pattern. And there
  was a curious irony in the fact that, at the moment in history when the
  East was desperately trying to acquire the technology of the West, the West
  was turning to the East in search of spiritual guidance.2
  Hopefully, much good may, in the long run, emerge from this ferment of
  ideas and philosophies. The extrem-
  
  2 See my debate with Dr. Alan Watts on mysticism and technology, "At the
  Interface," Playboy magazine, January 1972.
                8
 ists on both sides will cancel out; what will be left may be a greater
 reverence for the organic world, but not an uncritical acceptance of all
 that is "natural." There are many natural things that should be stamped on,
 hardand much that is artificial that should be given the utmost
 encouragement.
  I am happy to see that, even in the first edition of this book, I had come
  out strongly against some of the waste and stupidity of the modem
  industrial state (see, e.g-, Chapter 12), though I do not claim to be a
  premature Ecofreak. At the same time, I cannot pretend that this work will
  be of very much use to those who are struggling to rectify the Ms of
  today's societies. In fact, in some areas it may well be worse than
  useless, because I am not concerned with the problems of the near future,
  but with ultimate possibilities. The subtitle "An Inquiry into the Limits
  of the Possible" describes exactly what I had in mind. I can well imagine
  how discouraging it might be to those struggling to solve today's problems
  with today's technologies to read about the wonderful tools we will
  possess-in the middle of the next century. The other day I had to take a
  taxi through the teeming slums of Calcutta to deliver a talk largely based
  on this book. In those circumstances, it was not easy to be optimistic
  about any future.
  I would like to express my thanks to all those readers who have made useful
  comments on the original edition, and particularly to Robert E. Button,
  COMSAT's Director of Goverdmental and Foundation Relations, who has used
  the work as a textbook for his University of Virginia classes for several
  years-and whose nudgings are partly responsible for this revision.
  Some of the ideas in this volume have also been developed in more detail,
  or in other directions, in two later books: Voices from the Sky and Report
  on Planet Three.

                     ARTHUR C. CLARKE
 Colombo, Ceylon, 1972

                9
 Introduction

 It is impossible to predict the future, and all attempts to do so in any
 detail appear ludicrous within a very few years. This book has a more
 realistic yet at the same time more ambitious aim. It does not try to
 describe the future, but to define the boundaries within which possible
 futures must lie. If we regard the ages which stretch ahead of us as an
 unmapped and unexplored country, what I am attempting to do is to survey its
 frontiers and to get some idea of its extent. The detailed geography of the
 interior must remain unknown-until we reach it.
  With a few exceptions, notably Chapter 8, 1 am limiting myself to a single
  aspect of the future-its technology, not the society that will be based
  upon it. This is not such a limitation as it may seem, for science will
  dominate the future even more than it dominates the present. Moreover, it
  is only in this field that prediction is at all possible; there are some
  general laws governing scientific extrapolation, as there are not (pace
  Marx) in the case of politics or economics.
I also believe-and hope-that politics and economics I I
 will cease to be as important in the future as they have been in the past;
 the time will come when most of our present controversies on these matters
 will seem as trivial, or as meaningless, as the theological debates in which
 the keenest minds of the Middle Ages dissipated their energies. Politics and
 economics are concerned with power and wealth, neither of which should be
 the primary, still less the exclusive, concern of full-grown men.
  Many writers have, of course, tried to describe the technological wonders
  of the future, with varying degrees of success. Jules Verne is the classic
  example-and one never likely to recur, for he was born at a unique moment
  of time and took full advantage of it. His life (18281905) neatly coincided
  with the rise of applied science; it almost exactly spans the interval
  between the first locomotive and the first airplane. Only one other man has
  exceeded Verne in the range and accuracy of his predictions: this is the
  American editor and inventor Hugo Gernsback (1884-1967). Though his
  narrative gifts did not match the great Frenchinan's, and his fame is not
  therefore of the same magnitude, Gemsback's indirect influence through his
  various magazines was comparable to Verne's.
  With few exceptions, scientists seem to make rather poor prophets; this is
  rather surprising, for imagination is one of the first requirements of a
  good scientist. Yet, time and again, distinguished astronomers and
  physicists have made utter fools of themselves by declaring publicly that
  such-and-such a project was impossible; I shall have pleasure, in the next
  two chapters, in parading some splendid cautionary examples. The great
  problem, it seems, is finding a single person who combines sound scientific
  knowledge-or at least the feel for sciencewith a really flexible
  imagination. Verne qualified perfectly, and so did Wells, whenever he
  wished. But Wells, unlike Verne, was also a great literary artist (though
  he often pretended otherwise) and very sensibly did not allow himself to be
  shackled by mere facts if they proved inconvenient.
Having evoked the great shades of Verne and Wells, 1 12
 would not go so far as to claim that only readers or writers of science
 fiction are really competent to discuss the possibilities of the future. It
 is no longer necessary, as it was a few years ago, to defend this genre from
 the attacks of ignorant or downright malicious critics; the finest work in
 the medium stands comparison with all but the very best fiction being
 published today. But we are not concerned here with the literary qualities
 of science fiction-only with its technical content. Over the last thirty
 years, tens of thousands of stories have explored all the conceivable, and
 most of the inconceivable, possibilities of the future; there are few things
 that can happen that have not been described somewhere, in books or
 magazines. A critical-the adjective is important-reading of science fiction
 is essential training for anyone wishing to look more than ten years ahead.
 The facts of the future can hardly be imagined ab initio by those who are
 unfamiliar with the fantasies of the past.
  This claim may produce indignation, especially among those second-rate
  scientists who sometimes make fan of science fiction (I have never known a
  first-rate one to do so--and I know several who write it). But the simple
  fact is that anyone with sufficient imagination to assess the future
  realistically would, inevitably, be attracted to this form of literature.
  I do not for a moment suggest that more than I per cent of science fiction
  readers would be reliable prophets; but I do suggest that almost 100 per
  cent of reliable prophets will be science fiction readersor writers.
  As for my own qualifications for the job, I am content to let the published
  record speak for itself. Although like all other propagandists for space
  flight, I overestimated the time scale and underestimated the cost, I am
  not in the least contrite about this error. Had we kiiown, back in the
  1930's, that it was going to cost billions of dollars to develop space
  vehicles, we would have been completely discouraged; in those days no one
  could have believed that such sums would ever be available.
  Ile speed with which space exploration is progressing would have seemed
  equally unlikely. When Hermann 13
  t

 Oberth's pioneering book Die Rakete zu den Planetenraeumen was reviewed by
 Nature in 1924, that journal remarked, with great daring, "In these days of
 unprecedented achievements one cannot venture to suggest that even Herr
 Oberth's ambitious scheme may not be realised before the human race is
 extinct." It has been realized, in large measure, before Professor Oberth is
 extinct.
  I can claim a slightly better record than Nature's reviewer. On glancing
  into my first novel Prelude to Space (written in 1947) 1 am amused to see
  that though I scored a direct hit by giving 1959 as the date of the first
  Moon rocket, I put manned satellites in 1970 and the landing on the Moon in
  1978. This seemed wildly optimistic to most people at the time, but now
  demonstrates my innate conservatism. A still better proof of this is pro-
  vided by the fact that I made no attempt whatsoever, in 1945, to patent the
  communication satellite. (See Chapter 16.) 1 couldn't have done so, as it
  happens; but at least I would have made the effort, had I dreamed that the
  first experimental models would be operating while I was still in my
  forties.
  -In any event, this book is not concerned with time scales--only with
  ultimate goals. At the present rate of progress, it is impossible to
  imagine any technical feat that cannot be achieved, if it can be achieved
  at all, within the next five hundred years. But for the purposes of this
  inquiry, it is all the same whether the things discussed can be done in ten
  years, or in ten thousand. My only concern is with what, not with when.
  For this reason, many of the ideas developed in this book will be mutually
  contradictory. To give an example, a really perfect system of
  communications would have an Fxtremely inhibiting effect on transportation.
  Less obvious is the converse; if travel became instantaneous, would anyone
  bother to communicate? The future will have to choose between many
  competing superlatives; in such cases, I have described each possibility as
  if the other did not exist.
  In a similar manner, some chapters end on an optimistic note, others on a
  pessimistic. According to the point of 14
 view, both unlimited optimism and unlimited pessimism about the future are
 equally justified. In the final chapter, I have tried to reconcile both.
  it has been said that the art of living lies in knowing where to stop, and
  going a little further. In Chapters 14 and 15 1 have attempted to do this,
  by discussing conceptions which are almost certainly not science-fact, but
  science-fantasy. Some people may regard a serious treatment of such ideas
  as invisibility and the fourth dimension as a waste of time, but in this
  context it is fully justified. It is as important to discover what cannot
  be done as what can be done; and it is sometimes considerably more amusing.
  While writing this introduction, I came across a review of a somewhat
  pedestrian Russian book about the twenty-first century. The distinguished
  British scientist writing the review found the work extremely reasonable
  and the author's extrapolations quite convincing.
  I hope this charge will not be leveled against me. If this book seems
  completely reasonable and all my extrapolations convincing, I will not have
  succeeded in looking very far ahead; for the one fact about the future of
  which we can be certain is that it will be utterly fantastic.

 15
 PROFILES OF THE FUTURE

 j
 Hazards of Prophecy:
  The Faflure of Nerve

 Before one attempts to set up in business as a prophet, it is instructive to
 see what success others have made of this dangerous occupation-and it is
 even more instructive to see where they have failed.
  With monotonous regularity, apparently competent men have laid down the law
  about what is technically possible or impossible-and have been proved
  utterly wrong, sometimes while the ink was scarcely dry from their pens. On
  careful analysis, it appears that these debacles fall into two classes,
  which I will call "failures of nerve" and "failures of imagination."
  TIfe failure of nerve seems to be the more common; it occurs when even
  given all the relevant facts the would-be prophet cannot see that they
  point to an inescapable conclusioh. Some of these failures are so ludicrous
  as to be almost unbelievable, and would form an interesting subject for
  psychological analysis, "They said it couldn't be done" is a phrase that
  occurs throughout the history of invention; I do not know if anyone has
  ever looked into the 19
 reasons why "they" said so, often with quite unnecessary vehemence.
  It is now impossible for us to recall the mental climate which existed when
  the first locomotives were being built, and critics gravely asserted that
  suffocation lay in wait for anyone who reached the awful speed of thirty
  miles an hour. It is equally difficult to believe that, only eighty years
  ago, the idea of the domestic electric light was pooh-poohed by all the
  "experts'~--with the exception of a thirty-one-year-old American inventor
  named Tbomas Alva Edison. When gas securities nose-dived in 1878 because
  Edison (already a formidable figure, with the phonograph and the carbon
  microphone to his credit), announced that he was working on the
  incandescent lamp, the British Parliament set up a committee to look into
  the matter. (Westminster can beat Washington hands down at this game.)
  The distinguished witnesses reported, to the relief of the gas companies,
  that Edison's ideas were "good enough for our transatlantic friends ... but
  unworthy of the attention of practical or scientific men." And Sir William
  Preece, engineer-in-chief of the British Post Office, roundly declared that
  "Subdivision of the electric light is an absolute ignis famus." One feels
  that the fatuousness was not in the ignis.
  The scientific absurdity being pilloried, be it noted, is not some
  wild-and-woolly dream like perpetual motion, but the humble little electric
  light bulb, which three generations of men have taken for granted, except
  when it burns out and leaves them in the dark. Yet although in this matter
  Edison saw far beyond his contemporaries, he too in later life was guilty
  of the same shortsightedness that afflicted Preece, for he opposed the
  introduction of alternating current.
  The most famous, and perhaps the most instructive, failures of nerve have
  occurred in the fields of aero- and astronautics. At the beginning of the
  twentieth century, scientists were almost unanimous in declaring that
  heavier-than-air fight was impossible, and that anyone who attempted to
  build airplanes was a fool. The great 20
 American astronomer, Simon Newcomb, wrote a celebrated essay which
 concluded:

   The demonstration that no possible combination -of known substances, known
   forms of machinery and known forms of force, can be united in a practical
   machine by which man shall fly long distances through the air, seems to
   the writer as complete as it is possible for the demonstration of any
   physical fact to be.

  Oddly enough, Newcomb was sufficiently broad minded to admit that some
  wholly new discovery-he mentioned the neutralization of gravity-might make
  flight practical. One cannot, therefore, accuse him of lacking imagination;
  his error was in attempting to marshal the facts of aerodynamics when he
  did not understand that science. His failure of nerve lay in not realizing
  that the means of flight were already at hand.
  For Newcomb's article received wide publicity at just about the time that
  the Wright brothers, not having a suitable antigravity device in their
  bicycle shop, were mounting a gasoline engine on wings. When news of their
  success reached the astronomer, he was only momentarily taken aback. Flying
  machines might be a marginal possibility, he conceded-but they were
  certainly of no practical importance, for it was quite out of the question
  that they could carry the extra weight of a passenger as well as that of a
  pilot.
  Such refusal to face facts which now seem obvious has continued throughout
  the history of aviation. Let me quote another astronomer, William H.
  Pickering, straightening out the uninformed public a few years after the
  first airplanes had started to fly.

   The popular mind                often pictures gigantic flying
 machines speeding across the Atlantic and carrying in
 numerable passengers in a way analogous to our mod
 ern steamships.... It seems safe to say that such ideas
 must be wholly visionary, and even if a machine could
                21
 get across with one or two passengers the expense would be prohibitive to
 any but the capitalist who could own his own yacht.
   Another popular fallacy is to expect enormous speed to be obtained. It
   must be remembered that the resistance of the air increases as the square
   of the speed and the work as the cube.... If with 30 h.p. we can now
   attain a speed of 40 m.p.h., then in order to reach a speed of 100 m.p.h.
   we must use a motor capable of 470 h.p.... it is clear that with our
   present devices there is no hope of competing for racing speed with either
   our locomotives or our automobiles.

  It so happens that most of his fellow astronomers con
 sidered Pickerinp far too imaginative; he was prone to see
 vegetation-and even evidence for insect life-on the
 Moon. I am glad to say that by the time he died in 1938
 at the ripe age of ei ' Lyhtv, Professor Pickering had seen air
 planes traveling at 400 m.p.h., and carrying considerably
 more than "one or two" passengers.
  Closer to the present, the opening of the space age hag produced a mass
  vindication (and refutation) of prophecies on a scale and at a speed never
  before witnessed. Having taken some part in this myself, and being no more
  immune than the next man to the pleasures of saying, "I told you so," I
  would like to recall a few of the statements about space flight that have
  been made by prominent scientists in the past. It is necessary for someone
  to do this, and to jog the remarkably selective memories of the pessimists.
  The speed with which those who once declaimed, "It's impossible" can switch
  to, "I said it could be done all the time" is really astounding.
  As far as the general public is concerned, the idea of
 space flight as a serious possibility first appeared on the
 horizon in the 1920's, largely as a result of newspaper re
 ports of the work of the American Robert Goddard and
 the Rumanian Hermann Oberth. (The much earlier
 studies of Tsiolkovsky in Russia then being almost un
 known outside his own country.) When the ideas of God
                22
 dard and Oberth, usually distorted by the press, filtered through to the
 scientific world, they were received with hoots of derision. For a sample of
 the kind of criticism the pioneers of astronautics had to face, I present
 this masterpiece from a paper published by one Professor A. W. Bickerton, in
 1926. It should be read carefully, for as an example of the cocksure
 thinking of the time it would be very hard to beat.

   This foolish idea of shooting at the moon is an example of the absurd
   length to which vicious specialisation will carry scientists working in
   thought-tight compartments. Let us critically examine the proposal. For
   a projectile entirely to escape the gravitation of the earth, it needs a
   velocity of 7 miles a second. The thermal energy of a gramme at this speed
   is 15,180 calories.... The energy of our most violent explosive-
   nitroglycerine-is less than 1,500 calories per gramme. Consequently, even
   had the explosive nothing to carry, it has only one-tenth of the energy
   necessary to escape the earth.... Hence the proposition appears to be
   basically impossible....

  Indignant readers in the Colombo public library pointed angrily to the
  SILENCE notices when I discovered this little gem. It is worth examining it
  in some detail to see just where "vicious specialisation," if one may coin
  a phrase, led the professor so badly astray.
  His first error Res in the sentence: "The energy of our most violent
  explosive-nitroglycerine ..." One would have thought it obvious that
  energy, not violence, is what we want from a rocket fuel; and as a matter
  of fact nitroglycerine and similar explosives contain much less energy,
  weight for weight, than such mixtures as kerosene and liquid oxygen. This
  had been carefully pointed out by Tsiolkovsky and Goddard years before.
  Bickerton's second error is much more culpable. What of it, if
  nitroglycerine has only a tenth of the energy necessary to escape from the
  Earth? That merely means that 23
 you have to use at least ten pounds of nitroglycerine to launch a single
 pound of payload.'
  For the fuel itself has not got to escape from Earth; it can all be burned
  quite close to our planet, and as long as it imparts its energy to the
  payload, this is all that matters. When Lunik Il lifted thirty-three years
  after Professor Bickerton said it was impossible, most of its several
  hundred tons of kerosene and liquid oxygen never got very far from
  Russia-but the half-ton payload reached the Mare Imbrium.
  As a comment on the above, I might add that Professor Bickerton, who was an
  active popularizer of science, numbered among his published books one with
  the title Perils of a Pioneer. Of the perils that all pioneers must face,
  few are more disheartening than the Bickertons.
  Right through the 1930's and 1940's, eminent scientists continued to deride
  the rocket pioneers-when they bothered to notice them at all. Anyone who
  has access to a good college library can find, preserved for posterity in
  the dignified pages of the January 1941 Philosophical Magazine, an example
  that makes a worthy mate to the one I have just quoted.
  It is. a paper by the distinguished Canadian astronomer Professor J. W.
  Campbell, of the University of Alberta, entitled "Rocket Flight to the
  Moon." Opening with a quotation from a 1938 Edmonton paper to the effect
  that "rocket flight to the Moon now seems less remote than television
  appeared a hundred years ago," the professor then looks into the subject
  mathematically. After several pages of analysis, he arrives at the
  conclusion that it would require a million tons of take-off weight to carry
  one pound of payload on the round trip.
  The correct figure, for today's primitive fuels and technologies, is very
  roughly one ton per pound-a depressing ratio, but hardly as bad as that
  calculated by the profes-
  
  I The dead weight of the rocket (propellent tanks, motors', etc.) would
  actually make the ratio very much higher, but that does not affect the
  argument
                24
 sor. Yet his mathematics was impeccable; so what went wrong?
  Merely his initial assumptions, which were hopelessly unrealistic. He chose
  a path for the rocket which was fantastically extravagant in energy, and he
  assumed the use of an acceleration so low that most of the fuel would be,
  wasted at low altitudes, fighting the Earth's gravitational field. It was
  as if he had calculated the performance of an automobile-when the brakes
  were on. No wonder that he concluded: "While it is always dangerous to make
  a negative prediction, it would appear that the statement that rocket
  flight to the moon does not seem so remote as television did less than one
  hundred years ago is over-optimistic." I am sure that when the
  Philosophical Magazine subscribers read those words, back in 1941, many of
  them thought, "Well, that should put those crazy rocket men in their
  placel"
  Yet the correct results had been published by Tsiolkovsky, Oberth and
  Goddard years before; though the work of the first two would have been very
  hard to consult at the time, Goddard's paper "A Method of Reaching Extreme
  Altitudes" was already a classic and had been issued by that scarcely
  obscure body, the Smithsonian Institution. If Professor Campbell had only
  consulted it (or indeed any competent writer on the subject-there were
  some, even in 1941) he would not have misled his readers and himself.
  The lesson to be learned from these examples is one that can never be
  repeated too often, and is one that is seldom understood by laymen-who have
  an almost superstitious awe of mathematics. But mathematics is only a tool,
  though an immensely powerful one. No equations, however impressive and
  complex, can arrive at the truth if the initial assumptions are incorrect.
  It is really quite amazing by what margins competent but conservative
  scientists and engineers can miss the mark, when they start with the
  preconceived idea that what they are investigating is impossible. When this
  happens, the most wellinformed men become blinded by their prejudices and
  are unable to see what lies directly ahead of them. What is 25
 even more incredible, they refuse to learn from experience and will continue
 to make the same mistake over and over again.
  Some of my best friends are astronomers, and I am sorry to keep throwing
  stones at them-but they do seem to have an appalling record as prophets. If
  you still doubt this, let me tell a story so ironic that you might well ac-
  cuse me of making it up. But I am not that much of a cynic-, the facts are
  on file for anyone to check.
  Back in the dark ages of 1935, the founder of the British Interplanetary
  Society, P. E. Cleator, was rash enough to write the first book on
  astronautics published in England. His Rockets through Space gave an
  (incidentally highly entertaining) account of the experiments that had been
  carried out by the German and American rocket pioneers, and their plans for
  such commonplaces of today as giant multi-stage boosters and satellites.
  Rather surprisingly, the staid scientific journal Nature reviewed the book
  in its issue for March 14, 1936, and summed up as follows:

   It must be said at once that the whole procedure sketched in the present
   volume presents dffficulties of so fundamental a nature that we are forced
   to dismiss the notion as essentially impracticable, in spite of the
   author's insistent appeal to put aside prejudice and to recollect the
   supposed impossibility of heavier-than-air fight before it was actually
   accomplished. An analogy such as this may be misleading, and we believe
   it to'be so in this case....

  Well, the whole world now knows just how misleading this analogy was,
  though the reviewer, identified only by the unusual initials R.v.d.R.W. was
  of course fully entitled to his opinion.
  Just twenty years later---after President Eisenhower had announced the
  United States satellite program-a new Astronomer Royal arrived in England
  to take up his appointment. The press asked him to give his views on space
  fight, and after two decades Dr. Richard van der 26
 Riet Woolley had seen no reason to change his mind. "Space travel," he
 snorted, "is utter bilge."
  The newspapers did not allow him to for get this, when
 Sputnik I went up the very next year. Later-irony piled
 upon irony-Dr. Woolley became, by virtue of his posi
 tion as Astronomer Royal, a leading member of the com
 mittee advising the British government on space research.
 The feelings of those who have been trying, for a gener
 ation, to get the United Kingdom interested in space can
 well be imagined .2
  Even those who suggested that rockets might be used for more modest, though
  much more reprehensible, purposes were overruled by the scientific
  authorities--except in Germany and Russia.
  When the existence of the 200-mile-range V-2 was disclosed to an astonished
  world, there was considerable speculation about intercontinental missiles.
  This was firmly squashed by Dr. Vannevar Bush, the civilian general of the
  United States scientific war effort, in evidence, before a Senate committee
  on December 3, 1945. Listen:

   There has been a great deal said about a 3,000 miles high-angle rocket.
   In my opinion such a thing is impossible for many years. The people who
   have been writing these things that annoy me, have been talking about a
   3,000 mile high-angle rocket shot from one continent to another, carrying
   an atomic bomb and so directed as to be a precise weapon which would land
   exactly on a certain target, such as a city.
   I say, technically, I don't think anyone in the world knows how to do such
   a thing, and I feel confident that it will not be done for a very long
   period of time to come.... I think we can leave that out of our thinking.

  2 In all fairness to Dr. Woolley, I would like to record that his 1936
  review contained the suggestion-probably for the first time -that rockets
  could contribute to astronomical knowledge by making observations in
  ultraviolet light beyond the absorbing screen of the Earths atmosphere.
  Thanks to the Orbiting Astronomical Observatories and their successors,
  this idea has been overwhelmingly justified.
                27
 I wish the American public would leave that out of their thinking.

  A few months earlier (in May 1945) Prime Minister Churchill's scientific
  advisor Lord Cherwell had expressed similar views in a House of Lords
  debate. This was only to be expected, for Cherwell was an extremely
  conservative and opinionated scientist who had advised the government that
  the V-2 itself was only a propaganda rumor.3
  In the May 1945 debate on defense, Lord Cherwell impressed his peers by a
  dazzling display of mental arithmetic from which he correctly concluded
  that a very long-range rocket must consist of more than 90 per cent fuel,
  and thus would have a negligible payload. The conclusion he let his
  listeners draw from this was that such a device would be wholly
  impracticable.
  That was true enough in the spring of 1945, but it was no longer true in
  the summer. One astonishing feature of the House of Lords debate is the
  casual way in which much-too-well-informed peers used the words "atomic
  bomb," at a time when this was the best-kept secret of the war. (The
  Alamogordo test was still two months in the future!) Security must have
  been horrified, and Lord Cherwell-who of course knew all about the
  Manhattan Project-was quite justified in telling his inquisitive colleagues
  not to believe everything they heard, even though in this case it happened
  to be perfectly true.
  When Dr. Bush spoke to the Senate committee in December of the same year,
  the only important secret about the atomic bomb was that it weighed five
  tons. Anyone could then work out in his head, as Lord Cherwell had done,
  that a rocket to deliver it across intercontinental ranges would have to
  weigh about 200 tons---as against the mere 14 tons of the then
  awe-inspiring V-2.
 The outcome was the greatest failure of nerve in an

  8 Cherwell's influence-malign or otherwise--has been the subject of a
  vigorous debate since the publication of Sir Charles Snow's Science and
  Government.
               28
 history, which changed the future of the world-indeed, of many worlds. Faced
 with the same facts and the same calculations, American and Russian
 technology took two separate roads. The Pentagon-accountable to the tax-
 payer-virtually abandoned long-range rockets for almost half a decade, until
 the development of thermonuclear bombs made it possible to build warheads
 five times lighter yet several hundred times more powerful than the
 low-powered and now obsolete device that was dropped on Hiroshima.
  The Russians had no such inhibitions. Faced with the need for a 200-ton
  rocket, they went right ahead and built it. By the time it was perfected,
  it was no longer required for military purposes, for Soviet physicists had
  bypassed the United States' billion-dollar tritium bomb cul-de-sac and gone
  straight to the far cheaper lithium bomb. Having backed the wrong horse in
  rocketry, the Russians then entered it for a much more important event-and
  won the race into space.
  Of the many lessons to be drawn from this slice of recent history, the one
  that I wish to emphasize is this. Anything that is theoretically possible
  will be achieved in practice, no matter what the technical difficulties, if
  it is desired greatly enough. It is no argument against any project to say:
  "Ile idea's fantasticl" Most of the things that have happened in the last
  fifty years have been fantastic, and it is only by assuming that they will
  continue to be so that we have any hope of anticipating the future.
  To do this-to avoid that failure of nerve for which history exacts so
  merciless a penalty-we must have the courage to follow all technical
  extrapolations to their logical conclusion. Yet even this is not enough, as
  I shall now demonstrate. To predict the future we need logic; but we also
  need faith and imagination which can sometimes defy logic itself.

                29
                                 2

 Hazards of Prophecy:
  The Faflure of linagination

 In the last chapter I suggested that many of the negative statements about
 scientific possibilities, and the gross failures of past prophets to predict
 what lay immediately ahead of them, could be described as failures of nerve.
 All the basic facts of aeronautics were available-in the writings of Cayley,
 Stringfellow, Chanute, and otherswhen Simon Newcomb "proved" that flight was
 impossible. He simply lacked the courage to face those facts. All the
 fundamental equations and principles of space travel had been worked out by
 Tsiolkovsky, Goddard, and Oberth for years--often decades-when distinguished
 scientists were making fan of would-be astronauts. Here again, the failure
 to appreciate the facts was not so much intellectual as moral. The critics
 did not have the courage that their scientific convictions should have given
 them; they could not believe the truth even when it had been spelled out
 before their eyes, in their own language of mathematics. We all know this
 type of cowardice, because at some time or other we all exhibit it.
The second kind of prophetic failure is less blame30
 worthy, and more interesting. It arises when all the available facts are
 appreciated and marshaled correctly-but when the really vital facts are
 still undiscovered, and the possibility of their existence is not admitted.
  A famous example of this is provided by the philosopher Auguste Comte, who
  in his Cours de Philosophie Postive (1835) attempted to define the limits
  within which scientific knowledge must lie. In his chapter on astronomy
  (Book 2, Chapter 1) he wrote these words concerning the heavenly bodies:

   We see how we may determine their forms, their distances, their bulk,
   their motions, but we can never know anything of their chemical or
   mineralogical structure; and much less, that of organised beings living
   on their surface.... We must keep carefully apart the idea of the solar
   system and that of the universe, and be always assured that our only true
   interest is in the former. Within this boundary alone is astronomy the
   supreme and positive science that we have determined it to be ... the
   stars serve us scientifically only as providing positions with which we
   may compare the interior movements of our system.

  In other words, Comte decided that the stars could never be more than
  celestial reference points, of no intrinsic concern to the astronomer. Only
  in the case of the planets could we hope for any definite knowledge, and
  even that knowledge would be limited to geometry and dynamics. Comte would
  probably have decided that such a science as "astrophysics" was a priori
  impossible.
  Yet within half a century of his death, almost the whole of astronomy was
  astrophysics, and very few professional astronomers had much interest in
  the planets. Comte's assertion had been utterly refuted by the invention of
  the spectroscope, which not only revealed the "chemical structure" of the
  heavenly bodies but has now told us far more about the distant stars than
  we know of our planetary neighbors.
                31
  Comte cannot be blamed for not imagining the spectrocope; no one could have
  imagined it, or the still more ophisticated instruments that have now
  joined it in the astronomer's armory. But he provides a warning that should
  always be borne in mind; even things that are undoubtedly impossible with
  existing or foreseeable techniques may prove to be easy as a result of new
  scientific breakthroughs. From their very nature, these breakthroughs can
  never be anticipated; but they have enabled us to bypass so many
  insuperable obstacles in the past that no picture of the future can hope to
  be valid if it ignores them.
  Another celebrated failure of imagination was that persisted in by Lord
  Rutherford, who more than any other man laid bare the internal structure of
  the atom. Rutherford frequently made fun of those sensation mongers who
  predicted that we would one day be able to harness the energy locked up in
  matter. Yet only five years after his death in 1937 , the first chain
  reaction was started in Chi cago. What Rutherford, for all his wonderful
  insight, had failed to take into account was that a nuclear reaction might
  be discovered that would release more energy than that required to start
  it. To liberate the energy of matter, what was wanted was a nuclear "fire"
  analogous to chemical combustion, and the fission of uranium provided this.
  Once that was discovered, the harnessing of atomic energy was inevitable,
  though without the pressures of war it might well have taken the better
  part of a century.
  The example of Lord Rutherford demonstrates that it is not the man who
  knows most about a subject, and is the acknowledged master of his field,
  who can give the most reliable pointers to its future. Too great a burden
  of knowledge can clog the wheels of imagination; I have tried to embody
  this fact of observation in Clarke's Law, which may be formulated as
  follows:

  When a distinguished but elderly scientist states that
 something is possible, he is almost certainly right. When he states that
 something is impossible, he is very probably wrong.
                32
  Perhaps the adjective "elderly" requires definition. In physics,
  mathematics, and astronautics it means over thirty; in the other
  disciplines, senile decay is sometimes postponed to the forties. There are,
  of course, glorious exceptions; but as every researcher just out of college
  knows, scientists of over fifty are good for nothing but board meetings,
  and should at all costs be kept out of the laboratory!
  Too much imagination is much rarer than too little; when it occurs, it
  usually involves its unfortunate possessor in frustration and
  failure-unless he is sensible enough merely to write about his ideas, and
  not to attempt their realization. In the first category we find all the
  science-fiction authors, historians of the future, creators of utopias-and
  the two Bacons, Roger and Francis.
  Friar Roger (c. 1214-1292) imagined optical instraments and mechanically
  propelled boats and flying machines-devices far beyond the existing or even
  foreseeable technology of his time. It is hard to believe that these words
  were written in the thirteenth century:

   Instruments may be made by which the largest ships,
 with only one man guiding them, will be carried with
 greater velocity than if they were full of sailors. Chari
 ots may be constructed that will move with incredible
 rapidity without the help of animals. Instruments of fly
 ing may be formed in which a man, sitting at his ease
 and meditating in any subject, may beat the air with his
 artificial wings after the manner of birds ... as also
 machines which will enable men to walk at the bottom
 of the seas. . . .

  This passage is a triumph of imagination over hard fact. Everything in it
  has come true, yet at the time it was written it was more an act of faith
  than of logic. It is probable that all long-range prediction, if it is to
  be accurate, must be of this nature. The real future is not logically
  foreseeable.
  A splendid example of a man whose imagination ran ahead of his age was the
  English mathematician Charles 33
 Babbage (1792-1871). As long ago as 1819, Babbage had worked out the
 principles underlying automatic computing machines. He realized that all
 mathematical calculations could be broken down into a series of step-by-step
 operations that could in theory, be carried out by a machine. With the aid
 of a government grant which eventually totaled ae 17,000-a very substantial
 sum of money in the 1820's-he started to build his "analytical engine."
  Though he devoted the rest of his life, and much of his private fortune, to
  the project , Babbage was unable to complete the machine. What defeated him
  was the fact that precision engineering of the standard he needed to build
  his cogs and gears simply did not exist at the time. By his efforts he
  helped to create the machine-tool industry-so that in the long run the
  government got back very much more than its ze 17,000-and today it would be
  a perfectly straightforward matter to complete Babbage's computer, which
  now stands as one of the most fascinating exhibits in the London Science
  Museum. In his own lifetime, however, Babbage was only able to demonstrate
  the operation of a relatively small portion of the complete machine. A
  dozen years after his death, his biographer wrote: "This extraordinary
  monument of theoretical genius accordingly remains, and doubtless will
  forever remain, a theoretical possibility."
  There is not much left of that "doubtless" today. At this moment there are
  thousands of computers working on the principles that Babbage clearly
  outlined more than a century ago-but with a range and a speed of which he
  could never have dreamed. For what makes the case of Charles Babbage so
  interesting, and so pathetic, is that he was not one but two technological
  revolutions ahead of his time. Had the precision-tool industry existed in
  1820, he could have built his "analytical engine" and it would have worked,
  much faster than a human computer, but very slowly by the standards of
  today. For it would have been geared-literally-to the speed with which cogs
  and shafts and cams and ratchets can operate.
  Automatic calculating machines could not come into their own until
  electronics made possible speeds of oper34
 ation thousands and millions of times swifter than could be achieved with
 purely mechanical devices. This level of technology was reached in the
 1940's, and Babbage was then promptly vindicated. His failure was not one of
 imagination: it lay in being born a hundred years too soon.
  One can only prepare for the unpredictable by trying to keep an open and
  unprejudiced mind-a feat which is extremely difficult to achieve, even with
  the best will in the world. Indeed, a completely open mind would be an
  empty one, and freedom from all prejudices and preconceptions is an
  unattainable ideal. Yet there is one form of mental exercise that can
  provide good basic training for would-be prophets: Anyone who wishes to
  cope with the future should travel back in imagination a single life-
  time-say to 1900-and ask himself just how much of today's technology would
  be, not merely incredible, but incomprehensible to the keenest scientific
  brains of that time.
  1900 is a good round date to choose because it was just about then that all
  hell started to break loose in science. As James B. Conant has put it:

   Somewhere about 1900 science took a totally unexpected turn. There had
   previously been several revolutionary theories and more than one
   epoch-making discovery in the history of science, but what occurred
   between 1900 and, say, 1930 was something different; it was a failure of
   a general prediction about what might be confidently expected from
   experimentation.

 P. W. Bridgman has put it even more strongly:

   The physicist has passed through an intellectual crisis forced by the
   discovery of experimental facts of a sort which he had not previously
   envisaged, and which he would not even have thought possible.

  The collapse of "classical" science actually began with Roentgen's
  discovery of X-rays in 1895; here was the first 35
 clear indication, in a form that everyone could appreciate, that the
 commonsense picture of the universe was not sensible after all. X-rays-the
 very name reflects the bafflement of scientists and laymen alike-could
 travel through solid matter, like light through a sheet of glass. No one had
 ever imagined or predicted such a thing; that one would be able to peer into
 the interior of the human body-and thereby revolutionize medicine and
 surgerywwas something that the most daring prophet had never suggested.
  The discovery of X-rays was the first great breakthrough into the realms
  where no human mind had ever ventured before. Yet it gave scarcely a hint
  of stiff more astonishing developments to come-radioactivity, the internal
  structure of the atom, relativity, the quantum theory, the uncertainty
  principle....
  As a result of this, the inventions and technical devices of our modem
  world can be divided into two sharply defined classes. On the one hand
  there are those machines whose working would have been fully understood by
  any of the great thinkers of the past; on the other, there are those that
  would be utterly baffling to the finest minds of antiquity. And not merely
  of antiquity; there are devices now coming into use that might well have
  driven Edison or Marconi insane had they tried to fathom their opCration.
  Let me give some examples to emphasize this point. If you showed a modern
  diesel engine, an automobile, a steam turbine, or a helicopter to Benjamin
  Franklin, Galileo, Leonardo da Vinci, and Archimedes-a list spanning two
  thousand years of time-not one of them would have any difficulty in
  understanding how these machines worked. Leonardo, in fact, would recognize
  several from his notebooks. All four men would be astonished at the
  materials and the workmanship, which would have seemed magical in its
  precision, but once they had got over that surprise they would feel quite
  at home-as long as they did not delve too deeply into the auxiliary control
  and electrical systems.
But now suppose that they were confronted by a televi36
 Sion set, an electronic computer, a nuclear reactor, a radar installation.
 Quite apart from the complexity of these' devices, the individual elements
 of which they are composed would be incomprehensible to any man born before
 this century. Whatever his degree of education or intemgence, he would not
 possess the mental framework that could accommodate electron beams,
 transistors, atomic fission, wave guides and cathode-ray tubes.
  The difficulty, let me repeat, is not one of complexity; some of the
  simplest modern devices would be the most difficult to explain. A
  particularly good example is given by the atomic bomb (at least, the early
  models). What could be simpler than banging two lumps of metal together?
  Yet how could one explain to Archimedes that the result could be more
  devastation than that produced by all the wars between the Trojans and the
  Greeks?
  Suppose you went to any scientist up to the late nineteenth century and
  told him: "Here are two pieces of a substance called uranium 235. If you
  hold them apart, nothing will happen. But if you bring them together sud-
  denly, you will liberate as much energy as you could obtain from burning
  ten thousand tons of coal." No matter how farsighted and imaginative he
  might be, your pretwentieth century scientist would have said: "What utter
  nonsensel That's magic, not science. Such things can't happen in the real
  world." Around 1890, when the foundations of physics and thermodynamics had
  (it seemed) been securely laid, he could have told you exactly why it was
  nonsense.
  "Energy cannot be created out of nowhere," he might have said. "It has to
  come from chemical reactions, electrical batteries, coiled springs,
  compressed gas, spm*tlm*g flywheels, or some other clearly defined source.
  All such sources are ruled, out in this case-and even if they were not, the
  energy output you mention is absurd. Why, it is more than a million times
  that available from the most powerful chemical reactionl"
  The fascinating thing about this particular example is that, even when the
  existence of atomic energy was fully appreciated-say right up to
  1940-almost all scientists 37
 would still have laughed at the idea of liberating it by bringing pieces of
 metal together. Those who believed that the energy of the nucleus ever could
 be released almost certainly pictured complicated electrical devices"atom
 smashers" and so forth-doing the job. (In the long run, this will probably
 be the case; it seems that we will need such machines to fuse hydrogen
 nuclei on the industrial scale. But once again, who knows?)
  The wholly unexpected discovery of uranium fission in 1939 made possible
  such absurdly simple (in principle, if not in practice) devices as the
  atomic bomb and the nuclear chain reactor. No scientist could ever have
  predicted them; if he had, all his colleagues would have laughed at him.
  It is highly instructive, and stimulating to the imagination, to make a
  list of the inventions and discoveries that have been anticipated-and those
  that have not. Here is my attempt to do so.
  All the items on the left have already been achieved or discovered, and all
  have an element of the unexpected or the downright astonishing about them.
  To the best of my knowledge, not one was foreseen very much in advance of
  the moment of revelation.
  On the right, however, are concepts that have been around for hundreds or
  thousands of years. Some have been achieved; others will be achieved;
  others may be impossible. But which?

  THE UNEXPECTED THE EXPECTED
  X-rays          automobiles
  nuclear energyflying machines
  radio, TV     steam engines
  electronics      submarines
  photography      spaceships
  sound recording  telephones
  quantum mechanics          robots
  relativity       death rays
  transistors   transmutation
  masers; lasersartiflcial life
  superconductors;           immortality
                38
   superfluids    invisibility atomic clocks; levitation
   Mi5ssbauer effect              teleportation
 determining composition          communication with dead
   of celestial bodies        observing the past,
 dating the past the future
   (Carbon 14, etc.)       telepathy
 detecting invisible
   planets
 the ionosphere;
   van Allen Belts

  The right-hand list is deliberately provocative; it includes sheer fantasy
  as well as serious scientific speculation. But the only way of discovering
  the limits of the possible is to venture a little way past them into the
  impossible.' In the chapters that follow, this is exactly what I hope to
  do; yet I am very much afraid that from time to time I too will exhibit
  failure of imagination if not failure of nerve. For as I glance down the
  left-hand column I am aware of a few items which, only ten years ago, I
  would have thought were impossible....

  I The French edition of this book rather surprised me by calling this
  Clarke's Second Law. (See page 25 for the First, which is now rather
  well-known.) I accept the label, and have also formulated a Third: "Any
  sufficiently advanced technology is indistinguishable from magic."
  As three laws were good enough for Newton, I have modestly decided to stop
  there.
                39
                                 3

 The Future of Transport

 Most of the energy expended in the history of the world has been used to
 move things from one place to another. For thousands upon thousands of
 years, the rate of movement was very low-about two or three miles an hour,
 the pace of a walking man. Even the domestication of the horse did not raise
 this figure appreciably, for though a racehorse can exceed forty miles an
 hour for very short periods, the main use of the horse has always been as a
 slow-moving beast of burden and a hauler of vehicles. The fastest of
 these-the stagecoaches immortalized by Dickens-could seldom have traveled at
 more than ten miles an hour on the roads that existed before the nineteenth
 century.
  For almost the whole of human history and prehistory, therefore, men's
  thoughts and their ways of life have been restricted to the tiny band of
  the speed spectrum between one and ten miles an hour. Yet within the span
  of a few generations, the velocity of travel has been multiplied a
  hundredfold; indeed, there are good grounds for thinking that the
  acceleration that has taken place round the midtwentieth century will never
  again be matched.
                40
  Speed, however, is not the only criterion of transport, and there are times
  when it is positively undesirable--especially if it conflicts with safety,
  comfort or economics. As far as transportation at ground level is
  concerned, we may well have reached (if not passed) the practical Emit of
  speed, and future improvements must He in other directions. No one wants to
  travel down Fifth Avenue at the velocity of sound, but many New Yorkers
  would be very happy if they could always be sure of doing so at the speed
  of a stagecoach.
  There are many ways of classifying methods of transportation, the most
  obvious being by media-land, sea, air or space. But these divisions are
  becoming more and more arbitrary, now that there are vehicles that operate
  equally efficiently in two or more of them. For the present~purpose, a
  scheme based on distance is the most convenient; on our 8,000-mile diameter
  planet, only four
 ranges are involved.

