PROFILES OF THE FUTURE' An inquiry into the Limits of the Possible
by
ARTHUR C. CLARKE


Revised edition

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. CONTENTS

preface .. .. .. .. .. . 7

Introduction .. .. .. .."

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 of Plenty.....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 upon 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
bibliography 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.
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 ext rem 2 See my debate with Dr.  Alan
Watts on mysticism and technology, "At the

Interface," Playboy magazine, January 1972.  Scientists 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,
hard and 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 modern
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  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, I 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 Frenchman'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
science with 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
readers or 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 known, 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.

he speed with which space exploration is progressing would have seemed
equally unlikely.  When Hermann 13

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) I 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 provided by the fact that I made no attempt
whatsoever, in 1945, to patent the communication satellite.  (See
Chapter 16.) I 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 I 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.

 PROFILES OF THE FUTURE

 Hazards of Prophecy:

The Failure 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."

The 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-pooh ed 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 flight 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 modern steamships.... It seems safe to say that such
ideas must be wholly visionary, and even if a machine could 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 hp.  we can
now attain a speed of 40 mph."  then in order to reach a speed of 100
mph.  we must use a motor capable of 470 hp.... 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 considered 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 el Lyhtv, Professor Pickering had seen air planes traveling at
400 mph."  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 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
explosivenitroglycerine-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 propel lent tanks, motors', etc.) would
actually make the ratio very much higher, but that does not affect the
arguments or.  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 well informed 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 accuse 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 dfficulties 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 flight 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 flight, 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 position as Astronomer Royal, a
leading member of the committee advising the British government on
space research.

The feelings of those who have been trying, for a generation 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.  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.  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 taxpayer-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:

"he 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.


The Failure 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 others when 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 Philosophic 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.
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 Chicago  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.  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 flying
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 ac 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 operation 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 lifetime-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 modern 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 tele vi36  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 suddenly, 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 pre twentieth 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, spinning 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 energy flying 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 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.

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 mid twentieth
century will never again be matched.  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 Short Car bus' Truck pipe (suburban,
rail, boat, line rail rural) escalator 3. 1 ~-ItOOO Medium Car
bus'Fruck, rail, (continental) rail, boat, airplane airplane, GEM.,

GEM."  VTOL

VTOL

4. 1, 00Low' airplane Rail, ship, 10,000 (inter-ship, GEM.  aircraft
continental) ramjet, rocket GEM submarine

GEM.: Gro and ect M hine.  VTOL: Vertical Takeoff and Landing
Aircraft.  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 IQs 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.  (It is 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.  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 Wave' 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 increasing 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 "The
Roads Must

Roll," Robert Heinlein suggested that travel even over considerable
distances would one day be based on the conveyor belt 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
hands will be required if we hope to build expressways traveling at
fifty or more miles an hour at their center.

he ideal moving road would be one that had a smoothly 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; this 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 seriously, 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 an isotropic--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 an isotropic 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 Fallot Night, since incorporated in The City and the
Stars.  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 reach 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 road would 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 modern 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; meanwhile, let us take a brief glance at the future of the
automobile as we know it.

It will become much lighter-and hence more efficient-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 solid state physics.

These improvements, however, will be much less

the fact that the automobile of the day after-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 he's ahead.  On airless worlds like the Moon,
Mercury, and the satellites of the planets, alternative forms of
transport may be impracticable, 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 will not be true of its successors, the short and
medium range air buses 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 mph."  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 mph.

Range: 600 miles

Payload: 4 tons

Total weight: 20 tons 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 opoone 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 worked out technical
details, but also for its philosophical-religious content--considerably
too adult for the escapist, "main-stream" magazines.  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 ship owners 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 it may rise
only a few inches above the ground.  For the nemesis of the oceangoing
freighter may not be the submarine 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-fiction 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 civilization.  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 USSR." 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 GEMs.

Although GEMs 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 airplanes and helicopters through the sky.