                        MODE
 RAiqGv--MrLF,s DESIGNATION PASSENGERFREIGFIT
 1. 1-1                   Very ortFoot, horse,Truck, pipe
         (local,           bicycle,line, conveyor
         urban)       scooter, car,
                 bus, subway,
                 escalator
 2. 10-100                    ShortCar, bus,Truck, pipe
         (suburban,                rail, boat,line, rail
         rural)           escalator
 3. 1 ~-ItOOO                      MediumCar, bus,Fruck, rail,
         (continental)             rail, boat,airplane,
                 airplane,         G.E.M.,
                 G.E.M.,       VTOL
                 VTOL
 4. 1, 00-                        Low'airplane, Rail, ship,
 10,000                    (inter-ship, G.E.M.,aircraft,
         continental)             ramjet, rocketG.E.M.,
                          submarine
 G.E.M.: Gro ind ect M ,hine. VTOL: Vertical Takeoff and Landing Aircraft.
                41
  In the first category-very short ranges--only police, doctors, and firemen
  have any need to travel at over fifty miles an hour, or any right to
  inflict such speeds on the community. For this range, I would suggest that
  the ideal means of individual transportation is the motor scooter or the
  very small bubble-car. Indeed, I would like to be thoroughly reactionary
  and suggest that the almost obsolete habit of walking still has much to
  recommend it in terms of physical health, mental well-being, and frequently
  speed, as anyone who has ever been caught in a big city traffic jam will
  admit. Perhaps the only excuse for not walking, when short distances are
  involved, is the weather, and even this excuse will eventually vanish. In
  the cities, of course, the weather will be fully controlled before another
  century has passed; and outside them, even if we cannot control it, we will
  certainly be able to predict it and make plans accordingly.
  While we are in this backward-looking mood, let me make an even more
  startling suggestion. The best personal transport vehicle man has ever
  possessed-where only short ranges are concerned and the weather is good-is
  the horse. It is self-steering, self-reproducing, never goes out of
  style-and only a double-decker bus gives a comparable view of the scenery.
  I admit that there are some disadvantages; horses are expensive to
  maintain, prone to embarrassing behavior, and are not really very bright.
  But these are not fundamental limitations, for one day we will be able to
  increase the intelligence of our domestic animals, or evolve wholly new
  ones with much higher I.Q.'s than any existing now.
  When this happens, much of the short-range transport-at least in rural
  areas-may once again be nonmechanical, though not necessarily equine. The
  horse may not turn out to be the best choice in the long run; something
  like a compact elephant might be preferable, because of its dexterity.
  (Itis the only quadruped that can carry out delicate handling operations
  while remaining a quadruped.) In any event it should be herbivorous;
  carnivores are much too expensive to feed, and might take a fancy to their
  riders.
                42
  What I am suggesting is an animal large enough to carry a man at a fair
  speed, and intelligent enough to forage for itself without creating a
  nuisance or getting lost. It would report for duty at regular times, or
  when summoned over a radio command circuit, and it could carry out many
  simple errands by itself, without direct human ion. It seems to me that
  there would be quite a for such a creature; and where there is a demand,
  eventually there is a supply.
  Turning from this biological wishful thinking back to the world of
  machinery, the only novel item in the very short range category is the
  conveyor. By this I mean all continuously moving systems such as escalators
  or the "Moving Waye' described by H. G. Wells in The Sleeper Wakes.
  A few small-scale experiments in pedestrian conveyor systems have been
  considered and discussed in New York and London, to remove the notorious
  bottlenecks between Grand Central Station and Times Square, and between the
  Monument and the Bank of England. A sane city, designed from the ground up
  for the convenience of its inhabitants, would be crisscrossed with slowly
  moving sidewalks at different levels; perhaps the north-south ones would be
  on the even levels, the east-west ones on the odd, with frequent changeover
  points between them.
  The layout of a conveyor-belt city would be somewhat dull and mechanical,
  for obvious engineering reasons, though it need not be as monotonously
  rectilinear as Manhattan. I suspect that the greatest difficulties in the
  way of its realization would not be technical or economic, but social. The
  idea of free public transport, though it makes good common sense, will be
  anathema to a great many people. Already I can picture the violent campaign
  the Cab Drivers' Union would launch in favor of rugged individualism,
  against the horrors of socialized transportation.
  Yet, it is becoming obvious that vehicles-except public utility ones-cannot
  be permitted much longer in urban areas. We have taken some time to face
  this fact; more than two thousand years have passed since increas43
 ing trafUc congestion in Rome compelled Julius Caesar to ban all wheeled
 vehicles during the hours of daylight, and the situation has become slightly
 worse since 46 B.c. If private cars are to continue to operate inside the
 cities, we will have to put all the buildings on stilts so that the entire
 ground area can be used for highways and parking lots-and even this may not
 solve the problem.
  Though it seems unlikely that pedestrian conveyors will ever be used except
  over short distances, there is some possibility that they may have wider
  applications. About thirty years ago, in a short story "T'lie Roads Must
  Roll," Robert Heinlein suggested that travel even over considerable
  distances would one day be based on the conveyorbelt system-if only because
  the mounting carnage of the gasoline war rules out the continued use of
  automobiles. Heinlein developed, in his usual meticulous detail, both the
  sociology and the technology of the rolling road culture. He imagined vast
  multi-strip highways, with central express sections traveling at a hundred
  miles an hour, complete with dining places and rest rooms.
  The engineering problems of such a system would be enormous, but not
  insuperable (they could hardly be compared with those overcome in the
  development of nuclear weapons, though the capital sums involved would be
  even greater). It is my own feeling, however, that the mechanical
  difficulties would be so serious that their solution in terms of
  present-day technology would not be worth the trouble; Heinlein himself was
  careful to point out what might happen if a high-speed belt snapped with a
  few thousand passengers aboard it....
  The fundamental problem of continuously moving
 pedestrian conveyors is: How do you get on to them
 safely? Anyone who has observed a nervous old lady
 hovering on the brink of an escalator will appreciate this
 point, and I do not think that we can expect ordinary
 members of the public, possibly loaded down with shop
 ping bags or infants, to cope with speed differentials of
 over five miles an hour. This means that a large number
 of adjacent bands will be required if we hope to build ex
                44
 pressways, traveling at fifty or more miles an hour at their center.
  Ile ideal moving road would be one that had a s~7mthly increasing speed
  gradient from edge to center, so that there were no sudden jumps in
  velocity. No solid material can behave in this manner, and at first sight
  the concept appears to be physically unrealizable. But is it?
  The flow of a river exhibits this kind of behavior. Immediately adjacent to
  the bank, the liquid is motionless; then the velocity of the surface layer
  increases steadily toward the middle, falling off again toward the other
  bank. You can prove this by dropping a line of corks across a uniformly
  flowing river; thi line will quickly bow into a curve as the corks at the
  center move ahead of those at the edge. Nature has provided the prototype
  of the perfect moving way-for those small insects that can walk on water.
  In one of my earlier novels' I suggested, not very senously, that we might
  some day invent or develop a material that would be sufficiently solid in
  the vertical direction to support the weight of a man, yet fluid enough in
  the horizontAl plane to allow it to move at variable speeds. A great many
  substances are in some degree "anisotropic"--that is, their properties vary
  in different directions. The classic example is wood; as every carpenter
  knows, its behavior along the grain is completely different from that at
  right angles to it.
  Perhaps local electric, magnetic or other fields, acting on powders or
  dense liquid, might produce the desired anisotropic effect; remember what
  happens to iron filings in the presence of a magnetic field. What I am
  trying to visualize (and I must admit that this is hopeful whistling in the
  technological dark) is a fairly thin layer of substance X, supported on a
  fixed solid base within which the necessary polarizing fields are
  generated. These fields give X its rigidity in the vertical direction, and
  also impart the desired velocity gradient across the strip. You can step on

  'Against the Fall ot Night, since incorporated in The City and the Stars.
                45
 to the edge with perfect confidence, because it is almost stationary. But if
 you walk toward the center, you will experience a smooth and steady increase
 in speed until you ieach the. express section. There would be no sudden
 jumps, as is inevitable with any system of parallel belts.
  A continuous speed variation right across the roadwould be quite annoying;
  it would be impossible to stand still, for one foot would creep ahead of
  the other. The solution would be to have fairly wide uniform velocity
  bands, which might be marked out by colored lighting, separated by narrow
  transition strips where the speed increased rapidly but smoothly. The bands
  could be easily varied in width and direction according to the flow of
  traffic, merely by altering the pattern of the field that produced them. At
  the end of the road, the field would be switched off, substance X would
  revert to a normal, wellbehaved liquid or powder, and could be pumped back
  to the beginning of the circuit through pipelines.
  The whole concept is so beautiful, and such an improvement on the
  conventional scheme of moving belts, that it will be a great pity if it
  turns out to be totally impossible....
  On the other hand, there may be still more advanced solutions to the
  problem of pedestrian traffic. If we ever discover a method of controlling
  gravity (a possibility to be discussed in more detail in Chapter 5) that
  will give us much greater powers than the neutralization of weight. We will
  be able to produce not only levitation but guided movement in any desired
  direction=up or down, horizontally or vertically.
  Because our generation has already known the "weightlessness" of sea and
  space, we should not find completely fantastic the picture of a city full
  of effortlessly floating pedestrians-if one can still call them that. It is
  a little hair-raising, though, to realize what vertical transportation
  would imply in a structure the size of the Empire State Building. There
  would be no elevator cages-just plain shafts, straight up and down for a
  thousand feet. But to their occupants, under the influence. of a gravity
  field that had been artificially twisted through ninety degrees, they 46
 would appear to be horizontal tunnels along which they were being swept like
 thistledown before a gentle breeze. Only if the power failed would they come
 back to reality with, if you win pardon the metaphor, a bump.
  It is obvious that anyone from our age would not last for long, physically
  or psychologically, inside such a city. But how long would a man from 1800
  survive in one of ours?
  Even if they are banned from the city, motor vehicles are likely to
  dominate the short (10-100 mile) range of transportation for a long time to
  come. There are few men now alive who can remember when it was otherwise;
  the automobile is so much a part of our existence that it seems hard to
  believe that it is a child of our century.
  Looked at dispassionately, it is an incredible device, which no sane
  society would tolerate. If anyone before 1900 could have seen the
  approaches to a modem city on a Monday mornina or a Friday evemng, he might
  have imagined that he ~vas in hell-and he would not be far wrong.
  Here we have a situation in which millions of vehicles, each a miracle of
  (often unnecessary) complication, are hurtling in all directions under the
  impulse of anything up to two hundred horsepower. Many of them are the size
  of small houses and contain a couple of tons of sophisticated alloys-yet
  often carry a single passenger. They can travel at a hundred miles an hour,
  but are lucky if they average forty. In one lifetime they have consumed
  more irreplaceable fuel than has been used in the whole previous history of
  mankind. The roads to support them, inadequate though they are, cost as
  much as a small war; the analogy is a good one, for the casualties are on
  the same scale.
  Yet despite the appalling expense in spiritual as well as material values
  (look what Detroit has done to esthetics) our civilization could not
  survive for ten minutes without the automobile. Though it can obviously be
  improved, it seems hard to believe that it can be replaced by anything
  fundamentally different. The world has moved on wheels 47
 for six thousand years, and there is an unbroken sequence from the ox cart
 to the Cadillac.
  Yet one day that sequence will be broken-perhaps by ground effect vehicles
  riding on air blasts, perhaps by gravity control, perhaps by still more
  revolutionary means. I shall discuss these possibilities elsewhere; mean-
  while, let us take a brief glance at the future of the automobile as we
  know it.
  It will become much lighter-and hence more efflcient-as materials improve.
  Its complicated and toxic gasoline engine (which has probably killed as
  many people by air pollution as by direct physical impact) will be replaced
  by clean and silent electric motors, built into the wheels themselves and
  so wasting no body space. This implies, of course, the development of a
  really compact and lightweight method of storing or producing electricity,
  at least an order of magnitude better than our present clumsy batteries.
  Such an invention has been overdue for about fifty years; it may be made
  possible either through improvements in fuel cells, or as a byproduct of
  solidstate physics.
 These improvements, however, will be much less
        I the fact that the automobile of the dayafter-tomorrow will not be
        driven by its owner, but by itself; indeed, it may one day be a
        serious offense to drive an automobile on a public highway. I would
        not care to say how long it will take to introduce completely
        computerized motoring, but dozens of techniques already developed by
        airlines and railroads already point the way to it. Automatic
        blocks, electronic road signs, radar obstacle detectors,
        navigational grids-even today we can visualize the basic elements
        required. An automatic highway system will, of course, be fabulously
        expensive to install and maintain-but in the long run it will be
        much cheaper, in terms of time, frustration, and human lives, than
        the present manual one.
  The auto-mobile of the future will really live up to the first half of its
  name; you need merely tell it your destination-by dialing a code, or
  perhaps even verbally-and it will travel there by the most efficient route,
  after first 48
 checking with the highway information system for blockages and traffic jams.
 As a mere incidental, this would virtually solve the parking problem. Once
 your car had delivered you at the office, you could instruct it to head out
 of town again. It would then report for duty in the evening when summoned by
 radio, or at a prearranged time. This is only one of the advantages of
 having a built-in chauffeur.
  Some people, I know, enjoy driving, for reasons which are simple and
  Freudian, though none the worse for that. Their desires could easily be
  fulfilled at suitable times and places-but not on the public highways. For
  my own part, I steadfastly refuse to have anything to do with vehicles in
  which I cannot read when I am traveling. It is therefore impossible for me
  to own a car; at this early stage in its technical development, a car would
  own me.
  The most revolutionary-indeed, from the viewpoint of our grandfathers the
  most incredible-event in the history of transport has been the rise of
  aviation. Eventually all passenger traffic will go by air when
  stage-lengths of more than a couple of hundred miles are concerned; the
  railroads recognize this, as is proved by their often unconcealed efforts
  to discourage customers. They would much prefer to concentrate on freight,
  which is more profitable and far less troublesome, for it is seldom in a
  frantic hurry and does not object to being parked in sidings for a few
  hours. Nor does it insist that its feet be warmed and its martinis
  chilled-vide Peter Arno?s famous cartoon.
  The story of the railroads, which have served mankind so well for almost a
  century and a half, is now entering its final chapter. As industry becomes
  decentralized, as the use of coal for fuel diminishes and nuclear power
  enables the factories to move nearer to their sources of supply, so the
  very need for shifting megatons of raw materials over thousands of miles
  will dwindle away. With it will pass the chief function of the railroad,
  which has always been the moving of freight, not of passengers.
  Already pome young countries-Australia, for example-have Virtually bypassed
  the railroad age and are 49
 building transportation systems based on highways and airlines. In a few
 more decades, today's Pullmans and diners and roomettes will be as much
 period pieces as the Mississippi paddle-boats, and will evoke equal
 nostalgia.
  Nevertheless, by a strange paradox it is quite possible that the heroic age
  of railroads still Hes ahead. On airless worlds like the Moon, Mercury, and
  the satellites of the planets, alternative forms of transport may be im-
  practicable, and the absence of atmosphere will permit very high speeds
  even at ground level. Such a situation almost demands railroads-using that
  term to mean any system employing fixed tracks. On rugged, low-gravity
  worlds there is a good deal to be said for cars suspended from overhead
  monorails or cables, which could be slung across valleys and chasms and
  craters, with complete indifference to the geography below them. A century
  from now, the face of the Moon may be covered with such a network, linking
  together the pressurized cities of the first extraterrestrial colony.
  Meanwhile, back on Earth, the flow of passenger traffic into the air will
  be still further accelerated when VTOL (Vertical Take-off and Landing)
  aircraft are perfected. Though the helicopter, for all its importance in
  more specialized fields, has had little effect on public transportation,
  this wiff not be true of its successors, the short and medium range
  airbuses of the near future. What form they will take, and what principle
  they will operate on, no one can foresee at the moment-but no one has any
  doubts that practical versions will soon be developed from some or other of
  the horrid-looking devices that are now laboriously heaving themselves off
  the ground with the aid of jets, rotors,'or tilting wings. We will not have
  conquered the air until we can go straight up and come straight down-as
  slowly as we please.
  As far as intercontinental transportation is concerned, the battle is
  already over, the decision already made. Where speed is required, the
  airlines have no competition. Indeed, the ridiculous situation has now been
  reached where traveling to and from the airport, and getting 50
 through the Paper Curtains at either end, takes longer than a transatlantic
 flight.
  Nevertheless, aircraft speeds will increase very iubstantially over the
  next few decades, and such restrictions as exist are economic rather than
  technological. (The airlines have to pay for the current generation of
  jets, and would be most unhappy if suddenly confronted with the supersonic
  transports they fully expect to be buying in the 1970's.) This belief that
  major advances in performance are still to come is an aftermath of the jet
  and rocket revolutions of the 1945-1955 period, when all existing records
  were so thoroughly shattered that conservatism about the future seemed
  ludicrous.
  That was not always the case, as the examples I have given in Chapter 1
  demonstrated. I would like to give one more, because it is easy to forget
  how often the views of technical and scientific authorities about future
  progress fall hopelessly short of the truth. Yet the "experts" continue to
  make the same mistakes, and many of them will go through their predictable
  routines again when these words appear in print.
  Back in 1929 a leading aeronautical engineer, now well-known to you in
  quite a different connection (I'll give his name in a moment) wrote a paper
  on the future of aviation which opened with the words: "The forecast is
  freely made that within a few years passenger-carrying aeroplanes will be
  travelling at over 300 m.p.h., the speed record today." This, he stated
  pontifically, was gross journalistic exaggeration, as "the commercial
  aeroplane will have a definite range of development ahead of it beyond
  which no further advance can be anticipated."
  Here are the advances this farsighted prophet anticipated when the airplane
  had reached the limit of its development, probably by the year 1980:

          Speed: 110-130 m.p.h.
          Range: 600 miles
          Payload: 4 tons
          Total weight: 20 tons
                51
  Well, everyone of these figures had been multiplied by more than five by
  the time their proponent died in 1960, mourned by thousands of readers in
  many countries. For in 1929 he was N. S. Norway, chief calculator on the
  R.100 airship design; but in 1960 he was famous as Nevil Shute. One can
  only hope, as he himself must have done, that On the Beach turns out to be
  as wide of the mark as the earlier and lesser-known prediction.
  Even the earliest versions of the Concorde demonstrated that we can build
  "conventional" jet transports op-
          oone or two thousand miles an hour. == I at no journey on Earth
          could last for more than six hours, and very few would be of over
          two or three hours' duration. A worldwide pattern of long-distance
          mass transportation might develop, far more like today's bus and
          rail services than anything now offered by the airlines. Meals and
          stewardesses would be as inappropriate as on the IRT or the London
          Underground; the analogy may be all-too-close, for some operators
          have suggested that ultra-cheap air coaches could be ran on a
          Standing Room Only basis. Those who have already experienced the
          joys of a transatlantic economy flight in the company of a dozen
          bilious babies may be glad to know that the future has yet deeper
          delights in store.
  In the face of competition from the air, the shipping lines have wisely
  concentrated on selling comfort and leisure. Although on most routes more
  passengers now travel by air than by sea, this traffic has not all been won
  at the expense of the ocean liners. Indeed, there has been (at least in
  Europe) a major building program which has seen the launching of such
  magnificent ships as Oriana, Leonardo da Vinci and Canberra. Some of these
  are pure passenger vessels-that is, they do not rely on freight for any
  part of their income. Whatever the future brings, such ships will continue
  to ply the ocean for as long as men remain men and feel the call of their
  ancient home, the sea.
  The end of the freight-carrying ship-the tramps and the windjammers and the
  galleons and the quinqueremes which for six thousand years have carried the
  cargoes of 52
 the world-is already in sight; in another century, only a few will be left
 as picturesque survivals in out-of-the-way places. After ages without a
 rival, the cargo ship is now challenged simultaneously on three fronts.
  One challenge is from below the water. The submarine is a much more
  efficient vehicle than the surface ship, which wastes much of its energy on
  the production of waves. With the advent of nuclear energy, the high-speed,
  long-range submarine envisaged years ago by Jules Verne is at last
  practical, but so far has been developed only for military purposes.
  Whether the heavy initial costs, and the problems of underwater operation,
  will make the cargo submarine economical is another question.
  An interesting compromise which almost certainly is economical is the
  flexible towed container now being developed in the United Kingdom for
  liquid cargoes. These giant plastic sausages (which can be rolled up and
  shipped-or even flown--cheaply from point to point when they are not in
  use) have now been built in lengths of up to three hundred feet, and there
  is no obvious limit to size. Since they can be towed completely submerged,
  they have the efficiency of the submarine without its mechanical and
  navigational complications. And they can be built very lightly and cheaply,
  since their structural strength is extremely low. Unlike rigid ships, they
  do not resist waves, but give with them. They will even "kink" at sharp
  angles when their tug makes an abrupt turn.
  With commendable honesty, the inventor of the "Dracone" (the trade name for
  the flexible submarine tanker) has admitted "I got the idea from a
  science-fiction story." This was presumably Frank Herbert's excellent novel
  The Dragon in the Sea,2 which dealt with a hair-raising wartime voyage by
  an atomic submarine towing a string of submersible oil barges. It is,
  indeed, as

  2 Originally published in Astounding Science Fiction as "Under Pressure";
  also as a pocket book with the title "21st Century Sub." This story is
  unusual not only for its beautifully workedout technical details, but also
  for its philosophical-religious content--considerably too adult for the
  escapist, "main-stream" magazines.
                53
 oil tankers that such vessels may have their greatest use: Petroleum
 products constitute half of the world's total of goods moved by sea, now
 running at about a billion tons a year. Certain Greek shipowners may well
 view with apprehension the replacement of their beautiful tankers by
 overgrown plastic bottles.
  Other bulk cargoes (grain, coal, minerals, and raw materials generally)
  could be carried in the same manner. In most of these cases, speed is not
  important; what matters is that a continuous flow be maintained. Where
  speed is vital, air freight will be used for all except the bulkiest
  cargoes; and one day, even for these.
  Air transport is just at the beginning of its evolution; to set limits to
  what it may become would be folly, as the examples I have quoted clearly
  show. Though less than 1 per cent of today's freight travels by air, the
  time may come when it will all do so. Some of it may fly thousands of feet
  in the sky; but some-and perhaps most of itmay rise only a few inches above
  the ground. For the nemesis of the oceangoing freighter may not be the sub-
  marine or the airplane, but the Ground Effect Machine, riding on curtains
  of air over land and sea.
  This novel and quite unexpected development may be important not only in
  itself but as a pointer to the future. For the first time it allows us to
  float really heavy loads in the air. This may or may not revolutionize
  transport, but it will certainly set men thinking seriously about genuine
  gravity control, one rather trivial application of which I have already
  mentioned.
  Gravity control-"anti-gravity," as the science-flction writers call it-may
  prove to be impossible, but the Ground Effect Machine is already here. Now
  let us see what it, and its hypothetical successor, may do to our civ-
  ilization.

                54
 Riding on Air

 Our century has seen two great revolutions in transport, each of which has
 changed the very pattern of human society. The automobile and the airplane
 have created a world that no man of a hundred years ago could have conceived
 in his wildest dreams. Yet both are now being challenged by something so new
 that it does not even have a name-something that may make the future as
 strange and alien to us as our world of superhighways and giant airports
 would be to a man from 1890. For this third revolution may bring about the
 passing of the wheel, our faithful servant since the dawn of history.
  In many countries-the United States, England, the U.S.S.R., Switzerland,
  and doubtless elsewhere-major engineering efforts are now in progress to
  develop vehicles which literally Boat on air. The pioneering Saunders-Roe
  SR-NI "Hovercraft" led to the 160-ton SR-N4's, which have ferried thousands
  of passengers across the English Channel, and far larger models are on the
  drawing board. They all depend for their operation on what is known as 55
 "Ground Effect," and for this reason have been called Ground Effect Machines
 or G.E.M.'s.
  Although G.E.M.'s since they support themselves by downward blasts of air,
  have a superficial resemblance to helicopters, they operate on quite
  different principles. If you are content to float only a few inches from
  the ground, you can support, for the same horsepower, many times the load
  that a helicopter can lift into the open sky. You can demonstrate this in
  your own home by an extremely simple experiment
  Suspend an electric fan in the middle of the room, so that it is free to
  move back and forth; then switch it on. You will find that the fan recoils
  a quarter of an inch or so, owing to the blast of air it produces. The
  thrust is not very great, yet this is the effect which drives all our air-
  planes and helicopters through the sky.
  Now take the same fan and hang it facine the wall, as close to it as the
  wire guard will allow you. This time, when you switch it on, you win find
  that the recoil is two or three times greater am before, because some of
  the air blast is being trapped as a kind of cushion between the fan and the
  wan. The more effective the trapping, the bigger the recoil. If you fitted
  a shroud or cowling round the fan to prevent the air from spilling out in
  all directions, the kick would increase still further.
  This tells us what we must do if we wish to ride on a cushion of air.
  Visualize a flat surface, and a slightly hollowed plate lying. on top of
  it--such as a saucer, face downward. If we could blow into the saucer with
  sufficient force, it would rise until the air spilled out round the rim,
  and would remain floating a fraction of an inch above the ground.
  In the right circumstances, even a small quantity of, air can produce a
  remarkable amount of lift. The scientists of the European Centre for
  Nuclear Research (CERN) recently put this effect to good use. They were
  confronted
              ovi r equipment weighing up to
 with the problem of m ing three hundred tons-and, even trickier, of
 positioning it in the laboratory to within a fraction of a millimeter.
 So they used saucer-shaped steel discs, about a yard
                56
 across, with rubber gaskets around the edges. When air at ~ pressure of
 seventy pounds per square inch is blown into such a pad, it can lift ten or
 twenty tons with ease. Equally important, there is so little friction that
 you can push the load around the lab with your fingers.
  It is obvious that industry and heavy engineering will find many uses for
  these floating saucers, and one trivial but amusing application of them has
  already entered the, home. There is now a vacuum cleaner on the market that
  drifts effortlessly above the carpet, supported on its own exhaust, so that
  the busy housewife can get back to the TV set that vital few seconds
  earlier.
  But what has all this got to do, you may wonder, with general
  transportation? There are not many road surfaces as smooth as laboratory
  floors, or even dining-room carpets, so it would hardly seem that the good
  old-fashioned wheel has much to worry about.
  However, this is a shortsighted view, as the scientists who started looking
  into the theory of the ground effect soon discovered. Although the
  small-scale devices just mentioned will operate only on smooth, flat
  surfaces, when they are built in larger sizes the situation is completely
  different-and fraught with excitement to the transportation engineer.
  For the bigger you make your G.E.M., the higher it will ride off the ground
  and, therefore, the rougher the terrain it can cross. The Saunders-Roe
  SR-NI skimmed along at a maximum altitude of fifteen inches, but its larger
  successors will float at shoulder height on the invisible cushion formed by
  their curtains of downward-moving air.
  Because they have no physical contact with the surface beneath them,
  G.E.M.'s can travel with equal ease over ice, snow, sand, plowed fields,
  swamps, molten lava-you name it, the G.E.M. can cross it. All other
  transport vehicles are specialized beasts, able to tackle only one or two
  kinds of terrain; and nothing has yet been invented that can travel swiftly
  and smoothly over a single one of the surfaces just mentioned. But to the
  G.E.M. they are all aliko-and a superhighnw is no better.
                57
  It takes some time to grasp this idea, and to realize that the immense
  networks of roads upon which two generations of mankind have spent a
  substantial fraction of their wealth may soon become obsolete. Traffic
  lanes of a sort would still be needed, of course, to keep vehicles out of
  residential areas, and to avoid the chaos that would result if every driver
  took the straightest line to his destination that geography allowed. But
  they need no longer be paved-they would merely be graded, so that they were
  clear of obstacles more than, say, six inches high. They would not even
  have to be laid on good foundations, for the weight of a G.E.M. is spread
  over several square yards, not concentrated at a few points of contact.
  Today's turnpikes might well last for generations without any further
  maintenance if they had to carry only airsupported vehicles; the concrete
  could crack and become covered with moss-it would not matter in the least.
  There will clearly be enormous savings in road costsamounting to billions
  a year-once we have abolished the wheel. But there will be a very difficult
  transition period before the characteristic road sign of the 1990's becomes
  universal: NO WHEELED VEHICLES ON THIS HIGHWAY.
  Since the G.E.M.'s or aircars of the future need stick to the traffic lanes
  only when their drivers feel like it, the chief motoring offense at the
  turn of the century will not be speeding,but trespass. It is too much to
  expect that refugees from the cities, with the power to move like clouds
  over the length and breadth of the land, will refrain from entering and
  exploring any attractive piece of scenery that takes their fancy.
  Barbed-wire may make a second debut in the West as irate farmers try to
  keep weekenders from littering their land with picnic trash. Strategically
  placed rocks would be more effective, but they would have to be spaced
  close together, otherwise the invaders could slip between them.
  There are few spots that a skillful aircar driver could not reach, and the
  breakdown vans of the future are going to receive S.O.S. calls from
  families stranded in some very odd places. The Grand Canyon, for
  example-what a challenge that presents to the airborne motorist! It might
  58
 even be possible to develop a specialized form of G.E.M. that could climb
 mountains; the driver could take his time-and throw out ground anchors if
 necessary-as he worked his way cautiously up the slanting surfaces of rock,
 snow, or ice. But this would, definitely, not be an operation for beginners.
  If such ideas seem a little farfetched, that is because we still belong to
  the age of the wheel, and our minds cannot free themselves from its
  tyranny-perfectly summed up in the warning SOFT SHOULDERS. This is a phrase
  that will be meaningless to our grandchildren; to them, if a surface is
  reasonably plane, it will not matter whether it consists of concrete or
  quagmire.
  It is only fair to point out that the large-scale use of private or family
  G.E.M.'s may not be a very practical proposition while we have to depend on
  the gasoline engine. Apart from the noise-and dust-it requires several
  hundred horsepower to produce speeds of only 60 m.p.h. Although there will
  certainly be great improvements in performance, it seems that at the
  present moment the smaller types of G.E.M. are of interest chiefly to the
  armed forces, farmers who have to deal with.broken or flooded land, movie
  directors after unusual tracking shots, and similar specialized customers
  who can foot the gas bills.
  But the gas engine is on its way out, as any petroleum geologist will
  assure you in his more unguarded moments. Before very much longer, out of
  sheer necessity, we must find some other source of power-perhaps a
  sophisticated type of electric battery, with at least a hundred times the
  capacity of today's clumsy monsters. Whatever the answer, within a few more
  decades there will be lightweight, long-endurance motors of some kind,
  ready to take over when the oil wells run dry. These will power the private
  aircars of the future, as the gasoline engine has driven the earthbound
  automobiles of the past.
  With the emancipation of traffic from the road, we will at last have
  achieved real mobility over the face of the Earth. The importance of this
  to Africa, Australia, South America, Antarctica, and all countries that
  lack (and now 59
 may never possess) well-developed highway systems can scarcely be
 overestimated. Pampas, steppes, veldt, prairies, snowfields, swamps,
 deserts---all will be able to carry heavy, high-speed traffic more smoothly,
 and perhaps more economically, than the finest roads that exist today. The
 opening up of the polar regions may well depend upon the speed with which
 freight-carrying G.E.M.'s are developed.
  We will return to this subject later, but now it is time to go to sea. For
  G.E.M.'s, of course, can travel with equal ease over land or water. As they
  grow larger and faster, these sizeable vehicles may have a revolutionary
  effect upon commerce, international politics, and even the distribution of
  population. We do not need any hypothetical new power plants to make them
  practical; when we start thinking in terms of thousands of tons, today's
  gas turbines are quite adequate and tomorrow's nuclear reactors will be
  even better. As soon as we have gathered enough experience from the present
  primitive models, we will be able to build giant, oceangoing G.E.M.'s
  capable of carrying intercontinental cargoes at speeds of at least a
  hundred miles an hour.
  Unlike today's ships, the air-supported liners and freighters of the next
  generation will be low, flat-bottomed vessels. They will be extremely
  maneuverable--G.E.M.'s can move backward or sideways simply by altering the
  direction of their air blasts--and will normally float at an altitude of
  about ten feet. This will enable them to skim smoothly over all but the
  very roughest seas. One consequence of this is that they could be quite
  lightly constructed, and would, therefore, be much more efficient than
  seaborne ships, which must be built to'withstand enormous stresses and
  strains.
  Their speed would enable them to outrun or avoid all storms; in any event,
  by the time they become operational the meteorological satellites will have
  provided us with a worldwide weather service, and every captain will know
  exactly what to expect during the few hours he is at sea. In a hurricane,
  a large G.E.M. might even be safer than a 60
 conventional ship of the same size, for it would be above most of the wave
 action.
  Because a "hovership" is completely indifferent to breakers, reefs, and
  shoals, it could operate in waters where no other type of marine craft
  could navigate. This may open up to commercial and game fishermen thousands
  of square miles of absolutely virgin territory, and may revolutionize the
  life of island communities. Vast areas of the Great Barrier Reef-the
  1,250-mile-long coral rampart guarding the northeastern coast of Aus-
  tralia---are almost inaccessible except in a dead calm, and many of its
  smaller islands have never been visited by man. A reliable G.E.M. bus
  service would, alas, tam these minute pandanus-clad jewels into desirable
  housing estates and holiday resorts.
  As the G.E.M. is the most frictionless type of vehicle yet invented, it can
  certainly travel much faster than any existing type of marine craft,
  including 300 m.p.h. jetpropelled hydroplanes. This suggests that the
  airlines may be in for some stiff competition, for there are many pas-
  sengers willing to spend days-but not weeks-at sea, especially if a smooth
  ride can be guaranteed. A vessel that could cruise at a modest 150 m.p.h.
  could get from London to New York in a day, thus neatly plugging the gap in
  the speed spectrum between the Queen Mary and the Boeing 747.
  What makes the G.E.M. so attractive as a passenger vehicle is its built-in
  safety factor. When the engines of an airliner fail, or any major defect
  develops in the structure, there is little hope for those aboard. But
  almost anything could happen to a G.E.M., short of a head-on collision, and
  it would gently settle down onto its floats, without spilling a single
  drink in the bar. It would have no need for the immensely elaborate and
  expensive navigational and safety networks essential for air transport; in
  an emergency, the captain could always sit tight and think matters over,
  without worrying about his fuel reserve. From this point of view, G.E.M.'s
  seem to combine the best features of ships and aircraft, with remarkably
  few of their disadvantages.
                61
  The most shattering implications of G.E.M.'s do not, however, arise from
  their speed or their safety, but from the fact that they can ignore the
  divisions between land and sea. An oceangoing G.E.M. need not stop at the
  coastline; it can continue on inland with a supreme indifference to the
  great harbors and seaports that have been established by five thousand
  years of maritime commerce. (The SR-N1 has run up a beach with twenty fully
  armed Marines aboard; imagine what a fleet of such assault craft could have
  done on D-Day.)
  Any stretch of coast that was not fronted by sheer cliffs would be an open
  door to G.E.M. freighters or liners. They could continue on inland with
  scarcely a pause for a thousand miles if need be, to deliver cargoes and
  passengers in the heart of a continent. All they would require would be
  fairly wide traffic lanes or throughways, clear of obstacles more than a
  yard or two inheight; old railway tracks, of which there will be a good
  supply by the close of this century, will do excellently. And these lanes
  need not be dead ground, as are today's highways and railroads. They could
  be used for a wide variety of agricultural purposes-though not, it must be
  admitted, for the growing of wheat. The man-made gales would be a little
  too severe.
  All this is very bad news for San Francisco, New Orleans, London, Los
  Amgeles, Naples, Marseilles and any other seaport you care to name. But it
  is much worse news for Egypt and Panama.
  Precisely. The "ships" of the future are not going to crawl along narrow
  ditches at five miles and a thousand dollars an hour, when they can skim
  over land at twenty times the speed-and can pick and choose their routes
  with almost the same freedom as in the open sea.
  The political consequences of this will be, to say the least, extremely
  interesting. The entire Middle East situation would be very different if
  Israel (or for that matter half a dozen other countries) could put the Suez
  Canal permanently out of business merely by offering unspoiled desert on
  highly competitive terms. And as for Panama-I 62
 will leave that for the quiet contemplation of the United States Navy and
 State Department.
  It is an instructive and mind-stretching exercise to take a relief map of
  the world, and to imagine where the G.E.M.'s trade routes of the future
  will He. Half a century from now, will Oklahoma City be a greater port than
  Chicago? (Think of the millions of tons of shipping that could maneuver on
  the Great Plains!) What is the best way to take a 100-thousand-ton
  freighter through the Rockies, the Andes, or the Himalayas? Will
  Switzerland become a major shipbuilding nation? Will purely waterborne
  craft survive at all, when land and ocean become a single continuum?
  These are questions that we will soon have to answer. The sudden and
  unexpected development of the G.E.M. requires us to indulge in some
  particularly agile mental gymnastics; in our preoccupation with cargoes
  hurled through the upper atmosphere at the speed of sound, we have
  completely overlooked a major revolution at sea level-one which may have
  brought us quite literally to the end of the road.

 63
                                 5

 Beyond Gravity

 Of all the natural forces, gravity is the most mysterious and the most
 implacable. It controls our lives from birth to death, killing or maiming us
 if we make the slightest slip. No wonder that, conscious of their earthbound
 slavery, men have always looked wistfully at birds and clouds, and have
 pictured the sky as the abode of the gods. The very expression "heavenly
 being" implies a freedom from gravity which, until the present, we have
 known only in our dreams.
  There have been many explanations of those dreams, some psychologists
  trying to find their origin in our assumed arboreal past-though it is
  unlikely that many of our direct ancestors ever spent their lives jumping
  from tree to tree. One could argue just as convincingly that the familiar
  levitation dream is not a memory from the past, but a premonition of the
  future. Some day "weightlessness" or reduced gravity will be a common, and
  perhaps even a normal, state of mankind. The day may come when there are
  more people living on space stations and worlds of low gravity than on this
  planet; indeed, when 64
 the history of the human race is written, the estimated one hundred billion
 men who have already spent laborious lives struggling against gravitation
 may turn out to be a tiny minority. Perhaps our space-faring descendants
 will be as little concerned with gravity as were our remote ancestors, when
 they floated effortlessly in the buoyant sea.
  Even now, most of the creatures on this planet are hardly aware that
  gravity exists. Though it dominates the lives of large land animals such as
  elephants, horses, men, and dogs, to anything much smaller than a mouse it
  is seldom more than a mild inconvenience. To the insects it is not even
  that; Ries and mosquitoes are so light and fragile that the air itself
  buoys them up, and gravity bothers them no more than it does a fish.
  But it bothers us a great deal, especially now that we are making
  determined efforts to escape from it. Quite apart from our current interest
  in space flight, the problem of gravitation has always worried physicists.
  It seems to stand completely apart from all the other forces-light, heat,
  electricity, magnetism-which can be generated in many different ways, and
  are freely interconvertible. Indeed, most of modern technology is based
  upon such conversions--of heat into electricity, electricity into light,
  and so on.
  Yet we cannot generate gravity at all, and it appears completely
  indifferent to all the influences which we may bring to bear on it. As far
  as we know, the only way a gravitational field can be produced is by the
  presence of matter. Every particle of matter has an attraction for every
  other particle of matter in the universe, and the sum total of those
  attractions, in any one spot, is the local gravity. Naturally, this varies
  from world to world, since some planets contain large amounts of matter and
  others very little. In our solar system the four giant planets Jupiter,
  Saturn, Uranus and Neptune all have surface gravities greater than
  Earth's-two and a half times greater in the case of Jupiter. At the other
  extreme, there are moons and asteroids where gravity is so low that one
  would have to look hard at a falling object for the first few seconds to
  see that it was moving.
                65
  Gravitation is an incredibly, almost unimaginably, weak force. This may
  seem to contradict both common sense and everyday experience, yet when we
  consider the statement it is obviously true. Really gigantic quantities of
  matter-the six thousand million million million tons of the Earth-are
  required to produce the rather modest gravity field in which we live. We
  can generate magnetic or electric forces hundreds of times more powerful
  with a few pounds of iron or copper. When you lift a piece of iron with a
  simple horseshoe magnet, the amount of metal the magnet contains is
  out-pulling the whole Earth. The extreme weakness of gravitational forces
  makes our total inability to control or modify them all the more puzzling
  and exasperating.
  From time to time, one hears rumors that research teams are working on the
  problem of gravity control, or "anti-gravity," but these stories always
  turn out to be misinterpretations. No competent scientist, at this stage of
  our ignorance, would deliberately set out to look for a way of overcoming
  gravity. What a number of physicists and mathematicians are doing, however,
  is something less ambitious; they are simply trying to uncover basic
  knowledge about gravity. If this plodding, fundamental work does lead to
  some form of gravity control, that will be wonderful; but I doubt if many
  people in the field believe that it will. The opinion of most scientists is
  probably well summed up by a remark made by Dr. John Pierce, late of the
  Bell Telephone Laboratories. "Antigravity," he said, "is strictly for the
  birds." But the birds don't need it-and we do.
  There is some evidence, surprisingly enough, that businessmen and company
  executives are less skeptical than scientists about anti-gravity devices.
  In 1960 the Harvard Business Review carried out a "Survey on the Space
  Program," and received almost two thousand re-plies to its detailed
  five-page questionnaire.
  When asked to rate the degree of probability of various by-products of
  space research, the executives voted for anti-gravity as follows: almost
  certain, 11 per cent; very likely, 21 per cent; possible, 42 per cent; very
  unlikely, 21 66
 per cent; never will happen, 6 per cent. They rated it, in -fact , as rather
 more likely than mining or colonizing the planets; I feel fairly confident
 that most scientists would consider it much less likely. However, at the
 present moment in time, the judgment of Harvard businessmen on the subject
 is likely to be just as good, or as bad, as that of professional physicists.
  We still know so little about gravitation that we are not even sure if it
  travels through space at a definite speedlike radio or light waves-or
  whether it is "always there." Until the time of Einstein, scientists
  thought that the latter was the case, and that gravitation was propagated
  instantaneously. Today, the general opinion is that it travels at the speed
  of light and that, also like light, it has some kind of wave structure.
  If "gravitational waves" do exist, they will be fantastically difficult to
  detect, because they carry very little energy. It has been calculated that
  the gravity waves radiated by the whole Earth have an energy of about a
  millionth of a horsepower, and the total emission from the entire solar
  system-the Sun and all the planets-is only half a horsepower. Any
  conceivable man-made gravitational-wave generator would be billions of
  billions of times feebler than this.
  Nevertheless, attempts have been made to detect these waves. Success was
  first reported by Dr. John Weber of the University of Maryland in 1969; he
  believes he has observed bursts of gravitational radiation coming from some
  unknown and mysterious source at the center of the Galaxy. Exciting though
  these discoveries are, it will be a very long time before we can expect any
  practical applications from them. And it may be never.
  Yet every few years, some hopeful inventor builds and actually
  demonstrates, at least to his own satisfaction, an anti-gravity device.
  These are always laboratory models, producing (or, rather, apparently
  producing) only a very tiny lift. Some of the machines are electrical,
  others purely mechanical, based on what might be called the "bootstrap
  principle," and containing unbalanced flywheels, cranks, springs, and
  oscillating weights. The idea 67
 behind these is that action and reaction may not always be equal and
 opposite, and there may sometimes be a little net force left over in one
 direction. Thus though everyone agrees that you can't lift yourself by a
 steady pull on your bootstraps, perhaps a series of properly timed jerks
 might have a different result.
  Put this way, the idea seems completely absurd, but it is not easy to
  refute an intelligent and sincere inventor with a beautifully made machine
  containing dozens of parts, moving in every possible direction, who
  maintains that his oscillating contraption produces a net lift of half an
  ounce and that a bigger model could take you to the Moon. You may be 99.999
  per cent sure that he is wrong, yet be quite unable to prove it. If gravity
  control is ever discovered, it will surely depend upon much more so-
  phisticated techniques than mechanical devices-and it will probably be
  found as a byproduct of work in some completely unexpected field of
  physics.
  It is also probable that we will not make much progress in understanding
  gravity until we are able to isolate ourselves and our instruments from it
  by establishing laboratories in space. Attempting to study it on the
  Earth's surface is rather like testing hi-fi equipment in a boiler factory;
  the effects we are looking for may be swamped by the background. Only in a
  satellite laboratory will we be able to investigate the properties of
  matter under weightless conditions.
  The reason why objects are-usually~--weightless in space is one of those
  elusive simplicities that is almost invariably misunderstood. Many people,
  misled by careless journalists, are still under the impression that an
  astronaut is weightless because he is "beyond the puff of gravity."
  This is completely wrong. Nowhere in the universenot even in the remotest
  galaxy that appears as a faint smudge on a Palomar photograph-would one be
  literally beyond the pull of Earth! s gravity, though a few million miles
  away it is almost negligible. It falls off slowly with distance, and at the
  modest altitudes of the closer satellites and space labs is still almost as
  powerful as at sea level. When the first astronauts looked down on Earth 68
 from a height of two hundred miles, the gravity field in which they were
 moving still had 90 per cent of its normal value. Yet, despite this, they
 weighed exactly nothing.
  If this seems confusing, it is largely due to poor semantics. The trouble
  is that we dwellers on the Earth's surface have grown accustomed to using
  the words "gravity" and "weight" almost interchangeably. In ordinary
  terrestrial situations, this is safe enough; whenever there's weight theres
  gravity, and vice versa. But they are really quite separate entities, and
  either can occur independently of the other. In space, they normally do.
  On occasion, they can do so on Earth, as the following
 experiment will prove. I suggest you think about it rather
 than actually conduct it, but if you are unconvinced by
 my logic, go right ahead. You will have the tremendous
 precedent of Galileo, who also refused to accept argument
 b                                 erim. oof. However, I disclaim
arreasppeal,eq t e~f ental pr Pons ba f any damage.
  You will need a quick-acting trapdoor (one of those used by hangmen will do
  admirably) and a pair of bathroom scales. Put the scales on the trapdoor
  and stand on them. They will, of course, register your weight.
  Now, while your eyes are fixed on the scale, get one of your acquaintances
  ("That's not an office for a friend, my lord," as Volumnius said to Brutus
  on a slightly similar occasion) to spring the trapdoor. At once the needle
  will drop to zero; you will be weightless. But you will certainly not be
  beyond the pull of gravity; you will be 100 per cent under its influence,
  as you will discover.a fraction of a second later.
  Why are you weightless in these circumstances? Well, weight is a force, and
  a force cannot be felt if it has no point of application-if there is
  nothing for it to push against. You cannot feel any force when you push
  against a freely swinging door; nor can you feel any weight when you have
  no support and are falling freely. An astronaut, except when he is firing
  his rockets, is always falling freely. The "fall!' may be downward or
  upward or sideways-as in the case of an orbiting satellite, which is in an
  eternal fall around the world. The direction does not 69
 matter; as long as the fall is free and unrestrained, anyone experiencing it
 will be weightless.
  You can be weightless, therefore, even where there is plenty of gravity.
  The reverse is also true; you don't need gravity to give you weight. A
  change of speed-in other words, an acceleration-will do just as well.
  To prove this, let us imagine a still more improbable experiment than the
  one just described. Take your bathroom scales to a remote spot between the
  stars, where gravity is, for. all practical purposes, zero. Floating there
  in space you will again be weightless; as you stand on the scales, they
  will read zero.
  Now attach a rocket motor to the underside of the scales, and start it
  firing. As the scales press against your feet, you will feel a perfectly
  convincing sensation of weight. If the thrust of the rocket motor is
  correctly adjusted, it can give you, by virtue of your acceleration, ex-
  actly the same weight that you have on Earth. For all that you could tell,
  unless your other senses revealed the truth, you might be standing still on
  the surface of the Earth, feeling its gravity, instead of speeding between
  the stars.
  This sensation of "weight" produced by acceleration is quite familiar; we
  notice it in an elevator starting to move upward, and (in the horizontal,
  not the vertical, direction) in a car making a fast getaway or suddenly
  braking. It is possible to produce artificial weight of almost unlimited
  extent by the simple means of acceleration, and quite surprising amounts of
  it are encountered in everyday life. A child on a garden swing, for
  example, can easily range from zero weight at the upper limit of
  oscillation, when the swing is for an instant at rest, to three times
  normal weight at the bottom of the are. And when you jump off a chair or a
  wall, the shock of hitting the ground can, momentarily, give you dozens of
  times your normal weight.
  We measure such forces in terms of so many "gravities" or 66g's," meaning
  that a person experiencing say IOg would feel ten times his ordinary
  weight. But the actual gravity of the Earth is not involved when the weight
  force is produced wholly by acceleration, and it is unfor70
 tunate that the same word is used to describe an effect which may have two
 completely different causes.
  The most convenient way of producing artificial weight is not acceleration
  in a straight line-which would quickly take one over the horizon-but motion
  in a circle. As anybody who has ridden a carrousel knows, swift circular
  movement can generate substantial forces; this was the principle of the
  cream separators that some of us country boys can still remember from our
  days on the farm. The modem versions of these machines are the giant
  centrifuges now used in space medicine research, which can easily give a
  man ten or twenty times his normal weight.
  Small laboratory models can do far better than this. The Beams
  Ultracentrifuge, spinning at the unbelievable speed of 1,500,000
  revolutions a second (not minute!) produces forces of more than I billion
  gravities. Here at any rate we have far outdone nature: It seems most
  unlikely that there exist gravitational fields, anywhere in the universe,
  more than a few hundred thousand times more powerful than Earth's. (How
  wrong I was! See Chapter 9.)
  It is easy enough, therefore, to produce artificial weight, and we may do
  just this in our spaceships and space stations when we get tired of
  floating around inside them. A gentle spin will give a sensation which is
  indistinguishable from gravity---except for the minor point that 4(up" is
  toward the center of the vehicle, not away from it as in the case of the
  Earth.
  We can imitate gravity, then-but we cannot control it. Above all, we cannot
  cancel or neutralize it. True levitation is still a dream. The only ways in
  which we can hover in midair are by floating, with the aid of balloons, or
  by reaction, as with airplanes, helicopters, rockets and jet-lift devices.
  The first method is limited in scope and demands very large volumes of
  expensive or inflammable gases; the second is not only expensive but
  exceedingly noisy, and liable to let one down with a bump. What we would
  like is some nice, clean way, probably electrical or atomic, of abolishing
  gravity at the throw of a switch.
  Despite the above-mentioned skepticism of the physicists, there seems no
  fundamental impossibility about such 71
 a device--as long as it obeys certain well-established natural laws. The
 most important of these is the principle of the conservation of energy,
 which may be paraphrased as: "You can't get something for nothing."
  The conservation of energy at once rules out the delightfully simple
  "gravity screen" used by H . G. Wells in The First Men in the Moon. In this
  greatest of all space fantasies (which still retains its magic after
  three-quarters of a century) the scientist Cavor manufactured a material
  which was opaque to gravity, just as a sheet of metal is to light, or an
  insulator to electricity. A sphere coated with "Cavorite" was able,
  according to Wells, to float away from the Earth with all its contents. By
  opening and closing the shutters, the space travelers could move in any
  desired direction.
  The idea sounds plausible--especially when Wells has finished with it-but
  unfortunately it just won't worL Cavorite involves a physical
  contradiction, like the phrase "An immovable force and an irresistible
  object." If Cavorite did exist, it could be used as a limitless source of
  energy. You could employ it to lift a heavy weight-then let the weight fall
  again under gravity to do work. The cycle could be repeated endlessly,
  giving that dream of all. motorists--a fuelless engine. This, to everyone
  except inventors of perpetual motion machines, is an obvious impossibility.
  Though gravity screens of this simple type can be dismissed, there is
  nothing inherently absurd in the idea that there may be substances which
  possess negative gravity, so that they fall upward instead of downward.
  From the nature of things, we would hardly expect to find such materials on
  Earth; they would float around out in space, avoiding the planets like the
  plague.
  Negative-gravity matter          should not be confused with
 the-equally hypothetical-antimatter whose existence is
 postulated by some physicists. This is matter made up of
 fundamental particles with electric charges opposed to
 those in normal matter; thus electrons are replaced by
 positrons, and so on. Such a substance would still fall
 downward, not upward, in an ordinary gravitational field;
                72
 but as soon as it came into contact with normal matter, the two masses would
 annihilate each other in a burst of energy far fiercer than that from an
 atomic bomb.
  Anti-gravity matter would not be quite so tricky as this to handle, but it
  would certainly pose problems. To bring it down to Earth would require just
  as much energy as lifting the same amount of normal matter from Earth out
  into space. Thus an asteroid miner who filled the bold of his space jeep
  with negative-gravity matter would have a terrible time getting home. Earth
  would repel him with all its force, and he would have to fight every foot
  of the way downward.
  Thus negative-gravity substances, even if they exist, would have rather a
  restricted use. They might be employed as structural materials; buildings
  containing equal amounts of normal and negative-gravity matter would weigh
  exactly nothing, so could be of unlimited height. The architect's main
  problem would be anchoring them against high winds.
  It is conceivable that by some treatment we might permanently "degravitize"
  ordinary substances, in much the same way that we can turn a piece of iron
  into a permanent magnet. (Less well known is the fact that continuously
  charged bodies-"permanent electrets"--can also be made.) To do so would
  require a great expenditure of energy, for to degravitize one ton of matter
  is equivalent to lifting it completely away from the Earth. As any rocket
  engineer will tell you, this requires as much energy as raising four
  thousand tons a height of one mile. That four thousand mile-tons of energy
  is the price of weightlessness-the entrance fee to the universe. There are
  no concessions and no cheap rates. You may have to pay more, but you can
  never pay less.
  On the whole, a permanently degravitized or weightless substance seems less
  plausible than the gravity neutralizer or "gravitator." This would be a
  device, supplied with energy from some external power source, which would
  cancel gravity as long as it was switched on. It is important to realize
  that such a machine would give not only
                73
 weightlessness, but something even more valuable--propulsion.
  For if we exactly neutralized weight, we would float motionless in midair;
  but if we over-neutralized it, we would shoot upward with steadily
  increasing speed. Thus any form of gravity control would also be a
  propulsion system; we should expect this, as gravity and acceleration are
  so intimately linked. It would be a wholly novel form of propulsion, and it
  is difficult to see what it would "push against." Every prime mover must
  have some point of reaction; even the rocket, the only known device that
  can give us a thrust in a vacuum, pushes on its own burned exhaust gases.
  The term "space drive," or just plain "drive," has been coined for such
  nonexistent but highly desirable propulsion systems, not to be confused
  with the overdrives and underdrives peddled by Detroit. It is an act of
  faith among science-fiction writers, and an increasing number of people in
  the astronautics business, that there must be some safer, quieter, cheaper,
  and generally less messy way of getting to the planets than the rocket. The
  monsters standing at Cape Canaveral contain as much energy as the first
  atomic bomb in their fuel tanks-and it is less reliably controlled. Sooner
  or later there is going to be a really nasty accident;' we need a space
  drive urgently, not only to explore the solar system, but to protect the
  state of Florida.
  It may seem a little premature to speculate about the uses of a device
  which may not even be possible, and is certainly beyond the present horizon
  of science. But it is a general rule that whenever there is a technical
  need, something always comes along to satisfy it--or to bypass it. For this
  reason, I feel sure that eventually we will have some means of either
  neutralizing gravity or overpowering it by brute force. In any event, it
  will give us both levitation and propulsion, in amounts determined only by
  the available power.