Now take the same fan and hang it facing 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 wall.  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 ming
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 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 GEM."  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,

GEMs can travel with equal ease over ice, snow, sand, plowed fields,
swamps, molten lava-you name it, the GEM.  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

GEM.  they are all aliko-and a superhighnw is no better.  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 GEM.  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 air supported 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 costs amounting 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 GEMs or air cars 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 air car driver could not reach, and
the breakdown vans of the future are going to receive SOS.  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 even be possible to develop a specialized form of GEM.  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

GEMs 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 mph. Although there
will certainly be great improvements in performance, it seems that at
the present moment the smaller types of GEM.  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 air cars 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, snow fields 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 GEMs
are developed.

We will return to this subject later, but now it is time to go to sea.
For

GEMs, 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 GEMs 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--GEMs 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 GEM.  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 hover ship 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 Australia---are almost inaccessible except in a
dead calm, and many of its smaller islands have never been visited by
man.  A reliable GEM.  bus service would, alas, tam these minute
pandanus-clad jewels into desirable housing estates and holiday
resorts.

As the GEM.  is the most frictionless type of vehicle yet invented, it
can certainly travel much faster than any existing type of marine
craft, including 300 mph.  jet propelled hydroplanes.  This suggests
that the airlines may be in for some stiff competition, for there are
many passengers 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 mph.  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 GEM.  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 GEM."  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, GEMs seem to combine the best
features of ships and aircraft, with remarkably few of their
disadvantages.  The most shattering implications of GEMs 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 GEM.
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 GEM.  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 in height 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 GEMs 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 GEM.  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.

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 inter convertible  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.  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 speed like 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 sophisticated 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 universe not 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 the res 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 crim.  oof.  However, I disclaim arreasppeal,eq the~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, exactly 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 un
fortunate 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 modern 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 fuel less
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; 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
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 under drives 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.  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 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, We 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.  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 mph.  DATE OF ENTRY To BAND _T_ 1-10 'cica1,000,000 B-C2
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  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 mph."  but it certainly
became possible around 1880.  The Empire State Express touched 112 mph.
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 flight 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 mph. 
well before 1970-which we didn't.  Stiff more unlikely is the result
obtained by continuing this nal ve extrapolation-that 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 mph."  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 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 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
propel lent load.  Such a system is far beyond sight at the moment,
because it could not be based upon fission-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 fuel less 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 discovered.

After all, there is nothing fundamentally absurd about the idea.  We
sailed the seas for thousands of years in fuel less 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 mph.  At this
rate it would take almost fourteen minutes to reach orbiting speed
(18,000 mph.), 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 unfair 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 mph."  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 sufficient 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 orbital 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 mph."  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.

VELOCITY TIME TO ORBIT FORCE ExPERIENCED

EARTr-r BY PASSENGERS (mph.) 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 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 mph.  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 mph.  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 mph.  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 mph.
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 inertia less 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 hairpin 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 net hod 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 extreme 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.  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.  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 light 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
Disintegration 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.

Especially 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 city to 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 at ions 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 naieve (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.  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
newspaper 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 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 un imaginary large number of energy states and
spacial configurations in which those atoms happen to be at a given
moment of time.  Modern physics (especially 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 in definables 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.  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 modern
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 M6bills 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 M6bills 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 flat lander 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 M6bills 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.  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.  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.

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 Antarctic--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 conflict 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 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-at homes
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
ari ve 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 modern 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 FAr the 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.  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 cold ward and
storm ward 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
coincides 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 modern 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 dream swill 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 intelligent 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 intelligence 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
continued 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 tick inc 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 challenge.  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 Transformation 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 relatives, 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 combined 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

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) 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 prototype 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 burn 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.  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.  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 swimming 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 meteorology 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'.  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.  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-entry 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 flashing high 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
hydrogen 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.  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 hydrogen,
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 ago!  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 stella revolution  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.  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 achievement-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 thousand 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).