  I The Russians had one first, when their giant booster blew up in 1969.
                74
  If anti-gravity devices turn out to be bulky and expensive, their use will
  be limited to fixed installations and to large vehicles-perhaps of a size
  which we have not yet seen on this planet. Much of the energy of mankind is
  expended in moving vast quantities of oil, coal, ores, and other raw
  materials from point to point-quantities measured in hundreds of millions
  of tons per year. Many of the world's mineral deposits are useless because
  they are inaccessible; perhaps we may be able to open them up through the
  air, by the use of relatively slow-moving anti-gravity freighters hauling
  a few hundred thousand tons at a time across the sky.
  One can even imagine the bulk movement of freight or raw materials along
  "gravity pipelines," directed and focused fields in which objects would be
  supported and would move like iron toward a magnet. Our descendants may be
  quite accustomed to seeing their goods and chattels sailing from place to
  place without visible means of support. On an even larger scale, gravity
  and propulsion fields might be used to control and redirect the winds and
  the ocean currents; if weather modification is ever to be practical,
  something of this sort is certainly necessary.
  The value of gravity control for space vehicles, both for propulsion and
  the comfort of their occupants, needs no further discussion-but there are
  other astronautical uses that are not so obvious. Jupiter, the largest of
  the planets, is barred from direct human exploration by its high gravity,
  two and a half times that of Earth. This giant world has so many other
  unpleasant characteristics (an enormously dense, turbulent and poisonous
  atmosphere, for example) that few people take very seriously the idea that
  we will ever attempt its manned exploration; the assumption is that we will
  always -rely on robots.
  I doubt this; in any event, there are always going to be cases when robots
  will run into trouble and men will have to get them out of it. Sooner or
  later there will be scientific and operational requirements for the human
  exploration of Jupiter; one day we may even wish to establish a permanent
  base there. This will'demand some kind of gravity control-unless we breed
  a special class of Jovian 75
 colonist with the physiques of gorillas. (For more about the exploration of
 Jupiter, see Chapter 9.)
  If this seems a little remote and fantastic, let me remind you that much
  closer to home there is an even more important example of a high-gravity
  planet which, perhaps less than fifty years from now, men may not be able
  to visit. That planet is our own Earth.
  Without gravity control, we may be condemning the space travelers and
  settlers of the future to perpetual exHe. A man who has lived for a few
  years on the Moon, where he has known only a sixth of his terrestrial
  weight, would be a helpless cripple back on Earth. It might take him months
  of painful practice before he could walk again, and children born on the
  Moon (as they will be within another generation) might never be able to
  make the adjustment. One can think of few things more likely to breed
  bitterness and interplanetary discord than such gravitational expatriation.
  To avoid this we need a really portable gravity-control unit, so compact
  that a man could strap it on his shoulders or round his waist. Indeed, it
  might even be a permanent part of his clothing, taken as much for granted
  as his wristwatch or his personal transceiver. He could use it to reduce
  his apparent weight down to zero, or to provide propulsion.
  Anyone who is prepared to admit that gravity control is possible at all
  should not boggle at this further development. Miniaturization is one of
  the everyday miracles of our age, for better or for worse. The first
  thermonuclear bomb was as big as a house; today's economy-sized warheads
  are the size of wastepaper baskets-and from one of those baskets comes
  enough energy to carry the liner Queen Elizabeth to Mars. This everyday
  fact of modern n3issilry is, I submit, far more fantastic than the
  possibility of personal gravity control.
  The one-man gravitator, if it could be made cheaply enough, would be among
  the most revolutionary inventions of all times. Like birds and fish, we
  would have escaped from the tyranny of the vertical-we would have gained
  the freedom of the third dimension. In the city, no
                76
 one would use the elevator if there was a convenient window. The degree of
 effortless mobility that would be attained would demand re-education to an
 entire new way of life--an almost avian order of existence. By the time it
 arrives, it will not be unfamiliar, for countless films of spacemen in orbit
 will have made everyone accustomed to the idea of weightlessness, and eager
 to share its pleasures. Perhaps the levitator may do for the mountains what
 the aqualung has done for the sea. The Sherpas and Alpine guides will, of
 course, be indignant; but progress is inexorable. It is only a matter of
 time before tourists are floating all over the Himalayas, and the summit of
 Everest is as crowded as the seabed round the Florida Keys or off Cannes.
  Even if the extreme of personal, one-man levitation turns out to be
  impossible, ~ve may still be able to build small vehicles in which we can
  drift slowly and silently (both are important) through the sky. The very
  idea of hovering in space was a fantasy a generation ago, until the
  helicopter opened our eyes. Now that experimental Ground Effect Machines
  are floating off in every direction on cushions of air, we will not be
  satisfied until we can roam at will over the face of the Earth, with a
  freedom that neither the automobile nor the airplane can ever give.
  What the ultimate outcome of that freedom may be, no one can guess-but I
  have one final suggestion. When gravity can be controlled, our very homes
  may take to the air. Houses would no longer be rooted in a single spot;
  they would be far more mobile than today's trailers, free to move across
  land and sea, from continent to continent. And from climate to climate, for
  they would follow the sun with the changing seasons, or head into the
  mountains for the winter sports.
  The first men were nomads; so may be the last, on an infinitely more
  advanced technical level. The completely mobile home would require, quite
  apart from its presently unattainable propulsion system, power,
  communication and other services equally beyond today's technology. But
  not, as we shall see later, beyond tomorrow's.
This would mean the end of cities, which may well be 77
 doomed for other reasons. And it would mean the end of
 all geographical and regional loyalties, at least in the in
 tense form that we know today. Man might become a
 wanderer over the face of the Earth-a gypsy driving a
 nuclear-power caravan from oasis to oasis, across the
 deserts of ' the sky.
  Yet when that day comes, he will not feel a rootless exHe with no place to
  call his own. A globe that can be circumnavigated in ninety minutes can
  never again mean what it did to our ancestors. For those who come after us,
  the only true loneliness will lie between the stars. Wherever they may fly
  or float on this little Earth, they will always be at home.

 78
 The Quest for Speed

 This has often been called the Age of Speed, and for once the popular label
 is wholly correct. Never before has the velocity of transportation increased
 at such a staggering rate; it may never do so again.
  Both these statements are borne out if we make a table showing all possible
  ranges or bands of speed, listed in orders of magnitude, and then note the
  decade at which each range was entered. The result is somewhat startling:

        SPEED RANGE     APPRo)amATE
 BAND                  (m.p.h.)DATE OF ENTRY To BAND
  _T_      1-10 'cica1,000,000 B-C-
 2                        10-100ditto
 3                        100-1,0001880
 4                        1,000 - 10,0001950
 5                        10,000 - 100,0001960
 6                        100,000 - 1,000,000
 7                        1,000,000 - 10,000,000
 8                        10,000,000 - 100,000,000
 9                        100,000,000 - 1,000,000,000

                79
  After spending the whole of prehistory and most of history in the first two
  speed bands, mankind shot through the third in a single lifetime. (I do not
  know the precise date at which a locomotive attained 100 m.p.h., but it
  certainly became possible around 1880. The Empire State Express touched 112
  m.p.h. on the New York Central line in 1893.) Even more astonishing is the
  fact that we passed through the whole of the fourth band in just over a
  decade; the period 1950 to 1960 covers (to the accuracy we are concerned
  with here) the huge jump from supersonic fight in the atmosphere to orbital
  flight outside it.
  This, of course, was the result of the breakthrough in rocketry, which has
  produced what the mathematicians would call a discontinuity in the speed
  curve. We can hardly expect this acceleration to continue at the same rate;
  that would imply, for example, that we reached 100,000 m.p.h. well before
  1970-which we didn't. Stiff more unlikely is the result obtained by
  continuing this nalve extrapolation-tbat we shall have reached band 9, and
  the ultimate speed limit of the universe, before the year 2010.
  For the final entry in the table is imaginary; band 9 should really read
  "100,000,000-670,615,000 m.p.h." There is no such thing as a speed beyond
  this last figure; it is the velocity of light.
  Let us ignore the question as to why this is a speed limit, and what-if
  anything-we can do about it, and concentrate on the lower end of the
  velocity spectrum. Bands I to 4 cover the entire range of speeds necessary
  for all terrestrial purposes; indeed, many of us are content to remain in
  band 3, and consider -that today's jetliners already travel quite fast
  enough.
  For ultrahigh speed services, at several thousand miles an hour, it will be
  necessary to use rockets, and it seems unlikely that these can ever be
  economical on the basis of chemical propellants. Although we can now shoot
  a man around- the world in ninety minutes, about a hundred tons of fuel has
  to be burned to do so. Even when rockets are fully developed, it is
  doubtful if the figure could be reduced to less than ten tons per
  passenger. This is some
                80
 twenty times the already impressive half-ton of kerosene per passenger
 consumed by the big jets of today on a long-distance flight. (Of course, the
 rocket has to carry its oxygen as well-the penalty it must pay for traveling
 outside the atmosphere.)
  Since efforts are now under way to develop the Space Shuttle, which will
  carry a dozen or more passengers up to orbit, it might seem that this could
  lead to comme ial rocket transportation-if only on a special, premium-fare
  basis. If this seems a little unlikely, it is worth remembering that when
  the first jets started to fly, few people thought that the new engines
  could ever be used for anything except short-range, military applications.
  Yet within twenty years, they had transformed the airlines of the world,
  and shrunk our planet to less than half its previous size.
  There are two lines of development that might make very high-speed
  transportation an economic possibility. The first is a cheap, safe, and
  clean nuclear propulsion system, which would greatly reduce the propellent
  load. Such a system is far beyond sight at the moment, because it could not
  be based upon flssion-the only means currently available for releasing the
  energy of the atom. At the risk of making myself appear a reactionary old
  fogy, I do not believe that uranium and plutonium-fueled devices should be
  allowed off the ground. Aircraft (here is a daring prediction) will always
  crash; it is bad enough to be sprayed by burning kerosene, but such
  disasters are at least local and temporary. Fallout is neither.
  The only mobile nuclear power plants that can be tolerated in the air and
  nearby space must be free from radioactivity. We cannot build such systems
  at the moment, but we may be able to do so when we have achieved controlled
  thermonuclear reactions. Then, with a few pounds of lithium and heavy
  hydrogen as fuel, we will be able to fly substantial payloads round the
  world at up to orbital speed-1 8,000 miles an hour.
  It has also been suggested-and this is one of those ideas that sound much
  too good to be true-that fuelless aircraft may be developed which can fly
  indefinitely in the 81
 upper atmosphere, powered by the natural sources of energy that exist there.
 These sources have already been tapped in a number of spectacular
 experiments. When sodium vapor is discharged from a rocket at the correct
 altitude, it triggers a reaction between the electrified atoms which lie on
 the boundaries between air and space. As a result, a visible glow may spread
 across many miles of the sky. It is the energy of sunlight, collected by the
 atoms during the day and released when it receives the right stimulus.
  Unfortunately, though the total amount of energy stored in the upper
  atmosphere is very large, it is also very dilute. Enormous volumes of
  rarefied gas would have to be collected and processed to give any useful
  result. If some kind of high-speed ramjet could scoop up the thin air, and
  release enough of its energy in the form of heat to produce an adequate
  thrust, then it could fly forever with no expenditure of fuel. At the
  moment this seems unlikely, for the drag of the air scoops would be much
  greater than the thrust that could be expected, but the idea should not be
  dismissed out of hand. A few decades ago we had no idea that such energy
  sources existed; there may be stiff more powerful ones yet to be discov-
  ered.
  After all, there is nothing fundamentally absurd about the idea. We sailed
  the seas for thousands of years in fuelless ships, powered by the free
  energy of the winds. And that energy too, comes ultimately from the Sun.
  However, even if fuel were free and unlimited, there would still be
  obstacles at very high flight speeds. Circus performers can tolerate being
  shot from cannon, but paying passengers object to high accelerations-and
  those are inevitable if we hope to attain really high speeds.
  Even today, the take-off of a jet seems to keep one glued to the seat for
  a very long time-yet the acceleration involved is only a fraction of one
  gravity, and the speed eventually attained very modest compared with those
  we are now discussing.
  Let us look at a few figures. An acceleration of I-g means that in each
  second speed is increasing at the rate 82
 of 22 m.p.h. At this rate it would take almost fourteen minutes to reach
 orbiting speed (18,000 m.p.h.), and during the whole of that time every
 passenger would feel that he had another man sitting on his lap. Then (on
 the longest possible flight, half the circumference of the Earth) there
 would be twenty minutes of completely weightless flight which would probably
 be even more disconcerting. And after that, another fourteen-minute, 1-g
 period, while the speed was being reduced to zero. At no time during the
 trip could anyone claim to be comfortable, and for the weightless portion of
 the flight even the famous paper bag would be unusable. It might not be un-
 fair to say that in round-the-world satellite transportation, half the time
 the toilet is out of reach, and the other half of the time it is out of
 order.
  A close satellite orbit represents a kind of natural speed limit for travel
  round the Earth; once a body is established in it, it circles effortlessly
  at 18,000 m.p.h., taking about 90 minutes per revolution. If we try to
  travel faster than this, we run into a new set of problems.
  Everyone has experienced the "centrifugal force" that results during a
  high-speed turn in a car or airplane. I use the quotation marks because
  what you feel then is not really a force at all, but the natural resentment
  of your body at being denied its inalienable right to continue traveling in
  a straight line at uniform velocity. The only force actually involved is
  that which has to be exerted by the seat of your vehicle to prevent you
  from doing this.
  In flying round the world, or indeed during any movement on the face of the
  Earth, you are traveling in a circle of four thousand miles' radius. At
  normal speeds, you never notice the negligible extra force needed to keep
  you attached to the ground; your weight is more than sufflcient to provide
  it. At 18,000 miles an hour, however, the inward or downward force required
  would exactly equal your weight. This, of course, is the condition for or-
  bital flight; the Earth's pull is just sufficient to hold on to a body
  moving around it at this speed.
  If you travel faster than 18,000 miles an hour, you must provide an
  additional downward force to keep your83
 self in orbit; Earth alone cannot do it. A situation thus arises-which the
 pioneers of aviation could scarcely have imagined when they were struggling
 to get off the ground-when a flying machine has to be held down to keep it
 at the correct altitude; without some tethering force, it will fly off into
 space, like a stone from a sling.
  In the case of a vehicle circling the Earth at 25,000 m.p.h., the extra
  force needed to keep it in orbit amounts to exactly one gravity. This might
  be provided by rockets driving the spacecraft toward the center of the
  Earth with an acceleration of 1-g. Yet it would get no closer, and the only
  difference between this powered trajectory and a normal free satellite
  orbit is that it would be quicker-one hour instead of ninety minutes-and
  that the occupants of the vehicle would no longer be weightless. They
  would, in fact, appear to have their ordinary weight, but its direction
  would be reversed. "Down" would be toward the stars; Earth would be hanging
  above the anxious astronauts, spinning on its axis every sixty minutes. -
  At greater speeds, stiff larger forces would have to be employed to keep
  the vehicle in its artificial-in the sense of naturally impossible-orbit.
  Although there seems no practical use for such performances, which would
  require enormous amounts of energy, man's love of record breaking will
  presumably lead to ultra-high-speed circuits of the globe as soon as they
  become technically feasible. It is interesting to calculate the
  accelerations and times that such Rights would involve; they are shown in
  the table below.

 VELOCITYTIME TO ORBIT FORCE ExPERIENCED
            EARTr-r              BY PASSENGERS
 (m.p.h.)          (minutes)(gravities)
 18,000                   90    0
 25,000                   60    1
 31,000                   48    2
 36,000                   42    3
 40,000                   37    4
 44,000                   34    5
 60,000                   25    -10
 100,000                  15   30
                84
  Going round the world in less than thirty minutes is thus going to be a
  rugged proposition, as well as an expensive one. To do it in fifteen
  minutes, thirty gravities would have to be endured; this might be possible,
  if the occupant-who would not take much active interest in the proceedings,
  anyway-was totally immersed in water. I suggest, however, that such a
  performance would already have passed the limit of sanity. It is
  impracticable to make hairpin turns round an astronomical pinpoint like the
  Earth. Though men will travel round the world quite comfortably in eighty
  minutes, they will never do so in eight, with any means of propulsion known
  today.
  That last clause is not just a cautious afterthought. One day, I suggest,
  we will have methods of propulsion fundamentally different from any that
  have ever existed in the past. All known vehicles, without exception,
  accelerate their occupants by giving them a physical push which they feel
  through their boots or the seats of their pants. This is true of ox carts
  and bicycles, of automobiles and rockets. That it need not always be true
  is suggested by the curious behavior of gravitational fields.
  When you fall freely under Earth's gravity, you are increasing speed at the
  rate of 22 m.p.h. every second-but you do not feel anything at all. This
  would be true no matter how intense the gravity field; if you were dropped
  toward Jupiter, you would accelerate at 60 m.p.h. every second, for
  Jupiter's gravity is more than two and a half times Earth's. Near the Sun
  you would increase speed at the rate of 600 m.p.h. each second, and again
  you would feel no force acting upon you. There are stars-white dwarfs-with
  gravity fields more than a thousand times as strong as Jupiter's; in the
  vicinity of such a star, you might add 100,000 m.p.h. to your speed every
  second without the slightest discomfort-until, of course, it was time to
  pull out.
  The reason you would experience no sensation or physical stress when being
  accelerated by a gravity field of any intensity is that it would act
  simultaneously upon every atom of your body. There would be no push
  transmit85
 ted through you layer by layer from the seat or the floor of the vehicle.
  You have doubtless realized where this argument is leading. If, as I have
  suggested in the preceding chapter, we can ever control and direct gravity
  fields, this will give us far more than the ability to float around like
  clouds. It will enable us to accelerate in any direction, at a rate limited
  only by the power available, without feeling any mechanical stress or
  force. Such a method of propulsion might be called an "inertialess drive"-a
  term I have borrowed (with much else) from that veteran science-fiction
  writer Dr. E. E. Smith, though he used it in a somewhat different sense.
  With such a drive, our vehicles could stop and start almost
  instantaneously. Perhaps even more important, they would be virtually
  crash-proof. Protected by their artificial gravity fields, they could run
  into each other at hundreds of miles an hour with no damage to anything
  except the nervous systems of their occupants. They could make right-angled
  turns or bairpin bends, and though the reactions of a human pilot would be
  far too slow to operate them, men could ride in them with perfect safety
  and comfort. It might be arranged that, whatever acceleration they were
  actually undergoing, there would be a net or uncompensated force of just
  one gravity acting on the passengers, so that they would always feel their
  normal weight.
  Though we can manage quite well, here on Earth, without such sophisticated
  methods of propulsion, they will ultimately become available as a byproduct
  of space research. The rocket-let us face it-is not a practical !nethod of
  getting around, as anyone who has ever stood in the open within a mile of
  a big static test will agree. We have to find something quieter, cleaner,
  and more reliable-and something that will enable us to enter those now
  unattainable speed bands 6, 7, 8, and finally 9.
  For in the long run-and now I am looking perhaps centuries ahead-we will
  have used and discarded all the vehicles that we have employed in our climb
  up to the velocity spectrum; the time will come when the ICBM ap86
 pears no swifter than the Assyrian war chariot. The three thousand years
 that lie between them is but a moment in the whole span of history, past and
 future-and for most of that span, men will be interested only in the two ex-
 treme ends of the speed band.
  They will always, I hope, be content to wander about the world at two or
  three miles an hour, absorbing its beauty and its mystery. But when they
  are not doing this, they will be in a hurry: and then they will be
  satisfied with nothing short of that ultimate 670,615,000 miles an hour.
  Even this speed, of course, will be totally inadequate to meet the
  challenge of interstellar space, but as far as the Earth is concerned it
  would amount to instantaneous transportation. A light wave could circle the
  globe in a seventh of a second; now let us see whether men can ever hope to
  do the same.

 87
 World without Distance

 The idea of instantaneous transport-"teleportation"-is very old, and is
 embodied in many Eastern religions. There must be millions of people alive
 at this moment who believe that it has already been achieved, by Yogis and
 other adepts, through the exercise of sheer willpower. Anyone who has seen
 a good display of fire walking, as I have done,' must admit that the mind
 has almost unbelievable power over matter-but in this particular case I beg
 to be skeptical.
  One of the best proofs that mental teleportation is not possible was given,
  somewhat ironically, in a novel which described a society based upon it.
  Alfred Bester's The Stars My Destination opened with the interesting idea
  that a man threatened by sudden death might unconsciously and involuntarily
  teleport himself to safety. The fact that there is no authentic record of
  this happening, despite the millions of opportunities provided every year
  for putting the matter to the test, seems an excellent argument that it is
  not possible.

 I See Chapter 17.
                88
  So let us consider teleportation in terms of known and foreseeable science,
  not wholly unknown and hypothetical mental powers. The only approach to the
  problem seems to be through electronics; we have learned to send sounds and
  images round the world at the velocity of light, so why not solid
  objects-even men?
  It is important to realize that the above sentence contains a fundamental
  misstatement of fact, though I doubt if many people would spot it. We
  don't,by radio or TV or any other means, send sounds and images anywhere.
  They remain at their place of origin, and there, within a fraction of a
  second, they perish. What we do send is information-a description or plan
  which happens to be in the form of electrical waves-from which the original
  sights and sounds can be recreated.
  In the case of sound, the problem is relatively simple and may now be
  regarded as solved, for with really good equipment it is impossible to
  distinguish the copy from the original. The task is simple (with due
  apologies to the several generations of scientists and audio engineers who
  have beaten out their brains over it) because sound is one-dimensional.
  That is to say, any sound-no matter bow complex-can be represented as a
  quantity which at any instant has a single value.
  It is, when one thinks about it, quite extraordinary that the massed
  resources of Wagner or Berlioz can be completely contained in a single
  wavering line etched on a disc of plastic. But this is true, if the line's
  excursions are sufficiently detailed. Since the human ear cannot perceive
  sounds of frequencies beyond 20,000 vibrations a second, this sets a limit
  to the amount of detail that a sound channel need carry-or its bandwidth,
  to use the technical term.
  For vision, the situation is much more complicated, because we are now
  dealing with a two-dimensional pattern of light and shade. Whereas at a
  single instant a sound can possess just one level of loudness, a scene
  possesses thousands of variations in brilliance. All these have to be dealt
  with if we wish to transmit an image.
The television engineers solved the problem not by 89
 tackling it as a whole, but by carving it up into bits. In the TV camera a
 single scene is dissected into some quarter of a million picture elements,
 in much the same way that a photograph is screened by the cut maker for
 newspaper reproduction. What the camera does, in effect, is to carry out an
 incredibly rapid survey or sampling of the light values over the scene, and
 to report them to the receiving end of the equipment, which acts on the
 information and reproduces corresponding light values on the screen of the
 cathode-ray tube. At any given instant, a TV system is transmitting the
 image of a single point, but because a quarter of a million such images
 flash upon the screen in a fraction of a second we get the illusion of a
 complete picture. And because the whole process is repeated thirty times a
 second (twenty-five in countries with fifty cycle mains) the picture appears
 to be continuous and moving.
  In a single second, therefore, an almost astronomical amount of information
  about li2ht and shade has to be passed through a TV channel. Thirty times
  a quarter of a million means 7,500,000 separate signals a second; in
  practice a bandwidth of 4,000,000 cycles per second gives the adequate but
  hardly brilliant standard of definition provided by our domestic TV sets.
  If you think that is good, compare it for detail some day with a
  high-quality photograph of the same size as your screen.
  Now let us do some technological day dreaming, following in the footsteps
  of a great many science-fiction writers. (Perhaps starting with Conan
  Doyle; see one of his lesser-known Professor Challenger stories, The Disin-
  tegration Machine, published in the 1920's.) Imagine a super X-ray device
  that could scan a solid object, atom by atom, just as a TV camera scans a
  scene in the studio. It would produce a string of electrical impulses
  stating in effect: Here is an atom of carbon; here a billionth of an inch
  further to the right is nothing; another billionth of an inch along is an
  atom of oxygen-and so on, until the entire object had been uniquely and
  explicitly described. Granted the possibility of such a device, it would
  not seem very much more difficult to reverse the process and build 90
 up, from the information transmitted, a duplicate of the original, identical
 with it in every way. We might call such a system a "matter transmitter,"
 but the term would be misleading. It would no more transmit matter than a TV
 station transmits light; it would transmit information from which a suitable
 supply of unorganized matter in the receiver could be arranged into the
 desired form. Yet the result could be, in effect, instantaneous
 transportation-or at least transportation at the speed of radio waves, which
 can circle the world in a seventh of a second.
  The practical difficulties, however, are so gigantic that as soon as they
  are spelled out the whole idea seems absurd. One has only to compare the
  two entities involved; there is a universe of difference between a flat
  image of rather low definition, and a solid body with its infinite wealth
  and complexity of microscopic detail down to the very atoms. Can any words
  or description span the gulf between the photograph of a man-and the man
  himself?
  To indicate the nature of the problem, suppose you were asked to make an
  exact duplicate of New York City, down to every brick, pane of glass,
  curbstone, doorknob, gas pipe, water main, and piece of electric wiring.
  EspeciaRy the latter, for not only would the replica of the city have to be
  perfect in all its physical details, but its multitudinous power and
  telephone circuits would have to be carrying exactly the same currents as
  were those of the original at the moment of reproduction.
  It would, obviously, take an army of architects and engineers to compile
  the necessary description of the cityto carry out the scanning process, if
  we revert to television parlance. And in that time the city would have
  changed so much that the job would have to be done over again; in fact, it
  could never be completed.
  Yet a human being is not less than a million, and probably a million
  million, times more complex than such a simple artifact as New York City.
  (We will ignore for the moment the not unimportant distinction that one
  object is a living, sentient creature, and the other is not.) We can
  assume, therefore, that the copying process would take correspondingly
  longer. If it took a year to scan New 91
 York-a highly optimistic assumption-then to carry out the same process for
 a single human being would probably require all the time that is available
 before the stars go out. And to pass the resultant information through any
 comm ni ations channel would probably take about as long.
  We can see this merely by looking at the figures involved. There are, very
  roughly 5 X 1027 atoms in a human body, as compared with the 250,000
  picture elements in a TV image. It takes a TV channel one-thirtieth of a
  second to handle these; simple arithmetic shows that a channel of the same
  capacity would take about 2 X 1013, or 20,000,000,000,000 years, to
  transmit a "matter image" from one spot to another. It would be quicker to
  walk.
  Though the above analysis is childishly na7ve (any communications engineer
  can think of ways of knocking five or six zeros from this figure), it does
  indicate the magnitude of the problem, and the impossibility of solving it
  with presently imaginable techniques. It does not prove that it can never
  be done, but merely that it is far beyond the scope of today's science. For
  us even to attempt it would be as if Leonardo da Vinci tried to build a
  purely mechanical (i.e. non-electric) television system.
  This analogy is such a close one that it is worth developing it a little
  further. How would Leonardo have tackled the problem of sending a
  high-definition (250,000 picture elements) image from one point to another?
  You will be surprised to find that he could have done it, though it would
  have been a pointless tour-de-force. This is how he might have proceeded:
  A large lens would"have projected the image to be transmitted into a
  darkened room, on to a white screen. (The camera obscura, which does just
  this, was quite familiar to Leonardo, who described it in his notebooks.)
  Over the picture would be laid a rectangular grid or sieve, with 500 wires
  to a side, so that the image was divided into 250,000 separate elements.
  Each wire would be numbered, so that a pair of 3-figure coordinates, such
  as 123:456, would identify every point in the field.
                92
  It would then be necessary for some sharp-eyed individual to examine the
  picture element by element and say yes or no according to whether or not
  that element was illuminated. (If you imagine yourself going over a newspa-
  per cut with a magnifying glass, you have a very good idea of the
  procedure.) If "0" meant darkness and "1" light, the whole picture could be
  described, within these limits of definition, by a series of 7-figure
  numbers.
        would mean that the element on the extreme top left was illuminated;
        "0:500:500," that the last one on the bottom right was dark.
  Now Leonardo has the problem of transmitting this series of a 250,000
  7-figure numbers to a distant point. That could be done in many
  ways-semaphores, flashing lights, and so on. At the receiving end, the
  image could be synthesized by putting black dots in the appropriate places
  on a blank 500 X 500 grid, or by having a quarter of a million tiny
  shutters that could be opened and closed in front of a white sheet, or in
  a dozen other ways.
  And how long would all this take? The bottleneck would probably be the
  semaphore; Leonardo would be very lucky to send one digit a second, and he
  has 1,750,000 to cope with. So it would require about twenty days, not to
  mention a fantastic amount of effort and eyestrain, to transmit this single
  image.
  Leonardo could cut down the time, at the cost of mechanical complication,
  by having a number of men working in parallel, but he would soon reach the
  point of diminishing returns. Twenty operators, all scanning the image and
  sending their information over separate semaphores, would certainly get in
  each other's way; even so, they could not complete the task in less than a
  day. That it could ever be performed in a thirtieth of a second would have
  seemed to Leonardo, perhaps the most farseeing man who ever lived, an
  absolute and unquestionable impossibility. Yet five hundred years after his
  birth, thanks to electronics, it was happening in most of the homes in the
  civilized world.
  It may well be that there are technologies as much beyond electronics as
  electronics is beyond the clumsy
                93
 machinery of the Middle Ages; within the framework of such technologies,
 even the scanning, transmission, and reconstruction of an object as complex
 as a human being may prove to be possible-and in a reasonably short period
 of time, say a matter of a few minutes. Yet even this does not mean that we
 will ever be able to send a living man, with his thoughts, memories, and his
 unique feeling of identity, over the equivalent of a radio circuit. For a
 man is more than the sum of his atoms; he is at least that, plus all the
 unimaginary large number of energy states and spacial configurations in
 which those atoms happen to be at a given moment of time. Modem physics (es-
 pecially Heisenberg's uncertainty principle) maintains that it is
 fundamentally impossible to measure all those states and configurations with
 absolute accuracy-that, in fact, the very conception is meaningless. Like a
 carbon copy, the duplicate would have to have some degree of blurring, from
 the nature of things. The blurring might be too small to matter (like the
 noise on a high-quality tape recording) or it might be so bad that the copy
 would be unrecognizable, like a newspaper cut that has been screened too
 many times. Producers of horror movies, please note: Worse things could
 happen than The Fly.
  I make no apologies for the purely mechanistic approach in this discussion;
  we have enough technical problems already on our hands without bringing in
  such indefinables as the soul and the spirit. It may well be argaed that
  even if we could reproduce a man down to his ultimate atoms, the result
  would not be a living creature--or if it was, not the creature we started
  with. Yet such a reproduction would be a. minimum requirement; we might
  have to do much more, but we would certainly have to do that.
  There is one philosophical point, however, which I cannot ignore and which
  has doubtless already occurred to you. If this type of transportation is
  possible at all, it would have some hair-raising consequences.
  For a matter transmitter is not "merely" a transmitter; it is potentially
  a multiplier, which could turn out any number of copies indistinguishable
  from the originaL 94
 There would be as many copies as there were receiving sets; or perhaps the
 "signal" could be recorded and played back over and over again through the
 same receiver. In this connection, it is relevant to point out that the cost
 of the raw materials in a human body is a couple of dollars.
  One day, all manufacturing processes will be based on this idea, which is
  certainly practical with simple, inanimate objects and even fairly complex
  but non-living materials.2 We do not object to thousands of identical
  ashtrays or teacups or automobiles; but society would collapse into a
  nightmare confusion if confronted with hundreds of men each
  claiming-correctly-to be the same person. Even two or three replicas of a
  key statesman could result in chaos, and the possibilities for crime,
  intrigue, and warfare are so appalling that here would undoubtedly be an
  invention far more dangerous than any atom bomb. Yet the fact that a thing
  is horrible does not make it impossible, as the inhabitants of Hiroshima
  discovered. We may well hope that a matter transmitter/duplicator that can
  handle human beings will always remain beyond achievement, but I suspect
  that some day we will have to face the problems it raises.
  I also suspect that the brute-force, television-type of approach just
  outlined will not be the best way of achieving instantaneous
  transportation; the real answer (if indeed there is one) may be very much
  more subtle. It may involve the very nature of space itself.
  Space, someone once remarked with great acuteness, is what stops everything
  from being in the same place. But suppose we want two things to be in the
  same place--or, better still, two places to be in'the same place?
  The idea that space is fixed, invariant, and absolute has taken a beating
  during the last fifty years, thanks largely to Einstein. But even before
  the theory of relativity made us take a keen, hard look at ideas that had
  always seemed common sense, the concept of classical or Euclidean space had
  been challenged by a number of philosophers

 2 See Chapter 13 for a Mer discussion.
                95
 and mathematicians. (Especially Nikolai Ivanovich Lobachevski 1793-1856,
 whose indignant ghost is now waiting to have a few words with Mr. Tom Lehrer
 of the irreverent phonograph records.)
  There are at least two ways in which space may have properties more complex
  than those described in the geometry books that most of us vaguely remember
  from our school days. It can disobey the fundamental axioms of Euclid; or
  it can have more than three dimensions. Much more frightful possibilities
  have been imagined by modem geometricians-whose motto is "If it can be
  visualized, it isn't geometry'!--but we can thankfully disregard these.
  The fourth dimension has been out of fashion for quite a while: it was
  popular round the turn of the century, and perhaps it may come back into
  style some day. There is nothing particularly difficult about the idea that
  there could be something as much "higher" than the cube as that is higher
  than the square, and it is quite easy to work out the properties of four or
  indeed n-dimensional figures, by analogy with those of lower dimensions. We
  will be doing this in Chapter 14.
  Though I am willing (well, fairly willing) to stand correction on this
  matter, I do not think that multidimensional Euclidean space allows the
  possibility of shortcuts between points in our familiar three-dimensional
  world. Two points with a certain separation in 3-space will stiff have at
  least that separation in any higher space. If, however, we imagine that
  space can be bent or curved, so that the axioms of Euclid no longer apply,
  then some interesting possibilities arise.
  Once again, these can be appreciated only by analogy. Think of that
  familiar but mysterious figure, the M6bius strip--formed by gluing two ends
  of a strip of paper together after giving it a half twist. As is well
  known, the result is a "single-sided surface," a fact which you can prove
  very easily by running your finger along it. (At this point I suggest that
  you make a M6bius strip, which will take you about thirty seconds and is
  well worth the effort.)
Take hold of the strip between thumb and forefinger. 96
 With a pencil, you can trace a continuous line from your thumb to your
 forefinger by going once around the strip. (Or is it only half a circuit?
 But that's another story.) If you were a "flatlander" able to travel only on
 the surface of the strip, this might be a very considerable distance.
  On the other band, if you could move through the thickness of the paper-the
  direct line between thumb and forefinger-the distance would be very short.
  Instead of ten inches, it might be a few thousandths of an inch.
  This simple little experiment suggests some very complex possibilities.
  Types of space can be imagined in which two points A and B might be a long
  way apart in one direction, but quite close in another.
  Because we can imagine this situation, it does not mean that it is
  physically realizable, or that there are "holes in space" through which we
  can take shortcuts across the universe. We believe, however, that the
  geometry of space is variable-a fact which would have seemed absurd to all
  the mathematicians who lived in the two-thousand-yearlong shadow of Euclid.
  Space can be altered by the presence of gravitational fields-thougb this
  may be putting the cart before the horse; gravitational "fields," socalled,
  are the result, not the cause, of curvatures in space.
  One day, perhaps, we may gain control of fields or forces which will allow
  us to alter the structure of space in useful manners, possibly tying it
  into pretzel-shaped knots with properties even more remarkable than those
  of the M6bius strip. The old science-fiction idea of the 64space-warp" may
  not be pure fantasy; one day it may be part of our normal lives, enabling
  us to step from one continent to another (or one world to another?) as
  easily as from one room to the next.
  Or the answer may come in some totally novel and unexpected way, as it has
  done so often in the past. We must assume that speeds of transportation
  will continue to increase to the limits of the technically feasible, and we
  are in no position to say where those limits may lie. Signals can travel at
  the speed of light, and material objects at not far short of it. Some day
  we may do the same.
                97
  There is, however, one trend which may work against the establishment of a
  virtually instantaneous global transportation system. As communications
  improve, until all the senses--and not merely vision and hearing-can be
  projected anywhere on the face of the Earth, men will have less and less
  incentive to travel. This situation was envisaged half a century ago by E.
  M. Forster in his famous short story "The Machine Stops," where he pictured
  our remote descendants as living in single cells, scarcely ever leaving
  them but being able to establish instant TV contact with anyone else on
  Earth, wherever he might be.
  In his own lifetime Forster has seen TV perfected far beyond his imaginings
  of three decades ago, and his vision of the future may be, in its
  essentials, not so far from the truth. Telecommunication and transportation
  are opposing forces, which so far have always struck a balance. If the
  first should ever win, the world of Forster's story would be the result.
  On the other hand, a transportation breakthrough like that which the rise
  of electronics brought to communications would lead to a world of limitless
  and effortless mobility. Gone would be all the barriers of distance that
  once sundered man from man, country from country. The transformation that
  the telephone has wrought in business and social life would be as nothing
  to that which the "teleportee' would bring to the whole of our
  civilization. To dismiss in a single sentence a possibility that would
  revolutionize (if not abolish) most of commerce and industry-imagine what
  would happen if we could transmit raw materials or manufactured goods
  instantaneously round the face of the planet! This would be billions of
  times less difficult, technically, than transmitting such fragile and
  complex entities as human beings, and I have little doubt that it will be
  achieved within a few centuries.
  Through all the ages, man has fought against two great enemies-time and
  space. Time he may never wholly conquer, and the sheer immensity of space
  may also defeat him when he has ventured more than a few light-years from
  the Sun. Yet on this little Earth, at least, he may one day claim a final
  victory.
                98
  I do not know how it will be done, and perhaps everything I have said may
  merely have convinced you that it is impossible. But I believe that the
  time will come when we can move from pole to pole within the throb of a
  single heartbeat.
  It will be one of history's little jokes if, when we attain this power, we
  are no longer interested in using it.

 99
                                 8

 Rocket to the Renaissance

 Four and half centuries ago, European civilization started expanding into
 the unknown, in a slow but irresistible explosion fueled by the energies of
 the Renaissance. After a thousand years of huddling round the Mediterranean,
 Western man had discovered a new frontier beyond the sea. We know the very
 day when he found it-and the day when he lost it. The American frontier
 opened on October 12, 1492; it closed on May 10, 1869, when the last spoke
 was driven in the transcontinental railroad.
  In all the long history of man, ours is the first age with no new frontiers
  on land or sea, and many of our troubles stem from this fact. It is true
  that, even now, there are vast areas of the Earth still unexploited and
  even unexplored, but dealing with them will only be a mopping-up operation.
  Though the oceans will keep us busy for centuries to come, the countdown
  started even for them, when the bathyscaphe Trieste descended into the
  ultimate deep of the Marianas Trench.
  There are no more undiscovered continents; set out toward any horizon, and
  on its other side you will find 100
 someone already waiting to check your visa and your vaccination certificate.
  This loss of the unknown has been a bitter blow to all romantics and
  adventurers. In the words of Walter Prescott Webb, the historian of the
  Southwest:

   The end of an age is always touched with
 sadness.... The people are going to miss the frontier
 more than words can express. For centuries they heard
 its call, listened to its promise, and bet their lives and
 fortunes on its outcome. It calls no more. . . .

  Professor Webb's lament, I am glad to say, is a few million years
  premature. Even while he was writing it in the small state of Texas, not a
  thousand miles to his west the vapor trails above White Sands were pointing
  to a frontier unimaginably vaster than any that our world has ever
  known-the frontier of space.
  The road to the stars has been discovered none too soon. Civilization
  cannot exist without new frontiers; it needs them both physically and
  spiritually. The physical need is obvious-new lands, new resources, new
  materials. The spiritual need is less apparent, but in the long run it is
  more important. We do not live by bread alone; we need adventure, variety,
  novelty, romance. As the psychologists have shown by their sensory
  deprivation experiments, a man goes swiftly mad if he is isolated in a
  silent, darkened room, cut off completely from the external world. What is
  true of individuals is also true of societies; they too can become insane
  without sufficient stimulus.
  It may seem overoptimistic to claim that man's forthcoming escape from
  Earth, and the crossing of interplanetary space, will trigger a new
  renaissance and break the patterns into which our society, and our arts,
  must otherwise freeze. Yet this is exactly what I propose to do; first,
  however, it is necessary to demolish some common misconceptions.
  The space frontier is infinite, beyond all possibility of exhaustion; but
  the opportunity and the challenge it presents are both totally different
  from any that we have 101
 met in our own world in the past. All the moons and planets of this solar
 system are strange, hostile places that may never harbor more than a few
 thousand human inhabitants, who will be at least as carefully handpicked as
 the population of Los Alamos. The age of mass colonization has gone forever.
 Space has room for many things, but not for "your tired, your poor, your
 huddled masses yearning to breathe free. . . ." Any statue of liberty on
 Martian soil will have inscribed upon its base "Give me your nuclear
 physicists, your chemical engineers, your biologists and mathematicians."
 The immigrants of the twenty-first century will have much more in common
 with those of the seventeenth century than the nineteenth. For the
 Mayflower, it is worth remembering, was loaded to the scuppers with
 eggheads.
  The often-expressed idea that the planets can solve the problem of
  overpopulation is thus a complete fallacy. Humanity is now increasing at
  the rate of over 100,000 a day, and no conceivable "space-lift" could make
  serious inroads in this appalling figure.
  With present techniques, the combined military budgets of all nations might
  just about suffice to land ten men on the Moon every day. Yet even if space
  transportation were free, instead of being fabulously expensive, that would
  scarcely help matters-for there is not a single planet upon which men could
  live and work without elaborate mechanical aids. On all of them we shall
  need the paraphernalia of space suits, synthetic air factories, pressure
  domes, totally enclosed hydroponic farms. One day our lunar and Martian
  colonies will be self-supporting, but if we are looking for living room for
  our surplus population, it would be far cheaper to find it in the Ant-
  arctic--or even on the bottom of the Atlantic Ocean.
  No, the population battle must be fought and won here
 on Earth, and the longer we postpone the inevitable con
 flict the more horrifying,the weapons that will be needed
 for victory. (Compulsory abortion and infanticide, and
 anti-heterosexual legislation-with its reverse-may be
 some of the milder expedients.) Yet though the planets
 cannot save us, this is a matter in which logic may not
                102
 count. The weight of increasing numbers-the suffocating sense of pressure as
 the walls of the ant-heap crowd ever closer-will help to power man's drive
 into space, even if -no more than a millionth of humanity can ever go there.
  Perhaps the battle is already lost, here on this planet. As Sir George
  Darwin has suggested in his depressing little book, The Next Million Years,
  ours may be a golden age, compared with the endless vistas of famine and
  poverty that must follow when the billions of the future fight over Earth's
  waning resources. If this is true, it is all the more vital that we
  establish self-sustaining colonies on the planets. They may have a chance
  of surviving, and preserving something of our culture, even if civilization
  breaks down completely on the mother world.
  Though the planets can give no physical relief to the congested and
  impoverished Earth, their intellectual and emotional contribution may be
  enormous. The discoveries of the first expeditions, the struggles of the
  pioneers to establish themselves on other worlds-these will inspire a
  feeling of purpose and achievement among the stay-athomes. They will know,
  as they watch their TV screens, that History with a capital H is starting
  again. The sense of wonder, which we have almost lost, will return to life;
  and so will the spirit of adventure.
  It is difficult to overrate the importance of this-though it is easy to
  poke fun at it by making cynical remarks about "escapism." Only a few
  people can be pioneers or discoverers, but everyone who is even half arive
  occasionally feels the need for adventure and excitement. If you require
  proof of this, look at the countless horse operas now galloping across the
  ether. The myth of a West that never was has been created to fill the
  vacuum in our modem lives, and it fills it well. Sooner or later, however,
  one tires of myths (many of us have long since tired of this one) and then
  it is time to seek new territory. There is a poignant symbolism in the fact
  that the giant rockets now stand poised on the edge of the Pacific, where
  the covered wagons halted only two lifetimes ago.
  Already, a slow but profound reorientation of our culture is under way, as
  men's thoughts become polarized 103
 toward space. Even before the first living creature left FArth's atmosphere,
 the process had started in the most influential area-the nursery. Space toys
 have been commonplace for years; so have cartoons and, "Take me to your
 leader" jokes that would have been incomprehensible only a decade ago.
 Increasing awareness of the universe has even, alas, contributed to our
 psychopathology. A fascinating parallel could be drawn between the flying
 saucer cults and the witchcraft mania of the seventeenth century. The
 mentalities involved are the same, and I hereby present the notion to any
 would-be Ph.D. in search of a thesis.
  As the exploration of the solar system proceeds, human society will become
  more and more permeated with the ideas, discoveries, and experiences of
  astronautics. They will have their greatest effect, of course, upon the men
  and women who actually go out into space to establish either temporary
  bases or permanent colonies on the planets. Because we do not know what
  they will encounter, it is scarcely profitable to speculate about the
  societies that may evolve, a hundred or a thousand years from now, upon the
  Moon, Mars, Venus, Titan, and the other major solid bodies of the solar
  system. (We can write off the giant planets, Jupiter, Saturn, Uranus, and
  Neptune, which have no stable surfaces.) The outcome of our ventures in
  space must await the verdict of history; certainly we will witness, on a
  scale their author never imagined, the testing of Toynbee's laws of
  "challenge and response." In this context, these words from the abridged
  Study of History are well worth pondering:

  Affiliated civilisations ... produce their most striking early
  manifestations in places outside the area occupied by the "parent"
  civilisation. The superiority of the response evoked by new ground is most
  strikingly illustrated when the new ground has to be reached by a
  sea-passage.... Peoples occupying frontier positions, exposed to constant
  attack, achieve a more brilliant development than their neighbours in more
  sheltered positions.
                104
  Alter "sea" to "space" and the analogy is obvious; as for the "constant
  attack," nature will provide this more competently than any merely human
  adversaries. Ellsworth Huntington has summed up the same idea in a
  memorable phrase, pointing out that the march of civilization has been
  "coldward and stormward." The time has come now to pit our skill and
  resolution against climates and environments more hostile than any that
  this Earth can show.
  As has happened so often in the past, the challenge may be too great. We
  may establish colonies on the planets, but they may be unable to maintain
  themselves at more than a marginal level of existence, with no energy left
  over to spark any cultural achievements. History has one parallel as
  striking as it is ominous, for long ago the Polynesians achieved a
  technical tour-de-force which may well be compared with the conquest of
  space. By establishing regular maritime traffic across the greatest of
  oceans, writes Toynbee, they "won their footing on the specks of dry land
  which are scattered through the watery wilderness of the Pacific almost as
  sparsely as the stars are scattered through space." But the effort defeated
  them at last, and they relapsed into primitive life. We might never have
  known of their astonishing achievement had it not left, on Easter Island,
  a memorial that can hardly be overlooked. There may be many Easter Islands
  of space in the aeons to come-abandoned planets littered not with monoliths
  but with the equally enigmatic debris of another defeated technology.
  Whatever the eventual outcome of our exploration of space, we can be
  reasonably certain of some immedin
 benefits-.and I am deliberately ignoring such "practical" returns as the
 multibillion dollar improvements in weather forecasting and communications,
 which may in themselves put space travel on a paying basis. The creation of
 wealth is certainly not to be despised, but in the long run the only human
 activities really worthwhile are the search for knowledge, and the creation
 of beauty. This is beyond argument; the only point of debate is which comes
 first.
Only a small part of mankind will ever be thrilled to 105
 discover the electron density around the Moon, the precise composition of
 the Jovian atmosphere, or the strength of Mercury's magnetic field. Though
 the existence of whole nations may one day be determined by such facts, and
 others still more esoteric, these are matters which concern the mind, and
 not the heart. Civilizations are respected for their intellectual
 achievements; they are loved--or despised-for their works of art. Can we
 even guess, today, what art will come from space?
  Let us first consider literature, for the trajectory of any civilization is
  most accurately traced by its writers. To quote again from Professor Webb's
  The Great Frontier: "We find that in general each nation's Golden Age coin-
  cides more or less with that nation's supremacy in frontier activity.... It
  seems that as the frontier boom got under way in any country, the literary
  genius of that nation was liberated. . . ."
  The writer cannot escape from his environment, however hard he tries. When
  the frontier is open we have Homer and Shakespeare-or, to choose less
  Olympian examples nearer to our own age, Melville, Conrad, and Mark Twain.
  When it is closed, the time has come for Tennessee Williams and the
  Beatniks-and for Proust, whose horizon toward the end of his life was a
  cork-lined room. (If Lewis Carroll had lived today, he might have given us
  not Alice but Lolita.)
  It is too naive to imagine that astronautics will restore the epic and the
  saga in anything like their original forms; space flight will be too well
  documented, and Homer started off with the great advantage of being
  untrammeled by too many facts. But surely the discoveries and adventures,
  the triumphs and inevitable tragedies that must accompany man's drive
  toward the stars will one day inspire a new heroic literature, and bring
  forth latter-day equivalents of The Golden Fleece, Gulliver's Travels, Moby
  Dick, Robinson Crusoe, or The Ancient Mariner.
  The fact that the conquest of the air has done nothing of the sort must not
  be allowed to confuse the issue. It is true that the literature of flight
  is very sparse (Lindbergh and Saint-Exup6ry are almost the only examples
  that 106
 come to mind) but the reason is obvious. The aviator spends only a few hours
 in his element, and travels to places that are already known. (In the few
 cases where he flies over unexplored territory, he is seldom able to land
 there.) The space voyager, on the other hand, may be on his way for weeks,
 months, or years, to regions that no man has ever seen save dimly through a
 telescope. Space flight has, therefore, very little in common with aviation;
 it is much closer in spirit to ocean voyaging, which has inspired so many of
 our greatest works of literature.
  It is perhaps too early to speculate about the impact of space flight on
  music and the visual arts. Here again one can only hope-and hope is
  certainly needed, when one looks at the canvases upon which some
  contemporary painters all too accurately express their psyches. The
  prospect for modem music is a little more favorable; now that electronic
  computers have been taught to compose it, we may confidently expect that
  before long some of them will learn to enjoy it, thus saving us the
  trouble.
  Maybe these ancient art forms have come to the end of the line, and the
  still unimaginable experiences that await us beyond the atmosphere will
  inspire new forms of expression. The low or non-existent gravity, for
  example, will certainly give rise to a strange, other-worldly architecture,
  fragile and delicate as a dream. And what, I wonder, will Swan Lake be like
  on Mars, when the dancers have only a third of their terrestrial weight-or
  on the Moon, where they will have merely a sixth?
  The complete absence of gravity-a sensation which no human being has ever
  experienced since the beginning of the world, yet which is mysteriously
  familiar in dreamswill have a profound impact upon every type of human
  activity. It will make possible a whole constellation of new sports and
  games, and transform many existing ones. This final prediction we can make
  with confidence, if some impatience: Weightlessness will open up novel and
  hitherto unsuspected realms of erotica. And about time too.
  All our aesthetic ideas and standards are derived from the natural world
  around us, and it may well turn out that many of them are peculiar to
  Earth. No other planet has 107
 blue sides and seas, green grass, hills softly rounded by erosion, rivers
 and waterfalls, a single brilliant moon. Nowhere in space will we rest our
 eyes upon the familiar shapes of trees and plants, or any of the animals
 which share our world. Whatever life we meet will be as strange and alien as
 the nightmare creatures of the ocean abyss, or of the insect empire whose
 horrors are normally hidden from us by their microscopic scale. It is even
 possible that the physical environments of the other planets may turn out to
 be unbearably hideous; it is equally possible that they lead us to new and
 more universal ideas of beauty, less limited by our earthbound upbringing.
  The existence of extraterrestrial life is, of course, the greatest of the
  many unknowns awaiting us- on the planets. We are now at the point of
  discovering whether there is vegetation on Mars; the Mariner and Viking
  missions should settle this matter one way or the other. On this strange
  little world, the struggle for existence may lead to some weird results. We
  had better be careful when we land.
  Where there is vegetation, there may be higher forms of life; given
  sufficient time, nature explores all possibilities. Mars has had plenty of
  time, so those parasites on the vegetable kingdom known as animals may have
  evolved there. They will be very peculiar animals, for they will have no
  lungs. There is not much purpose in breathing when the atmosphere is
  practically devoid of oxygen.
  Beyond this, biological speculation is not only pointless but distinctly
  unwise, since we will know the truth within another ten or twenty years-and
  perhaps much sooner. The time is fast approaching when we will discover,
  once and for all, whether the Martians exist.
  Contact- with a contemporary, nonhuman civilization will be the most
  exciting thing that has ever happened to our race; the possibilities for
  good and evil are endless. Within a decade or so, some of the classic
  themes of science fiction may enter the realm of practical politics. It is
  much more likely, however, that if Mars ever has produced intelligent life,
  we have missed it by geological ages. Since all the planets have been in
  existence for at least 108
 five billion years, the probability of culture flourishing on two of them at
 the same time must be extremely small.
  Yet the impact of even an extinct civilization could be overwhelming; the
  European Renaissance, remember, was triggered by the rediscovery of a
  culture that flourished more than a thousand years earlier. When our
  archaeologists reach Mars, they may find waiting for us a heritage as great
  as that which we owe to Greece and Rome. The Chinese scholar Hu Shih has
  remarked: "Contact with strange civilisations brings new standards of
  value, with which the native culture is re-examined and re-evaluated, and
  conscious reformation and' regeneration are the natural outcome." Hu Shih
  was speaking of the Chinese literary renaissance, circa 1915. Perhaps these
  words may apply to a terrestrial renaissance a century hence.
  We should not, however, pin too much hope on Mars, or upon any of the
  worlds of this solar system. If inteffigent life exists elsewhere in the
  universe, we may have to seek it upon the planets of other suns. They are
  separated from us by a gulf millions-I repeat, millions--of times greater
  than that dividing us from our next-door neighbors Mars and Venus. Until a
  few years ago, even the most optimistic scientists thought it impossible
  that we could ever span this frightful abyss, which light itself takes
  years to cross at a tireless 670,000,000 miles an hour. Yet now, by one of
  the most extraordinary and unexpected breakthroughs in the history of
  technology, there is a good chance that we may make contact with intelli-
  gerice outside the solar system before we discover the humblest mosses or
  lichens inside it.
  This breakthrough has occurred in electronics. It now appears that by far
  the greater part of our'exploration of space will be by radio. It can put
  us in touch with worlds that we can never visit-even with worlds that have
  long since ceased to exist. The radio telescope, and not the rocket, may be
  the instrument that first establishes contact with intelligence beyond the
  Earth.
  A few decades ago, this idea would have seemed absurd. But now we have
  receivers of such sensitivity, and antennas of such enormous size, that we
  can hope to pick 109
 up radio signals from the nearer stars-if there is anyone out there to send
 them. The search for such signals began early in 1960 at the National Radio
 Astronomy Observatory, Greenbank, West Virginia, and has since been con-
 tinued by other observatories--especially in the Soviet Union. This is
 perhaps the most momentous quest upon which men have ever embarked; sooner
 or later, it will be successful.
  From the background of cosmic noise, the hiss and crackle of exploding
  stars and colliding galaxies, we will some day filter out the faint,
  rhythmic pulses which are the voice of intelligence. At first we will know
  only (only!) that there are other minds than ours in the universe; later we
  will learn to interpret these signals. Some of them, it is fair to assume,
  will carry images-the equivalent of picture telegraphy, or even television.
  It win be fairly easy to deduce the coding and reconstruct these images.
  One day, perhaps not far in the future, some cathode-ray screen will show
  pictures from another world.
  Let me repeat that this is no fantasy. At this very moment millions of
  dollars' worth of electronic equipment are engaged upon the search. It may
  not be successful until the radio astronomers can get into orbit, where
  they can build antennas miles across and can screen them from the incessant
  din of Earth. We may have to wait ten--or a hundred-years for the first
  results; no matter. The point I wish to make is that even if we can never
  leave the solar system in a physical sense, we -may yet learn something
  about the civilizations circling other stars-and they may learn about us.
  For as soon as we detect messages from space, we will attempt to answer
  them.
  There are fascinating and endless grounds for speculation here; let us
  consider just a few of the possibilities. (And in a universe of a hundred
  thousand million suns, almost any possibility is a certainty-somewhere,
  sometime.) We have known radio for barely a lifetime, and TV for barely a
  generation; all our techniques of electronic communication must be
  incredibly primitive. Yet even now, if put to it, we could send all that is
  best in our 110
 culture pulsing across the light-years. (Perhaps we have already sent much
 of the worst.)
  Music, painting, sculpture, even architecture present no problems, since
  they involve easily transmitted patterns. Literature raises much greater
  difficulties; it could be transmitted, but could it be communicated, even
  if it were preceded by the most elaborate radio equivalent of the Rosetta
  stone? The fact that here on Earth many writers, and most poets, have
  ceased to communicate with their fellow beings indicates a few of the
  difficulties.
  But something must be lost in any contact between cultures; what is gained
  is far more important. In the ages to come we may lock minds with many
  strange beings, and

                                 e s

 before the building of the pyramids. Even s is a modest estimate; a radio
 wave arriving now from a star at the heart of the Milky Way (the stellar
 whirlpool in whose lonely outer reaches our Sun gyrates) must have started
 its journey around 25,000 B.C. When Toynbee defined renaissances as
 "contacts between civilisations in time" he could hardly have guessed that
 this phrase might one day have an astronomical application.
  Radio prehistory-electronic archaeology-may have consequences at least as
  great as the classical studies of the past. The races whose messages we
  interpret and whose images we reconstruct will obviously be of a very high
  order, and the impact of their art and technology upon our own culture will
  be enormous. The rediscovery of Greek and Latin literature in the fifteenth
  century, the avalanche of knowledge when the Manhattan Project was
  revealed, the glories uncovered at the opening at Tutankhamen's tomb, the
  excavation of Troy, the publication of the Principia and The Origin of
  Species-these widely dissimilar examples may hint at the stimulus and
  excitement that may come when we have learned to interpret III
 the messages which for ages have fallen upon the heedless Earth.
  Not all of these messages-not many, perhaps-will bring us comfort. The
  proof, which is now only a matter of time, that this young species of ours
  is low in. the scale of cosmic intelligence will be a shattering blow to
  our pride. Few of our current religions can be expected to survive it,
  contrary to the optimistic forecasts from certain quarters. The assertion
  that "God created man in his own image," is tickinc, like a time bomb in
  the foundations of Christianity. As the hierarchy of the universe is slowly
  disclosed to us, we will have to face this chilling fact: If there are any
  gods whose chief concern is man, they cannot be very important gods.
  The examples I have given, and the possibilities I have outlined, should be
  enough to prove that there is rather more to space exploration than
  shooting men into orbit, or taking photos of the far side of the Moon.
  These are merely the trivial preliminaries to the age of discovery that is
  now about to dawn. Though that age will provide the necessary ingredients
  for a renaissance, we cannot be sure that one will follow. The present
  situation has no exact parallel in the history of mankind; the past can
  provide hints, but no firm guidance. To find anything comparable with our
  forthcoming ventures into space, we must go back far beyond Columbus, far
  beyond Odysseus-far, indeed, beyond the first ape-man. We must contemplate
  the moment, now irrevocably lost in the mists of time, when the ancestor of
  all of us came crawling out of the sea.
  For this is where life began, and where most of this planet's life remains
  to this day, trapped in a meaningless cycle of birth and death. Only the
  creatures who dared the hostile, alien land were able to develop
  intelligence; now that intelligence is about to face a still greater chal-
  lenge. It may even be that this beautiful Earth of ours is no more than a
  brief resting place between the sea of salt where we were born, and the sea
  of stars on which we must now venture forth.
There are, of course, many who would deny this, with 112
 varying degrees of indignation or even fear. Consider the, following extract
 from Lewis Mumford's The Tran4ormation of Man:

  Post-historic man's starvation of life would reach its culminating point in
  interplanetary travel.... Under such conditions, life would again narrow
  down to the physiological functions of breathing, eating, and excretion....
  By comparison, the Egyptian cult of the dead was overflowing with vitality;
  from a mummy in his tomb one can still gather more of the attributes of a
  full human being than from a spaceman.

  I am afraid that Professor Mumford's view of space travel is slightly
  myopic, and conditioned by the present primitive state of the art. But when
  he also writes: "No one can pretend ... that existence on a space satellite
  or on the barren face of the moon would bear any resemblance to human life"
  he may well be expressing a truth he had not intended. "Existence on dry
  land," the more conservative fish may have said to their amphibious rela-
  tives, a billion years ago, "will bear no resemblance to piscatorial life.
  We will stay where we are."
 They did. They are still fish.
  It can hardly be denied that Professor Mumford's view is held, consciously
  or otherwise, by large numbers of influential Americans and Britons,
  particularly, those older ones who determine policy. This prompts certain
  somber conclusions; perhaps the West has already suffered that failure of
  nerve which is one of the first signs that a civilization has
  contracted-out from the future.
  The whole structure of Western society may well be unfitted for the effort
  that the conquest of space demands. No nation can afford to divert its
  ablest men into such essentially noncreative, and occasionally parasitic,
  occupations as law, advertising, and banking. Nor can it afford to squander
  indefinitely the technical manpower it does possess. Some years ago Life
  magazine published a photograph which was a horrifying social document; it
  showed 7,000 engineers massed behind the car that their com113
 bined efforts, plus several hundred million dollars, had
 just produced. The time may well come when the United
 States, if it wishes to stay in space, will have to consider
 freezing automobile design.for a few years --- or better still,
 reverting to the last models that were any good, which
 some authorities date around 1954.
  It does not necessarily follow that the Soviet Union can do much better; if
  it expects to master space by its own efforts, it will soon find that it
  has bitten off more than it can chew. The combined resources of mankind are
  inadequate for the task, and always will be. We may regard with some
  amusement the Russians' attempts to "go it alone," and should be patient
  with their quaint old-fashioned flag waving as they plant the hammer and
  sickle on the Moon. All such flurries of patriotism will be necessarily
  short-lived. The Russians themselves destroyed the concept of nationality,
  when they sent Sputnik I flashing across a hundred frontiers. But because
  this is perfectly obvious, it will be some little time before everyone sees
  it, and all governments realize that the only runner in the much-vaunted
  space race is-man.
  Despite the perils and problems of our times, we should be glad that we are
  living in this age. Every civilization is Eke a surf rider, carried forward
  on the crest of a wave. The wave bearing us has scarcely started its run;
  those who thought it was already slackening spoke centuries too soon. We
  are poised now, in the precarious but exhilarating balance that is the
  essence of real living, the antithesis of mere existence. Behind us lie the
  reefs we have already passed; beneath us the great wave, as yet barely
  flecked with foam, humps its back still higher from the sea.
 And ahead ... ?
  We cannot tell; we are too far out to see the unknown land. It is enough to
  ride the wave-'

  I The whole of the above chapter was written at the beginning of 1960,
  almost ten years before the first Apollo landing; however, the argument and
  conclusions seem even more relevant today, now that the first era of lunar
  exploration has ended.
  I have developed these ideas in much greater detail in the epilogue to the
  Apollo 11 astronauts' own book, First on the Moon. 114
                                 9

 You Can't Get There from Here

 There is a striking though clumsy phrase from the autobiography of the
 nineteenth century writer Richard Jeffries that has stuck in my mind for
 many years: "The unattainable blue of the flower of the sky." Unattainable:
 that is a word we seldom use these days, now that men have walked on the
 surface of the Moon. Yet only a century ago the poles were utterly unknown,
 much of Africa was still as mysterious as in the time of King Solomon, and
 no human being had descended a hundred feet into the sea or risen more than
 a mile into the air. We have gone so far in so short a time, and will
 obviously go so much further if our species survives its adolescence, that
 I would like to pose a question which would have seemed very odd to our
 ancestors. It is this: Is there any place which will always remain
 inaccessible to us, whatever scientific advances the future may bring?
  One candidate springs to mind at once. Only four thousand miles from where
  I am sitting there is a point far more difficult to reach than the other
  side of the Moonor, for that matter, than the other side of Pluto. It is
  also 115
 four thousand miles from you; as you have probably guessed, I refer to the
 center of the Earth.
  With all apologies to Jules Verne, one cannot reach this interesting spot
  by descending into the crater of Mount Sneffels. In fact, it is impossible
  to descend more than a couple of miles through any system of craters, caves
  or tunnels-natural or artificial. The deepest
 goes down only 7,000 feet.
  Just as it does in the sea, the pressure below the Earth's surface
  increases with depth, owing to the weight of the material above. The
  surface rocks of our planet are about three times as dense as water;
  therefore, as we go downward into the Earth the pressure rises three times
  as quickly as in the sea. When the bathyscaphe Trieste reached the
  Challenger Deep, seven miles below the Pacific, there was a pressure of
  over a thousand tons on every square foot of its surface, and the walls of
  the observation sphere had to be made of steel five inches thick. The same
  pressure would be reached only two miles down inside the Earth, and this is
  a mere scratch on the surface of the globe. At the Earth's center, the
  pressure is estimated to be over three million tons per square foot, or
  three thousand times that which Trieste encountered.
  Under such pressures, rocks and metals flow like Hquids. In addition, the
  temperature rises steadily toward the interior, reaching perhaps 6,000' F.
  at the center. It is obvious, therefore, that we cannot hope to find a
  ready~ made road into the heart of our planet, and the old idea of a hollow
  Earth (once put forward as a serious scientific theory) must be reluctantly
  dismissed-together with a whole host of subterranean fantasies such as
  Edgar Rice Burroughs' At the Earth's Core.
  The greatest depth to            which the oil companies-the
 most energetic of underground explorers-have so far
 drilled is just over five miles. This is a quarter of the way
 through the solid crust of the Earth, which is about
 twenty miles thick beneath the continents; under the
 oceans, the crust is much thinner and it should soon be
 possible to drill through it (the so-called Mohole Project)
                116
 to obtain samples of the unknown material upon which it floats.
  The conventional drilling technique involves turning a bit at the end of
  thousands of feet of pipe, rotated by an engine at the surface. As the
  drill gets deeper, more and more energy is lost in friction against the
  hole, and it takes hours to lift and lower the miles of piping every time
  a drill has to be changed.
  Newer methods do away with the rotating pipe and put the power source on
  the drill itself, driving it electrically or by hydraulic pressure. The
  Russians, who have pioneered in this field, have also developed what is
  effectively a rocket drill, which burns its way into the ground behind a
  6,000* oxy-kerosene jet. Using one or other of these techniques, it would
  now be possible to drill a ten-mile shaft at the cost of several million
  dollars. This would take us halfway through the crust of the Earth--or a
  four-hundredth of the way to the center.
  A six-inch drill hole is not what most people have in mind when they speak
  of underground exploration, so let ~s look at some more exciting
  possibilities. Russian mining engineers have already built man-carrying
  mechanical moles for tunneling at shallow depths; they are very similar to
  the device that Burroughs' hero employed to reach Pellucidar, the world
  inside the Earth. These machines solve the problem of soil disposal in
  exactly the same way as does the common or garden mole, which was the pro-
  totype on which their design was based; the earth loosened by the drilling
  head is compacted and tamped to form the tunnel wall.
  Even in fairly soft soil, the mechanical mole is very slow-moving. Its
  speed is limited to a mile or so a day by the power available (electricity
  is supplied through a trailing cable) and by the wear and tear on the
  drilling mechanism. An earth probe that really hoped to get anywhere would
  have to have a fundamentally new type of excavating technique, and a very
  considerable supply of energy.
  Nuclear reactions could provide the energy underground, as they already do
  undersea. As for the method 117
 of excavation, here again the Russians (who seem to be as interested in
 subterranean as in astronomical exploration) have suggested one answer. They
 are now using high-frequency electric currents to blast a way through rocks
 by sheer heat; and an underground are could bum its way through the Earth
 just as fast as one could pour energy into it. Ultrasonic vibrations and
 lasers might also do the trick; they are now being employed on a small scale
 for cutting through materials too hard to be worked with ordinary tools.
  A man-carrying, nuclear-powered "subterrene" is a nice concept for any
  claustrophobe to meditate upon. For most purposes, there would be little
  point in putting a man in if; he would have to rely entirely upon the
  machine's instruments, and his own senses could contribute nothing to the
  enterprise. All the scientific observations and collection of samples could
  be done automatically according to a prearranged program. Moreover, with no
  human crew to sustain, the vehicle could take its time. It might spend
  weeks or months wandering around the roots of the Himalayas or under the
  bed of the Atlantic before it beaded for home with its cargo of knowledge.
  The depth that such an Earth probe could reach would be limited by the
  pressure its walls could sustain. This might be very high indeed, if it
  were designed as a solid body and the empty spaces inside it were filled
  with liquid to provide additional strength. (Another argument for having no
  crew.)
  In the laboratory, steady pressures of a quarter of a million tons per
  square foot have now been produced; this is equivalent to the pressure four
  hundred miles inside the Earth. This does not mean that we can build
  vehicles theoretically capable of going four hundred miles down, but a
  tenth of this figure does not seem beyond the bounds of possibility.
  Temperature is a less serious problem; apart from occasional hot spots like
  volcanoes, the temperatures in the crust do not exceed six or seven hundred
  degrees Fahrenheit. It appears, therefore, that we may eventually explore
  most of the Earth's crust, if we really wish to do 118
 so, with machines which can be visualized in terms of today's engineering
 techniques.
  Difficult though the problems of physically exploring the outer layers of
  the Earth may be, they are quite trivial compared with those we would have
  to face if we hope to travel into the mantle (the next 1,800 miles) or the
  core (from 1,800 miles down to the center). No existing technology could
  help us here; all the materials and forces now available are hopelessly
  inadequate to deal with the combined effects of 6,000' F. and 3 million
  tons to the square foot. Under such conditions, we could not hold open a
  hollow space as large as a pinhead for more than a fraction of a second;
  our toughest metals would not only flow like water, but would be converted
  into new and denser materials.
  Any exploration of the Earth's deep interior cannot, therefore, be carried
  out by direct physical means, until tuid unless we gain control of forces
  several orders of magnitude more powerful than those we possess today. But
  where we cannot travel, we may yet observe.
  To see into the Earth with the precision and the definition with which we
  can explore the interior of our own bodies would be a marvelous
  achievement, of the greatest scientific and practical value. An X-ray
  photograph would have been unbelievable to an 1860 doctor; yet now we are
  building up what are virtually crude X-ray photos of the Earth, from the
  wave patterns produced by natural earthquakes or by explosions. (We can now
  make bangs big enough to shake our planet; it is not generally realized
  that the greatest explosion ever recorded-that of Karakotoa in 1883-could
  be matched by a large fusion bomb.)'
  The pictures are still very crude and lacking in fine detail; in
  particular, they tell us virtually nothing about the dense central core,
  which is almost four thousand miles in diameter. We do not even know what
  it is composed of; the old theory that it is made of iron has been somewhat

  I For "large," now read "small." Such is progress, since this chapter was
  written.
                119
 discredited lately, and it may well turn out to be some fairly conventional
 rock compressed by the enormous pressure into a form denser than lead.
  What we want in order to explore this region are waves that will pass
  through the solid Earth as easily as X-rays pass through a human body, or
  light waves through the atmosphere, bringing back to us the information
  they gather on their journey. But such an idea is obviously absurd; you
  have only to think of the eight thousand miles of impenetrable rock and
  metal that screen you from the Antipodes.
  Well, think again. There are, if not waves, entities, to which this massive
  Earth is as transparent as a soap bubble. One is gravitation; though I have
  never met a physicist who would give me a straight answer to the question,
  "Is gravity propagated in waves?" there is no doubt that it goes straight
  through the Earth as if it weren't there.
  Something equally penetrating is that most peculiar and elusive of atomic
  particles, the neutrino. All other particles are stopped by a few inches,
  or at most a few feet, of materials such as lead. But the incredible
  neutrino, having no mass and no charge,2 can shoot through a lead screen
  fifty light-years thick without being - noticeably inconvenienced. Torrents
  of them are sweeping, at the velocity of light, through our so-called solid
  Earth at this very moment, and only one in a million million notices the
  trilling obstruction.
  I am not suggesting that we could use either gravity or neutrino beams to
  give us close-ups of the Earth's core; both are probably too penetrating
  for the job, since you cannot scan an object with rays that go through it
  completely. But if such extraordinary entities exist in nature, there may
  be others that possess the properties we need, and that we can use to map
  the interior of our planet as the radiologists map the inside of our
  bodies.
  We may well discover, when such a survey is made, that there is nothing
  particularly interesting deep down in-
  
2 To put you out of your misery, it does have a spin.
120
                                      side the Earth-merely homogeneous shells of rock or metal, growing denser
 and denser toward the center. Almost invariably, however, the universe turns
 out to be more complicated and surprising than we could have supposed;
 consider the way in which "empty" space was found to be crowded with radio
 waves, cosmic dust, stray atoms, charged particles, and heaven knows what,
 just as soon as we started to explore it. If nature runs true to form, we
 will discover something deep inside the Earth that we will not be content
 merely to survey from a distance. We will want to get at it.
  It may want to get at us, as I suggested some years ago in a short story
  called "The Fires Within." This was based on the fact that forms of matter
  exist, under high pressure, so dense that by comparison ordinary rock would
  seem more tenuous than air. Indeed, this is a gross understatement; granite
  is about 2,000 times as dense as air, but the "collapsed matter" in the
  heart of a dwarf star is 100,000 times, and in some cases 10 million times,
  as dense as granite. Although even the pressures inside the Earth are far
  too small to crush atoms to this inconceivable density, I assumed, for
  purely fictional purposes, that creatures made of compressed matter might
  be swi Ming round inside the Earth as fish swim in the sea. I hope that no
  one takes the idea any more seriously than I did, but it may serve as a
  fable to prepare us for truths almost equally surprising, and much more
  subtle.
  If our descendants--or their machines-ever succeed in sinking far down into
  the molten interior of the Earth, it may be through the use of techniques
  developed very far from home for quite different purposes. To consider
  these, let us take a detour far out into space-to the giant planet Jupiter,
  which our first automatic probes will be circling and surveying in the
  1970's.
  I am a little tired of reading, in books about space travel, that Jupiter
  is a planet upon which men will "certainly" never land-although I cannot
  pretend that I am very anxious to go there myself. Here is a world with
  eleven times the diameter of Earth, and more than a hundred times its area;
  if our entire planet was spread out 121
 across the face of Jupiter, it would appear about the size of India on the
 terrestrial globe. But we have never made any maps of Jupiter, for we have
 never seen its surface; like that of Venus, it is perpetually hidden by
 clouds---or what, for want of a better word, we may call clouds.
  They are drawn out in ever-shifting parallel bands by the swift spin of the
  planet, and across half a billion miles of space we can watch the progress
  of mammoth storms or disturbances, many of them larger than Earth. The me-
  teorology of Jupiter is a science whose very foundations are not yet laid;
  out there in the cold twilight so far from the Sun, a huge atmosphere of
  hydrogen and helium is being torn by unknown forces. Yet despite these
  convulsions, some features manage to survive for years at a time; the most
  famous of these is the Great Red Spot, an immense oval object some 25,000
  miles long which has been observed, on and off, certainly for 120 years and
  perhaps for three centuries.
  Because of Jupiter's size, and the scale of the events taking place there,
  it is natural to assume that its atmosphere is very much deeper than
  ours-perhaps thousands, rather than a hundred, miles in thickness. But this
  is not the case; because Jupiter's gravity is more than two and half times
  Earth's, the planet's atmosphere is compressed into a layer which may be
  only fifty miles deep.
  At the bottom of that layer, the pressure must mount to values which we
  know only in the depths of our oceans. To enter the atmosphere of Jupiter
  we would need not merely a spaceship, but a bathyscaphe. There may be no
  definite solid surface on which any vehicle could land; the hydrogen may
  become steadily more dense until it turns first to a liquid slush,
  then-when the pressure reaches a thousand times that at the bottom of the
  Challenger Deep, to a metallic solid.
  Yet some day, men are going to visit this world; the exploration of'Jupiter
  may be one of the greatest enterprises of the twenty-first century. Jupiter
  will be the laboratory in which we will learn to withstand, control, and
  use really high pressures, and from this work may arise vast new 122
 industries in the years to come. (There is no lack of raw materials on a
 world that weighs three hundred times as much as Earth.) When we have
 learned how to survive in the lower levels of the Jovian atmosphere, we will
 be better prepared to burrow into our own planet.
  On Jupiter our main problems will be pressure-and perhaps the sheer
  violence of gales that may blow at hundreds of miles an hour. We will not
  have to contend with high temperatures; the outer layers of the atmosphere
  are at about 250* below zero F. but at "ground level," it may be slightly
  tropical, though that is now anyone's guess. If there are places in the
  solar system that are unattainable because of temperature alone, we must
  look for them much closer to the Sun.
  The planet Mercury is an obvious choice. This little world-just over 3,000
  miles in diameter, has such a slow rotation period that the sun takes
  eighty-eight of our days to cross the sky. As the solar radiation is also
  ten times more intense than on Earth, the temperature at the center of the
  illuminated hemisphere, must rise to seven or eight hundred degrees
  Fahrenheit. And on the dark side, where the only heat received is the
  feeble glow of starlight, it is at least four hundred degrees below zero.
  These temperatures, extreme though they are by ordinary standards, are well
  inside the range of today's industrial and scientific techniques. The
  conquest of Mercury will not be an easy project, and not a few men and
  machines will perish in the attempt. But we will have to get closer-much
  closer-to the Sun before we run into real trouble.
  The temperature rises quite slowly at first as we move in toward the
  central fire of the Sun; here are some figures which show what would happen
  to a spaceship whose hull was at a comfortable 650 F. in the vicinity of
  Earth.
  As the ship went past Venus, 67 million miles from the Sun, the hull would
  reach 1600 F.; at the orbit of Mercury, 36 million miles from the Sun, it
  would touch 4000 F. We would have to approach the Sun to within 10 million
  miles before the temperature passed 1,000'.
                123
  Five million miles out, it would be approaching 2,000*; one million miles,
  4,5000 F. This last distance is only half a million miles above the surface
  of the Sun , which is at a temperature of about 9,000' F.
  Materials are known which remain solid at temperatures above 6,000* F.;
  graphite starts evaporating around 6,8000 F., while hafnium carbide holds
  out to 7,500* F.-the record, to the best of my knowledge. Thus we could
  send a hafnium carbide nose cone to well within a million miles of the
  Sun-a hundredth of the Earth's distance-and hope to get it back in one
  piece. Instrumentcarrying, expendable probes, well protected with layers of
  refractory material which slowly boiled away, could even reach the surface
  of the Sun before they disintegrated.
  But how close to the Sun could a man-carrying ship approach in safety? The
  answer to this question depends upon the skill and ingenuity of the
  refrigeration experts: my guess is that five million miles is an attainable
  distance even with a crew-carrying vehicle.
  There is one useful trick we may employ to get quite close to the Sun in
  (almost) perfect safety. This is to use a convenient asteroid or comet as
  a sunshade, and the best choice known at the moment is the little llying
  mountain appropriately named Icarus.
  This minor planet travels on an orbit that every thirteen months brings it
  within a mere 17 million miles of the Sun. Occasionally, it also passes
  quite close to Earth; it will be within 4 million miles of us in 1968.
  Icarus is an irregular chunk of rock one or two miles in diameter, and at
  perihelion, beneath a sun that appears thirty times as big in the sky as it
  does from Earth, the surface of this little world may reach temperatures
  not far short of a 1,0000 F. But it casts a cone of shadow into space; and
  in the cold shelter of that shadow, a ship could ride safely around the
  Sun.
  In a short story called "Summertime on Icarus" I described how - scientists
  might embark on such a somewhat hair-raising sleigh ride to get themselves
  and their

 8 See Tale of Ten Worlds.
                124
 instruments close to the Sun, which would be unable to touch them as long as
 they remained on the cool side of their mile-thick shield of rock. Though it
 would be possible to construct artificial heat shields, like today's re-en-
 try nose cones, it will be a long time before we can give ourselves the
 protection that Icarus would provide for nothing. Small though it is, this
 minor planet must weigh about 10 billion tons.
  There may be other asteroids that go even closer to the Sun; if there are
  not, we may one day make them do so by a nudge at the right point in the
  orbit. And then, dug well in below the surface, scientists would be able to
  skim the atmosphere of the Sun, whipping across it and out again into space
  on a tight hairpin bend.
  It is interesting to work out how long the. ride would take. Being a rather
  small star, the Sun is "only" three million miles in circumference. A
  satellite just outside its atmosphere would move at about a million miles
  an hour, so would circle it every three hours.
  A comet or asteroid falling toward the Sun from the distance of Earth would
  be moving somewhat faster than this at its point of closest approach. It
  would flash across the surface of the Sun at a million and a quarter miles
  an hour, and so would make its swing round the Sun in little more than an
  hour, before heading off into space again. Even if a few megatons of rock
  boiled away in the process, the instruments and observers deep inside the
  asteroid would be safe-unless, of course, there was a navigational error
  and they plunged too deeply into the solar atmosphere, to burn up through
  friction as so many artificial satellites of Earth have already done.
  What a ride that would be! Imagine flashinghigh above the center of a giant
  sunspot, a gaping crater a hundred thousand miles across, spanned by
  bridges of fire over which our planet Earth could roll like a child's hoop
  along a sidewalk. The explosion of the most powerful hy~-drogen bomb would
  pass unnoticed in that inferno, where whole continents of incandescent gas
  leap skyward at hundreds of miles a second, sometimes escaping completely
  into space.
                125
  Ray Bradbury, in his short story "The Golden Apples of the Sun," once
  described the descent of a spaceship into the solar atmosphere to obtain a
  sample of the Sun (which we now know, incidentally, to be 90 per cent hy-
  drogen, 10 per cent helium, plus a mere trace of all the other elements).
  When I first read this story, I dismissed it as charming fantasy; now I am
  not so sure. In one sense we have already reached out and touched the Sun,
  for we made radar contact with it in 1959-and how unbelievable that would
  have seemed a generation agol Even a close physical approach no longer
  seems completely out of the question, thanks to the development of the new
  science of plasma physics, born within the last ten years.
  Plasma physics, sometimes known by the jaw-breaking name of
  magneto-hydrodynamics, is concerned with the handling of very hot gases in
  magnetic fields. Already it has enabled us to produce temperatures of tens
  of millions of degrees in the laboratory, and ultimately it may lead to the
  goal of limitless power from hydrogen fusion. I suggest that, when we have
  acquired some real mastery of this infant science, it will also give us
  magnetic or electric shields that can provide far more effective protection
  against both temperature and pressure than can be obtained from any walls
  of metal. The old science-fiction idea of the impenetrable shield of force
  may no longer be a dream; we may be forced to discover it, as the only real
  answer to the ICBM. When we possess it we may have a key not only to the
  interior of the EartK, but to the interior of the Sun. And perhaps, as is
  suggested in Chapter 12, even more than that.

  This search for the unattainable has taken us, in imagination, to some
  strange and hostile places. The center of the Earth, the depths of the
  Jovian atmosphere, the surface.of the Sun-though these are certainly beyond
  the reach of today's technologies, I have given reasons for thinking that
  they need not be forever out of bounds, if we really desire to visit them.
  But we have far from exhausted the universe's capacity for ingenious
  surprises; 126
 and if you are still with me, we have one more call to make.
  I have already mentioned dwarf stars, which are tiny suns in the last
  stages of stellar evolution. Some of them are smaller than Earth, yet they
  contain packed within their few thousand miles of radius as much matter as
  goes to make up a normal star. The very atoms of which they are composed
  are crushed beneath the enormous pressures in their interiors, to densities
  which may rise to many millions of times that of water. A cubic inch of
  matter from such a star may weigh more than a hundred tons.
  Though most dwarfs are red or white-hot, cool "black dwarfs" are a
  theoretical possibility. They would be the very end of the evolutionary
  line, and would be extremely difficult to detect because, like planets,
  they would radiate no light of their own but could be observed only by
  reflection, or when they eclipsed some other body. Since our Galaxy is
  still quite young-not much more than 25 bilHon years old-it is probable
  that none of its stars has yet reached the final black dwarf stage; but
  their time will come.
  These stellar corpses will be among the most fascinating (and sinister)
  objects in the universe. Their combination of great mass and tiny size
  would give them enormous gravitational fields-up to a million times as
  powerful as Earth's. A world with such a gravity would have to be perfectly
  spherical; no hills or mountains could rear themselves more than a fraction
  of an inch above its surface, and its atmosphere would be only a few feet
  in depth.
  At a million gravities, all objects-even if made of the strongest
  metal-would flow under their own weight until they had flattened themselves
  into a thin film. A man could weigh as much as the Queen Elizabeth and
  would collapse so quickly that his disintegration could not be followed by
  the naked eye, for it would take less than a thousandth of a second. A fall
  through a distance of a third of an inch would be equivalent to falling, on
  Earth, from the top of Mount Everest to sea level.
                127
  Yet despite the enormous gravitational field, it would be possible to
  approach within a few hundred feet of such a body. A spaceship or a
  space-probe aimed into a sufficiently precise orbit could, in theory at
  least, swing past it like a comet whipping round the Sun. If you were in
  such a ship you would feel nothing, even at the moment of closest approach.
  At an acceleration of a million gravities, you would still be completely
  weightless, for you would be in free fall. The ship would reach a maximum
  speed of some 25 million miles an hour as it raced low over the surface of
  the dying star; then it would recede into space once more, escaping beyond
  its reach.
  But what of an actual landing on a dwarf? Well, such a feat is conceivable
  if we make two assumptions, neither of which violates any known physical
  laws. We would need propulsion systems several million times more powerful
  than any known today, and we would require an absolutely complete and
  reliable means of neutralizing gravity, so that the crushing external field
  could be canceled to six decimal places. If even 0.001 per cent of that
  frightful gravity "leaked" into the ship, its occupants would be pulped.
  They would never feel anything, of course, if the compensating field
  failed; it would all be over so quickly that the nerve fibers would have no
  time to react.
  The world of a black dwarf would be weird almost beyond imagination; the
  very geometry of space would be affected by the gravitational field, and
  light itself would no longer travel in perfectly straight lines, but would
  suffer appreciable bending. What other distortions of the natural order of
  things might take place in such a world we cannot guess today, which is one
  reason we will go there if it ever proves possible.
  In our own time, men have peered through the portholes of a bathyscaphe
  into a region, only inches away, where they would be crushed in a fraction
  of a second by a pressure of a thousand tons on every square foot of their
  bodies. That was a wonderful acbievement-a triumph of courage and
  engineering skill. Centuries in the future, and light-years from Earth,
  there may be men 128
 peering out of portholes into the still more ferocious environment of a
 dwarf star.
  And how strange it Will be, to look down upon the smooth, geometrically
  perfect surface on the other side of the ship's compensating field-and to
  realize that, in terms of Earth's feeble gravity, you are more than a thou-
  sand miles tall.

         POSTSCRIPT: Neutron Stars

  Since this chapter was written, the radio astronomers have discovered
  "pulsars," which are believed to be neutron stars-objects about ten miles
  across, with a density a hundred million times that of the already
  incredible White Dwarfs. The gravity at the surface of such an object would
  be a hundred billion (100,000,000,000) times that of Earth-or a hundred
  thousand times that of a White Dwarf!
  Despite Clarke's First Law, my imagination quails at the thought of landing
  on such an object. Even a free-orbit approach within several radii (a few
  dozen miles!) would be excessively dangerous, because of the enormous tidal
  forces involved (see "Neutron Tide" in The Wind from the Sun).

 129
 -A

                                10

 Space, the Unconquerable

 Man will never conquer space. After all that has been said in the last two
 chapters, this statement sounds ludicrous. Yet it expresses a truth which
 our forefathers knew, which we have forgotten-and which our descendants must
 learn again, in heartbreak and loneliness.
  Our age is in many ways unique, full of events and phenomena which never
  occurred before and can never happen again. They distort our thinking,
  making us believe that what is true now will be true forever, though
  perhaps on a larger scale. Because we have annihilated distance on this
  planet, we imagine that we can do it once again. The facts are far
  otherwise, and we will see them more clearly if we forget the present and
  turn our minds toward the past.
  To our ancestors, the vastness of the Earth was a dominant fact controlling
  their thoughts and lives. In all earlier ages than ours, the world was wide
  indeed and no man could ever see more than a tiny fraction of its
  immensity. A few hundred miles-a thousand, at the most-was infinity. Great
  empires and cultures could 130
 flourish on the same continent, knowing nothing of each other's existence
 save fables and rumors faint as from a distant planet. When the pioneers and
 adventurers of the past left their homes in search of new lands, they said
 good-by forever to the places of their birth and the companions of their
 youth. Only a lifetime ago, parents waved farewell to their emigrating
 children in the virtual certainty that they would never meet again.
  And now, within one incredible generation, all this has changed. Over the
  seas where Odysseus wandered for a decade, the tourist-laden jets whisper
  their way within the hour. And above that, the closer satellites span the
  distance between Troy and Ithaca in less than a minute.
  Psychologically as well as physically, there are no longer any remote
  places on Earth. When a friend leaves for what was once a far country, even
  if he has no intention of returning, we cannot feel that same sense of
  irrevocable separation that saddened our forefathers. We know that he is
  only hours away by jet liner, and that we have merely to reach for the
  telephone to hear his voice. And in a very few years, when the satellite
  communication network is perfected, we will be able to see friends on the
  far side of the Earth as easily as we talk to them on the other side of the
  town. Then the world will shrink no more, for it will have become a
  dimensionless point.
  But the new stage that is opening up for the human drama will never shrink
  as the old one has done. We have abolished space here on the little Earth;
  we can never abolish the space that yawns between the stars. Once again, as
  in the days when Homer sang, we are face to face with immensity and must
  accept its grandeur and terror, its inspiring possibilities and its
  dreadful restraints. From a world that has become too small, we are moving
  out into one that will be forever too large, whose frontiers will recede
  from us always more swiftly than we can reach out toward them.
  Consider first the fairly modest solar, or planetary, distances which we
  are now preparing to assault. The very first Lunik made a substantial
  impression upon them, traveling more than two hundred million miles from
  131
 Earth-six times the distance to Mars. When we have harnessed nuclear energy
 for space flight, the solar system will contract until it is little larger
 than the Earth today. The remotest of the planets will be perhaps no more
 than a week's travel from Earth, while Mars and Venus will be only a few
 hours away.
  This achievement, which will be witnessed within a century, might appear to
  make even the solar system a comfortable, homey place, with such giant
  planets as Saturn and Jupiter playing much the same role in our thoughts as
  do Africa or Asia today. (Their qualitative differences of climate,
  atmosphere, and gravity, fundamental though they are, do not concern us at
  the moment.) To some extent this may be true, yet as soon as we pass beyond
  the orbit of the Moon, a mere quartermillion miles away, we will meet the
  first of the barriers that will sunder Earth from her scattered children.
  The marvelous telephone and television network that will soon enmesh the
  whole world, making all men neighbors, cannot be extended into space. It
  will never be possible to converse with anyone on another planet.
  Do not misunderstand this statement. Even with today's radio equipment, the
  problem of sending speech to the other planets is almost trivial. But the
  messages will take minutes-sometimes hours--on their journey, because radio
  and light waves travel at the same limited speed of 186,000 miles a second.
  Twenty years from now you will be able to listen to a friend on Mars, but
  the words you bear will have left his mouth at least three minutes earlier,
  and your reply will take a corresponding time to reach him. In such
  circumstances, an exchange of verbal messages is possible--but not a
  conversation. Even in the case of the nearby Moon, the two-and-a-half
  second time lag will be annoying. At distances of more than a million
  miles, it will be intolerable.
  To a culture which has come to take instantaneous communication for
  granted, as part of the very structure of civilized life, this "time
  barrier" may have a profound psychological impact. It will be a perpetual
  reminder of universal laws and limitations against which not all our 132
 technology can ever prevail. For it seems as certain as anything can be that
 no signal-still less any material object--can ever travel faster than light.
  The velocity of light is the ultimate speed limit, being part of the very
  structure of space and time. Within the narrow confines of the solar
  system, it win not handicap us too severely, once we have accepted the
  delays in communication which it involves. At the worst, these will amount
  to eleven hours-the time it takes a radio signal to span the orbit of
  Pluto, the outer-most planet. Between the three inner worlds Earth, Mars,
  and Venus, it will never be more than twenty minutes-not enough to inter-
  fere seriously with commerce or administration, but more than sufficient to
  shatter those personal links of sound or vision that can give us a sense of
  direct contact with friends on Earth, wherever they may be.
  It is when we move out beyond the confines of the solar system that we come
  face to face with an altogether new order of cosmic reality. Even today,
  many otherwise educated men-like those savages who can count to three but
  lump together all numbers beyond four-cannot grasp the profound distinction
  between solar and stellar space. The first is the space enclosing our
  neighboring worlds, the planets; the second is that which embraces those
  distant suns, the stars. And it is literally millia?" of times greater.
  There is no such abrupt change of scale in terrestrial affairs. To obtain
  a mental picture of the distance to the nearest star, as compared with the
  distance to the nearest planet, you must imagine a world in which the
  closest object to you is only five feet away-and then there is nothing else
  to see until you have traveled a thousand miles.
  Many conservative scientists, appalled by these cosmic gulfs, have denied
  that they can ever be crossed. Some people never learn; those who not long
  ago laughed at the idea of travel to the planets, are now quite sure that
  the stars will always be beyond our reach. And again they are wrong, for
  they have failed to grasp the great lesson of our age--that if something is
  possible in theory, and no fundamental scientific laws oppose its
  realization, then 133
 sooner or later it will be achieved-granted a sufficiently powerful
 incentive.
  One day-it may be in this century, or it may be a thousand years from
  now-we shall discover a really efficient means of propelling our space
  vehicles. Every technical device is always developed to its limit (unless
  it is superseded by something better) and the ultimate speed for spaceships
  is the velocity of light. They will never reach that goal, but they will
  get very close to it. And then the nearest star will be less than five
  years' voyaging from Earth.
  Our exploring ships will spread outward from their home over an
  ever-expanding sphere of space. It is a sphere which will grow at
  almost-but never quite-the speed of light. Five years to the triple system
  of Alpha Centauri, ten to that strangely matched doublet Sirius A and B,
  eleven to the tantalizing enigma of 61 Cygni, the first star suspected of
  possessing a planet. These journeys are long, but they are not impossible.
  Man has always accepted whatever price was necessary for his explorations
  and discoveries, and the price of space is time.
  Even voyages which may last for centuries or millenniums will one day be
  attempted. Suspended animation, an undoubted possibility, may be the key to
  interstellar travel. Self-contained cosmic arks which will be tiny trav-
  eling worlds in their own right may be another solution, for they would
  make possible journeys of unlimited extent, lasting generation after
  generation. The famous time dilation effect predicted by the theory of
  relativity, whereby time appears. to pass more slowly for a traveler moving
  at almost the speed of light, may be yet a third." And there are others.
  With so many theoretical possibilities for interstellar flight, we can be
  sure that at least one will be realized in practice. Remember the history
  of the atomic bomb; there were three different ways in which it could be
  made, and

  I See Chapter 11, which contains a hopeful attempt to make this effect
  plausible-if not to explain it.
               134
 no one knew which was best. So they were all tried-and they all worked.
  Looking far into the future, therefore, we must picture a slow (little more
  than half a billion miles an hour!) expansion of human activities outward
  from the solar system, among the suns scattered across the region of the
  Galaxy in which we now find ourselves. These suns are on the average five
  light-years apart; in other words, we can never get from one to the next in
  less than five years. -
  To bring home what this means, let us use a down-toearth analogy. Imagine
  a vast ocean, sprinkled with islands-some desert, others perhaps inhabited.
  On one of these islands an energetic race has just discovered the art of
  building ships. It is preparing to explore the ocean, but must face the
  fact that the very nearest island is five years' voyaging away, and that no
  possible improvement in the technique of shipbuilding will ever reduce this
  time.
  In these circumstances (which are those in which we will soon find
  ourselves) what could the islanders achieve? After a few centuries, they
  might have established colonies on many of the nearby islands, and have
  briefly explored many others. The daughter colonies might themselves have
  sent out further pioneers, and so a kind of chain reaction would spread the
  original culture over a steadily expanding area of the ocean.
  But now consider the effects of the inevitable, unavoidable time lag. There
  could be only the most tenuous contact between the home island and its
  offspring. Returning messengers could report what had happened on the
  nearest colony-five years ago. They could never bring information more up
  to date than that, and dispatches from the more distant parts of the ocean
  would be from still further in the past-perhaps centuries behind the times.
  There would never be news from the other islands, but only history.
  No oceanic Alexander or Caesar could ever establish an empire beyond his
  own coral reef; he would be dead before his orders reached his governors.
  Any form of control or administration over other islands * would be utterly
  impossible, and all parallels from our own history thus 135
 cease to have any meaning. It is for this reason that the popular
 science-fiction stories of interstellar empires and intrigues become pure
 fantasies, with no basis in reality. Try to imagine how the War of
 Independence would have gone if news of Bunker Hill had not arrived in
 England until Disraeli was Victoria's prime minister, and his urgent
 instructions on how to deal with the situation had reached America during
 President Eisenhower's second term. Stated in this way, the whole concept of
 interstellar administration or culture is seen to be an absurdity.
 . All the star-borne colonies of the future will be independent, whether
 they wish it or not. Their liberty will be inviolably protected by time as
 well as space. They must go their own way and achieve their own destiny,
 with no help or hindrance from Mother Earth.
  At this point, we will move the discussion on to a new level and deal with
  an obvious objection. Can we be sure that the velocity of light is indeed
  a limiting factor? So many "impassable" barriers have been shattered in the
  past; perhaps this one may go the way of all the others.
  We will not argue the point, or give the reasons scientists believe that
  light can never be outraced by any form of radiation or any material
  object. Instead, let us assume the contrary and see just where it gets us.
  We will even take the most optimistic possible case, and imagine that the
  speed of transportation may eventually become infinite.
  Picture a time when, by the development of techniques as far beyond our
  present engineering as a transistor is beyond a stone ax, we can reach
  anywhere we please instantaneously, with no more effect than by dialing a
  number. This would indeed cut the universe down to size, and reduce its
  physical immensity to nothingness. What would be left?
  Everything that really matters. For the universe has two aspects-its scale,
  and its overwhelming, mind-numbing complexity. Having abolished the first,
  we are now face-to-face with the second.
  What we must now try to visualize is not size, but quantity. Most people
  today are familiar with the simple
               136
 notation which scientists use to describe large numbers; it consists merely
 of counting zeros, so that a hundred becomes 102, a million, 106, a billion,
 109 and so on. This useful trick enables us to work with quantities of any
 magnitude, and even defense budget totals look modest when expressed as
 $5.76 X 109 instead of $5,7,60,000,000.
  The number of other suns in our own Galaxy (that is, the whirlpool of stars
  and cosmic dust of which our Sun is an out-of-town member, lying in one of
  the remoter spiral arms) is estimated at about 1011--or written in full,
  100,000,000,000. Our present telescopes can observe something like 109
  other galaxies, and they show no sign of thinning out even at the extreme
  limit of vision. There are probably at least as many galaxies in the whole
  of creation as there are stars in our own Galaxy, but let us confine
  ourselves to those we can see. They must contain a total of about 1011
  times 109 stars, or 1020 stars altogether.
  One followed by twenty other digits is, of course, a number beyond all
  understanding. There is no hope of ever coming to grips with it, but there
  are ways of hinting at its implications.
  Just now we assumed that the time might come when we could dial ourselves,
  by some miracle of matter transmission, effortlessly and instantly round
  the cosmos, as today we call a number in our local exchange. What would the
  cosmic telephone directory look like if its contents were restricted to
  suns and it made no effort to Est individual planets, still less the
  minions of places on each planet?
  Ile directories for such cities as London and New York are already getting
  somewhat out of hand, but they list only about a million-106-numbers. The
  cosmic directory would be 1014 times bigger, to hold its 1020 nUMbers. It
  would contain more pages than all the books that have ever been produced
  since the invention of the printing press.
  To continue our fantasy a little further, here is
 another consequence of twenty-digit telephone num
                137
 bers. Think of the possibilities of cosmic chaos, if dialing
 27945015423811986385 instead of 27945015243811986385 could put you at the
 wrong end of Creation.... This is no trifling example; look well and
 carefully at these arrays of digits, savoring their weight and meaning,
 remembering that we may need every one of them to count the total tally of
 the stars, and even more to number their planets.
  Before such numbers, even spirits brave enough to face the challenge of the
  light-years must quail. The detailed examination of all the grains of sand
  on an the beaches of the world is a far smaller task than the exploration
  of the universe.
  And so we return to our opening statement. Space can be mapped and crossed
  and occupied without definable limit; but it can never be conquered. When
  our race has reached its ultimate achievements, and the stars themselves
  are scattered no more widely than the seed of Adam, even then we shall
  still be like ants crawling on the face of the Earth. The ants have covered
  the world, but have they conquered it-for what do their countless colonies
  know of it, or of each other?
  So it will be with us as we spread outward from Mother Earth, loosening the
  bonds of kinship and understanding, hearing faint and belated rumors at
  second--or third---or thousandth-hand of an ever-dwindling fraction of the
  entire human race. Though Earth will try to keep in touch with her
  children, in the end all the efforts of her archivists and historians will
  be defeated by time and distance, and the sheer bulk of material. For the
  number of distinct societies or nations, when our race is twice its present
  age, may be far greater than the total number of all the men who have ever
  lived up to the present time.
  We have left the realm of comprehension in our vain effort to grasp the
  scale of the universe; so it must always be, sooner rather than later.
  When you are next out of doors on a summer night, turn your head toward the
  zenith. Almost vertically above you will be shining the brightest star of
  the northern skies-~-Vega of the Lyre, twenty-six years away at the 138
 speed of light, near enough the point-of-no-return for us short-lived
 creatures. Past this blue-white beacon, fifty times as brilliant as our
 sun, we may send our minds and bodies, but never our hearts.
  For no man will ever turn homeward from beyond Vega to greet again those
  he knew and loved on Earth.

 i
 I
 I

 139           1 i .
 About Time

 Man is the only animal to be troubled by time, and from that concern comes
 much of his finest art, a great deal of his religion, and almost all his
 science. For it was the temporal regularity of nature-the rising of sun and
 stars, the slower rhythm of the seasons-which led to the concept of law and
 order and in turn to astronomy, the first of all sciences. Changeless
 environments like the deep ocean or the cloud-wrapped surface of Venus
 provide no stimulus to intelligence and in such places it may never be able
 to arise.
  It is not surprising, therefore, that human cultures which exist in regions
  of negligible climatic variation, like Polynesia and tropical Africa, are
  primitive and have little conception of time. Other cultures, forced by
  their surroundings to be aware of time, have become obsessed by it. Perhaps
  the classic example is that of ancient Egypt, where life was regulated by
  the annual flooding of the Nile. No other civilization, before or since,
  has made such determined efforts to challenge eternity, and even to deny
  the existence of death.
                140
  Time has been a basic element in all religions, where it has been combined
  with such ideas as reincarnation, foretelling the future, resurrection, and
  the worshiping of the heavenly bodies-as shown by the monolithic calendar
  of Stonehenge, the zodiac from the Dendera Temple, and the ecclesiastical
  architecture of the Mayas. Some faiths (Christianity, for instance) bave
  placed Creation and the beginning of time at very recent dates in the past,
  and have anticipated the end of the universe in the near future. Other
  religions, such as Hinduism, have looked back through enormous vistas of
  time and forward to even greater ones. It was with reluctance that Western
  astronomers realized that the East was right, and that the age of the
  universe is to be measured in billions rather than millions of years-if it
  can be measured at all.
  And it is only in the last fifty years that we have learned something about
  the true nature of time, and have even been able to influence its
  progress-though as yet, by no more than millionths of a second. Ours is the
  first generation, since balance wheels and pendulums started oscillating,
  to realize that time is neither absolute nor inexorable, and that the
  tyranny of the clock may not last forever.
  It is hard not to think of time as an adversary, and in a sense, all the
  achievements of human civilization are the trophies that man has won in his
  war against time. Whatever their motives may have been, the cave artists of
  Lascaux were the first to win any gains for mankind. About a thousand
  generations ago, when the mammoth and the saber-toothed tiger still walked
  the Earth, they discovered a way of sending not merely their bones but some
  at least of their thoughts and feelings into the future. We can look
  through their eyes, across the gulfs of time, and see the animals that
  shared their world. But we can see little more than that.
  The invention of poetry, perhaps as part of religious rituals, was the next
  advance. Ordinary words and phrases are fleeting, forgotten as soon as
  uttered. However, once they are arranged in a pattern, something magical
  hap141
 pens. As Shakespeare (most time-obsessed of writers) truly remarked:

    Not marble, nor the gilded monuments Of princes, shall outlive this
    powerful rhyme.

  Bards and minstrels like Homer carried in their heads the only record of
  prehistory we possess, though until the invention of writing it was always
  liable to distortion or total loss.
  Writing-perhaps the most important single invention of mankind--changed all
  that. Plato and Caesar speak to us across the ages more clearly than most
  of our fellowmen. And with the invention of the printing press, the written
  word became virtually immortal. Manuscripts and scrolls and papyri are
  vulnerable and easily destroyed, but since the time of Gutenberg, very few
  works of permanent value can have vanished into oblivion.
  Little more than a century ago, writing and the visual arts were reinforced
  by the wonderful recording device of the camera. Photography is such a
  commonplace that we have long forgotten how marvelous it really is; if it
  were as difficult and expensive to take a photograph as, say, to launch a
  satellite, we would then give the camera the credit that is due to it.
  No other artifact created by the brain or the hand is as evocative as a
  photograph. It alone can take us back into the past, can make us feel-in
  joy or sadness-"This is how it really was, in such a place and at such a
  time." A cheap box camera can provide for any one of us what the greatest
  sculptors of the ancient world labored for years to give the Emperor
  Hadrian-the exact image of a lost love. With the invention of photography,
  some aspects of the past became for the first time directly accessible,
  with the minimum of selective intervention and distortion by a human mind.
  Not the least important respect in which the American Civil War differed
  from all previous conflicts was the presence of Matthew Brady.
  The camera-and especially the movie camera, when it
 arrived some fifty years later-gave us the power not
                142
 merely to recapture time but to dissect and distort it. Sights too swift or
 too slow for the human eye to follow were suddenly made visible by
 high-speed and time-lapse photography. Anyone who has watched the vicious
 battle to the death between two vines, tearing at each other with hour-long
 slashes of their tendrils, can never again feel the same way about the
 vegetable kingdom. The movements of clouds, the splash of a raindrop, the
 passage of the seasons, the beat of a hummingbird's wings--before our
 century men could only guess at these things, or glimpse them merely as
 independent, unrelated snapshots. Now they can watch them with their own
 eyes and see them as an organic, connected whole.
  When the phonograph broke upon the world in 1877, time lost its absolute
  control over sound as well as sight. Like the camera, the phonograph was
  totally unexpected, though the ingenious Cyrano de Bergerac had mentioned
  "talking books" in one of his scientific romances. However, unlike the
  camera and most other modern inventions, the phonograph stands in a class
  by itself because of its extreme simplicity. It does not detract from
  Edison's achievement to say that, given the necessary instructions, any
  competent Greek artificer could have built an instrument that could have
  saved the voices of Socrates or Demosthenes for us. In the Athens museum
  there are the remains of an astronomical computer far more complex than an
  acoustic phonograph, and sometimes I wonder....
  Impressive though the achievements of the last hundred years have been,
  they are pitiful when we consider what we would like to do about time if we
  had the power. Philosophers, scientists, and poets have wracked their
  brains over with the problem of time; a man who combined all three roles
  expressed a universal regret when he lamented, almost a thousand years ago:
  "The moving finger writes, and having writ, Moves on. ..." All our "piety
  and wit" are powerless to alter the past, or even to change the rate at
  which we are swept into the future. Yet this may not always be the case.
If we make a list of the powers that we would like to 143
 have over time, irrespective of their feasibility, it might run as follows:

       Seeing the past
       Reconstructing the past
       Changing the past
       Traveling into the past
       Accelerating or retarding the present
       Traveling into the future
       Seeing the future

 I can think of no possibilities (or for that matter impossibilities) not
 covered by one of these headings; let us see what we may hope to do about
 each of them.
  As far as the first is concerned, it is worth remembering that we never see
  or experience anything but the past. The sounds you are hearing now come
  from a thousandth of a second back in time for every foot they have had to
  travel to reach your ears. This is best demonstrated during a thunderstorm,
  when the peal from a flash twelve miles away will not be heard for a full
  minute. If you ever see a flash and hear the thunder simultaneously, you
  will be lucky to be alive. I have done it once and do not recommend the
  experience.
 . What is true of sound is also true of light, though on a scale. almost
 exactly a million times shorter. The peal of thunder from a lightning flash
 twelve miles away may take a minute to reach you, but your eyes know about
 it in less than a ten thousandth of a second. For all. ordinary terrestrial
 purposes, therefore, the speed of light is infinite. It is only when we look
 out into space that we see events that occurred centuries, or even millions
 of years, ago.
  This is a very limited kind of penetration into the past; in particular, it
  offers no possibility of seeing into our own past. Nor can we hope that,
  when we have reached the worlds of nearby suns, we will find advanced races
  who have been watching us and recording our own lost history through
  super-telescopes-an idea that has been suggested by some naTive
  science-fiction authors. The light waves from any events on the Earth's
  surface are badly 144
 scrambled on their way out through the atmosphereeven when clouds allow them
 to escape at all. And after that, they are so swiftly weakened by distance
 that no telescope could be built, even in theory, that would allow one to
 observe terrestrial objects smaller than several miles across from the
 distance of Mars. No creatures in a stellar system nine hundred light-years
 away are now watching the Battle of Hastings. The rays that started in 1066
 are, by now, too feeble even to show an image of the whole Earth.
  For there is a limit to the amplification of light, set by the nature of
  the light waves themselves, and no scientific advances can circumvent it.
  In much the same way, we cannot hope to recapture vanished sounds, once
  they have dwindled below the general level of background noise. It has
  sometimes been said that no sound ever dies, but merely becomes too faint
  to be beard. This is not true; the vibrations from any sound are so swiftly
  damped out that, within a few seconds, they cease to exist in any physical
  sense.. No amplifier can recapture the words you spoke a minute ago; even
  if it had infinite sensitivity, it would merely reproduce the random hiss
  of the air molecules as they collide with one another.
  If there is any way in which we can ever observe the past, it must depend
  upon technologies not only unborn but today unimagined. Yet the idea does
  not involve any logical contradictions or scientific absurdities, and in
  view of what has already happened in archaeological research, only a very
  foolish man would claim that it is impossible. For we have now recovered
  knowledge from the past which it seems obvious must have been lost forever,
  beyond all hope of recovery. How could we possibly expect to measure the
  rainfall in the year 784 A.D.? That can be done by examining the thickness
  of tree rings. How can we find the age of a piece of bone of unknown
  origin? Carbon 14 dating can do just this. Which way did the compass needle
  point, twenty thousand years ago? The orientation of magnetic particles in
  ancient clays will ten us. How has the temperature of the oceans varied
  during the last half million years? We now have-and this is per145
 haps the most amazing achievement of all-a "time thermometer" which actually
 follows the coming and going of the Ice Ages, so that we can say with some
 confidence that 210,000 years ago the average temperature of the sea was 84*
 F., whereas 30,000 years latei it had dropped to 70*. You are hardly likely
 to guess how this has been discovered; the trick is in knowing that the
 chalky shells of certain marine animals have a composition depending upon
 the temperature of the water in which they were formed, so that this can be
 deduced from a delicate and sophisticated analysis. Thus Professor Urey was
 able to tell that a fossil mollusc that lived in the seas covering Scotland
 150 million years ago was born in the summer, when the water temperature was
 700, lived four years, and died in the spring.
  Not long ago, such knowledge of the past would have seemed clairvoyance,
  not science. it has been achieved through the development of sensitive
  measuring instruments (byproducts, usually, of atomic research) which can
  detect the incredibly faint traces left upon objects by their past history.
  No one can yet say how far such techniques may be extended. There may be a
  sense in which all events leave some mark upon the universe, at a level
  notyet reached by our instruments. (But possibly, under very abnormal
  circumstances, by our senses: Is this the explanation of ghosts?) The time
  may come when we can read such marks, now as invisible to us as the plain
  signs of a trail to an Indian scout or an aborigine tracker. And then, the
  curtain will lift from the past.
  At first sight, the ability to look back into time would seem the most
  wonderful power that could be given to men. All lost knowledge would be
  recovered, all mysteries explained, all crimes solved, all bidden treasure
  found. History would no longer be a patchwork of surmises and conjectures;
  where today we guess, we would know. And perhaps we might even reach the
  stage so poetically described by Wells in his short story "The Grisly FoW':

   A day may come when these recovered memories
may grow as vivid as if we in our own persons had 146
 been there and shared the thrill and fear of those
 mordial. days; a day may come when the great beastMf the past wifl leap to
 life again in our imaginations, when we shall walk again in vanished scenes,
 stretch painted limbs we thought were dust, and feel again the sunshine of
 a million years ago.

  With such powers we would indeed be like gods, able to roam at will down
  the ages. But only gods, surely, are fit to possess such powers. If the
  past were suddenly opened up to our inspection, we would be overwhelmed not
  only by the sheer mass of material, but by the brutality, horror, and
  tragedy of the centuries that lie behind us. Ii is one thing to read about
  massacres, battles, plagues, inquisitions, or to see them enacted in the
  movies. But what man could bear to look upon the immutable evil of the
  past, knowing that what be saw was real and beyond all remedy? Better,
  indeed, that the good and the bad lie forever beyond such detailed
  scrutiny.
  And there is another aspect of the matter. How would
 we care for the idea that, at some unknown time in the
 future, men not unlike ourselves except for their superior
 science may be peering into our lives, watching an our
 follies and vices as well as our rarer virtues? The next
 moment when you are engaged in some discreditable ac
 tion, pause to contemplate th e thought that you may be a
 specimen before a class in primitive psy 'chology, a thou
 sand years from now. A still worse possibility is that the
 voyeurs of some decadent future age may use their per
 verted science to spy upon our lives. Yk perhaps even
 that is better than the prospect that we may be too simple
 and archaic to interest them at all.
  The reconstruction of the past is an idea even more fantastic than its
  observation; it includes that, and goes far beyond it. Indeed, it is
  nothing less than the concept of resurrection, looked at in a scientific
  rather than a religious sense.
  Suppose that sometime in the future men acquire the power to observe the
  past in such detail that they can record the movement of every atom that
  ever existed. 147
 Suppose they then reconstruct, on the basis of this information, selected
 people, animals, and places from the past. Thus though you actually died in
 the twentieth century, another "you," complete with all memories up to the
 moment of observation, might suddenly find himself in the far future,
 continuing to live a new existence from then onward.
  The fact that this is about as wild a fantasy as the mind of man can
  conceive does not mean that it should be dismissed as ridiculous. The
  suggestion has been put forward-by a French philosopher, I believe-that by
  some such means the people of the future might attempt to redress the evils
  of the past. It would, of course, do nothing of the sort. Even if some
  super-science did recreate the victims of long-forgotten injustices and
  crimes, allowing them to continue their lives in happier circumstances,
  that would not change the sufferings of the originals in the least.
  To do that-to alter the past, and make the moving finger erase its
  inscription-is a fit subject for fantasy, but not for science. To change
  the past involves so many paradoxes and contradictions that we are, surely,
  justified in regarding it as impossible. The classic argument against time
  travel is that it would allow a man to go back into the past and to kill
  one of his direct ancestors, thus making himself-and probably a
  considerable fraction of the human race-nonexistent.
  Some ingenious, writers (notably Robert Heinlein and Fritz Leiber) have
  accepted this challenge and said, in effect: "Very well-suppose such
  paradoxes do occur. What then?" One of their answers is the concept of
  parallel time tracks. They assume that the past is not immutable-that one
  could, for instance, go back to 1865 and deflect the aim of John Wilkes
  Booth in Ford's Theatre. But by so doing, one would abolish our world and
  create another, whose history would diverge so much from ours that it would
  eventually become wholly different.
  Perhaps in a sense all possible universes have an existence, like the
  tracks in an infinite railroad yard, but we merely move along one set of
  rails at a time. If we could 148
 travel back-ward, and change some key event in the past, all we would really
 be doing would be going back to a switch point and setting off on another
 time track.
  But it may not be as simple, if you will pardon the expression, as this.
  Other writers have developed the theme that, even if we could change
  individual events in the past, the inertia of history is so enormous that
  it would make no difference. Thus you might save Lincoln from Booth's
  bullet-only to have another Confederate sympathizer waiting with a bomb in
  the foyer. And so on....
  Ile most convincing argument against time travel is the remarkable scarcity
  of time travelers. However unpleasant our age may appear to the future,
  surely one would expect scholars and students to visit us, if such a thing
  were possible at all. Though they might try to disguise themselves,
  accidents would be bound to happenjust as they would if we went back to
  imperial Rome with cameras and tape recorders concealed under our nylon to-
  gas. Time traveling could never be kept secret for very long; over and over
  again down the ages, chronic argonauts (to use the original and singularly
  uninspiring title of Wells' The Time Machine) would get into trouble and
  inadvertently disclose themselves. As it is, the chief evidence of a
  security leak from the future appears to be the notebooks of Leonardo da
  Vinci. Their parade of inventions from the succeeding centuries is
  astonishing, but hardly conclusive proof that fifteenth century Italy had
  visitors from elsewhere.
  Some science-fiction writers have tried to get round this difficulty by
  suggesting that time is a spiral; though we may not be able to move along
  it, we can perhaps hop from coil to coil, visiting points so many millions
  of years apart that there is no danger of embarrassing collisions between
  cultures. Big-game hunters from the future may have wiped out the
  dinosaurs, but the age of Homo sapiens may lie in a blind region which they
  cannot reach.
  You will gather from this that I do not take time travel very seriouslv;
  nor, I think, does anyone else-even the writers who have devoted most
  effort and ingenuity to it. Yet the theme is one of the most
  fascinating-and some149
 times the most moving-in the whole of literature, inspiring works as varied
 as Jurgen and Berkeley Square. It appeals to the deepest of all instincts in
 mankind, and for that reason it will never die.
  A much less farfetched and more realistic idea than travel into the past is
  that we might be able to vary the rate at which we move-or appear to
  move-into the future. To some extent, drugs already do this. For an anes-
  thetized man, time passes at an infinite rate. He closes his eyes for a
  second-and opens them perhaps hours later. Stimulants can have a slight
  effect in the other direction, and there have been many reports of the
  mental acceleration, real or imagined, produced by mescalin, hashish, and
  other narcotics. Even if there were no undesirable side effects, such a
  distortion of the time sense could only be very limited. No matter how fast
  a man's mind operated, the sheer inertia of his body would prevent him from
  moving his limbs at much more than their normal speed. If you put a
  super-fuel in the gas tank of your car, the engine will tear itself to
  pieces-and the body of a man is an infinitely more delicately balanced
  organism than an automobile enRine. We may be able to slow it down to an
  almost unlimited extent, making possible the old dream of suspended
  animation and a one-way trip into the future like that exnerienced by Rip
  Van Winkle. But we cannot accelerate it by means of drugs, so that a man
  could run a one-minute mile or do a day's work in an hour.
  Yet perhaps this could be achieved in some other way, if we draw a
  distinction between subjective and objective time. The first is the time
  experienced or apprehended by the human mind, which can appear to go slow
  or fast with varying mental states-within the limits just discussed. The
  second is the time measured by such inanimate devices as clocks,
  oscillating crystals or vibrating atoms, and until this century it was an
  act of faith among scientists that whatever we thought, objective time
  f1owed at a steady, unvarying rate. Not the least of the shocks produced by
  the theory of relativity was the discovery that this is simply not true.
                150
  Curiously enough, the ancient Egyptians might have found it easy to accept
  the relativity of time. Their first simple sundials had faces graduated in
  equal arcs, so that the lengths of their "hours" necessarily varied during
  the day. When, some centuries later, they developed water clocks which ran
  at a constant rate, they were so conditioned to the idea of variable time
  that they devoted great efforts to calibrating their clocks so that they
  agreed with their sundials! "In the flow of water," says Rudolf Thiel in
  his book And There Was Light, "they had a direct image of steadily flowing
  time. But with extraordinary skiff and ingenuity they artifically produced
  irregularity in a regular natural phenomenon, in order to make time flow in
  the only manner that seemed right to them; with the inconstancy of their
  sundials."
  The variability of time is a natural and inevitable consequence of
  Einstein's discovery that time and space cannot be discussed separately,
  but are aspects of a single entity which he called space-time. Contrary to
  popular opinion, the arguments leading to this conclusion are not so
  abstruse and mathematical as to be beyond the layman; they are in fact so
  elementary as to be baffling in their very simplicity. (I wonder how often
  Einstein was infuriated by the phrase, "Is that all there is to it?") The
  problem of explaining relativity is like that of convincing an ancient
  Egyptian that his water clock was really superior to his sundial, or of
  persuading a medieval monk that people need not fall off the other side of
  a spherical Earth. Once preconceived ideas are cleared away, the rest is
  simple.
  I have no intention of explaining relativity here, since every public
  library contains its quota of popular books on the subject. (One of the
  very best, recently reissued after thirty-five years as a Harper Torchbook,
  is Readable Relativity, by Clement V. Durell. How odd that the most
  celebrated literary relativist of today should have an almost identical
  surname.) Here, however, is what I hope may be a useful analogy:
  In ordinary life we are accustomed to divide space into three dimensions or
  directions, which we call sideways, 151
 forward and upward. One of these directions is not quite on a par with the
 others, as anyone will find if he steps out of a tenth floor window, but
 forward and sideways are completely arbitrary (relative). They depend purely
 on the point of view of the individual observer; if he turns, they turn with
 him.
  When we look into the matter a little more closely, we find that even the
  direction we call upward is not as absolute as we usually assume. It
  changes constantly over the face of the Earth-a fact that distressed early
  theologians attempting to locate heaven. But even in one spot, it can have
  different apparent directions. When you are in a jet liner during the
  takeoff, you will feel the vertical tilt as you accelerate along the
  runway, and if your seat could swivel it would line itself up with a new
  set of axes. Your upward and forward are no longer the same as those of a
  man in the airport lounge; you both occupy the same region of space, but
  now divide it up in a slightly different way. Some of his horizontal has
  become some of your vertical.
  In a roughly comparable manner, observers moving at differing speeds divide
  up space-time in slightly different proportions, so that one, to put it
  somewhat crudely, gets a little more time and a little less space than the
  otherthough the sum total is always the same. (Adding time and space may
  sound like adding apples and oranges, but we won't worry about the
  elementary mathematical trick used to do it.) Tbus the rate at which time
  flows in any system-inside a spaceship, for example-depends upon the speed
  with which that system is moving, and also upon the gravitational fields it
  is experiencing.
  At normal speeds, and in ordinary gravitational fields, the time distortion
  is absolutely negligible. Even in an artificial satellite whirling round
  the globe at 18,000 miles an hour, a clock would lose only one tick in 3
  billion. An astronaut making a single orbit round the Earth would have aged
  a millionth of a second less than his companions on the ground; the other
  effects of the flight, would rather easily counterbalance this.
Only since 1959 has it been possible to demonstrate 152
 this incredibly tiny stretching of time at the modest speeds of terrestrial
 bodies. No man-made clock could do it, but thanks to a brilliant technique
 evolved by the German physicist M!3ssbauer we can now use vibrating atoms to
 measure time to an accuracy of considerably better than one part in a
 million million. Not, please note, one part in a million, but one part in a
 million million.
  Let us pause for a moment to consider what this means, for it is another
  victory over time-a metrical victory which the builders of the first
  sundials and water clocks could scarcely have imagined. A clock accurate to
  one part in a million million, which is virtually what Dr. M6ssbauer has
  given us, would lose only one second in thirty thousand years-a single tick
  between the first cave painters of Lascaux and the first colonists of Mars.
  Such accuracy in the measurement of distance would enable us to notice if
  the Earth's diameter increased or decreased by the thickness of a
  bacterium.
  Although this time stretching or dilation effect is so tiny at ordinary
  speeds, it becomes large at extraordinary ones, and very large indeed as
  one approaches the velocity of fight. In a spaceship traveling at 87 per
  cent of the speed of light, or 580 million miles an hour, time would be
  passing at only half the rate it flows on Earth. At 99.5 per cent of the
  speed of light-667 million miles per hourthe rate would be slowed tenfold;
  a month in the spaceship would be almost a year on Earth. (Relativists
  will, I hope, forgive me for certain oversimplifications and hidden
  assumptions in these statements; everyone else, please ignore this
  parenthesis.)
  The important point to note is that there would be absolutely no way in
  which the space travelers could tell that anything odd was happening to
  them. Everything aboard the vehicle would appear to be perfectly normal-and
  indeed it would be. Not until they returned to Earth would they discover
  that far more time had elapsed there than in the speeding ship. This is the
  so-called time paradox which would allow, in principle at least, a man to
  come back to Earth centuries or millenniums after he had left it, having
  himself aged only a few yeak3. To anyone
               153
 familiar with the theory of relativity, however, it is no paradox, at all:
 it is merely a natural consequence of the structure of space and time.
  The main application of this time-stretching effect is for flight to the
  stars, if this is ever achieved. Though such flights may last centuries, it
  will not seem so to the astronauts. But an inescapable byproduct of
  long-range space travel is travel into the future--one-way travel, of
  course. An interstellar voyager could return to his own earth, but never to
  his own age.
  That such an astonishing event is possible at all would have been flatly
  denied fifty years ago, but now it is an accepted axiom of science. This
  leads us to wonder if there may not be other ways in which time could be
  stretched or distorted-ways which avoid the inconvenience of traveling
  several light-years.
  I must say at once that the prospect does not look at all hopeful. In
  theory, oscillation or vibration could have a similar effect on time-but
  the rates involved would be so enormous that no material object could hold
  together under the strain. Since gravity, as well as speed, also affects
  the flow of time, this line of approach looks slightly more promising. If
  we ever learn to control gravity, we may also learn to control time. Once
  again, titanic forces would be required to produce minute time distortions.
  Even on the surface of a white dwarf star, where gravity is thousands of
  times more powerful than on Earth, it would require very accurate clocks to
  reveal that time was running slowly.
  You will have noticed            that the few known means of
 distorting time are not only exceedingly difficult to apply,
 but also work in the least useful direction. Though there
 are occasions when we would like to slow ourselves down
 with respect to the rest of the world, so that time ap
 peared to go by in a flash, the reverse process would be
 far more valuable. There is no one who, at some moment
 or other, has not felt a desperate need for more time; of
 ten a few minutes--even a few seconds-would make the
 difference between life and death. Working against the
                154
 clock would be no problem in a world where one could make the clock stand
 still, even if only for a while.
  We have no idea how this might be done; neither the theory of relativity
  nor anything else gives us a single clue. But a real acceleration of
  time-not the subjective and limited one produced by drugs-would be of such
  great value that if it is at all possible we will one day discover how to
  attain and use it. A society in which the United Nations could get through
  an all-day emergency session while the rest of New York had its coffee
  break, or in which an author could take an hour off to write an eighty
  thousand word book, is difficult to imagine and would be rather hard on the
  nerves. It may not be desirable and is certainly not likely; but I dare not
  say that it is impossible.
  Traveling into the future is the one kind of time travel we all indulge in,
  at the steady speed of twenty-four hours every day. That we may be able to
  alter this rate does not, as we have seen, involve any scientific
  absurdities. In addition to high-speed space voyaging, suspended animation
  may also allow us to travel down the centuries and see what the future
  holds in store, beyond the normal expectation of life.
  But by time travel, most people mean something considerably more ambitious
  than that. They mean going into the future and coming back to the present
  again, preferably with a complete list of stock market quotations. This, of
  course, implies traveling into the past-for from the point of view of the
  future we are (were?) the past; and this, we have already decided, is quite
  impossible.
  I would be willing to state that seeing into the future---clearly a less
  ambitious project than actually visiting it-is equally impossible, were it
  not for the impressive amount of evidence to the contrary. There have
  always, of course, been prophets and oracles who claimed the ability to
  foretell the future. "Beware the Ides of March" is perhaps the most famous
  of such predictions. In recent years the work of Professor Rhine at Duke
  University, and of Dr. Soal and his colleagues in England, has produced
  much more concrete proof of "precognition!-155
 though it is all in the form of statistics, for which most people have an
 instinctive distrust. In this case, the distrust may be justified; perhaps
 there is something fundamentally wrong with the mathematical analysis of the
 card-guessing experiments on which most claims for precognition are based.
 The whole subject is so complicated, and so loaded with prejudice and
 emotion, that I propose to tiptoe hastily away from it; if you want any more
 information, look up Rhine, J. B., in the card index of your local library.
  Whether the future can be known, even in principle, is one of the subtlest
  of all philosophical questions. A century and a half ago, when Newtonian
  mechanics had reached its greatest triumphs in predicting the movements of
  the heavenly bodies, the answer was a qualified "Yes." Given the initial
  positions and velocities of all the atoms in the universe, an all-wise
  mathematician could calculate everything that would happen to the end of
  time. The future was predetermined down to the minutest detail, and
  therefore it could-in theory- be predicted.
  We now know that this view is much too naive, for it is based on a false
  assumption. It is impossible to specify the initial positions and
  velocities of all the atoms in the universe--to the absolute degree of
  accuracy such a calculation would require. There is an intrinsic
  "fuzziness" or uncertainty about the fundamental particles which !neans
  that we can never know exactly what they are doing at this moment-still
  less a hundred years hence. Though some events-eclipses, population
  statistics, perhaps some day even the weather--can be predicted with
  considerable accuracy, the mathematical road into the fatare is a narrow
  one and eventually peters. out into the quagmire of indeterminacy. If any
  seer or sibyl has in truth really obtained knowledge of the future, it is
  by some means not only unknown to present science, but flatly contravening
  it.
  Yet we know so little about time, and have made such scanty progress in
  understanding and controlling it, that we cannot -rule out even such
  outrageous possibilities as limited access to the future. Professor J. B.
  S. Haldane 156
 once shrewdly remarked: "The Universe is not only queerer than we imagine-it
 is queerer than we can imagine." Even the theory of relativity may only hint
 at the ultimate queerness of time.
  In his poem "The Future," Matthew Arnold described man as a wanderer "born
  in a ship, On the breast of the river of Time." Through all, history, that
  ship has been drifting rudderless and uncontrolled; now, perhaps, he is
  learning how to start the engines. They will never be powerful enough to
  overcome the current; at the best, he may delay his departure, and get a
  better view of the lands around him, and the ports he has left forever. Or
  he may speed up his progress, and dart downstream more swiftly than the
  current would otherwise bear him. What he can never do is to turn back and
  revisit the upper reaches of the river.
  And in the end, for all his efforts, it will sweep him with his hopes and
  dreams out into the unknown ocean:

      As the pale waste widens around himAs the banks fade dimmer awayAs
      the stars come out, and the night-wind Brings up the stream Murmurs
      and scents of the infinite sea.

 157
                               12

 Ages of Plenty

 The raw materials of civilization, as of life itself, are matter and energy,
 which we now know to be two sides of the same coin. For most of human
 history, and all of prehistory, only the most modest quantities of either
 were used by man. During the course of a year, one of our remote ancestors
 consumed about a quarter of a ton of food, half a ton of water, and
 negligible quantities of hide, sticks, stones, and clay. The energy he
 expended was that created by his own muscles, plus an occasional small con-
 tribution in the form of wood fires.
  With the rise of technology, that simple picture has changed beyond
  recognition. The yearly consumption of the average American citizen is more
  than half a ton of steel, seven tons of coal, and hundreds of pounds of
  metals and chemicals whose very existence was unknown to science a century
  ago. Every year, over twenty tons of raw materials are dug from the earth
  to provide a modem man with the necessities-and luxuries--of life. No won-
  der we hear warnings from time to time of critical short158
 ages, and are told that within a few generations copper or lead may be added
 to the list of rare metals.
  Most of us take little notice of these alarms, because we have heard them
  before-and nothing has happened. The unexpected discovery of huge oil
  fields on the sea beds has, for the time being, silenced the Cassandras of
  the petroleum industry, who predicted that we would be running out of
  gasoline by the end of this century. They were wrong this time-but in the
  slightly longer run they will be right.
  Whatever new reserves may be discovered, "fossil fuels" such as coal and
  oil can last for only a few more centuries; then they will be gone forever.
  They will have served to launch man's technological culture into its tra-
  jectory, by providing easily available sources of energy, but they cannot
  sustain civilization over thousands of years. For this, we need something
  more permanent.
  Today, there can be little doubt that the long-term (and perhaps the
  short-term) answer to the fuel problem is nuclear energy. The weapons now
  stockpiled by the major powers could run all the machines on Earth for
  several years, if their energies could be used constructively. The warheads
  in the American arsenals alone are equivalent to thousands of millions of
  tons of oil or coal..
  It is not likely that fission reactions (those involving such heavy
  elements as thorium, uranium and plutonium) will play more than a temporary
  role in terrestrial affairs. One hopes they will not, for fission is the
  dirtiest and most unpleasant method of releasing energy that man has ever
  discovered. Some of the radioisotopes from today's reactors will still be
  causing trouble, and perhaps injuring unwary archaeologists, a thousand
  years from now.
  But beyond fission Hes fusion-the welding together of light atoms such as
  hydrogen and lithium. This is the reaction that drives the stars
  themselves; we have reproduced it on Earth, but have not yet tamed it. When
  we have done so, our power problems will have been solved forever-and there
  will be no poisonous byproducts, but only the clean ash of helium.
Controlled fusion is the supreme challenge of applied 159
 nuclear physics; some scientists believe it will be achieved in ten years,
 some in fifty. But almost all of them are sure that we will have fusion
 power long before our oil and coal run out, and will be able to draw fuel
 from the sea in virtually unlimited quantities.
  It may well be-indeed, at the moment it appears very likely-that fusion
  plants can be built only in very large sizes, so that no more than a
  handful would be required to run an entire country. That they can be made
  small and portable-so that they could be used to drive vehicles, for
  example-appears most improbable. Their main function will be to produce
  huge quantities of thermal and electrical energy, and we will still be
  faced with the problem of getting this energy to the millions of places
  where it is needed. Existing power systems can supply our houses-but what
  about our automobiles and aircraft, in the post-petroleum age?
  The desirable solution is some means of storing electricity which will be
  at least ten, and preferably a hundred, times more compact than the clumsy
  and messy batteries that have not improved fundamentally since the timi of
  young Tom Edison. This urgent need has already been mentioned in Chapter 3,
  in connection with electric automobiles, but there are countless other
  requirements for portable energy. Perhaps the forced draft of space
  technology will lead us fairly quickly to a lightweight power cell, holding
  as much energy per pound as gasoline; when we consider some of the other
  marvels of modem technology, it seems a modest enough demand.
  A much more farfetched idea is that we might be able to broadcast power
  from some central generating station, and pick it up anywhere on Earth by
  means of a device like a radio receiver. On a limited scale, this is
  already possible, though only at great difficulty and expense.
  Well-focused radio beams carrying up to a thousand horsepower of continuous
  energy can now be produced, and part of this energy could be intercepted by
  a large antenna system several miles away. Because of the inevitable
  spreading of the beam, however, most of its energy would be wasted, so the
  efficiency of the system would be very 160
 low. It would be like using a searchlight, ten miles away, to illuminate a
 house; most of the light would splash over the surrounding landscape. In the
 case of a high-powered radio beam, the lost energy would not merely be
 wasteful-it would be quite dangerous, as the builders of longrange radars
 have already discovered.
  Another fundamental objection to radio power is that the transmitter would
  have to pump out the same amount of energy whether or not it was being used
  at the other end. In our present distribution systems, the central gen-
  erating plant does not produce electricity until we call for it by
  switching on an appliance; there is "feedback" from consumer to generator.
  It would be extremely difficult, though not impossible, to arrange this
  with a radio power system.
  Beamed radio power seeins impracticable, therefore, except for very special
  applications; it might be useful between satellites and space vehicles if
  they were close together and not changing their relative positions. it
  would be quite hopeless, of course, for moving vehicles-the very point
  where it is most badly needed.
  Broadcast power, if it is ever achieved, must depend upon some principle or
  technology at present unknown. Fortunately, it is not something we must
  have-merely something that would be useful. If necessary, we win manage
  without it.
  As pure speculation, we should mention the possibility that other power
  sources may exist in the space around us, and that we may one day be able
  to tap them. Several are already known, but they are all extremely feeble
  or suffer from fundamental limitations. The most powerful is the radiation
  field of the Sun-that is, sunl~ight-and we are already using this to
  operate our space vehicles. The output of the solar hydrogen reactor is
  gigantic-about 5oo,ooo,000,000,000.000,000,000 horsepower-but by the time
  is reaches Earth the flood of energy has been drastically diluted by
  distance. A rough and easily remembered figure is that the energy of
  sunlight at sea level is about one horsepower per square yard; it varies
  widelv, of course, with atmospheric conditions. So far we have been 161
 able to convert about one-tenth of this energy into electricity (at a cost
 of a few thousand dollars per horsepower for present-day solar cells!) so a
 hundred horsepower automobile would require about a thousand square yards of
 collecting surface-even on a bright, sunny day. This is hardly a practicable
 proposition.
  We cannot tap the flood of solar energy profitably unless we move much
  closer to the Sun; even on Mercury, we could produce only about one
  horsepower of electrical energy per square yard of collecting surface. One
  day it may be possible to set up light traps very close to the Sun,' and
  beam the resultant energy to the points where it is required. If fusion
  power is not forthcoming, we will be forced to take some such drastic step
  as this. But spaceships had better avoid those power beams; they would be
  very effective death rays.
  All the other known energy sources are millions of times weaker than
  sunlight. Cosmic rays, for example, carry about as much energy as
  starlight; it would be much more profitable to build a moonbeam-powered
  engine than one driven by cosmic radiation. This may seem a paradox, in
  view of the well-known fact that these rays are often of enormous energy
  and can inflict severe biological damage. But the high energy rays
  (actually, particles) are so few and far between that their average power
  is negligible. If it were otherwise, we should not be here.
  The Earth's gravitational and magnetic fields are sometimes mentioned as
  potential sources of energy, but these have serious limitations. You cannot
  draw energy out of a gravitational field without letting some heavy
  object---already placed at a convenient altitude-fall through it. This, of
  course, is the basis of hydroelectric power, which is an indirect way of
  using solar energy. The Sun, evaporating water from the oceans, creates the
  mountain lakes whose gravitational energy we tap with our turbines.
  Hydroelectric power can never provide more than a few per cent of the total
  energy needed by the human

  1 At the solar surface, there is 65,000 horsepower of energy to be picked
  up from every square yardl
                162
 race, even if (which heaven forbid) every waterfall on the planet were
 funneled into power-productive channels. All other ways of harnessing
 gravitational energy would involve the movement of matter on a very large
 scale: flattening mountains, for example. If we ever undertake such
 projects, it will be for quite other purposes than the generation of power,
 and the total operation will almost certainly leave us with a net energy
 loss. Before you can pull down a mountain, you first have to break it into
 pieces.
  The Earth's magnetic field is so extremely feeble (a toy magnet is
  thousands of times stronger) that it is not even worth considering. From
  time to time one hears optimistic talk of "magnetic propulsion" for space
  vehicles, but this is a project somewhat comparable to escapmig from Earth
  via a ladder made of cobwebs. Terrestrial magnetic forces are just about as
  tough as gossamer.
  Yet so much of the universe is indetectable to our senses, and so many of
  its energies have been discovered only during the last few moments of
  historic time, that it would be rash to discount the idea of still unknown
  cosmic forces. The concept of nuclear energy seemed nonsense only a
  lifetime ago, and even when it was proved to exist, most scientists denied
  that it could ever be tapped. There is considerable evidence that a flood
  of energy is sweeping through all the stars and planets in the form known
  as neutrino radiation (discussed in more detail in ~~apter 9), which so far
  has practically defied an our
  wer of observation. So might Sir Isaac Newton, for all his genius, have
  failed to detect anything emerging from a radio antenna.
  For terrestrial projects, it does not greatly matter whether or not the
  universe contains unknown and untapped energy sources. The heavy hydrogen
  in the seas can drive all our machines, heat all our cities, for as far
  ahead as we can imagine. If, as is perfectly possible, we are short of
  energy two generations from now, it win be through our own incompetence. We
  will be like Stone Age men freezing to death on top of a coal bed.

For most of our raw materials, as for our power sources,
163
                                      we have been living on capital. We have been exploiting the easily available
 resources-the high-grade ores, the rich lodes where natural forces have
 concentrated the metals and minerals we need. These processes took a billion
 years or more; in mere centuries, we have looted treasures stored up over
 aeons. When they are gone, our civilIzAtion cannot mark time for a few
 hundred million years until they are restored.
  Once more, we will be forced to use our brains instead of our muscles. As
  Harrison Brown has pointed out in his book The Challenge of Man's Future,
  when all the ores are exhausted we can turn to ordinary rocks and clays:

 One hundred tons of average igneous rock such as granite contains 8 tons of
 aluminum, 5 tons of iron, I,200 pounds of titanium, 180 pounds of manganese,
 70 pounds of chromium, 40 pounds of nickel, 30 pounds of vanadium, 20 pounds
 of copper, 10 pounds of tungsten, and 4 pounds of lead.

  To extract these elements would require not only advanced chemical
  techniques, but very considerable amounts of energy. The rock would first
  have to be crushed, then treated by heat, electrolysis, and other means.
  However, as Harrison Brown also points out, a ton of granite contains
  enough uranium and thorium to provide energy equivalent to fifty tons of
  coal. All the energy we need for the processing is there in the rock
  itself.
  Another almost limitless source of basic raw materials is the sea. A single
  cubic mile of seawater contains, suspended or dissolved, about 150 million
  tons of solid material. Most of this (120 million tons) is common salt, but
  the remaining 30 million tons contains almost all the elements in
  impressive quantities. The most abundant is magnesium (about 18 million
  tons) and its large-scale extraction from the sea during the Second World
  War was a great, and highly significant, triumph of chemical engineering.
  It was not, however, the first element to be obtained from seawater, for
  the extraction of bromine in commercial quantities started as early as
  1924.
                164
  The difficulty with "mining" the sea is that the materials we wish to win
  from it- are present in very low concentrations. That 18 million tons of
  magnesium per cubic mile is an enormous figure (it would supply the world's
  needs, at the present rate, for several centuries) but it is dispersed in
  4 billion tons of water. Regarded as an ore, therefore, seawater contains
  only four parts of magnesium per million; on land, it is seldom profitable
  to work rocks containing less than one part in a hundred of the commoner
  metals. Many people have been hypnotized by the fact that a cubic mile of
  seawater contains about twenty tons of gold, but they would probably find
  richer pay dirt in their own back gardens.
  Nevertheless, the great developments in chemical processing that have taken
  place in recent years-especially as a result of the atomic energy program,
  where it became necessary to extract very small amounts of isotopes from
  much larger quantities of other materials-suggest that we may be able to
  work the sea long before we exhaust the resources of the land. Once again,
  the problem is largely one of power-power for pumping, evaporation,
  electrolysis. Success may come as part of a combined operation; the efforts
  under way in many countries to obtain drinkable water from the sea will
  produce enriched brines as a byproduct, and these may be the raw materials
  for the processing plants.
  One can imagine, perhaps before the end of this centur-y, huge
  general-purpose factories using cheap power from thermonuclear reactors to
  extract pure water, salt, magnesium, bromine, strontium, rubidium, copper,
  and many other metals from the sea. A notable exception from the list would
  be iron, which is far rarer in the oceans than under the continents.
  If mining the sea appears an unlikely project, it is worth remembering that
  for more than seventy years we have been mining the atmosphere. One of the
  big, but now forgotten, worries of the nineteenth century was the coming
  shortage of nitrates for fertilizers; natural sources were running low, and
  it was essential to find some way of 'fixing" the nitrogen in the air. The
  atmosphere contains 165
 some 4,000 million million tons of nitrogen, or more than a million tons for
 every person on Earth, so if it could be utilized directly there would never
 be any fear of further shortages.
  This feat was achieved by several methods in the opening years of this
  century. One process involves the bruteforce "burning" of ordinary air in
  a high-powered'electric arc, for at very high temperatures the nitrogen and
  oxygen in the atmosphere will combine. This is an example of what can be
  done when cheap power is available (the Norwegians were able to pioneer
  this process, thanks to their early lead in hydroelectric generation) and
  it is perhaps a pointer for the future.
  The really lavish use of concentrated energy sources for mining has hardly
  begun, but, as already mentioned in Chapter 9, the Russians have been
  experimenting with high-frequency electric arcs and rocket jets to break up
  or ,drill rocks too tough to be worked in any other way. And ultimately, of
  course, there is the prospect of using nuclear explosions for large-scale
  mining, if the problems of radioactive contamination can be avoided.
  When we consider that our deepest mines (now passing the 7,000 foot level)
  are mere pinpricks on the surface of our 8,000-mile diameter planet, it is
  obviously absurd to talk about fundamental shortages of any element or
  mineral. Within five--certainly ten-miles of us lie all the raw materials
  we can ever use. We need not go after them ourselves; mining by human
  workers is, none too soon, disappearing from beneath the face of the Earth.
  But machines can operate quite happily in temperatures of several hundred
  degrees and at pressures of scores of atmospheres, and this is just what
  the robot moles of the near future will be doing, miles beneath our feet.
  Of course it is far too difficult, and too expensive, to work seams several
  miles down-with existing techniques. Very well: we will have to discover
  wholly new methods, as the oil drillers and the sulphur miners have already
  done. The projects discussed in Chapter 9 will be forced upon us by sheer
  necessity as well as scientific curiosity.
Now let us widen our horizons somewhat. So far, we 166
 have been considering only this planet as a source of raw materials, but the
 Earth contains only about three milHonths of the total matter in the solar
 system. It is true that more than 99.9 per cent of that matter is in the
 Sun, where at first sight it would appear to be out of reach, but the
 planets, satellites, and asteroids contain between them
 ,the mass of four hundred and fifty Earths. By far the greatest part of this
 is in Jupiter (318 times the mass of Earth) but Saturn, Uranus, and Neptune
 also make sizable contributions. (95, 15 and 17 Earths, respectively.)
  In view of the present astronomical cost of space travel (about one
  thousand dollars per pound of payload for even the simplest orbital
  missions) it may seem fantastic to suggest that we will ever be able to
  mine and ship megatons of raw materials across the solar system. Even gold
  could hardly pay its way, and only diamonds would show a profit.
  This view, however, is colored by today's primitive state of the art, which
  depends upon hopelessly inefficient techniques. It is something of a shock
  to realize that, it we could use the energy really effectively, it would
  require only some 25 cents' worth of chemical fuel to lift a pound of
  payload completely clear of the Earth-and perhaps one or two cents to carry
  it from Moon to Earth. For a number of reasons, these figures repre'sent
  unattainable ideals; but they do indicate bow much room there is for
  improvement. Some studies of nuclear propulsion systems suggest that, even
  with techniques we can imagine today, space flight need be no more
  expensive than jet transportation; as far as inanimate cargos are
  concerned, it may be very much cheaper.
  Consider first the Moon. We know nothing as yet about its mineral
  resources, but they must be enormous, and some of them may be unique.
  Because the Moon has no atmosphere, and has a rather weak gravitational
  field, it would be quite feasible to project material from its surface
  "down" to Earth by means of electrically powered catapults or launching
  tracks. No rocket fuel would be needed-only a few cents' worth of
  electrical energy per pound of payload. (The capital cost of the launcher
  167
 would, of course, be very great; but it could be used an
 indefinite number of times.)     I
  It would thus be theoretically possible, as soon as large-scale industrial
  operations commence on the Moon, to ship back lunar products on a
  considerable scale, aboard robot freighters which could glide to assigned
  landing areas after they had dissipated their 25,000 m.p.h. re-entry speed
  in the upper atmosphere. The only rocket fuel used'in the entire process
  would be negligible amounts for steering and altitude control; all the
  energy would be provided by the fixed power plant of the Moon-based
  launcher.

  Going still further afield, we know that there are enormous quantities of
  metal (much of it the highest grade of nickel-iron) floating round the
  solar system in the form of meteorites and asteroids. The largest asteroid,
  Ceres, has a diameter of 450 miles, and there may be thousands over a mile
  across. It is interesting to note that a single iron asteroid 300 yards in
  diameter would supply the world's present needs for a year.
  What makes the asteroids particularly promising as a source of raw
  materials is their microscopic gravity. It needs practically no energy to
  escape from them; a man could jump off one of the smaller asteroids with
  ease. When nuclear propulsion systems have been perfected, it would be
  practical to nudge at least the smaller asteroids out of their orbits and
  inject them into paths that would lead, after a year or so, to the vicinity
  of Earth. Here they might be parked in orbit until they were cut up into
  suitably sized pieces; alternately, they might be allowed to fall directly
  to Earth.
  This last operation would require almost no consumption of fuel, as the
  Earth's gravitational field would do all the work. It would, however,
  demand extremely accurate and completely reliable guidance, for the
  consequences of error would be too terrible to contemplate. Even a very
  small asteroid could erase a city, and the impact of one containing a
  year's supply of iron would be equivalent to a 10,000 megaton explosion. It
  would make a hole at 168
 least ten times as large as Meteor Crater-so perhaps We had better use the
 Moon, not the Earth, for a dumping ground.
  If we ever discover means of controlling or directing gravitational fields
  (a problem discussed in Chapter 5) such astronomical engineering operations
  would become much more attractive. We might then be able to absorb the
  enormous energy of a descending asteroid and use it profitably, as today we
  use the energy of falling water., The energy would be an additional bonus,
  to be added to the value of the iron mountain we had gently lowered to
  Earth. Although this idea is the purest fantasy, no project which obeys the
  law of the conservation of energy should be dismissed out of hand.
  Lifting material from the giant planets is a very much less attractive
  proposition than mining the asteroids. The huge gravitational fields would
  make it difficult and expensive, even given unlimited amounts of
  thermonuclear power-and without this assumption, there is no point in
  discussing the matter. In addition, the Jupiter type of world appears to
  consist almost entirely of valueless light elements such as hydrogen,
  helium, carbon, and nitrogen; any heavier elements will be locked up
  thousands of miles down inside their cores.
  The same arguments apply, even more strongly, to the Sun. In this case,
  however, there is a factor which we may one day be able to use to our
  advantage. The material in the Sun is in the plasma state-that is, it is at
  such a high temperature that its atoms are all electrified or ionized.
  Plasmas conduct electricity far better than any metals, and their
  manipulation by magnetic fields is the basis of the important new science
  of magnetohydrodynamicsusually, for obvious reasons, referred to as MIM
  (See Chapter 9). We are now using many MHD techniques in research and
  industry to produce and contain gases at temperatures of millions of
  degrees, ,and we can observe similar processes in action on the Sun, where
  the magnetic fields around sunspots and flares are so intense that they
  hurl Earth-sized clouds of gas thousands of miles high in defiance of the
  solar gravity.
                169
  Tapping the Sun may sound a fantastic conception, but we ai~ already
  probing its atmosphere with our radio beams. Perhaps one day we may be able
  to release or trigger the titanic forces at work there, and selectively
  gather what we need of its incandescent substance. But before we attempt
  such Promethean exploits, we had better know exactly what we are doing.

  Having, in imagination, raided the solar system in the search for raw
  materials, let us come back to Earth and explore a completely different
  line of thought. It may never be really necessary to go beyond our own
  planet for anything we need-for the time will come when we can create any
  element, in any quantity, by nuclear transmutation.
  Until the discovery of uranium fission in 1939, practical transmutation
  remained as much a dream as it had been in the days of the old alchemists.
  Since the first reactors started operating in 1942, substantial amounts (to
  be measured in tons) of the synthetic metal plutonium have been
  manufactured, and vast quantities of other elements have been created as
  often unwanted and embarrassingly radioactive byproducts.
  But plutonium, with its overwhelmingly important military applications, is
  a very special case, and everyone is aware of the cost and complexity.of
  the plants needed to manufacture it. Gold is cheap by comparison, and
  synthesizing common metals like lead or copper or iron seems about as
  probable as mining them from the Sun.
  We must remember, however, that nuclear engineering is in roughly the same
  position as chemical engineering at the beginning of the nineteenth
  century, when the laws governing reactions between compounds were just
  beginning to be understood. We now synthesize, on the largest scale, drugs
  and plastics which yesterday's chemists could not even have produced in
  their laboratories. Within a few generations, we will surely be able to do
  the same thing with the elements.
  Starting with the simplest element hydrogen (one electron revolving around
  one proton) or its isotope deuter170
 ium. (one electron revolving round a nucleus of a proton plus a neutron) we
 can "fuse" atoms together to make heavier and heavier elements. This is the
 process operating in the Sun, as well as in the H-bomb; by various means,
 four atoms of hydrogen are combined to make one of helium, and in the
 reaction enormous quantities of energy are released. (In practice, the third
 element in the periodic table, lithium, is also employed.) The process is
 extremely difficult to start, and still harder to controlbut it is only the
 very first step in what might be christened "nuclear chemistry."
  At even higher pressures and temperatures than those produced in today's
  thermonuclear explosions or fusion devices, the helium atoms will
  themselves combine to form heavier elements; this is -what happens in the
  cores of stars. At first, these reactions release additional energy, but
  when we reach elements as heavy as iron or nickel the balance shifts and
  extra energy has to be supplied to create them. This is a consequence of
  the fact that the heaviest elements tend to be unstable and break down more
  easily than they fuse together. Building up elements is rather like piling
  up a column of bricks; the structure is stable at first, but after a while
  it is liable to spontaneous collapse.
  This is, of course, a very superficial account of nuclear synthesis; a
  detailed description of what happens inside stars is given in Fred Hoyle's
  Frontiers of Astronomy. You will find there that the temperatures involved
  are between 1,000 and 5,000 million degrees, and the pressures millions of
  billions of atmospheres, which hardly makes this line of attack look
  promising.
  But there are other ways of starting reactions, besides heat and pressure.
  The chemists have known this for many years; they employ catalysts which
  speed up reactions or make them take place at far lower temperatures than
  they would otherwise do. Much of modern industrial chemistry is founded on
  catalysts (vide the "cat crackers" of the oil refineries) and the actual
  composition of these is often a closely guarded trade secret.
Are there nuclear, as well as chemical, catalysts? Yes: 171
 in the Sun, carbon and nitrogen play this role. There may be many other
 nuclear catalysts, not necessarily elements. Among the legions of misnamed
 fundamental particles which now perplex the physicist-the mesons and posi-
 trons and neutrinos-there may be entities that can bring about fusion at
 temperatures and pressures that we can handle. Or there may be completely
 different ways of achieving nuclear synthesis, as unthinkable today as was
 the uranium reactor only thirty years ago.
  The seas of this planet contain 100,000,000,000,000000 tons of hydrogen and
  20,000,000,000,000 tons of deuterium. Soon we will learn to use these
  simplest of all atoms to yield unlimited power. Later-perhaps very much
  later-we will take the next step, and pile our nuclear building blocks on
  top of each other to create any element we please. When that day comes, the
  fact that gold, for example, might turn out to be slightly cheaper than
  lead will be of no particular importance.
  -This survey should be enough to indicate-though not to prove-that there
  need never be any permanent shortage of raw materials. Yet Sir George
  Darwin's prediction (page 103) that ours would be a golden age compared
  with the aeons of poverty to follow, may well be perfectly correct. In this
  inconceivably enormous universe, we can never run out of energy or matter.
  But we can all too easily run out of brains.

 172
                                13

 Aladdin's Lamp

 Men, unlike plants, cannot thrive on pure energy and a few simple chemical
 compounds. Ever since the gates of Eden clanged shut with such depressing
 finality, the human race has been engaged in a ceaseless struggle for food,
 shelter, and the material necessities of life. More than two million,
 million man-years have been expended in this agelong battle with nature, and
 only in the last four or five of the fifty thousand generations of mankind
 has the burden shown signs of lifting.
  The rise of modem science, and in particular the advent of mass production
  and automation, is of course responsible for this; but even these
  techniques are only pointers toward far more revolutionary methods of manu-
  facture. The time may come when the twin problems of production and
  distribution are solved so completely that every man can, almost literally,
  possess anything he pleases.
  To see how this may be achieved, we must forget all about our present ideas
  of manufacturing processes and go back to fundamentals. Any object in the
  physical 173
 world is completely specified or described by two factors: its composition,
 and its shape or pattern. This is quite obvious in a simple case; such as a
 one-inch cube of pure iron. Here, the two phrases "pure iron" and "one-inch
 cube" provide a complete definition of the object, and there is no more to
 be said. (To the first approximation, at least: an engineer would like to
 know the dimensional tolerances, a chemist the precise degree of purity, a
 physicist the isotopic composition.) From this brief description, containing
 only five essential words, anyone with the correct equipment and skills
 could make a perfect copy of the object specified.
  This is true, in principle, for much more complicated objects, such as
  radio sets, automobiles, or houses. In such cases it is necessary to have
  not only verbal descriptions but plans or blueprints--or their modern
  equivalent, pulses stored on magnetic tape. The tape which controls an
  automated production line carries, in suitably codedform, a complete
  physical description of the object being manufactured. Once the master tape
  has been made, the act of creation is finished. What follows is a
  mechanical process of replication, like printing a sheet of letterpress
  when the type has been set up.
  During the last few years, more and more complicated artifacts have been
  produced in this wholly automatic manner, though the initial cost of
  equipment (and skill) is so high that the process is worthwhile only where
  there is a demand for enormous numbers of copies. It requires a specialized
  machine to manufacture one particular type of object; a bottle-making
  machine cannot switch to cylinder heads. A completely general-purpose
  production line, able to produce anything merely from a change of instruc-
  tions, is inconceivable in terms of today's techniques.
  It may seem inconceivable in terms of any technique, because many (perhaps
  most) of the artifacts we employ and the materials we consume in everyday
  life are so complicated that it is impossible to specify them in explicit
  detail. Anyone who doubts this should try to write out the complete
  description of a suit of clothes, a pint of milk, or an egg, so that an
  omnipotent entity who had 174
 never seen any of these things could reproduce them perfectly.
  Perhaps a specification for a suit might be just possible today, if it were
  made of synthetic fabric; but not if it were made of organic materials like
  wool or silk. The pint of milk is a challenge that the biochemists of the
  future may be able to meet, but I shall be very surprised if, in this
  century, we have a complete analysis of all the fats, proteins, salts,
  vitamins and heaven knows what else that goes into this most comprehensive
  of foods. As for an egg-this represents an even higher order of complexity,
  both in chemistry and structure; most people would deny that there is the
  slightest possibility of ever creating such an object, except by the
  traditional methods.
  Yet let us not be discouraged. In Chapter 7, when discussing the
  possibility of instantaneous transportation, we considered a device that
  would scan solid objects atom by atom to make a "recording" that could
  ultimately be played back, either at the same spot or at a distance. Though
  such a device cannot be realized, or even remotely envisaged, in terms of
  today's science, no philosophical contradictions or absurdities are raised
  if we suppose its operations limited to fairly simple, inanimate objects.
  It is worth remembering that an ordinary camera can, in a thousandth of a
  second, make a "copy" of a picture containing milions of details. This
  would indeed have been a miracle to an artist of the Middle Ages. The
  camera is a generalpurpose machine for reproducing, with a considerable,
  though not complete, degree of accuracy, any pattern of light, shade, and
  color.
  Today we have devices which can do very much more than this, though even
  the names of most of them are not known to the general public. Neutron
  activation analyzers, infrared and X-ray spectrometers, gas chromatographs
  can perform, in a matter of seconds, detailed analyses of complex materials
  over which the chemists of a generation ago could have labored in vain for
  weeks. The scientists of the future will have far more sophisticated tools,
  that can lay bare all the secrets of any object presented to them and
  automatically record all its charac175
 teristics. Even a highly complex object could be completely specified on a
 modest amount of recording medium; you can put the Ninth Symphony on a few
 hundred feet of tape, and this involves much more information or detail
 than, say, a watch.
  It is the "playback," from recording to physical reality, which is rather
  difficult to visualize, but it may surprise many people to learn that this
  has already been achieved for certain small-scale operations. In the new
  technique of microelectronics, solid circuits are built up by controlled
  sprays of atoms, literally layer by layer. The resulting components are
  often too tiny to be seen by the naked eye (some are even invisible under
  high-powered microscopes) and the manufacturing process is of course auto-
  matically controlled. I would like to suggest that this represents one of
  the first primitive breakthroughs toward the type of production we have
  been trying to imagine. As the punched-tape of the Jacquard loom controls
  the weaving of the most complex fabrics (and has done so for two hundred
  years) so we may one day have machines that can lay a three-dimensional
  warp and woof, organi i g solid matter in space from the atoms upward. But
  for us
 'to attempt the design of those machines now would be rather like the
 imagined efforts of Leonardo da Vinci (page 92) to make a TV system.
  Leaping lightly across some centuries of intensive development and
  discovery, let us consider how the replicator would operate. It would
  consist of three basic partswhich we might call store, memory and
  organizer. The store would contain, or would have access to, all the
  necessary raw materials. The memory would contain the recorded instructions
  specifying the manufacture (a word which would then be even more misleading
  than it is today!) of all the objects within the size, mass, and complexity
  limitations of the machine. Within these limits, it could make
  anything-just as a phonograph can play any conceivable piece of music that
  is presented to it. The physical size of the memory could be quite small,
  even if it had a large built-in library of instructions for the most
  commonly needed artifacts. One can envision a sort of 176
 directory, Eke a Sears Roebuck catalogue, with each item indicated by a code
 number which could be dialed as required.
  The organizer would apply the instructions to the raw material, presenting
  the finished product to the outside world-or signaling its distress if it
  had run out of some essential ingredient. Even this might never happen, if
  the transmutation of matter ever becomes possible as a safe, small-scale
  operation, for then the replicator might operate on nothing but water or
  air. Starting with the simple elements, hydrogen, nitrogen, and oxygen, the
  machine would first synthesize higher ones, then organize these as
  requested. A rather delicate and fail-safe mass-balancing procedure would
  be necessary; otherwise the replicator would produce, as a highly unwanted
  byproduct, rather more energy than an H-bomb. This could be absorbed in the
  production of some easily disposable "ash" such as lead or gold.
  Despite what has been said earlier about the appalling difficulty of
  synthesizing hicber organic structures, it is absurd to suppose that
  machines cannot eventually create any material made by living cells. Any
  last-ditch vitalists who still doubt this are referred to Chapter 18, where
  they will discover why inanimate devices can be fundamentally more
  efficient and more versatile than living ones-though they are very far from
  being so at the present stage of our technology. There is no reason to
  suppose, therefore, that the ultimate replicator would not be able . to
  produce any food that men have ever desired or imagined. The creation of an
  impeccably prepared Met mignon might take a few seconds longer, and require
  a little more material, than that of a thumbtack, but the principle is the
  same. If this seems astonishing, no one today is surprised that a hi-fi set
  can reproduce a Stravinsky climax as easily as the twang of a tuning fork.
  The advent of the replicator would mean the end of all factories, and
  perhaps all transportation of raw materials and all farming. The entire
  structure of industry and commerce, as it is now organized, would cease to
  exist. Every family would produce all that is needed on the spot-as, 177
 indeed, it has had to do throughout most of human history. The present
 machine era of mass production would then be seen as a brief interregnum
 between two far longer periods of self-sufficiency, and the only valuable
 items of exchange would be the matrices, or recordings, which had to be
 inserted in the replicator to control its creations.
  No one who has read thus far will, I hope, argue that the replicator would
  itself be so expensive that nobody could possibly afford it. The prototype,
  it is true, is hardly likely to cost less than $1,000,000,000,000, spread
  over a few centuries of time. The second model would cost nothing, because
  the replicator's first job would be to produce other replicators. It is
  perhaps relevant to point out that in 1951 the great mathematician John von
  Neumann established the important principle that a machine could always be
  designed to build any describable machine-including itself. The human race
  has squalling proof of this several hundred thousand times a day.
  A society based on the replicator would be so completely different from
  ours that the present debate between capitalism and communism would become
  quite meaningless. All material possessions would be literally as cheap as
  dirt. Soiled handkerchiefs, diamond tiaras, Mona Lisas totally
  indistinguishable from the orginal, once-worn mink stoles, half-consumed
  bottles of the most superb champagnes-all would go back into the hopper
  when they were no longer required. Even the furniture in the .house of the
  future might cease to exist when it was not actually in use.
  At first sight, it might seem that nothing could be of any real value in
  this utopia of infinite riches-this world beyondthe wildest dreams of
  Aladdin. This is a superflcial reaction, such as might be expected from a
  tenth century monk if you told him that one day every man could possess all
  the books he could possibly read. The invention of the printing press has
  not made books less valuable, or less appreciated, because they are now
  among the commonest instead of the rarest of objects. Nor has music lost
  its charms, now that any amount can be obtained at the turn of a switch.
                178
  When material objects are all intrinsically worthless, perhaps only then
  will a real sense of values arise. Works of art would be cherished because
  they were beautiful, not because they were rare. Nothing-no
  "things'!--would be as priceless as craftsmanship, personal skills,
  professional services. One of the charges often made against our culture is
  that it is materialistic. How ironic it will be, therefore, if science
  gives us such total and absolute control over the material universe that
  its products no longer tempt us, because they can be too easily obtained.
  It is certainly fortunate that the replicator, if it can ever be built at
  all, lies far in the future, at the end of many social revolutions.
  Confronted by it, our own culture would collapse speedily into sybaritic
  hedonism, followed immediately by the boredom of absolute satiety. Some
  cynics may doubt if any society of human beings could adjust itself to
  unlimited abundance and the lifting of the curse of Adam-a curse which may
  be a blessing in disguise.
  Yet in every age, a few men have known such freedom, and not all of them
  have been corrupted by it. Indeed, I would define a civilized man as one
  who can be happily occupied for a lifetime even if he has no need to work
  for a living. This means that the greatest problem of the future is
  civilizing the human race; but we know that already.
  So we may hope, therefore, that one day our age of roaring factories and
  bulging warehouses will pass away, as the spinning wheel and the home loom
  and the butter churn passed before them. And then our descendants, no
  longer cluttered up with possessions, will remember what many of us have
  forgotten-that the only things in the world that really matter are such
  imponderables as beauty and wisdom, laughter and love.

               179
                                14

 Invisible Men and Other Prodigies

 Though this confession leaves me thoroughly dated, back there with
 Rin-Tin-Tin and Mary Pickford, for me one of the big moments in movies was
 when Claude Rains unwrapped the bandages around his head-and there was
 nothing inside them. The idea of invisibility, with all the powers it would
 bestow upon anyone who could command it, is eternally fascinating; I suspect
 that it is one of the C~mmonest of private daydreams. But it is a long time
 since it has appeared in adult science fiction, because it is a little too
 naYve for this sophisticated age. It smacks of magic, which is now very much
 out of fashion.
  Yet invisibility is not one of those concepts that involves an obvious
  violation of the laws of nature; on the contrary, there are plenty of
  objects that cannot be seen. Most gases are invisible; so are some liquids
  and a few solids, in the right circumstances. I have never had the
  privilege of looking for a large diamond in a tumbler of water, but I have
  searched for a contact lens in a bathtub, and that's as near to
  invisibility as I wish to get. Most of us have seen those arresting photos
  of workmen carrying 180
 large plate-glass windows; when glass is clean, and coated with an
 antireffection layer, it is almost as impossible to see as air.
  This gives the fantasy writer (and in The Invisible Man, Wells was writing
  fantasy, not science fiction) an easy way out. His hero has "merely" to
  invent a drug which gives his body the same optical properties as air, and
  he will promptly become invisible. Unfortunately-or luckily-this cannot be
  done, and it is easy to show why.
  Transparency is a most unusual property of a few exceptional substances,
  arising from the internal disposition of their atoms. If their atoms were
  arranged differently, they would no longer be transparent-and they would no
  longer be the same substances. You cannot take any compound at random and
  chemically torture it into transparency. And even if you could do so in one
  particular case, this would hardly help you to become an invisible man, for
  there are literally billions of separate and unbelievably complex chemical
  compounds in the human body. I doubt if the human species could last long
  enough to ran the necessary research programs on each one of these
  compounds.
  Moreover, the essential properties of many (if not most) depend upon the
  fact that they are not transparent. This ' is obvious in the case of the
  light-sensitive chemicals at the back of the eye, upon which we rely for
  our vision. If they no longer trapped light, we would be unable to see; and
  if our flesh were transparent, the eye would be unable to function because
  it would be flooded with radiation. You can't build a camera out of clear
  glass.
  Less obvious is the fact that myriads of the biochemical reactions upon
  which life depends would be thrown utterly out of balance, or would cease
  altogether, if the molecules taking part in them were transparent. A man
  who achieved invisibility by drugs would not only be blind; he would be
  dead.
  We need a more subtle approach to the problem, and several possibilities
  suggest themselves. Some have already been explored by nature; if a thing
  can be done, she usually does it, sooner or later. There are many circum181
 stances where camouflage is just as good as invisibility,
 and may even be better. Why go to the trouble of achiev
 ing genuine invisibility, if you can persuade those who
 look at you that you are something else? Poe's The Pur
 loined Letter and Chesterton's The Invisible Man are in
 teresting variations on this theme. In the lesser-known
 - Chesterton story, a man is murdered in a house which all
 observers swear has not been entered. "Then who made
 these footprints in the snow?" asks Father Brown with his
 usual egregious innocence. Nobody has noticed the post
 man-though everybody has seen him....
  Many insects and land animals have developed remarkable powers of
  camouflage, but their disguise, being fixed, is effective only in the right
  surroundings; it may be worse than useless in others. The greatest masters
  of deception, who can change their appearance to fit their background, are
  to be found not on the land but in the sea. Flatfish and cuttlefish have an
  almost unbelievable control over the hues and patterns of their bodies, and
  are able to change color within a few seconds when the need arises. A
  plaice lying on a checkerboard will reproduce the same pattern of black and
  white squares on its upper surface, and is even reputed to make a
  creditable attempt at a Scots tartan.
  The ability to match the scene behind you would be a kind of
  pseudo-transparency, but it is obvious that it could fool only observers
  looking at you from a single direction. It works with the flatfish simply
  because it is flat and is trying to bide itself from predators swimming
  above it. The same trick would not work anything like so well in the open
  water, though it is still worth trying; this is why many fish are
  dark-colored on the upper parts of their bodies, and light-colored beneath.
  It minimizes their visibility from above and from below.
  No conceivable optical or TV system could transmit a picture of the
  background through a solid body in such a way that it was invisible from
  more than a very limited number of viewpoints. You can prove this by
  setting up-mentally-a complicated experiment that no one is ever likely to
  try in practice. it is the electronic equivalent 182
 of what the flatfish attempts to do, when it is placed on a checkerboard.
  Imagine a man between two sandwich boards which are really large TV
  screens. He also has two cameras, one pointing to the front and the other
  to the rear. The forward-looking camera feeds a picture to the screen
  behind him, and vice versa.
  If the (fall color!) TV circuits were perfectly adjusted, then the man
  would be effectively, invisible from two points of view--one directly
  behind him, and one directly in front of him. Observers at these points
  would think that they were looking at some distant background, but part of
  it-the area covering the man-would actually be an image that precisely
  matched the reality. The slightest change of viewpoint would destroy the
  illusion; the TV picture would appear too big or too small, or would not
  fit its background, giving an effect like an out-of-adjustment Cinerama
  panel.
  It is obvious that such an "image-transmission" type of invisibility would
  be hopelessly limited, and I can think of only one story that has employed
  it. Back in the 1930's good old Amazing Stories published a tale featuring
  a coffin-sized glass box composed of prisms refracting the scene behind it,
  and containing a hollow interior within which a man could hide. Anyone
  observing the box would think that he was looking through an empty glass
  case, when he was really looking "round" an occupied one. 7le idea is
  ingenious--and might even work on a small scale, to the convenience of
  spies and smugglers. For though it would be impossible to transmit an image
  through the box so that it appeared undistorted to observers with different
  viewpoints, in this instance a considerable amount of distortion would be
  acceptable and indeed expected. I hand the problem over to the optical
  experts; certainly it does not help us much in the quest for general
  invisibility.
  Another now outmoded fictional method of achieving invisibility is by means
  of vibrations. Today we know much more about vibrations than we did a
  generation ago when, with a capital V, they were part of the stock-intrade
  of every spiritualist and medium. Radio, sonar, in183
 frared cookers, ultrasonic washers, and the rest have brought them firmly
 down to earth, and we no longer expect them to produce miracles.
  Vibrational invisibility is, however, a little more plausible than the
  nalve chemical variety peddled by Wells. It is based on a familiar analogy;
  everyone knows how the blades of an electric fan vanish when the motor gets
  up speed. Well, suppose all the atoms of our bodies could be set vibrating
  or oscillating at a sufficiently high frequency....
  The analogy is, of course, fallacious. We don't see through the fan blades,
  but past them; at every moment some of the background is uncovered, and at
  high enough speeds persistence of vision gives us the impression that we
  have a continuous view. If the fan blades overlapped, they would remain
  opaque-no matter how fast they were spinning.
  And there is another unfortunate complication. Vibration means heat-in fact
  it is heat-and our molecules and atoms are already moving as fast as we can
  take. Long before a man could be vibrated into invisibility, he would be
  cooked.
  The situation does not look promising; the cloak of invisibility appears to
  be a dream beyond scientific realization. Yet now comes a surprise; perhaps
  we have been approaching the problem from the wrong angle. Objective
  invisibility may well be impossible-but subjective invisibility is
  possible, and has often been publicly demonstrated.
  An expert hypnotist can persuade a subject not to see a certain person, and
  such is the power of the mind that the subject may be unable to do so even
  if that person is standing in full view. The subject will go to
  extraordinary lengths to "explain away" the invisible man even when the
  latter tries to prove that he is present: The individual under hypnosis may
  eventually get hysterical if, for example, he sees what he believes are
  unattached articles of furniture moving around the room.
  This fact is almost as amazing as genuine invisibility would be, and it
  suggests that, in the right circumstances 184
 and under appropriate influences (airborne drugs, subliminal suggestion,
 diversion of attention-to mention a few ideas) a person or object might be
 made effectively invisible to a fairly large group of people who were quite
 sure that they were in full possession of their senses. I advance this idea
 with some diffidence; but I have a hunch that if invisibility is ever
 achieved, it will be along these lines. It won't be done by drugs, optical
 devices, or vibrations.
  There is, however, a more-than-adequate substitute for invisibility, at
  least in fiction. An invisible man could be detected and trapped in many
  ways; not so a-shall we say?-impalpable one. Given the choice between
  invisibility and the power to walk through walls, I know which would be
  preferred by most people.
  Several science-fiction writers (notably Will Jenkins, alias Murray
  Leinster) have made valiant efforts to put matter penetration on a rational
  basis; the argument usually runs as follows:
  So-called "solid" matter is really almost all empty space-just specks of
  electricity in an enormous void. The spaces inside the atoms are,
  proportionately, as great as those between the planets and stars. Just as
  two solar systems, or even two galaxies, can pass right through each other
  without a single physical collision taking place, so two solids could
  interpenetrate-if only we knew just how to make them.
  About forty years ago, the ingenious Murray Leinster used an analogy which
  has stuck in my mind ever since. Two packs of cards can be passed through
  each other with little trouble or resistance, if they are kept parallel.
  Shuffle them higgledy-piggledy so that they point in all directions, and
  it's impossible. What we want therefore, is some polarizing field that will
  align or orientate all the atoms in a body; if we can do this, then two
  solids can slip through each other like parallel packs of cards.
  The argument was good enough for a 1935 Astounding Stories, but I am afraid
  that it will not convince this blasg generation. It is quite true that
  solar systems and galaxies can interpenetrate without actual physical
  collision, but the experience leaves an indelible mark on both partici185
 pants. Though the suns and planets concerned may not come within millions of
 miles of each other, their gravitational tugs swing them into completely new
 orbits. And when two galaxies collide, the reaction between their tenuous
 clouds of interstellar gas produces the greatest outbursts of energy yet
 discovered in this universe-titanic explosions of radio power that we have
 been able to detect ten thousand million light-years away.
  In much the same way, if two objects passed through each other, the forces
  between their atoms and molecules would produce so many changes that each
  would be altered out of recognition. Gases and liquids can interpenetrate
  because they have no (or very little) internal structure; they are
  amorphous and no amount of shuffling makes any difference to them. Chaos
  remains chaos however much you shake it up. But all solids have an internal
  architecture which may be exceedingly complex, and exists on at least two
  levels-microscopic and molecular. That structure is maintained by electric
  and other forces; if you alter those forces, the body becomes something
  else-and the process cannot be reversed. Anyone who doubts this might try
  to unscramble an egg; this would be a very simple problem compared with
  restoring to their original form two solids that had interpenetrated.
  There is, however, another possible road through matter-a tortuous and
  badly signposted road, for it leads us into the fourth dimension. Let us
  pluck up our courage and, ignoring the gibberings and weird shrieks from
  the mist on either side, strike out along this dubious path.
  Actually, all the occultism and nonsense can be removed from the subject by
  a simple trick of semantics. In this context, "dimension" means nothing
  more than "direction," so we will use the latter word, which sets no bells
  jangling in the subconscious and rouses no memories of H. P. Lovecraft,
  Arthur Machen, or Madame Blavatsky.
  We all know what the word "direction" means, and it is a fact of experience
  that in our normal everyday world any position or location can be
  completely specified by three directions, or coordinates, as the
  mathematician 186
 calls them. We might, in a convenient but completely arbitrary manner, label
 north-south as the first direction, east-west as the second direction and
 up-down as the third direction. The order could be changed around, and it
 doesn't matter in the least which direction (or dimension) is first, second,
 or third; the important'point is that there are only three of them. No one
 has yet discovered any place which cannot be reached (in principle, at
 least) by a movement along one or more of directions one, two and three.
  Although our universe has only three directions, it is possible to imagine
  that there are more, but that for some reason our senses are unable to
  perceive them. Geometries are then conceivable as much "higher," or more
  complex, than solid geometry as that is higher than plane geometry. We can
  speak of, even if we cannot visualize, the sequence of the one-directional
  straight line, the twodirectional square, the three-directional cube-and
  the four-directional hypercube, known as a tesseract. The properties of
  this figure are fascinating and quite easily understood (its "faces"
  consist of eight cubes, just as the faces of a cube consist of six squares)
  but to investigate them in any detail would be a digression which I must
  reluctantly forego. I have, however, a soft spot for the tesseract; my very
  first TV engagement was a live, twenty-minute lecture on its properties,
  illustrated by home-made wire models. After that baptism of fire, all later
  TV programs have been child's play.
  The best way of getting to grips with the fourth direction is to take a
  step downward into a two-directional world. It is not hard to conceive of
  a flat universe in which there is no such direction as heigbt-a plane
  world, like that sandwiched between two sheets of glass infinitely close.
  together. Call it Flatland;1 if it had rational inbabi-
  
  1 For the definitive study of this interesting universe, see the minor
  classic "Flatland" by "A. Square" (E. A. Abbott), now readily available in
  James Newman's World of Mathematics. It is still an entertaining fantasy,
  though to most modern readers the Victorian author's pseudonym appears even
  more appropriate than he realized.
               187
 tants, they would be familiar with the figures of plane geometry-lines,
 circles, triangles-but would be quite unable to imagine such incredible
 entities as spheres or cubes or pyramids.
  In Flatland, any closed curve--a circle, for examplewould compLetely
  enclose a space. There would be no way into it, except by breaking or
  penetrating the curve. The vaults of the Bank of Flatland could be simple
  squares, and their contents would be perfectly secure.
  Yet to beings like ourselves, capable of movement through the third
  direction of height, those bank vaults would be wide open. Not only could
  we look into them; we could reach into them and remove their contents,
  lifting them over the "wall" and dropping them back into Flatland to
  present the local police with a most disturbing and inexplicable problem.
  A sealed room would have been burgled-yet no one and nothing would have
  passed through its walls.
  The analogy is now obvious, when we extend it to our own universe. There
  could be no enclosed spaces in our three-directional world, to a being
  capable of movement through a fourth direction. (Note that he need travel
  only a minute fraction of an inch in this direction, just as we need jump
  only a hair's breadth to hop over the Flatlander's walls.) He could remove
  the contents of an egg without breaking the shell, carry out operations
  without leaving a scar, walk not through but past the walls of a locked
  room. Any law-abiding citizen can imagine an endless series of other
  interesting possibilities.
  I do not think that we can question the logic of this argument, even though
  Flatland itself becomes a little dubious when we investigate its physics.
  A fourth direction of space may indeed exist, though it will be very hard
  to find. (We are not concerned here, by the way, with the fact that time is
  often referred to as a fourth dimension. We are discussing only spacial
  dimensions; anyone who wants to make the issue unnecessarily complicated by
  bringing in time had better call it the fifth dimension, to keep it apart
  from the four we are trying to cope with.)
Another possibility is that, even if a fourth direction or 188
 dimension of space does not exist in nature, we may be able to create such
 an extension artificially. only a very little is needed, after all: a
 millionth of an inch will dol We bend space, to a minute extent, every time
 we generate an electric or magnetic field. Perhaps one day we may be able to
 bend a piece of it at right angles to itself.
  If you consider that all this is wild and far-out speculation, with no
  basis in reality and no observational facts to support it, you are 99 per
  cent correct. But I am encouraged to take the fourth dimension a little
  more seriously than I have done for many years because of a recent alarming
  debacle in nuclear physics, which has left everyone in a very thoughtful
  mood. It involves one of the most fundamental but disregarded concepts of
  everyday life-the difference between right and left.
  Let us return to Flatland for a moment. Imagine a rectangle in that
  two-dimensional world, and assume that it is cut into halves by being
  divided along a diagonal. (I suggest that you tear a sheet of paper in two
  to follow this demonstration. Note that it must be a rectangular sheet,
  with unequal sides-not a square.)
  Now the two triangular halves of the divided rectangle are identical in
  every respect. We can prove this by placing one on top of the other and
  noting that the upper one exactly covers the lower. The Flatlanders, of
  course, cannot perform this experiment, from the nature of their universe,
  but they can do something that is equivalent. They can put marks against
  the three comers of one triangle, push it out of the way, and show that its
  twin will occupy the same space. In all respects, therefore, the triangles
  are equal; or as Euclid would say, congruent.
  (What has all this to do with walking through walls and collecting
  souvenirs from the vaults of Fort Knox? Patience, please; there is no easy
  road to success, even via the fourth dimension.)
  At this point we will give the Flatlanders something to think about. We
  will pick up one of the triangles, flip it over, and put it back in
  Flatland.
  You will appreciate at once that something rather odd bas happened. Though
  they are still the same size, the 189
 two Mangles are no longer equal. They are now mirror images--one
 right-handed, one left-handed. No amount of pushing and maneuvering by the
 Flatlanders can make them occupy identical spaces. They differ from each
 other like a pair of boots or gloves, or screws of opposite pitch.
  Confronted by the miracle of a body being turned into its mirror image, a
  sufficiently intelligent Flatlander might deduce the only possible
  explanation-that the object had been "rotated" through a space at right
  angles to his own universe, the mythical third dimension. In exactly the
  same manner, if we ever encounter cases of solid bodies being converted
  into their images, it will be a proof that a fourth dimension exists.2

  2 H. G. Wells used this idea in The Plattner Story, where a man was
  reversed after a trip through the fourth dimension, being none the worse
  for the experience-though any surgeon who ever had to operate on him would
  be terribly confused. In Technical Error I pointed out that there might be
  other complications; a reversed man might starve to death in the midst of
  plenty, for many organic chemicals have mirror symmetry, and he might be
  unable to digest essential ingredients of food.

  Something quite as bad as this has just happened in nuclear physics, and
  the theoreticians are still reeling from the shock. In 1957 one of the
  long-standing "laws" of physics was overthrown-the principle of parity.
  This states, in effect, that there is no real distinction between left and
  right--one is just as good as the other as far as nature is concerned. For
  decades the principle had been regarded as self-evident, because any other
  assumption seemed absurd.
  Well, we have now discovered that in some nuclear rF actions nature is
  left-handed, while in others she is right-handed. This offends all our
  ideas of symmetry and the fitness of things, and it seems to me (though I
  am rushing in where angels with master's degrees in quantum mechanics might
  fear to tread) that one way of saving the situation is by invoking the
  fourth dimension. For then right-handedness and left-handedness will no
  longer bother us, because they will be identical. In a four-dimen190
 sional universe the distinction vanishes, and so, accordingly, does the
 paradox now worrying the physicists. The Nobel Prize committee can contact
 me through my publishers.
  In case anyone feels that four-dimensional effects on the nuclear scale,
  even if they exist, will be too small to be of practical use, may I remind
  him that a short while ago uranium fission concerned only a handful of
  atoms, not the entire human race. The principle is all that matters; the
  problem of size we can deal with later.
  I must admit that, when I started on the quest of invisibility a few
  thousand words back, I had no idea that it would lead into the fourth
  dimension. But that is typical of science; the direct and obvious approach
  is often the wrong one-the program aimed at one objective reaches a wholly
  different target. For centuries the alchemists mixed endless potions in
  their search for gold; they never found it, but they created chemistry. The
  transmutation of the elements lay, not through the retort and the crucible,
  but along a road which began in the glowing plasma of a vacuum tube. And it
  led to metals more precious, and even more deadly, than gold.
  Invisibility, the interpenetration of matter, the fourth dimension-these
  are the dreams and fantasies of science, and the probability is
  overwhelming that they will always remain so. But stranger things have
  happened in the past, and are happening now. As I write these words, this
  room and my body are sleeted by a myriad particles which I can neither see
  nor sense; some of them are sweeping upward like a silent vale through the
  solid core of Earth itself. Before such marvels, incredulity is chastened;
  and it would be wise to be skeptical even of skepticism.

 191
                               15

 The Road to Lilliput

 When the microscope was invented at the beginning of the seventeenth
 century, it revealed an entire new order of creation to mankind..Below the
 range of the visible was an unsuspected universe of living creatures,
 dwindling down, down, down to unimaginable minuteness. This discovery,
 coming at the same time as the telescope's revelations at the opposite end
 of the scale, set men thinking about the question of size.
 . One of the earliest-and certainly the most famousresults of that thinking
 was Gulliver's Travels. The genius of Swift (inspired by his own amateur
 observations; he bought a microscope for Stella) seized upon the change of
 perspective caused by magnification as a means of satire, and both Lilliput
 and Brobdingnag have now passed into our language. As also, though
 invariably misquoted, has Swift's stanza on the same theme:

      So, naturalists observe, a flea
      Has smaller fleas that on him prey;
      And these have smaller still to bite 'em,
      And so proceed ad infinitum.
                192
  Although it was quickly discovered, to the general relief, that Swift's
  Brobdingnag existed nowhere on Earth, the rather more attractive idea of
  minute or even microscopic races of men continued to fascinate writers. (It
  is n~ore attractive, of course, because we are all scared of giants,
  whereas we feel that we could cope with midgets. In reality, it would be
  just the reverse.) The classic story of the micro-world is Fitz-James
  O'Brien's The Diamond Lens, published in 1858, when the author was still in
  his twenties, with only four years of life ahead of him before his
  brilliant career would be cut short by the Civil War. The Diamond Lens
  describes what is perhaps the most frustrating romance in literature; it is
  the tragedy of a microscopist who falls in love with a woman too small to
  be visible to the naked eye, and who lives in the world of a water drop.
  Later writers did not let such an obstacle as mere size stand in the way of
  the plot; they invented drugs which contracted or expanded their characters
  as desired. The immortal Alice was perhaps the first to taste one of these
  potions, not yet listed in the pharmacopoeia; and nowhere else have the
  difficulties they could cause been so vividly described.
  The idea of the micro-, and indeed submicro-, world received a fresh lease
  of life in the 1920's, when the work of Rutherford and others laid bare the
  nuclear nature of the atom. The thought expressed in Swift's stanza was re-
  vived on a far more breathtaking scale. Every atom might be a miniature
  solar system, with electrons playing the role of inhabited planets-and,
  conversely, our solar system might be merely an atom in a super-universe.
  This theme was taken up with enthusiasm by the pro
 lific science-fiction writer Ray Cummings, who had a
 training that many of his colleagues might have envied
 he was Edison's secretary for five years. In The Girl in
 the Golden Atom (1919) and later stories, Cummings
 shrank a whole series of heroes down to sub-electronic
 size, passing somewhat glibly over such problems as the
 navigation of internuclear space and the location of the
 right atom (and the right girl) among the several million
                193
 million million million different atoms that exist in a few ounces of gold.
  Some years ago, Hollywood surprised many of us by making a remarkably good
  movie on the theme of smallness: I refer to The Incredible Shrinking Man,
  which 90 per cent of intelligent filmgoers probably judged by its
  unfortunate title and decided to miss. The most incredible thing about the
  shrinking man (and I imagine that we can thank the author and scriptwriter
  Richard Matheson for this) was the fact that he was so credible, and the
  avoidance of the conventional happy ending left his final fate both moving
  and strangely inspiring. But perhaps I am too easily satisfied; it is so
  rare to meet a glimmer of intelligence in what film producers are pleased
  to call science-fiction movies that one's gratitude tends to overflow.
  These stories of miniature and micro-worlds raise two distinct questions:
  could such worlds exist (not necessarily on our planet), and if so, could
  we observe or enter them?
  As far as the first question is concerned, I think we can give a definite
  answer, based upon laws familiar to all engineers and biologists, but not
  to those journalists who love to trot out such ancient fallacies as: "If an
  ant were as big as a man, it could carry a load of ten tons." In fact, it
  couldn't carry itself.
  At any level of size, certain things are possible, and others are
  impossible. The whole world of living creatures, with all its wonderful
  richness and variety, is dominated and controlled by the elementary fact of
  geometry which states: If you double the size of an object you multiply its
  area four times-but its volume (and hence weight) eight times. From this
  mathematical platitude, the most momentous consequences flow. It implies,
  for instance, that a mouse cannot be as big as an elephant, or an elephant
  as small as a mouse-and that a man cannot be the size of either.
  Let us consider the case of man. He is already a giant--one of the very
  largest of all the animals. This thought comes as something of a surprise
  to most people, 194
 who forget that the animals larger than man could have their names written
 on a single sheet of paper, while those that are smaller would fill volume
 after volume.
  H. sapiens shows a considerable range in size, though the extremes are very
  rare. The tallest man who has ever lived was perhaps five times the height
  of the smallest, but you would have to search through millions of cases to
  find a ratio of four to one--unless you happened to hit on a circus
  exhibiting both an eight-foot giant and a two-foot midget. And if you did,
  you would probably find that both were sick and unhappy people, with little
  chance of reaching the normal span of life.
  For the human body is a piece of architecture that has evolved to give its
  best performance when it is five or six feet tall. Double its height, and
  it would weigh eight times as much, but the bones which supported it would
  be increased in area of cross-section only four times. The stresses acting
  upon them would therefore be doubled in intensity; a twelve-foot giant is
  possible, but he would always be breaking his bones, and would have to be
  very careful how he moved. To make a twelve-foot version of Homo sapiens
  practical would involve a major redesign, not a straight scaling up. Tlie
  legs would have to be proportionally much thicker, as the example of the
  elephant proves. The horse and the elephant both follow the same basic
  quadripedal design-but compare the relative thickness of their legsl The
  elephant must be near the sensible limit of size for a land animal; this
  was reached (if not exceeded) by the forty-ton brontosaurus and that
  largest of all mammals, the incredible rhinoceros Baluchitherium, which
  stood eighteen feet high at the shoulder. (The head of a giraffe is. only
  sixteen feet from the ground!)
  Beyond this size, no structure of flesh and bone could support itself
  against gravity; if real giants exist anywhere in the universe, their bones
  will have to be made of metal, which would involve some difficult problems
  in biochemistry. Or they will have to five on worlds of low gravitypossibly
  in space itself, where weight ceases to exist. One of the most interesting
  questions in extraterrestrial zool195
 ogy is whether life can adapt itself to space by purely evolutionary
 processes. Almost all biologists would say "Certainly not!" but I think it
 unwise to sell nature short at the present state of our ignorance.
  In the direction of smallness, the problems that arise are not quite so
  obvious, but they are equally fundamental. At first sight there seems no
  very good reason why a man one foot high need not be a working proposition.
  There are plenty of mammals this size, based upon the same general design;
  some of the smaller monkeys, for example, are very much like little men.
  Closer examination, however, reveals that their proportions are quite
  different, their limbs much more slender than man's. For just as a man
  enlarged to a height of twenty feet would be impractically fragile and
  underpowered for his weight, so, conversely, one diminished to a height of
  a foot would be hopelessly clumsy and overmuscled. Small animals need much
  smaller limbs, as is dramatically shown by the insects with their often
  unbelievably delicate legs and wings. By the time the incredible shrinking
  man started to measure his height in inches, his grossly overpowered
  muscles would have torn him to pieces.
  But long before then, so many other things would have gone wrong that he
  would be dead from a dozen causes. All the elaborate mechanisms of the
  body-respiration, blood circulation, temperature control, to mention only
  the most obvious-would have failed. When he was a tenth of his original
  size, the incredible shrinking man would have a thousandth of his starting
  weight. (We won't inquire where that missing 99.9 per cent has gone; if he
  still has it, of course, he is fifty times as dense as platinum and has
  fallen through the floor.) Yet the area of his lung surfaces, stomach
  walls, vein and artery crosssections, has diminished not by a thousand, but
  only by a hundred. His entire metabolism would proceed at ten times the
  previous rate per unit of his mass; he would probably die of heatstroke
  through overproduction of energy.
This sort of argument can be followed to the same re196
 ductio ad absurdum conclusion for every one of the body's functions, and
 make it perfectly clear that even if the means existed for expanding or
 contracting a man, he would be incapacitated and then killed by quite a
 modest change of scale.' There is no chance that any man win ever be able to
 stalk warrior ants through the jungles of the grass, still less marry a
 princess in a golden atom.
  Having made this point, I would like to add one slight reservation. A very
  good case can be made to the effect that man is now considerably larger
  than he need be. Physical strength and the size that necessarily goes with
  it will be needed less and less in the future. Indeed, size will be a
  handicap-especially in the cramped quarters of space vehicles-and it has
  been half-seriously suggested that one way of alleviating the coming
  shortages of food and raw materials is to breed smaller people. Even a 10
  per cent reduction in the average height of the human race would have a
  very considerable effect, for smaller people would need smaller homes,
  cars, furniture, clothes-all the way along the line.
  There would be no midgets, of course, if everyone was three feet high, and
  the world could then quite comfortably support twice its present
  population. Few futures, however, seem less likely than this, for thanks to
  better food and medical care men are growing rather than shrinking.
  (Harvard graduates, admittedly a privileged class, have been gaining an
  inch a generation-an astonishing rate which suggests that they will be in
  real trouble around the year 3000.) Only a ruthless and all-powerful world
  dictatorship could reverse this trend; dictators are always small people
  and one can imagine some future Hider or Mussolini who determined to
  assuage his inferiority complex by making his subjects even smaller than he
  was-though he could hardly expect to see any noticeable results in his own
  lifetime.
 Although small living creatures cannot be manlike, and

  1 A very thorough treatment of this whole subject will be found in J. B. S.
  Haldane's On Being the Right Size and DArcy Thompson's On Magnitude, both
  in Volume 2 of James Newman's World of Mathematics.
               197
 no man could continue -to function if drastically reduced in size, this does
 not rule out the possibility that extremely small yet intelligent beings
 might exist if they were constructed upon nonhuman lines. By altering her
 designs nature can circumvent, to a quite remarkable degree, the limitations
 imposed by changes of scale. Consider, for example, the difference between
 the albatross and the tiniest midge, barely visible to the eye. Both are
 aerial creatures that fly by flapping their wings-and there the resemblance
 ceases. Anyone knowing only the midge could make a very convincing case for
 the impossibility of the albatross-and vice versa. Yet both exist, and both
 fly, though one weighs a billion times as much as the other. They represent
 the extreme ends of the evolutionary spectrum, when the resources of
 biological materials and mechanisms have been stretched to the limit. No
 bird much larger than an albatross could fly; as is demonstrated by the
 ostrich, the moa, and their giant ancestors, as terrifying as dinosaurs. No
 insect much smaller than a midge could have any control of its movements
 through the air; though it might float as helplessly as the planktonic
 creatures drift through the sea, it could not fly.
  Even a complete redesign, therefore, permits only a limited, and not a
  indefinite reduction in size. Sooner or later we come up against the fact
  that the basic structural elements of living creatures-the building blocks
  of life-cannot be made much smaller than they already are. All animals are
  constructed of cells, and all cells are of much the same size. Those from
  an elephant are only twice the size of those from a mouse.
  It is as if all living creatures were like houses, built from bricks which
  vary only slightly in size. If follows, therefore, that very small animals
  must also be very simple animals, because they can contain only a limited
  number of components. You cannot build a dolrs house out of full-sized
  bricks.
  Intelligence, whatever else it may be, is at least partly a byproduct of
  cellular complexity. Small brains cannot be as complex as large brains,
  because they must contain fewer cells. One can imagine the human brain
  still func198
 tioning well at half its present size-but not at one-tenth. If, on planets
 with powerful gravitational fields, living creatures are reduced to a height
 of a few inches, they cannot be intelligent-unless they make up for their
 lost height by increasing their area, to give an adequate volume of brain.
 There might be doll-like animals on 50-g worlds, but anything capable of
 rational thought would look not like a mannikin, but a pancake.
  Not only intelligence, but life itself, becomes impossible as we continue
  down the scale of size. Only just beyond the limit of today's microscopes,
  the essential granularity of nature makes its appearance. As the cell is
  the basic building block of all living creatures, so atoms and molecules
  are the building blocks of the cell. Some minute bacteria are only a few
  score molecules on a side; the viruses, which mark the frontier between
  life and nonlife, are even smaller. But no house can be smaller than a
  single brick, and nothing that lives can be smaller than a single protein
  molecule, which is the chemical basis of life. The largest proteins are
  about a millionth of a centimeter long; that is a nice round figure to
  remember, as the last milestone on the road down from the world of life.
  Although it is conceivable that more efficient types of organism may have
  evolved on other planets (indeed, it is somewhat immodest to assume
  otherwise) it seems very unlikely that they could be so much more efficient
  that they could alter those conclusions. We can dismiss, therefore, those
  ingenious stories of midget (or even microscopic) spaceships as pure
  fantasy. If you are ever persistently buzzed by a strange metallic object
  that looks like a beetle, it will be a beetle.
  There is not much that can or need -be said about theories of the
  sub-universe, and the suggestion that atoms may be miniature solar systems.
  Stories based on this theme are now virtually extinct; they were killed
  when it was discovered that electrons behaved in most unplanetary fashions,
  being waves at one moment and particles the next. The cozy and easily
  pictured Rutherford-Bohr atom lasted only a few years-and even in that
  model, electrons were assumed to jump instantaneously from orbit 199
 to orbit, which would have been very unsettling to their inhabitants. Wave
 mechanics, the uncertainty principle, and the detection of such puzzling
 particles as mesons and neutrinos made it very clear that atoms were nothing
 like solar systems, or indeed anything that the mind of men bad ever
 envisioned before.
  I might mention, with a slight shudder, that in Amazing Stories during
  1932-1935 one J. W. Skidmore produced an entire series of tales about a
  sub-atomic romance between an electron, Nega, and a proton, Posi. How any
  author could have spun this horrid whimsy out over five stories (or even
  one) I cannot now imagine; his success may be judged from the fact that
  though I read the entire Posi and Nega series at the time of publication,
  I cannot for the life of me remember whether boy eventually met girl, and,
  if so, what happened. The matter is beginning to prey on my mind, but as I
  am ten thousand miles from the Library of Congress there is nothing I can
  do about it.
  Almost invariably, stories of microcosmic universes ignored the fact that
  a change of size always involves a corresponding change of time rate. Small
  creatures live short, active lives; to birds and flies, we must be very
  slow-moving, sluggish creatures. If we go to the limiting case of the atom
  and suppose that the orbiting electrons are in fact worlds in their own
  right, they must have fantastically short "years." In the Rutherford-Bohr
  model of the hydrogen atom, the single orbital electron makes about a
  million billion revolutions round the nucleus every second. If this
  corresponds to the eighty-eight-day year of Mercury, the innermost planet
  in our solar system, it would mean that time in the hydrogen atom must pass
  about ten thousand million million million times more swiftly than it does
  in our microscopic universe.
  No science-fiction hero, therefore, could ever make two visits to the same
  subatomic world. If he stepped back into his own universe for a single
  hour, and then returned to the atom, he would find that hundreds of
  billions of years bad passed. And, conversely, any round trip to the
  micro-world would have to be practically instantaneous in our time,
  otherwise the traveler would die of old age 200
 among the atoms. I do recall one story in which a scientist sent his
 daughter and his assistant on a brief visit to the subatomic universe and
 was disconcerted to welcome back several hundred of their
 great-great-great-greatgrandchildren a couple of minutes later; even so, I
 fear that the author, though he was on the right track, grossly
 underestimated the magnitude of the problem. It would not be a question of
 a few human generations--but the lifetime of many suns.
  For time can be a barrier more unyielding than space; this will be
  particularly true if we ever discover, and attempt to communicate with,
  extremely large intelligent entities. A number of writers have explored
  this idea, which does not conflict with my earlier remarks about the im-
  possibility of giants. I was speaking then of planetary environments-and
  there may be creatures larger than planets.
  One writer to handle this theme was Fred Hoyle--and whatever view one may
  take of Professor Hoyle's cosmology, nobody doubts that he knows his
  physics. In The Black Cloud he described, with great plausibility and con-
  viction, a gaseous invader from interstellar space, some hundred million
  miles in diameter-in fact, a kind of intelligent comet.
  Even if the "thoughts" of such a creature were propagated by radio waves,
  as Hoyle suggested, it would take ten minutes for a single impulse to
  travel from one end of it to the other. A nerve impulse can make the trip
  across the human brain in a few thousandths of a second, so mental
  operations involving the whole of the black cloud would take perhaps a
  million times longer than those of a human mind. We would get very tired
  waiting for its answers; a short sentence would take a couple of months to
  deliver.
  However, the black cloud might be able to talk to us at our own rate, or
  even at the rate of our fastest teleprinters, by detailing a minute and
  localized fraction of itself to deal with so trivial a problem. In that
  case, we could hardly claim to be in communication with it as a whole, any
  more than a man could claim to have made contact 201
 with an ant, because his toe twitched when it walked across his foot.
  These are rather humbling thoughts, but I do not think that they are
  necessarily fantastic. Looking down toward the atom, we can see, a few
  orders of magnitude beneath us, first the end of intelligence, then the end
  of life. There is no such finality in the other direction, and as yet we
  have no inkling of our position in the hierarchy of the universe. There may
  be intellects among the stars as vast as worlds, or suns ... or solar
  systems. Indeed, the whole galaxy, as Olaf Stapledon suggested long ago,
  may be evolving toward consciousness, if it has not already done so. It
  contains, after all, ten times as many suns as there are cells in a human
  brain.
  The road to Lilliput is short, and it leads nowhere. But the road to
  Brobdingnag is another matter; we can see along it only a little way, as it
  winds outward through the stars, and we cannot guess what strange travelers
  it carriers. it may be well for our peace of mind if we never know.

 202
                               16

 Voices from the Sky'

 In the closing days of 1958, a human voice spoke for the first time from
 space. It was the President of the United States, broadcasting a Christmas
 message to the world. Yet that friendly greeting from an orbiting Atlas
 satellite, leaping across all barriers of geography and nationality, was as
 fateful a sound as any in the history of mankind. It marked the dawn of a
 new age of communication, which will transform the cultural, political,
 economic, and even linguistic patterns of our world.
  It is simple enough to demonstrate this logically-as I hope to do-but very
  difficult to grasp its full meaning. So wonderful are today's techniques of
  communication, so integrated into the very fabric of our society, that we
  overlook their gross limitations, and find it hard to imagine any
  substantial improvements. We are like the early Victorians who saw no value
  in the electric telegraph;

  I I have, quite deliberately, left this chapter (written in 1959)
  completely unaltered. For the reasons-and the updating--see the epilogue on
  page 213, and also the book Voices from the Sky. 203
 semaphores or flashing lights had always been good enough for those hustlers
 who wanted something faster than the mail coach.
  We may laugh at this attitude; yet we are still, for all our ability to
  pluck sound and vision from the empty air, scarcely out of the Morse-buzzer
  age. Within a few years, communications satellites beyond the atmosphere
  will make our present facilities seem as primitive as Indian smoke signals,
  and we as blind and deaf as our grandparents before the coming of the
  electron tube.
  All these revolutionary consequences stem from a fact so simple and so
  obvious that one almost hesitates to mention it. The radio waves which are
  now our chief message bearers travel in straight lines, like light itself.
  But the world, unfortunately, is round.
  Only the curious accident that the Earth is surrounded by a reflecting
  layer-the ionosphere-makes long-distance radio possible. This invisible
  miffor in the sky reflects back waves in the broadcast and short-wave
  bands, but its performance is somewhat erratic and it does not function at
  all on the very short waves. These slice straight through it and head on
  out into space, and thus cannot be used for long-distance communication.
  (Longdistance, that is, by terrestrial standards. They serve admirably for
  talking to planets and spaceships.)
  It is the television engineer who is most badly affected by this state of
  affairs. For technical reasons, TV is confined to the very short
  waves-precisely those which are not reflected back to Earth. TV programs go
  straight on out into space; they may be picked up beautifully on the Moon,
  but not in the next country.
  This is the reason literally hundreds of TV stations are needed to cover a
  large area like Europe or the United States. Still more serious, it is
  impossible to span the oceans; they remain as great an obstacle to TV as
  they were to the human voice before the invention of radio itself. To
  exchange TV programs between Europe and America would require a kind of
  electronic bucket chain of perhaps fifty ships moored in a line across the
  Atlantic, 204
 relaying the signals from one to the other. This is not, to say the least,
 a very practical solution.
  There is a simpler answer. Just one relay station will do the job-if it is
  in a satellite a few thousand miles above the Earth. All that would be
  required would be a receiver to pick up the signals from one continent, and
  a transmitter to rebroadcast them to the other.2
  But transatlantic TV is only a modest beginning. If the relay satellite
  were far enough out-say 10,000 miles-its broadcasts could blanket half the
  world. And two or three such satellites, equally spaced around our planet,
  could provide TV coverage from pole to pole. The clear, clean signals
  coming directly down from the sky, with no background interference and no
  ghostly echoes picked up by reflection from nearby buildings, would permit
  far higher standards of picture quality than those we tolerate today.
  Perhaps at this point I may be permitted what has been called the modest
  cough of the minor poet. To the best of my knowledge, the use of artificial
  satellites to provide global TV was first proposed by myself in the October
  1945 issue of the British radio journal Wireless World. The scheme then put
  forward, under the snappy title "Extraterrestrial Relays," envisaged the
  use of three satellites 22,000 miles above the equator. At this particular
  height, a satellite takes exactly twenty-four hours to complete one orbit,
  and thus stays fixed forever over the same spot on the Earth. The laws of
  celestial mechanics can thus provide us with the equivalent of invisible TV
  towers 22,000 miles high. Even as I write these words, preparations are
  being made by the Hughes Aircraft Company and the United States Army to
  launch communications satellites into this twenty-four hour orbit.
  At first sight, global TV may hardly seem a revolutionary force capable of
  transforming our civilization. Let us, therefore, look at some of its
  consequences in more detail.
  In a few years every large nation will be able to establish (or rent) its
  own space-borne radio and TV transmitters, able to broadcast really
  high-quality programs to

2 This chapter was written before the launching of Telstar.
205
                                      the entire planet. There will be no shortage of *avelengths-as there is
 today even for local services. One of the incidental advantages of satellite
 relays is that they will make available vast new bands of the radio
 spectrum, providing "ether space" for at least a million simultaneous TV
 channels, or a billion radio circuits!
  This will mean the end of all distance barriers to sound and vision alike.
  New Yorkers or Londoners will be able to tune in to Moscow or Peking as
  easily as to their local station. And, of course, vice versa.
  Think what this will mean. Until today, even radio has been parochial,
  except to the shortwave fan willing to put up with the fades and crackles
  and banshee wailings of the ionosphere. Yet now the great highway of the
  ether will be thrown open to the whole world, and all men will become
  neighbors-wbether they like it or not. Any form of censorship, political or
  otherwise, would be impossible; to jam signals coming down from the heavens
  is almost as difficult as blocking the light of the stars. The Russians
  could do nothing to stop their people from seeing the American way of life;
  on the other hand, Madison Avenue agencies and censorship committees might
  be equally distressed-though for different reasons-at a nationwide switch
  to uninhibited telecasts from Montmartre.
  Such freedom of communication will have an ultimately overwhelming effect
  on the cultural, political, and moral climate of our planet. It holds
  danger as well as promise. If you doubt this, consider the following quite
  unimaginative extrapolation, which might be entitled "How to Conquer the
  World without Anyone Noticing."
  By 1970 the U.S.S.R. has established the first highpowered satellite TV
  relay above Asia, broadcasting in several languages so that more than a
  billion human beings can understand the programs. At the same time, in a
  well-organized sales campaign spearheaded by demonstrations, Russian trade
  missions have been flooding the East with cheap, transistorized
  battery-powered receivers. There is scarcely a village which cannot afford
  one and it doesn't cost the U.S.S.R. a thing; it even makes a small profit
  on the deal.
                206
  And so millions who have never learned to read, who have never seen a
  movie, who have no rival distractions, fall under the hypnotic spell which
  even ostensibly educated nations have been unable to resist. Good
  entertainment, rapid (if slanted) news reporting, Russian language lessons,
  instructional programs of a "Do It Yourself" type useful to backward
  communities, quiz programs in which the first prizes are usually trips to
  the Soviet Union-it takes little imagination to see the pattern. In a few
  years of skillful propaganda, the uncommitted nations would be committed.3
  It may be no exaggeration to say that priority in establishing the
  satellite communication system may determine whether, fifty years from now,
  Russian or English is the main language of mankind. The TV satellite is
  mightier than the ICBM, and intercontinental TV may indeed be the ultimate
  weapon.
  But let us turn aside from the political aspects of the TV satellites and
  look in more detail at their domestic effects. One of these will be all to
  the good: We may see the end of the hideous antenna arrays that have rained
  the skylines of all our cities and made a mockery of architecture for the
  last decade. The antennas of the future will be small, neat saucers or lens
  systems like the now familiar radio telescopes. As they will he on their
  backs pointing up at the sky, they can be tucked into roofs and attics-and
  they will need no tottering towers to support

  8 1 can now add an interesting footnote to this. While conducting a panel
  discussion at the New York Coliseum in October 1961. as part of the
  American Rocket Society's "Space Flight Report to the Nation," I remarked
  that it would be an excellent idea if the United States established a
  global TV system in time to relay the 1964 Olympics to all nations. The
  next day this suggestion (I do not know its originator) was passed on to
  VicePresident Johnson, who was speaking at the Waldorf Astoria banquet
  which wound up the proceedings. The Vice-President was so impressed with
  the idea that he departed from his prepared text to include it; and I am
  now prepared to make a small bet that there will be. few towns of any size
  in the world which will not be tuning in, live, to Tokyo in 1964.
                207
 them high in the air. This aesthetic dividend, though small, should not be
 despised.
  The effect on the cultural content of our local TV and
 radio programs, when faced with direct competition from
 the whole world, is a subject for lively speculation. Some
 cynics maintain that the TV relay system is the best argur
 ment against space travel that has ever been conceived;
 they shudder at the thought of hundreds of simultaneous
 Westerns, thousands of rock-and-rolling disc jockeys. Yet
 the very profusion of available channels, each capable of
 being received by most of the human race, will make pos
 sible services of a quality and specialized nature quite out
 of the question today. There ar ' e probably enough viewers
 on Earth to make channels carrying nothing but Greek
 plays, lectures on symbolic logic, or championship chess
 matches an economic possibility.
  Many will look forward, with a certain malevolent glee, to the effects of
  outside competition upon commercial programs. At least a hundred million
  underprivileged Americans have never known the joys of hucksterless radio
  or TV; they are like readers who have become reconciled to the fact that
  the fifth page of every book consists of advertisements which they are not
  allowed to SkiP. If the Russians are clever enough to take advantage of
  their opportunity, they can gain an enormous audience merely by omitting
  the soap and laxative announcements.
  The advent of global TV and radio coverage Will end,
 for better or worse, the cultural and political isolation
 which still exists over the whole world, outside the great
 cities. As one who has traveled widely throughout the
 United States, I have long been appalled by the intellec
 tual vacuum into which you are plunged as soon as you
 get out of range of New York, San Francisco, Boston,
 Chicago, and a handful of other cities. This applies both
 to newspapers and to radio/TV; how often have I spent
 fruitless hours at places like Skunksville, Ugh., searching
 for a copy of the New York Times so that I could find
 out what was happening to the planet Earth. And as far
 as the ether waves are concerned, there are few more bar
 rowing experiences than a sweep across the radio bands in
                208
 the Deep South, especially on a Sunday morning. In England, at least, one is
 never far from civilization (i.e. the B.B.C.'s Third Programme).
  The abolition of all barriers to free intellectual and cultural intercourse
  will complete the revolution started by the automobile half a century ago
  and timidly continued by today's short-ranged electronics. It will mean the
  eventual end of the limited, small-town mentality which, it is true, has a
  certain charm (especially to nostalgic novelists, and especially from a
  distance). When all men, wherever they may be, have equal. access to the
  same vast communications network, they will inevitably become citizens of
  the world, and a major problem of the future will be the preservation of
  regional characteristics of value and interest. There is grave danger of
  global leveling-down; the troughs in man's cultural heritage must not be
  111led at the price of demolishing the peaks.
  The universal communication system will have a profound impact upon
  language. As already suggested, it may lead to a single dominant tongue,
  others becoming merely local dialects. More probably it will result in a
  bi- or trilingual planet; in this respect, Switzerland may be the prototype
  of tomorrow's world. Far higher above the Earth than the builders of Babel
  ever aspired to, we may at last undo the curse that was visited upon them.
  All that has been described so far--even this last development-will result
  from the application of existing techniques, merely made worldwide by the
  use of satellite relays. It is time now to consider some of the wholly new
  services which will become feasible, if we wish to exploit them.
  The most obvious is the personal transceiver, so small and compact that
  every man carries one with no more inconvenience than a wristwatch. This,
  of course, is an old dream, and anyone who doubts that it can be realized
  is simply unaware of current achievements in electronics. Radio receivers
  have now been built which make the most compact transistor portables look
  Eke 1925 cabinet models. The smallest so far revealed by the
  micro-miniaturization experts is about the size of a lump of sugar.
                209
  I Without going into technical details (of interest largely to those who
  can already think of the answers) the time will come when we will be able
  to call a person anywhere on Earth, merely by dialing a number. He win be
  located automatically, whether he is in mid-ocean, in the heart of a great
  city, or crossing the Sahara. This device alone may change the patterns of
  society and commerce as greatly as the telephone, its primitive ancestor,
  has already done.
  Its perils and disadvantages are obvious; there are no wholly beneficial
  inventions. Yet think of the countless lives it would save, the tragedies
  and heartbreaks it would avert. (Remember what the telephone has meant to
  lonely people everywhere.)
  No one need ever again be lost, for a simple positionand-direction-finding
  device could be incorporated in the receiver, based on the principle of
  today's radar navigational aids. And in case of danger or accident, help
  could be summoned merely by pressing an "Emergency" button.
  If you think that this will make the world a claustropbobically small
  place, in which you can never escape from friends or family, or even run
  any stimulating risks, you are quite correct. But you need not worry; there
  is more than enough of danger and distance in the bottomless chasm of
  space. Earth is home now; let us make it cozy and comfortable and safe. The
  pioneers will be elsewhere.
  As communications improve, so the need for transpoc.tation will decrease.
  Our grandchildren will scarcely believe that millions once spent hours of
  every day fighting their way into city offices-where, as often as not, they
  did nothing that could not have been achieved over telecommunication links.
  For global phone and vision services, enabling men to confer with each
  other anywhere on the planet, are only a beginning. Even now we have
  data-handling systems linking together factories and offices miles apart,
  controlling nationwide industrial empires. Electronics is already per-
  mitting the decentralization which rising rents and 210
 transport costs--not to mention the threat of the mushroom cloud-encourage
 more strongly every year.
  The business of the future may be run by executives who are scarcely ever
  in each other's physical presence. It will not even have an address or a
  central office--only the equivalent of a telephone number. For its files
  and records will be space rented in the memory units of computers that
  could be located anywhere on Earth: the information stored in them could
  read off on high-speed printers whenever any of the firm's offices needed
  it.
  The time may come when half the world's business will be transacted through
  vast memory banks beneath the Arizona desert, the Mongolian steppes, the
  Labrador muskeg, or wherever land is cheap and useless for any other
  purpose. For all spots on Earth, of course, would be equally accessible to
  the beams of the relay satellites: To sweep from pole to pole would mean
  merely turning the directional antennas through seventeen degrees.
  And so the captains of industry of the twenty-first century may Eve where
  they please, running their affairs through computer keyboards and
  information-bandling machines in their homes. Only on rare occasions '
  would there be any need for more of the personal touch than could be
  obtained via wide-screen full-color TV. The business lunch of the future
  could be conducted perfectly well with the two halves of the table ten
  thousand miles apart; 0 that would be missing would be the handshakes and
  exchange of cigars.
  Administrative and executive skills are not the only ones which would thus
  become independent of geography. Distance has already been abolished for
  the three basic senses of sight, hearing, and touch-the latter, thanks to
  the development of remote-handling devices in the atomic energy field. Any
  activity which depends on these senses can, therefore, be carried out over
  radio circuits. The time will certainly come when surgeons will be able to
  operate a world away from their patients, and every hospital will be able
  to call on the services of the best specialists, wherever they may be. We
  will have more to say in the 211
 next two chapters about the linking of human senses into communications
 networks.
  An application of satellites which has already been considered in some
  detail by the astronautical engineers is what has been called the orbital
  post office,, which will probably make airmail obsolete in the quite near
  future. Modem facsimile systems can automatically transmit and reproduce
  the equivalent of an entire book in less than a minute. By using these
  techniques, a single satellite could handle the whole of today's
  transatlantic correspondence.
  A few years from now, when you wish to send an urgent message, you will
  purchase a standard letter form on which you will write or type whatever
  you have to say. At the local office the form will be fed into a machine
  which scans the marks on the paper and converts them into electrical
  signals. These will be radioed up the nearest relay satellite, routed in
  the appropriate direction round the Earth, and picked up at the destination
  where they are reproduced on a blank form identical with the one you in-
  scribed. The transmission itself would take a fraction of a second; the
  door-to-door delivery would extend this time to several hours, but
  eventually letters should never take more than a day between any two points
  on the Earth. There are, of course, problems of privacy, which might be
  solved by robot handling at all stages of the operation. However, even the
  old-style human postmen have been known to read the mail.
  Perhaps a decade beyond the orbital post office lies something even more
  startling-the orbital newspaper. This will be made possible by more
  sophisticated descendants of the reproducing and facsimile machines now
  found in most up-to-date offices. One of these, working in conjunction with
  the TV set, will be able on demand to make a permanent record of the
  picture flashed on the screen. Thus when you want your daily paper, you
  will switch to the appropriate channel, press the right button-and collect
  the latest edition as it emerges from the slot. It may be merely a one-page
  news sheet; the editorials will be available on another cbannel-sports,
  book reviews, drama, advertising, on others. We will select what 212
 we need, and ignore the rest, thus saving whole forests for posterity. The
 orbital newspaper will have little more than the name in common with the
 newspaper of today.
  Nor will the matter end here. Over the same circuits we will be able to
  conjure up, from central libraries and information banks, copies of any
  document we desire from Magna Charta to the current Earth-Moon passenger
  schedules. Even books may one day be "distributed" in this manner, though
  their format will have to be changed drastically to make this possible.
  All publishers would do well to contemplate these really staggering
  prospects. Most affected will be newspapers and pocketbooks; practically
  untouched by the coming revolution will be art volumes and quality
  magazines, which involve not only fine printing but elaborate manufacturing
  processes. The dailies may well tremble; the glossy monthlies have little
  to fear.
  How mankind will cope with the avalanche of information and entertainment
  about to descend upon it from the skies, only the future can show. Once
  again science, with its usual cheerful irresponsibility, has left another
  squalling infant on civilization's doorstep. It may grow up to be as big a
  problem child as the one born amid the clicking of Geiger counters beneath
  the Chicago University squash court, back in 1942.
 . For will there be time to do any work at all on a planet saturated from
 pole to pole with fine entertainment, firstclass music, brilliant
 discussions, superbly executed atbletics, and every conceivable type of
 information service? Even now, it is claimed, our children spend a sixth of
 their waking lives glued to the cathode-ray tube. We are becoming a race of
 watchers, not of doers. The miraculous powers that are yet to come may well
 prove more than our self-discipline can withstand.
  If this is so, then the epitaph of our race should read, in fleeting,
  fluorescent letters: Whom the Gods would destroy, they first give TV.
  EprLOGUE: I have deliberately left the preceding chapter unchanged, since
  as an example of attempted-and partially fulfilled-prediction it would seem
  to be of some 213
 historic interest. The names TELSTAR, comsAT, and INTELsAT have now entered
 the consciousness of mankind, and the footnote on page 108 came true with
 the launching of syNcom. By the mid-seventies, the first direct-broadcast
 sateffites-whose programs can be received by ordinary TV sets with a few
 hundred dollars' worth of auxiliary equipment-will be in orbit, and the
 communications revolution will be upon us.
  To revert to the opening sentence of this chapter; on August 20, 1971, 1
  was privileged to meet Mrs. Mamie Eisenhower at the U.S. State Department,
  when we were both invited to the ceremonies attending the signing of the
  eighty-nation INTELSAT (International Telecommunications Satellite
  Organization) Agreement. My speech at the subsequent luncheon seems a good
  way of rounding off this chapter:

  I submit that the eventual impact of the communications satellite upon the
  whole human race will be at least as great as that of the telephone upon
  the socalled developed societies.
  In fact, as far as real communications are concerned, there are as yet no
  developed societies; we are all still in the semaphore and smoke-signal
  stage. And we are now about to witness an interesting situation in which
  many countries, particularly in Asia and Africa, are going to leapfrog a
  whole era of communications tecbnology and go straight into the space age.
  They will never know the vast networks of cables and microwave links that
  this continent has built at such enormous cost both in money and natural
  resources. The satellites can do far more and at far less expense to the
  environment.
  INTELSAT, of course, is concerned primarily with point-to-point
  communications involving large ground stations. It provides the first
  reliable, high-quality, wide-band links between all nations that wish to
  join, and the importance of this cannot be overestimated. Yet it is only
  a beginning, and I would like to look a little further into the future.
                214
  Two years from now, NASA will launch the first satellite, the ATS-F, which
  will have sufficient power for its signals to be picked up by an ordinary,
  domestic television set plus about $200 worth of additional equipment. In
  1974, this satellite will be stationed over India and, if all goes well,
  the first experiment in the use of space communications for mass education
  will begin.
  I have just come from India, where I have been making a TV film on The
  Promise of Space. In a village outside Delhi, we set up the prototype
  antenna-a simple, umbrella-shaped, wire-mesh structure about three meters
  across. Anyone can put it together in a few hours, and only one antenna per
  village is needed to start a social and economic revolution.
  The engineering problems of bringing education, literacy, improved hygiene,
  and agricultural techniques to every human being on this planet have now
  been solved. The cost would be about a dollar per person, per year. 'Me
  benefits in health, happiness, and wealth would be immeasurable.
  But, of course, the technical problem is the easy one. Do we have the
  imagination and the statesmanship to use this new tool for the benefit of
  all mankind? Or will it be used merely to peddle detergents and propaganda?
  I am an optimist; anyone interested in the future has to be. I believe that
  communications satellites can unite mankind. Let me remind you that,
  whatever the history books say, this great country was created a little
  more than a hundred years ago by two inventions. Without them, the United
  States was impossible; with them, it was inevitable. Those inventions, of
  course, were the railroad and the electric telegraph.
  Today, we are seeing on a global scale an almost exact parallel to that
  situation. What the railroads and the telegraph did here a century ago, the
  jets and the communi~ations satellites are doing now to all the world.
  I hope you will remember this analogy in the years ahead. For today,
  whether you intend it or not215
 whether you wish it or not-you have signed far more than just another
 intergovernmental agreement.
You have just signed a first draft of the Articles of
 Federation of the United States of Earth. &

 216
                               17

 Brain and Body

 The human brain is the most complicated structure in the known universe-but
 as practically nothing of the universe is known, it is probably fairly low
 in the hierarchy of organic computers. Nevertheless, it contains powers and
 potentialities still largely untapped, and perhaps unguessed-at. It is one
 of the strangest of all facts, impossible for the sensitive mind to
 contemplate without melancholy, that for at least fifty thousand years there
 have been men on this planet who could conduct a symphony orchestra,
 discover theorems in pure mathematics, act as secretaries of the United
 Nations, or pilot a spaceshiphad they been given the chance. Probably 99 per
 cent of human ability has been wholly wasted; even today, those of us who
 consider ourselves cultured and educated operate for most of our time as
 automatic machines, and glimpse the profounder resources of our minds only
 once or twice in a lifetime.
  In the speculations that follow, I shall ignore all paranormal
  and'so-called Psi phenomena. If these exist, and can be controlled, they
  may dominate the entire future of 217
 mental activity, and change the patterns of human culture in manners
 unpredictable today. But at the present stage of our ignorance, such
 surmises are profitless and lead all too readily into the quaking quagmires
 of mysticism. The known powers of the mind are already so astonishing that
 there is no need to invoke new ones.
  Let us first consider memory. No one has been able to form a reliable
  estimate of the number of facts or impressions the brain can store during
  a lifetime. There is considerable evidence that we never forget anything,
  we are just unable to put our hands on it at the moment. We seldom
  encounter really impressive feats of memory these days, because there is
  little need for them in our world of books and documents. Before the
  invention of writing, all history and literature had to be carried in the
  head and passed on by word of mouth. Even today, there are still men who
  can recite the whole of the Bible or the Koran, just as once they could
  recite Homer.
  The work of Dr. Wilder Penfield and his associates at Montreal has shown,
  in a dramatic fashion, that long-lost memories can be revived by the
  electrical stimulation of certain areas of the brain, almost as if a movie
  record were being played back in the mind. The subject relives, in vivid
  detail (color, scent, - sound) some past experience-L-but is aware that it
  is a memory, and not a present occurrence. Hypnotic techniques can also
  produce similar effects, a fact which was used to advantage by Freud for
  the treatment of mental disorders.
  When we discover how the brain manages to filter and store the blizzard of
  impressions pouring into it during every second of our lives, we may gain
  conscious or artificial control of memory. It would no longer be an
  inefficient, hit-and-miss process; if you wanted to reread a page of a
  newspaper you had seen at a certain moment thirty years ago, you could do
  just that, by stimulation of the proper brain cells. In a sense, this would
  be a kind of time travel into the past-perhaps the only kind that will ever
  be possible. It would be a wonderful power to possess, and-unlike many
  great powers-would appear to be almost wholly beneficial.
                218
  It could revolutionize legal procedures. No one could ever again answer
  "I've forgotten" to the classic question, "What were you doing on the night
  of the twenty-third?" Witnesses could no longer confuse the issue by
  accounts of what they thought they bad seen. Let us hope that memory
  stimulation would not be compulsory in the law courts, but if anyone
  pleaded this future version of the Fifth Amendment, the obvious conclusions
  would be drawn.
  And how wonderful it would be to go back through one's past, to revive old
  pleasures and, in the light of later knowledge, mitigate old sorrows and
  learn from ancient mistakes. It has been said, falsely, that a drowning
  man's life flashes before his eyes. Yet perhaps one day, in extreme old age
  those who no longer have any interest in the future ma~ be given the
  opportunity of reliving their past, and greeting again those they knew and
  loved when they were young. Even this, as we shall see later, might be not
  a preparation for death, but the prelude to a new birth.
  Perhaps even more important than the stimulation of old memories would be
  its inverse-the creation of new ones. It is hard to think of any invention
  that would be more valuable than the device which science-fiction writers
  have called a "mechanical educator." As depicted by authors and artists,
  this remarkable gadget usually resembles the old permanent-wave machine at
  a beauty salon, and it performs a rather similar function-though on the
  material inside the skull. It is not to be confused with the teaching
  machines now coming into widespread use, though one day these may be
  recognized as its remote ancestors.
  The mechanical educator could impress on the brain, in a matter of a few
  minutes, knowledge and skills which might otherwise take a lifetime to
  acquire. A very good analogy is the manufacture of a phonograph record; the
  music may have taken an hour to perform, but the disc is stamped out in a
  fraction of a second, and the plastic "remembere' the performance
  perfectly. This would have 219
 appeared impossible, even in theory, to the most imaginative of scientists
 only a century ago.
  Impressing information directly onto the brain, so that we can know things
  without ever learning them, seems equally impossible today; it must
  certainly remain out of the question until our understanding of mental
  processes has advanced immeasurably. Yet the mechanical educator-or some
  technique which performs similar functions -is such an urgent need that
  civilization cannot continue for many more decades without it. The
  knowledge in the world is doubling every ten years-and the rate is itself
  increasing. Already, twenty years of schooling are insufficient; soon we
  will have died of old age before we have learned how to live, and our
  entire culture will have collapsed owing to its incomprehensible
  complexity.
  In the past, whenever a need has arisen, it has always been filled with
  some promptitude. For this reason, though I have no idea how it would
  really operate, and suggest that it may be a complex of techniques rather
  than a piece of mechanical hardware, I feet fairly convinced that the
  mechanical educator will be invented. If it is not, then the line of
  evolution discussed in the next chapter will soon predominate, and the end
  of human culture is already in sight.
  There are many other possibilities, and some certainties, involving the
  direct manipulation of the brain. It has already been demonstrated that the
  behavior of animals-and men-can be profoundly modified if minute electrical
  impulses are fed into certain regions of the cerebral cortex. Personality
  can be completely altered, so that a cat will become terrified at the mere
  sight of a mouse, and a vicious monkey will become friendly and cooper-'
  ative.
  Perhaps the most sensational result of this experimentation, which may be
  fraught with more social consequences than the early work of the nuclear
  physicists, is the discovery of the so-called pleasure or rewarding centers
  in the brain. Animals with electrodes implanted in these areas quickly
  learn to operate the switch controlling the immensely enjoyable electrical
  stimulus, and develop 220
 such an addiction that nothing else interests them. MOnkeys have been known
 to press the reward button three times a second for eighteen hours on end,
 completely undistracted either by food or sex. There are also pain or
 punishment areas of the brain; an animal will work with equal
 single-mindedness to switch ofiF any current fed into these.
  The possibilities here, for good and evil, are so obvious that there is no
  point in exaggerating or discounting them. Electronic possession of human
  robots controlled from a central broadcasting station is something that
  even George Orwell never thought of; but it may be technically possible
  long before 1984.
  One of the many bizarre facts revealed by hypnosis is that false, but
  absolutely convincing, memories can be fed to a subject, who will later be
  prepared to swear that these things really happened to him. We have all
  experienced dreams so vivid that, on awaking, we confuse them with reality;
  for twenty years I have been haunted by the "memory" of a spectacular
  Spitfire crash which I have. never been able to classify as a real event or
  a hallucination.
  Artificial memories, if they could be composed, taped, and then fed into
  the brain by electrical or other means, would be a form of vicarious
  experience, far more vivid (because affecting all the senses) than anything
  that could be produced by the massed resources of Hollywood. They would,
  indeed, be the ultimate form of entertainment-a fictitious experience more
  real than reality. It has been questioned whether most people would want to
  live waking lives at all, if dream factories could fulfill every desire at
  the cost of a few cents for electricity.
  We should never forget that all our knowledge of the world around us comes
  through a very limited number of senses, of which sight and hearing are the
  most important. When these sense channels are bypassed, or their normal
  inputs interfered with, we experience illusions which have no external
  reality. One of the simplest ways of proving this is to sit for some time
  in a completely darkened room, and then to gently pinch your eyelids with
  your fin221
 gers. You will "see" the most fascinating shapes and colors, yet there is no
 light acting on the retina. The optic nerves have been fooled by pressure;
 if we knew the electrochemical coding whereby images are converted into
 sensations, we could give sight to men who have no eyes. For the much
 simpler, though stil extremely complex, sense of hearing, something like
 this has already been done on an experimental basis. The electrical pulses
 from microphones have been fed, after suitable processing, directly into the
 auditory nerves of deaf men, who have then been able to experience sound. I
 use the word "experience" rather than "hear," for we still have a long way
 togo before we can imitate the signaling system used by the ear; and that
 employed by the eye is vastly more complicated.
  This is a good point to mention a somewhat eerie experiment once carried
  out by the great physiologist Lord Adrian. Going one better than the
  witches in Macbeth, he took the eye of a toad and connected it to an
  amplifier and loudspeaker. As he moved about the laboratory, the dead eye
  imaged him on its retina, and the changing pattern of light and shade was
  converted into a series of audible clicks. The scientist was, in a crude
  way, using his sense of bearing to see through the eye of an animal.
  One can imagine almost unlimited extensions of this experiment. In
  principle, the sense impressions from any other living creature-animal or
  buman-might be wired directly into the appropriate sections of the brain.
  And so one could look through another man's eyes, and even gain some idea
  of what it must be like to inhabit a nonhuman body.
  We assume that our familiar senses give us a complete picture of our
  environment, but nothing could be further from the truth. We are stone-deaf
  and color-blind in a universe of impressions beyond the range of our
  senses. The world of a dog is a world of scent; that of a dolphin, a
  symphony of ultrasonic pulses as meaningful as sight. To the bee, on a
  cloudy day, the diffuse sunlight carries a direction sign utterly beyond
  our powers of discrimination, for it can detect the plane of vibration of
  the light 222
 waves. The rattlesnake strikes in total darkness toward the infrared glow of
 its living prey-as our guided missiles have learned to do only in the last
 few years. There are blind fish in muddy rivers who probe their opaque uni-
 verse with electric fields, the natural prototype of radar; and all fish
 have a curious organ, the lateral line, running along their bodies to detect
 vibrations and pressure changes in the water around them.
  Could we interpret such sense impressions, even if they were fed into our
  brains? Undoubtedly yes, but only after a great deal of training. We have
  to learn to use all our own,senses; a newborn baby cannot see, nor can a
  man whose sight is suddenly restored to him-though the visual mechanism in
  both cases may be functioning perfectly. The mind behind the brain must
  first analyze and classify the impulses reaching it, comparing them with
  other information from the external world-until it all builds up to a
  consistent picture. Not until then do we "see"; such integration should
  also be possible with other sense organs, though we will have to invent new
  verbs for the experience.
  The pilot of an aircraft, gathering data from his scores of dials and
  gauges, is performing a similar feat. He identifies himself with his
  vehicle, intellectually and perhaps even emotionally. One day, through
  telemetering: devices, we may be able to do the same with any animal. At
  last we will know the way of an eagle in the sky, a whale in the sea, or a
  tiger in the jungle. And so we will regain our kinship with the animal
  world, the loss of which is one of modem man's most grievous deprivations.
  To return to more down-to-earth concepts, there is no doubt that the range
  and delicacy of our own senses can be greatly extended by fairly simple
  means such as training or drugs. Anyone who has watched a blind man reading
  Braille, or locating objects by sound, will agree without hesitation. (I
  once saw a blind referee umpiring a table-tennis match-a feat I would not
  have believed possible. He bad even refereed world-championsbip games!)
  Though the blind provide the most spectacular cases of enhanced
  sensitivity, there are many other examples. Tea 223
 tasters, vintners, perfumers, deaf lip-readers, come to mind at once: So do
 those stage "clairvoyants" who can locate hidden objects by detecting almost
 imperceptible movements on the part of their aides.
  Th-ese feats are the result of intensive training, or compensation for the
  loss of some other sense. But as is well known (perhaps too well known)
  such drugs as mescaline and lysergic acid can also produce remarkable
  exaggerations of sensitivity, making the world appear far more real and
  vivid than in ordinary life. Even if this impression is wholly
  subjective-like the conviction of a drunken driver that he is controlling
  his car with Grand Prix skill-the phenomenon is an extremely interesting
  one, and may have important practical applications.
  A priceless mental power which is certainly attainable, because it has
  often been achieved, would be personal control over pain. The famous
  statement that "pain isn't real" may well be true-not that it is any help
  to most of us when we have the toothache. Most (but not all) pain serves a
  valuable function by acting as a warning sign, and those rare people who
  cannot experience it are in continual danger. One would not wish,
  therefore, to abolish pain, but it would be extremely useful to be able to
  bypass it, when it had served its purpose, by pressing a kind of mental
  override button.
  In the East, this is such a commonplace trick that no one is particularly
  surprised by it. I have seen, and Photographed in close-up, men and
  children walking ankle-deep in white-hot embers. Some were burned, but none
  felt any pain; they were in a state of hypnosis induced by religious
  ecstasy.'
  The recent development of sound analgesia proves that the mysterious West
  also has some tricks up its sleeve. In this technique, used with success by
  many dentists, the patient listens to a pair of earphones and has to keep
  ad-
  
  % One of my friends, while chatting with the chief fire walker at a Hindu
  shrine, once dropped a cigarette butt. The fire walker stood on it and
  promptly leaped into the air. So much for the "tough native soler theory;
  it is the psychological attitude--the mental preparation-that is
  all-imPortant-
                224
 justing a volume control so that he can hear music in the presence of
 background noise. While attending to this task, he is unable to feel any
 pain; it is as if all his incoming wires are too busy to accept any other
 messages. Probably this, Eke the performance of the fire walkers, is a form
 of self-hypnosis, but we can do it only with the aid of machines. Perhaps
 one day, like the yogas and fakirs, we may not need these mental crutches.
  From hypnosis it is a short step to sleep-that mysterious state in which we
  fritter away a third of our pitiably brief lives. No one has ever been able
  to prove that sleep is essential, though there is no doubt that we cannot
  do without it for more than a very few days. It appears to be the result of
  conditioning, over aeons of time, by the diurnal cycle of light and
  darkness. Because lack of illumination made it difficult to carry out any
  activities at night, most animals acquired the habit of sleeping until the
  sun returned. In much the same way, other animals acquired the habit of
  sleeping through the winter; but this does not mean to say that everyone
  has to go to bed from October to February. Nor need we always go to bed
  from 10 P.M. to 7 A.M.
  gome marine animals never sleep, although they may rest. Most sharks, for
  example, have to keep moving all their lives, or the flow of water through
  their gills will cease and lack of oxygen will kill them. The dolphins are
  confronted with an even worse dilemma; they -must return to the surface
  every two or three minutes to breathe, and so can never allow themselves a
  moment's unconsciousness. It would be very interesting to know if sleep
  occurs among the creatures of the ocean abyss, where there is never any
  change of light, and utter darkness has reigned for a hundred million
  years.
  The recent proof of the 'long-suspected fact that everyubody dreams has led
  to the theory that sleep is a psychological rather than a physiological
  necessity; as one scientist has put it, it allows us to go safely insane
  for a few hours a day. This seems a very implausible explanation, and it is
  just as likely that dreams are a random and accidental byproduct of the
  sleeping brain, for one would 225
 hardly expect so complex an organ to iwiteb itself off completely. (What do
 electronic computers dream about?)
  In any event, some prodigies, like Edison, have been able to lead active
  lives on two or three hours of sleep a day, while medical science has
  reported cases of individuals who have not slept for years at a time and
  have apparently been none the worse for it. Even if we cannot abolish sleep
  altogether, it would be an immense gain if we could concentrate it into a
  very few hours of really deep unconsciousness, chosen when convenient.
  It seems very likely that the development of global TV and cheap telephone
  networks cutting across all time zones will lead inevitably to a world
  organized on a twenty-four hour basis. This alone will make it imperative
  to minimize sleep; and it appears that the means for doing so is already at
  hand.
  Several years ago, the Russians put on the market a neat little "electric
  sleep apparatus" about the size of a shoe box and weighing only five
  pounds. Through electrodes resting on the eyelids and the nape,
  low-frequency pulses are applied to the cerebral cortex, and the subject
  promptly lapses into profound slumber. Though this device was apparently
  designed for medical use, it has been reported that many Soviet citizens
  are using it to cut down their sleeping time to a few hours a day.2
  Perhaps we shall always need the "balm of tired minds," but we will not
  have to spend a third of our lives applying it. On the other hand, there
  are occasions when protracted unconsciousness would be very valuable; it
  would be welcomed, for example, by convalescents recuperating after
  operations-and, above all, by space travelers on lengthy missions. It is in
  this connection that

  21 am sorry I ever mentioned this wretched device, and to quench a further
  flood of letters wish to make it clear that it is only obtainable through
  authorized medical channels-and I do not, repeat not, know where it can be
  purchased. No furffier letters on the subject will be read-let alone
  answered.
                226
 serious thought is now being given to the possibility of suspended
 animation, which we will need if we are ever to reach the stars, or travel
 more than a very few light-years from the neighborhood of the Sun.
  A safe and practical form of suspended animationwhich involves no medical
  impossibility and may indeed be regarded as an extension of
  anesthesia--could have major effects upon society. Men suffering from
  incurable diseases might choose to leapfrog ten or twenty years, in the
  hope that medical science might have caught up with their condition. The
  insane, and criminals beyond our present powers of redemption, might also
  be sent forward in time, in the expectation that the future could salvage
  them. Our descendants might not appreciate this legacy, of course; but at
  least they could not send it back.
  All this assumes-though no one has yet proved itthat the legend of Rip van
  Winkle is scientifically sound, and that the processes of aging would be
  slowed down, or even checked, during suspended animation. Thus a sleeping
  man could travel down the centuries, stopping from time to time and
  exploring the future as today we explore space. There are always misfits in
  every age who might prefer to do this, if they were given the opportunity,
  so that they could see the world that will exist far beyond their normal
  span of life.
  And this brings us to what is, perhaps, the greatest enigma of all. Is
  there a normal span of life, or do all men really die by accident? Though
  we now live, on the average, far longer than our ancestors, the absolute
  limit does not seem to have altered since records became available. The
  Biblical three-score-years-and-ten is still as valid t(>.day as it was four
  thousand years ago.
  No human being has been proved to have lived more than 115 years; the much
  higher figures often quoted are almost certainly due to fraud or error.
  Man, it seems, is the longest lived of all the mammals, but some fish and
  tortoises may attain their second century. And trees, of course, have
  incredible life-spans; the oldest known living organism is a small and
  unprepossessing brittlecone pine 227
 in the foothills of the Sierra Nevada. It has been growing, though hardly
 flourishing, for 4,600 years3.
  Death (though not aging) is obviously essential for progress, both social
  and biological. Even if it did not perish from overpopulation, a world of
  immortals would soon stagnate. In every sphere of human activity, one can
  find examples of the stultifying influence of men who have outlived their
  usefulness. Yet death-like sleep--does not appear to be biologically
  inevitable, even if it is an evolutionary necessity.
  Our bodies are not like machines; they never wear out, because they are
  continually rebuilt from new materials. If this process were uniformly
  efficient, we would be immortal. Unfortunately, after a few decades
  something seems to go wrong in the repair-and-maintenance department; the
  materials are as good as ever, but the old plans get lost or ignored, and
  vital services are not properly restored when they break down. It is as if
  the cells of the body can no longer remember the jobs they once did so
  well.
  The way of avoiding a failure of memory is to keep better records, and
  perhaps one day we will be able to help our bodies to do just that. The
  invention of the alphabet made mental forgetfulness no longer inevitable;
  the more sophisticated tools of future medicine may cure physical
  forgetfulness, by allowing us to preserve, in some suitable storage device,
  the ideal prototypes of our bodies. Deviations from the norm could then be
  checked from time to time and corrected, before they became serious.
  Because biological immortality and the preservation of youth are such
  potent lures, men will never cease to search for them, tantalized by the
  examples of creatures who live for centuries and undeterred by the
  unfortunate experience of Dr. Faust. It would be foolish to imagine that
  this search will never be successful, down all the ages that lie ahead.
  Whether success would be desirable is quite another matter.
 The body is the vehicle of the brain, and the brain is

 3 See National Geographic Magazine, March 1958.
                228
 the seat of the mind. In the past, this triad has been inseparable, but it
 will not always be so. If we cannot prevent our bodies from disintegrating,
 we may replace them while there is yet time.
  The replacement need not be another body of flesh and blood; it could be a
  machine, and this may represent the next stage in evolution. Even if the
  brain is not immortal, it could certainly live much longer than the body
  whoi6 diseases and accidents eventually bring it low. Many years ago, in a
  famous series of experiments, Russian surgeons kept a dog's head alive for
  some days by purely mechanical means. I do not know if they have yet
  succeeded with men, but I shall be surprised if they have not tried.
  If you think that an immobile brain would lead a very dull sort of life,
  you have not fully understood what has already been said about the senses.
  A brain connected by wire or radio links to suitable organs could
  participate in any conceivable experience, real or imaginary. When you
  touch something, are you really aware that your brain is not at your
  fingertips, but three feet away? And would you notice the difference, if
  that three feet were three thousand miles? Radio waves make such a journey
  more swiftly than the nervous impulses can travel along your arm.
  One can imagine a time when men who still inhabit organic bodies are
  regarded with pity by those who have passed on to an infinitely richer mode
  of existence, capable of throwing their consciousness or sphere of
  attention instantaneously to any point on land, sea, or sky where there is
  a suitable sensing organ. In adolescence we leave childhood behind; one day
  there may be a second and more portentous adolescence, when we bid farewell
  to the flesh.
  But even if we can keep the brain alive indefinitely, surely in the end it
  would be clogged with memories, overlaid like a palimpsest with so many
  impressions and experiences that there was no room for more? Eventually,
  perhaps yes, though I would repeat again that we have no idea of the
  ultimate capacity of a well-trained mind, even without the mechanical aids
  which will certainly become 229
 available. As a- good round figure, a thousand years would i6em. to be about
 the ultimate limit for continuous human existence--though suspended
 animation might spread this millennium across far longer vistas of time.
  Yet there may be a way past even this barrier, as I suggested in the novel
  The City and the Star.4 Ibis was an attempt to envisage a virtually eternal
  society, in the closed city of Diaspar a billion years from now. I would
  Eke to end by quoting the words in which my hero learns the facts of life
  from his old tutor, Jeserac:

  A human being, Eke any other object, is defined by its structur*e--its
  pattern. Ile pattern of a man is incredibly complex; yet Nature was once
  able to pack that pattern into a tiny cell, too small for the eye to see.
 ~ What Nature can do, Man can do also, in his own way. We do not know how
 long the task took. A million years, perhaps-but what is that? In the end
 our ancestors learned to analyse and store the information that would define
 any specific human being-and to use that information to recreate the
 original.
  The way in which information is stored is of no importance; all that
  matters is the information itself. It may be in the form of written words
  on paper, of varying magnetic fields, or patterns of electric charge. Men
  have used all these methods of storage, and many others. Suffice to say
  that long ago they were able to store themselves-or, to be more precise,
  the disembodied patterns from which they could be called back into ex-
  istence.
  In a little while, I shall prepare to leave this life. I shall go back
  through my memories, editing them and cancelling those I do not wish to
  keep. Then I shall walk into the Hall of Creation, but through a door that
  you have never seen. This old body will cease to exist, and so will
  consciousness itself. Nothing will be left of

  4Recently republished in the anthology, From the Ocean, From the Stars, New
  York: Harcourt, Brace & World, Im
               230
 Jeserac but a galaxy of electrons frozen in the heart of a crystal.
   I shall sleep, and without dreams. Then one day, perhaps a hundred
   thousand years from now, I shall find myself in a new body, meeting those
   who have been chosen to be my guardians.... At first I will know nothing
   of Diaspar and will have no memories of what I was before. Those memories
   will slowly return, at the end of my infancy, and I will build upon them
   as I move forward into my new cycle of existence.
   This is the pattern of our lives.... We have all been here many, many
   times before, though as the intervals of nonexistence vary according to
   random laws this present population will never repeat itself. The new
   Jeserac will have new and different friends and interests, but the old
   Jeserac-as much of him as I wish to save-will still exist.
   So at any moment only a hundredth of the citizens of Diaspar live and walk
   in its streets. The vast majority slumber in the memory banks, waiting for
   the signal that will call them forth on to the stage of existence once
   again. And so we have continuity, yet changeimmortality, but not
   stagnation....

  Is this fantasy? I do not know; but I suspect that the truths of the far
  future will be stranger still. In the next chapter, we will attempt to
  glimpse some of them.

  EprLor,uE: Recent work on "biological feedback," when brain impulses are
  computer-processed and then fed back through the senses, has opened up some
  very exciting possibilities. It appears that after a few hours of training
  with this equipment, subjects can perform feats of body control matching
  those of the most talented adepts of yoga. (See, e.g., Dave Rorvik, When
  Man Becomes Machine.)

               231
                               18_

 The Obsolescence of Man

 About a million years ago, an unprepossessing primate discovered that his
 forelimbs could be used for other purposes besides locomotion. Objects like
 sticks and stones could be grasped-and, once grasped, were useful for
 killing game, digging up roots, defending or attacking, and a hundred other
 jobs. On the third planet of the Sun, tools had appeared; and the place
 would never be the same again.
  Tbe first users of tools were not men-a fact appreciated only in the last
  year or two-but prehuman anthropoids; and by their discovery they doomed
  themselves. For even the most primitive of tools, such as a naturally
  pointed stone that happens to fit the hand, provides a tremendous physical
  and mental stimulus to the user. He has to walk erect; he no longer needs
  huge canine teeth--since sharp flints can do a better job-and be must
  develop manual dexterity of a high order. These are the specifications of
  Homo sapiens; as soon as they start to be filled, all earlier models are
  headed for rapid obso232
 lescence. To quote Professor Sherwood Washburn of the University of
 California's anthropology department: "It was the success of the simplest
 tools that started the whole -trend of human evolution and led to the
 civilizations of today."
  Note that phrase-"the whole trend of human evolution." The old idea that
  man invented tools is therefore a misleading half-truth; it would be more
  accurate to say that tools invented man. They were very primitive tools, in
  the hands of creatures who were little more than apes. Yet they led to
  us-and to the eventual extinction of the ape-men who first wielded them.
  Now the cycle is about to begin again; but neither history nor prehistory
  ever exactly repeats itself, and this time there will be a fascinating
  twist in the plot. The tools the ape-men invented caused them to evolve
  into their successor, Homo sapiens. The tool we have invented is our
  successor. Biological evolution has given way to a far more rapid
  process-technological evolution. To put it bluntly and brutally, the
  machine is going to take over.
  This, of course, is hardly an original idea. That the creations of man's
  brain might one day threaten and perhaps destroy him is such a tired clichg
  that no self-respecting science-fiction writer would dare to use it. It
  goes back, through Capek's RX.R., Samuel Butler' Erewhon, Mary Shelley's
  Frankenstein and the Faust legend to the mysterious but perhaps not wholly
  mythical figure of Daedalus, King Minos' one-man office of scientific
  research. For at least three thousand years, therefore, a vocal minority of
  mankind has had grave doubts about the ultimate outcome of technology. From
  the self-centered, human point of view, these doubts are justified. But
  that, I submit, will not be the only-or even the most important-point of
  view for much longer.
  When the first large-scale electronic computers appeared some twenty years
  ago, they were promptly nicknamed "Giant Brains"-and the scientific
  community, as a whole, took a poor view of the designation. But the
  scientists objected to the wrong word. The electronic computers were not
  giant brains; they were dwarf brains, and 233
 they still are, though they have grown a hundredfold within less than one
 generation of mankind. Yet even in their present flint-ax stage of
 evolution, they have done things which not long ago almost everyone would
 have claimed to be impossible-such as translating from one language to
 another, composing music, and playing a fair game of chess. And much more
 important than any of these infant jeux desprit is the fact that they have
 breached the barrier between brain and machine.
  This is one of the greatest-and perhaps one of the last-breakthroughs in
  the history of human thought, like the discovery that the Earth moves round
  the Sun, or that man is part of the animal kingdom, or that E = MC2 . All
  these ideas took time to sink in, and were frantically denied when first
  put forward. In the same way it will take a little while for men to realize
  that machines can not only think, but may one day think them off the face
  of the Earth.
  At this point you may reasonably ask: "Yes-but what do you mean by think?"
  I propose to sidestep that question, using a neat device for which I am
  indebted to the English mathematician A. M. Turing. Turing imagined a game
  played by two teleprinter operators in separate rooms-this impersonal link
  being used to remove all clues given by voice, appearance, and so forth.
  Suppose one operator was able to ask the other any questions he wished, and
  the other had to make suitable replies. If, after some hours or days of
  this conversation, the questioner could not decide whether his telegraphic
  acquaintance was human or purely mechanical, then he could hardly deny that
  he/it was capable of thought. An electronic brain that passed this test
  would, surely, have to be regarded as an intelligent entity. Anyone who
  argued otherwise would merely prove that he was less intelligent than the
  machine; he would be a splitter of nonexistent hairs, like the scholar who
  proved that the Odyssey was not written by Homer, but by another man of the
  same name.
  We are still decades-but not centuries-from building such a machine, yet
  already we are sure that it could be done. If Turing's experiment is never
  carried out, it will 234
 merely be because the intefligent machines of the future will have better
 things to do with their time than conduct extended conversations with men.
 I often talk with my dog, but I don't keep it up for long.
  The fact that the great computers of today are still high-speed morons,
  capable of doing nothing beyond the scope of the instructions carefully
  programmed into them, has given many people a spurious sense of security.
  No machine, they argue, can possibly be more intelligent than its
  makers-the men who designed it, and planned its functions. It may be a
  million times faster in operation, but that is quite irrelevant. Anything
  and everything that an electronic brain can do must also be within the
  scope of a human brain, if it had sufficient time and patience. Above all,
  it is maintained, no machine can show originality or creative power or the
  other attributes which are fondly labeled "human."
  The argument is wholly fallacious; those who still bring it forth are like
  the buggy-whip makers who used to poke fun at stranded Model T's. Even if
  it were true, it could give no comfort, as a careful reading of these
  remarks by Dr. Norbert Wiener will show:

 This attitude (the assumption that machines cannot possess any degree of
 originality) in my opinion should be rejected entirely.... It is my thesis
 that machines can and do transcend some of the limitations of their
 designers.... It may well be that in principle we cannot make any machine,
 the elements of whose behaviour we cannot comprehend sooner or later. This
 does not mean in any way that we shall be able to comprehend them in
 substantially less time than the operation of the machine, nor even within
 any given number of years or generations.... This means that though they are
 theoretically subject to human criticism, such criticism may be ineffective
 until a time long after it is relevant.

  In other words, even machines less intelligent than men might escape from
  our control by sheer speed of operation. And in fact, there is every reason
  to suppose that 235
 machines will become much more intelligent than their builders, as well as
 incomparably faster.
  There are still a few authorities who refuse to grant any degree of
  intelligence to machines, now or in the future. This attitude shows a
  striking parallel to that adopted by the chemists of the early nineteenth
  century. It was known then that all living organisms are formed from a few
  common elements-mostly carbon, hydrogen, oxygen, and nitrogen-but it was
  firmly believed that the materials of life could not be made from "mere"
  chemicals alone. There must be some other ingredient-some essence or vital
  principle, forever unknowable to man. No chemist could ever take carbon,
  hydrogen, and so forth and combine them to form any of the substances upon
  which life was based. There was an impassable barrier between the worlds of
  "inorganic" and "organic" chemistry.
  This mystique was destroyed in 1828, when W6hler synthesized urea, and
  showed that there was no difference at all between the chemical reactions
  taking place in the body, and those taking place inside a retort. It was a
  terrible shock to those pious souls who believed that the mechanics of life
  must always be beyond human understanding or imitation. Many people are
  equally shocked today by the suggestion that machines can think, but their
  dislike of the situation will not alter it in the least.
  Since this is not a treatise on computer design, you will not expect me to
  explain how to build a thinking machine. In fact, it is doubtful if any
  human being will ever be able to do this in detail, but one can indicate
  the sequence of events that will lead from H. sapiens to A sapiens. The
  first two or three steps on the road have already been taken, machines now
  exist that can learn by experience, profiting from their mistakes
  and-unlike human beings-never repeating them. Machines have been built
  which do not sit passively waiting for instructions, but which explore the
  world around them in a manner which can only be called inquisitive. Others
  look for proofs of theorems in mathematics or logic, and sometimes come up
  with surprising solutions that had never occurred to their makers.
                236
  These faint glimmerings of original intelligence are confined at the moment
  to a few laboratory models; they are wholly lacking in the giant computers
  that can now be bought by anyone who happens to have a few hundred thousand
  dollars to spare. But machine intelligence will grow, and it will start to
  range beyond the bounds of human thought as soon as the second generation
  of computers appears-the generation that has been designed, not by men, but
  by other, "almost intelligent" computers. And not only designed, but also
  built-for they will have far too many components for manual assembly.
  It is even possible that the first genuine thinking machines may be grown
  rather than constructed; already some crude but very stimulating
  experiments have been carried out along these lines. Several artificial
  organisms have been built which are capable of rewiring themselves to adapt
  to changing circumstances. Beyond this there is the possibility of
  computers which will start from relatively simple beginnings, be programmed
  to aim at specific goals, and search for them by constructing their own
  circuits, perhaps by growing networks of threads in a conducting medium.
  Such a growth may be no more than a mechanical analogy of what happens to
  every one of us in the first nine months of our existence.
  All speculations about intelligent machines are inevitably
  conditioned-indeed, inspired-by our knowledge of the human brain, the only
  thinking device currently on the market. No one, of course, pretends to
  understand the fall workings of the brain, or expects that such knowledge
  will be available in any foreseeable future. (It is a nice philosophical
  point as to whether the brain can ever, even in principle, understand
  itself.) But we do know enough about its physical structure to draw many
  conclusions about the limitations of "brains"--wbether organic or
  inorganic.
  There are approximately ten billion separate switches--or neurons-inside
  your skull, "wired" together in circuits of unimaginable complexity. Ten
  billion is such a large number that, until recently, it could be used as an
  argument against the achievement of mechanical intelli237
 gence. About twenty years ago a famous neurophysiolo
 gist made a statement (still produced like some protective
 incantation by the advocates of cerebral supremacy) to
 the effect that an electronic model of the human brain
 would have to be as large as the Empire State Building,
 and would need Niagara Falls to keep it cool when it was
 running.                         I
  This must now be classed with such interesting pronouncements as, "No
  heavier than air machine will ever be able to fly." For the calculation was
  made in the days of the vacuum tube (remember it?), and the transistor has
  now completely altered the picture. Indeed-such is the rate of
  technological progress today-the transistor itself is being replaced by
  still smaller and faster devices, based upon abstruse principles of quantum
  physics. If the problem was merely one of space, today's electronic tech-
  niques would allow us to pack a computer as complex as the human brain on
  to a single floor of the Empire State Building.
  Interlude for agonizing reappraisal. It's a tough job keeping up with
  science, and since I wrote that last paragraph the Marquardt Corporation's
  Astro Division has announced a new memory device which could store inside
  a six-foot cube all information recorded during the last 10,000 years. This
  means, of course, not only every book ever printed, but everything ever
  written in any language on paper, papyrus, parchment, or stone. It
  represents a canacity untold millions of times greater than that of a sin
  ' Lyle human memory, and though there is a mighty gulf between merely
  storing information and thinking creatively-the Library of Congress has
  never written a book-it does indicate that mechanical brains of enormous
  power could be quite small in physical size.
  This should not surprise anyone who remembers how radios have shrunk from
  the bulky cabinet models of the thirties to the vest-pocket (yet much more
  sophisticated) transistor sets of today. And the shrinkage is just gaining
  momentum, if I may employ such a mind-boggling phrase. Radio receivers the
  size of lumps of sugar have now been built; before long, they will be the
  size not of 238
 lumps but of grains, for the slogan of the micro-miniaturization experts is
 "If you can see it, it's too big."
  Just to prove that I am not exaggerating, here are some statistics you can
  use on the next hi-fi fanatic who takes you on a tour of his wall-to-wall
  installation. During the 1950's, the electronic engineers learned to pack
  up to a hundred thousand components into one cubic foot. (To give a basis
  of comparison, a good hi-fi set may contain two or three hundred
  components, a domestic radio about a hundred.) At the beginning of the
  1960's, the attainable figure was about a million components per cubic
  foot; in the 1970's, thanks to developments in solid-state engineering, it
  was heading for 100,000,000.
  Fantastic though this last figure is, the human brain surpasses it by a
  thousandfold, packing its ten billion neurons into a tenth of a cubic foot.
  And although smallness is not necessarily a virtue, even this may be
  nowhere near the limit of possible compactness.
  For the cells composing our brains are slow-actirIg. bulky, and wasteful of
  energy-compared with the scarcely more than atom-sized computer elements
  that are theoretically possible. The mathematician John von Neumann once
  calculated that electronic cells could be ten billion times more efficient
  than protoplasmic ones; already they are a million times swifter in
  operation, and speed can often be traded for size. If we take these ideas
  to their ultimate conclusion, it appears that a computer equivalent in
  power to one human brain need be no bigger than a matchbox.
  This slightly shattering thought becomes more reasonable when we take a
  critical look at flesh and blood and bone as engineering materials. All
  living creatures are marvelous, but let us keep our sense of proportion.
  Perhaps the most wonderful thing about Life is that it works at all, when
  it has to employ such extraordinary materials, and has to tackle its
  problems in such roundabout ways.
  As a perfect example of this, consider the eye. Suppose you were given the
  problem of designing a camera-for that, of course, is what the eye is-which
  has to be con239
 structed entirely of water and jelly, without using a scrap of glass, metal,
 or plastic. Obviously, it can't be done.
  You're quite right; the feat is impossible. The eye is an evolutionary
  miracle, but it's a lousy camera. You can prove this while you're reading
  the next sentence.
  Here's a medium-length word: -photography. Close one eye and keep the other
  fixed-repeat, fixed-on that center "g." You may be surprised to discover
  thatunless you cheat by altering the direction of your gazeyou cannot see
  the whole word clearly. It fades out three or four letters to the right and
  left.
  No camera ever built-even the cheapest-has as poor an optical performance
  as this. For color vision also, the human eye is nothing to boast about; it
  can operate only over a small band of the spectrum. To the worlds of the
  infrared and ultraviolet, visible to bees and other insects, it is
  completely blind.
  We are not conscious of these limitations because we have grown up with
  them, and indeed if they were corrected the brain would be quite unable to
  handle the vastly increased flood -of information. But let us not make a
  virtue of a necessity; if our eyes had the optical performance of even the
  cheapest miniature camera, we would live in an unimaginably richer and more
  colorful world.
  These defects are due to the fact that precision scientific instruments
  simply cannot be manufactured from living materials. With the eye, the ear,
  the nose-indeed, all the sense organs-evolution has performed a truly
  incredible job against fantastic odds. But it will not be good enough for
  the future; indeed, it is not good enough for the present.
  There are some senses that do not exist, that can probably never be
  provided by living structures, and that we need in a hurry. On this planet,
  to the best of our knowledge, no creature has ever developed organs that
  can detect radio waves or radioactivity. Though I would hate to lay down
  the law and claim that nowhere in the universe can there be organic Geiger
  counters or living TV sets, I think it highly improbable. There are some
  240
 jobs that can be done only by vacuum tubes or magnetic fields or electron
 beams, and are therefore beyond the capability of purely organic structures.
  There is another fundamental reason living machines such as you and I
  cannot hope to compete with nonliving ones. Quite apart from our poor
  materials, we are handicapped by one of the toughest engineering
  specifications ever issued. What sort of performance would you expect from
  a machine which has to grow several billionfold during the course of
  manufacture-and which has to be completely and continuously rebuilt,
  molecule by molecule, every few weeks? This is what happens to all of us,
  all the time; you are not the man you were last year, in the most literal
  sense of the expression.
 - Most of the energy and effort required to run the body goes into its
 perpetual tearing down and rebuilding-a cycle completed every few weeks. New
 York City, which is a very much simpler structure than a man, takes hundreds
 of times longer to remake itself. When one tries to picture the body's
 myriads of building contractors and utility companies all furiously at work,
 tearing up arteries and nerves and even bones, it is astonishing that there
 is any energy left over for the business of thinking.
  Now I am perfectly well aware that many of the "limitations" and "defects"
  just mentioned are nothing of the sort, looked at from another point of
  view. Living creatures, because of their very nature, can evolve from
  simple to complex organisms. They may well be the only path by which
  intelligence can be attained, for it is a little difficult to see how a
  lifeless planet can progress directly from metal ores and mineral deposits
  to electronic computers by its own unaided efforts.
  Though intelligence can arise only from life, it may then discard it.
  Perhaps at a later stage, as the mystics have suggested, it may also
  discard matter; but this leads us in realms of speculations which an
  unimaginative person like myself would prefer to avoid.
  One often-stressed advantage of living creatures is that they are
  self-repairing and reproduce themselves with ease-indeed, with enthusiasm.
  This superiority over 241
 machines will be short-lived; the general principles underlying the
 construction of self-repairing and self-reproducing machines have already
 been worked out. There is, incidentally, something ironically appropriate in
 the fact that A. M. Turing, the brilliant mathematician who pioneered in
 this field and first indicated how thinking machines might be built,
 apparently committed suicide a few years after publishing his results.
  The greatest single stimulus to the evolution of mechanical-as opposed to
  organic-intelligence is the challenge of space. Only a vanishingly small
  fraction of the universe is directly accessible to mankind, in the sense
  that we can live there without elaborate protection or mechanical aids. If
  we generously assume that humanity's potential Lebensraum extends from sea
  level to a height of three miles, over the whole Earth, that gives us a
  total of some half billion cubic miles. At first sight this is an
  impressive figure, especially when you remember that the entire human race
  could be packaged into a one-mile cube. But it is absolutely nothing, when
  set against Space with a capital "S." Our present telescopes, which Are
  certainly not the last word on the subject, sweep a volume at least a
  million million million million million million million million million
  million times greater.
  Though such a number is, of course, utterly beyond conception, it can be
  given a vivid meaning. If we reduced the known universe to the size of the
  Earth, then the portion in which we can live without space suits and
  pressure cabins is about the size,of a single atom
  It is true that, one day, we are going to explore and colonize many other
  atoms in this Earth-sized volume, but it will be at the cost of tremendous
  technical efforts, for most of our energies will be devoted to protecting
  our frail and sensitive bodies against the extremes of temperature,
  pressure, or gravity found in space and on other worlds. Within very wide
  limits, machines are indifferent to these extremes. Even more important,
  they can wait patiently through the years and the centuries that will be
  needed for travel to the far reaches of the universe.
Creatures of flesh and blood such as ourselves can ex242

                                   it,
 plore space and win control over infinitesimal fractions of it. But only
 creatures of metal and plastic can ever really conquer it, as indeed they
 have already started to do. The tiny brains of our Pioneers and Mariners
 barely hint at the mechanical intelligence that will one day be launched at
 the stars.
  It may well be that only in space, confronted with environnients fiercer
  and more complex than any to be found upon this planet, will intelligence
  be able to reach its fullest stature. Like other qualities, intelligence is
  developed by struggle and conflict; in the ages to come, the dullards may
  remain on placid Earth, and real genius will flourish only in space-the
  realm of the machine, not of flesh and blood.
  A striking parallel to this situation can already be found on our planet.
  Some millions of years ago, the most intelligent of the mammals withdrew
  from the battle of the dry land and returned to their ancestral home, the
  sea. They are still there, with brains larger and potentially more powerful
  than ours. But (as far as we know) they do not use them; the static
  environment of the sea makes little call upon intelligence. The porpoises
  and whales, which might have been our equals and perhaps our superiors had
  they remained on land, now race in simpleminded and innocent ecstasy beside
  the new sea monsters carrying a hundred megatons of death. Perhaps they,
  not we, made the right choice; but it is too late to join them now.
  If you have followed me so far, the protoplasmic computer inside your skull
  should now be programmed to accept the idea-at least for the sake of
  argument-that machines can be both more intelligent and more versatile than
  men, and may well be so in the very near future. So it is time to face the
  question: Where does that leave man?
  I suspect that this is not a question of very great importance-except, of
  course, to man. Perhaps the Neanderthalers made similar plaintive noises,
  around 100,000 B.c., when H. sapiens appeared on the scene, with his ugly
  vertical forehead and ridiculous protruding chin. Any 243
 Paleolithic philosopher who gave his colleagues the right answer would
 probably have ended up in the cooking pot; I am prepared to take that risk.
  The short-term answer may indeed be cheerful rather than depressing. There
  may be a brief golden age when men will glory in the power and range of
  their new partners. Barring war, this age lies directly ahead of us. As Dr.
  Simon Remo put it recently: "The extension of the human intellect by
  electronics will become our greatest occupation within a decade." That is
  undoubtedly true, if we bear in mind that at a somewhat later date the word
  66 extension" may be replaced by "extinction."
  One of the ways in which thinking machines will be able to help us is by
  taking over the humbler tasks of life, leaving the human brain free to
  concentrate on higher things. (Not, of course, that this is any guarantee
  that it will do so.) For a few generations, perhaps, every man will go
  through life with an electronic companion, which may be no bigger than
  today's transistor radios. It will dfigrow up" with him from infancy,
  learning his babits, his business affairs, taking over all the minor chores
  like routine correspondence and income-tax returns and engagements. On
  occasion it could even take its master's place, keeping appointments be
  preferred to miss, and then reporting back in as much detail as be desired.
  It could substitute for him over the telephone so completely that no one
  would be able to tell whether man or machine was speaking; a century from
  now, Turing's "game" may be an integral part of our social lives, with
  complications and possibilities which I leave to the imagination.
  You may remember that delightful robot, Robbie, from the movie Forbidden
  Planet. (One of the three or four movies so far made that anyone interested
  in science fiction can point to without blushing; the fact that the plot
  was Shakespeare's doubtless helped.) I submit, in all seriousness, that
  most of Robbie's abilities-together with those of a better known character,
  Jeeves-will one day be incorporated in a kind of electronic
  companion-secretary-valet. It will be much smaller and neater than the
  walking jukeboxes or mechanized suits of armor which 244
 Hollywood presents, with typical lack of imagination, when it wants to
 portray a robot. And it will be extremely talented, with quick-release
 connectors allowing it to be coupled to an unlimited variety of sense organs
 and limbs. It would, in fact, be a kind of general purpose, disembodied
 intelligence that could attach itself to whatever tools were needed for any
 particular occasion. One day it might be using microphones or elec-ic
 typewriters or TV cameras; on another, automobiles or airplanes-or the
 bodies of men and animals.
  And this is, perhaps the moment to deal with a conception which many
  peol-Je find even more horrifying than the idea that machines will replace
  or supersede us. It is the idea, already mentioned in the last chapter,
  that they may combine with us.
  I do not know who first thought of this; probably the physicist J. D.
  Bernal, who in 1929 published an extraordinary book of scientific
  predictions called The World, the Flesh and the Devil. In this slim volume
  recently reprinted by the Indiana University Press, Bernal decided that the
  numerous limitations of the human body could be overcome only by the use of
  mechanical attachments or substitutes-until, eventually, all that might be
  left of man's original organic body would be the brain.
  This idea is already far more plausible than when Bernal advanced it, for
  in the last few decades we have seen the development of mechanical hearts,
  kidneys, lungs, and other organs, and the wiring of electronic devices
  directly into the human nervous system.
  Olaf Stapledon developed this theme in his wonderful history of the future,
  Last and First Men, imagining an age of immortal "giant brains," many yards
  across, living in beehive-shaped cells, sustained by pumps and chemical
  plants. Tbouvh completely immobile, their sense organs could be wherever
  they wished, so their center of awareness--or consciousness, if you
  like--could be any~-where on Earth or in the space above it. This is an
  important point which we-who carry our brains around in the same fragile
  structure as our eyes, ears, and other sense organs, often with disastrous
  results-may easily fail to 245
 appreciate. Given perfected telecommunications, a fixed brain is no
 handicap, but rather the reverse. Your present brain, totally imprisoned
 behind its walls of bone, communicates with the outer world and receives its
 impressions of it over the telephone wires of the central nervous
 system-wires varying in length from a fraction of an inch to several feet.
 You would never know the diflerence if those "wires" were actually hundreds
 or thousands of miles long, or included mobile radio links, and your brain
 never moved at all.
  In a crude way-yet one that may accurately foreshadow the future-we have
  already extended our visual and tactile senses away from our bodies. The
  men who now work with radio isotopes, handling them with remotely
  controlled mechanical fingers and observing them by television, have
  achieved a partial separation between brain and sense organs. They are in
  one place; their minds effectively in another.
  Recently the word "Cyborg" (cybernetic organism) has been coined to
  describe the machine-animal of the type we have been discussing. Doctors
  Manfred Clynes and Nathan Kline of Rockland State Hospital, Orangeburg, New
  York, who invented the name, define a Cyborg in these stirring words: "an
  exogenously extended organizational complex functioning as a homeostatic
  system." To translate, this means a body which has machines hitched to it,
  or built into it, to take over or modify some of its functions.
  I suppose one could call a man in an iron lung a Cy
 borg, but the concept has far wider implications than this.
 One day we may be able to enter into temporary unions
 with any sufficiently sophisticated machines, thus being
 able not merely to control but to become a spaceship or a
 submarine or a TV network. This would give far more
 than purely intellectual satisfaction; the thrill that can be
 obtained from driving a racing car or flying an airplane
 may be only a pale ghost of the excitement our I great
 grandchildren may know, when the individual human con
 sciousness is free to roam at will from machine to
                246
 machine, through a the reaches of sea and sky and space.
  But how long will this partnership last? Can the synthesis of man and
  machine ever be stable, or will the purely organic component become such a
  hindrance that it has to be discarded? If this eventually happens-and I
  have given good reasons for thinking that it must-we have nothing to
  regret, and certainly nothing to fear.
  The popular idea, fostered by comic strips and the cheaper forms of science
  fiction, that intelligent machines must be malevolent entities hostile to
  man, is so absurd that it is hardly worth-wasting energy to refute it. I am
  almost tempted to argue that only unintelligent machines can be malevolent;
  anyone who has tried to start a balky outboard will probably agree. Those
  who picture machines as active enemies are merely projecting their own
  aggressive instincts, inherited from the jungle, into a world where such
  things do not exist. The higher the intelligence, the greater the degree of
  cooperativeness. If there is ever a war between men and machines, it is
  easy to guess who will start it.
  Yet however friendly and helpful the machines of the future may be, most
  people will feel that it is a rather bleak prospect for humanity if it ends
  up as a pampered specimen in some biological museum-even if that museum is
  the whole planet Earth. This, however, is an attitude I find impossible to
  share.
  No individual exists forever; why should we expect our species to be
  immortal? Man, said Nietzsche, is a rope stretched between the animal and
  the superhuman-a rope across the abyss. That will be a noble purpose to
  have served.

 247
                               19

 The Long Twilight

 Looking back over the preceding chapters, I am aware of numerous
 inconsistencies and some omissions. As for the first, I am unrepentant, for
 the reasons given in the introduction. In attempting to explore rival and
 indeed contradictory possibilities, I have tried to go to the end of the
 line in each case; sometimes this 1has led to a sense of pride in man's past
 and future achievements-sometimes to a conviction that we represent only a
 very early stage in the story of evolution, destined to pass away leaving
 little mark on the universe. Every reader must choose his own standpoint
 here; but whatever position he adopts, it would be advisable to leave a line
 of retreat.
  Concerning the omissions, some are due to a frank lack of interest on my
  part, others to a feeling that I did not have the necessary qualifications
  to discuss them. The last reason accounts for the fact that medical and
  biological themes were not developed in much more detail. It seems
  perfectly possible that many future achievements of production, sensing,
  data-processing, and manufacture may be based on living or quasi-living
  creatures, rather than 248
 inorganic devices. Nature provides, at zero cost, so many marvelous
 mechanisms that it seems foolish not to employ them to the utmost. I have
 little doubt that our descendants will use many intelligent animals to do
 jobs that could otherwise be performed only by very expensive and
 sophisticated robots.
  In this connection, I might have discussed the attempts now being made by
  Dr. Lilly and others to establish communication with dolphins.' I might
  have said a good deal more about the possibility of contacting
  extraterrestrial intelligences by radio or laser (coherent light) beams.
  One or both of these objectives will be achieved, sooner or later, but both
  open up vistas so unlimited that it is fruitless to speculate about them;
  there are no boundary posts here, as yet, to mark the border between
  science and fantasy,
  While on the subject of communication, I might also have discussed the
  urgent problem of communication between human beings. The development of
  "machine languages" for computers is, unquestionably, going to have
  considerable feedback on linguistics. Som scholars have already attempted
  to develop logical languages, free from the ambiguities and defects of all
  the existing ones. This is a far more ambitious project than devising yet
  another Esperanto or Interlingua; it goes to the very basis of thought.
  (One such effort is described in the article "Loglan" in Scientific
  American for June 1960.) Although I suspect that a logical language is one
  in which it is impossible to write poetry or love letters, its development
  should be welcomed. Perhaps the future will have two languages--one for
  thinking, and one for feeling. The second might be specific to the human
  race, but the first might have universal application.
  The control of weather, and ultimately of climate, is
 another subject which might have been discussed at some
 length. Apart from its obvious terrestrial importance, this
 will eventually lea ' d to what has been called "planetary
 engineering"-the large-scale modification of other celes-
  I See Man and Dolphin, by John C. Lilly (New York: Doubleday & Company,
  Inc., 1961).
               249
 tial bodies to make them inhabitable. The search for such activities,
 elsewhere in the universe, may be a major project for the astronomers of the
 future. Indeed, it has been a minor one in the past; the famous debate
 concerning the Martian "canals" is proof of this.
  Certain types of symmetrical or ordered structure, certain kinds of energy
  release, are so abnormal that they point to an intelligent origin. When the
  energy equivalent of several megatons appears in an area a few miles
  across, it can be a volcano; when it appears at a point source, it can only
  be a bomb.
  The radio astronomers are now discovering, some most extraordinary
  phenomena in other galaxies; Virgo A (Messier 87), for example, has a
  brilliant jet extending from its nucleus, like a searchlight beam hundreds
  of light-years long. What is so peculiar about this jet is the
  concentration of energy it contains-perhaps equivalent to that of millions
  of supernovae, or the radiation from millions of millions of ordinary
  stars. In fact, to power this jet, a mass equivalent to about a hundred
  suns would have to be completely annihilated!
  This is totally inexplicable in terms of any 'known natural process; it is
  like comparing an H-bomb to a geyser. The chances are that there is a
  natural explanatiOng which we have not yet discovered, but it is tempting
  to speculate about the alternative, Given sufficient time, rational beings
  might attain the power to manipulate not merely planets, not merelv stars,
  but the galaxies themselves. If the jet from M.87 is artificial, what is
  its purpose? Is it an attempt to signal across intergalactic space? A tool
  of cosmic engineers? A weapon? Or some byproduct of incomprehensible
  religions and philosophies-as on our own planet, the Great Pyramid is a
  gigantic symbol Of a now almost wholly alien mentality?
  Such projects would demand vistas of time, and continuity of cultures, on
  a scale inconceivable to us. The time is there; of that there is no doubt.
  Each generation of astronomers multiplies the age of the universe by ten;
  the current estimate appears to be about twenty-five billion years. If we
  say that human civilization has existed for 250
               THE PASr
      CabCUUMCATION                  MATKRLAISB1
 DATx TxAxxsoRrA-noer                INYoRmAnomMAXVFA~cCHEUMSTRYPHYSICS
                Steam angmes         Inorganic chemAtomic the"
                        istry
  Locomotive
         Camera
         Babbage calcu-              Urea Synthesized
          lator
  Steamship                 TelegraphMachine toolsSpectroscope
                              Conservation of
                Electricity          Organic chem-anew
                        istry
         Telephone
         Phonograph                  Electromspetim
         Ofsoe rn,ch                 Evolution
  Automobile                         Diesel engine
 1900                 Gasoline engineDyesX-ray$
  Airplane                           Electron
         vacuum tube                 Mass productionGeneticsRadioactivity
                       vitamins
                Nitrogen fixa-       plastics
 1910                                tion
                              hot"
         Radio           Quantunl a-?
                       Chrom
 1020                                Genes
                              Relativity
                              Atomic structurs,
 2930                                Language of bees
                       Hormones      Indeterminacy
         TV            Wave mechanics
                              Neutron
 low                          jetRadar
  Rocket
  Helicopter                         Tape recorders
         Electronic oom-             MagnesiumSyntheticsUranfurn asslas
          pute"                      from seaAntibioticsAccelerators
         Cybernetics                 Atomic energySiliconesRadio astronomy
 Iwo                       TransistorAutomation
  Shtellits                          MaserFusion bombTranquilizersI.C.Y.
  CEM                         LawParity ova&vwn

                251
  D. T. .                       Co=
  . . . .              Protein struo-Nucleon d-
 
 1960 1 Spaceship                 $satellitetureIWIT,
               THE FUTURE
   Space lab
 I= L- landing                     Cravity
   Nuclear roCI*                   Vraves
 I= planetary land-  Personal radio
    hiss                      Fusion powerE901"Off
         Translating               Cyborgs
 1990                 machinesEfficient electric Cmean lan-
         Artiricial Intel-          storageguages
 2WO Colonizing                     ligence,wWhelesr en-Time, perception
 Sub-nuclew
   Planets            Clobal libraryS erg)renhancementstruch"
 2010 Earth pwlm                    Telesensozy de-ea mining
           vices     weather controlNuclear I
 202D interstellar                  Logical lan- -Control of ~Ysts
          guages
 2D30                   probesRobotsSpace miningheredity
          Contact with         Bloengmeering
           extra-taffestri
 2M               TransmutationIntelligent-fra

 2DSO                   Crovity controlSuspended
   'Space driver              Memory playback Plimetaryanimation

 2M                           Mechanical edu-engineering
           cator                  S=
          Codingofartifacts         Artificial lifs
 2DTO                        Climate
2DSO Near-light spee& Machine En%M-CCOU01
 Int ellar g t        = exceeds
 2DDO                 M"tterReplf-t
   Ma
    edmg with,  world brain
 2100                  extra-terres.Astronomical
    trials  I engineeringI

                 252
 about a millionth of the age of this Galaxy, we may not be far wrong.
  But it also appears that the past duration of the Galaxy is a mere flicker
  of time, compared to the aeons that may lie ahead. At their present lavish
  rate of radiation, stars such as the Sun can continue to bum for billions
  of years; then, after various internal vicissitudes, they settle down to a
  more modest mode of existence as dwarf stars. The reformed stellar
  spendthrifts can then shine steadily for periods of time measured not in
  billions but in trillions (millions of millions) of years. The planets of
  such stars, if at the same distance from their primary as Earth (or even
  Mercury) would be frozen at temperatures hundreds of degrees below zero.
  But by the time we are considering, natural or artificial planets could
  have been moved sunward to huddle against the oncoming Ice Age as, long
  ago, our savage ancestors must have gathered around their fires to protect
  themselves from the cold and the creatures of the night.

  In a famous elegiac passage, Bertrand Russell once remarked

 . . . that all the labours of the ages, all the devotion, all the
 inspiration, all the noonday brightness of human genius, are destined to
 extinction in the vast death of the solar system, and that the whole temple
 of Man's achievement must inevitably be buried beneath the debris of a
 universe in ruin-all these things, if not quite beyond dispute, are yet so
 nearly certain, that no philosophy which rejects them can hope to stand.

  This may be true enough; yet the ruin of the universe is so inconceivably
  far ahead that it can never be any direct concern of our species. Or,
  perhaps, of any species that now exists, anywhere in the spinning whirlpool
  of stars we call the Milky Way.
  Our Galaxy is now in the brief springtime of its life-a springtime made
  glorious by such brilliant blue-wbite stars as Vega and Sirius, and, on a
  more humble scale, our own 253
 Sun. Not until all these have flamed through their incandescent youth, in a
 few fleeting billions of years, will the real history of the universe begin.
  It will be a history illuminated only by the reds and infrareds of dully
  glowing stars that would be almost invisible to our eyes; yet the somber
  hues of that all-but-eternal universe may be full of color and beauty to
  whatever strange beings have adapted to it. They will know that before them
  lie, not the millions of years in which we measure the eras of geology, nor
  the billions of years which span the past lives of the stars, but years to
  be counted literally in trillions.
  They will have time enough, in those endless aeons, to attempt all things,
  and to gather all knowledge. They will not be like gods, because no gods
  imagined by our minds have ever possessed the powers they will command. But
  for all that, they may envy us, basking in the bright afterglow of
  Creation; for we knew the universe when it was young.

           Chart of the Future

  The chart given is not, of course, to be taken too seriously, but it is
  both amusing and instructive to extrapolate the time scale of past
  scientific achievement into the future. If it does no more, the quick
  summary of what has happened in the last hundred-and-fifty years should
  convince anyone that no present-day imagination can hope to look beyond the
  years 2,100. 1 have not even tried to do SO.

  POSTSCRTPT: In updating this chart after ten years, I have made only four
  changes. Translating machines, efficient electric storage and cetacean
  languages have all proved tougher than expected * ; they have been moved
  for-*yard a decade. And gravity waves--originally in the mid-eighties-have
  been moved back; they were detected in 1969.

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