 -A

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 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
quarter million 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 interfere 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 mill
ia  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 traveling 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.  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-to earth 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 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?

he 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 numbers  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.

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.  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) have 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 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 atmosphere even 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 perhaps 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 later 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 not yet 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 RoW':

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
will 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 action pause to
contemplate the thought that you may be a specimen before a class in
primitive psychology, a thou sand years from now.  A still worse
possibility is that the voyeurs of some decadent future age may use
their perverted 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.... he 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 happen just as they would if we went back to imperial Rome
with cameras and tape recorders concealed under our nylon togas.  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
seriously; 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 anesthetized 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
me scaling 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 flowed 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.  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 other though 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.
Mossbauer 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 light.  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 hour the 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 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 similareflect 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
appeared 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 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 ne ans
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 fat are 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 him As the banks fade dimmer away As
the stars come out, and the night-wind Brings up the stream Murmurs and
scents of the infinite sea.

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 contribution 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 modern man with the necessities-and
luxuries--of life.  No wonder 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
trajectory, 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 he's 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 modern 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 long
range 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 generating 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 see ins 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, sum~ight-and we are
already using this to operate our space vehicles.  The output of the
solar hydrogen reactor is gigantic-about
500,000,000,000,000.000,000,000 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 widely, 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 solarenergy 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 solarenergy.  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 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 in detectable 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 chapter 9), which so far has practically defied an our were
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,  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.  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 century, 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 brute force "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 represent 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 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 mph.
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 magneto hydrodynamics 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.  Tapping the Sun may sound a fantastic
conception, but we are 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 deuterium  (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 control
but 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 thermonuclearexplosions 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 positrons 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.

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 age long 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 modern 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 manufacture.  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 coded form 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 instructions, 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 mi lions of details.
This would indeed have been a miracle to an artist of the Middle Ages.
The camera is a general purpose 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 char ac175
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 automatically 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 parts which 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 vita lists 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 beyond the wildest dreams
of

Aladdin.  This is a superficial 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.  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.

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 naY ve 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 antireflection 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
achieving genuine invisibility, if you can persuade those who look at
you that you are something else?  Poe's The Purloined Letter and
Chesterton's The Invisible Man are interesting 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.  The 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-in trade of every spiritualist and medium.  Radio, sonar,
infrared 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
nal ve 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. Love craft,

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 two directional
square, the three-directional cube-and the four-directional hypercube,
known as a tessera ct  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 tessera ct 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.  hents, 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 example would 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 corners 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 has 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 Planner 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-dim en190  signal 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.

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 famous results 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.  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 more 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 sub micro-, 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 revived 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 prolific 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 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.  The 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 brontosaur us 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
gravity possibly in space itself, where weight ceases to exist.  One of
the most interesting questions in extraterrestrial zoology 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 cross
sections 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 reductio
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. 
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 doll's
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 functioning 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 un planetary
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 had 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 had 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-great grandchildren 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 impossibility 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 conviction, 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.

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 miff or 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.  the
entire planet.  There will be no shortage of ave lengths-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-whether 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 USSR.  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 USSR.  a thing; it even makes a
small profit on the deal.  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 I 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

Vice President 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.  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 argument 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 possible services of a quality and
specialized nature quite out of the question today.  There are 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 huckster
less 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 intellectual 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 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.  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 position
and-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 claustrophobically 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 transportation 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 permitting 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-band ling 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.  Modern 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 inscribed.  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 channel-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 athletics,
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 satellites-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 technology 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.  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.  "The 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 inter governmental agreement.  You
have just signed a first draft of the Articles of

Federation of the United States of Earth.  &

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 un guessed-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 spaceship had 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.  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 had 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 may 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 "remembered' 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 cooperative

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 fingers  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 human-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 universe 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 modern 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 had even refereed
world-championship 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-imPortant224  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. Some 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.  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 animation which 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 it that 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 today 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 brittle cone 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.  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 this 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 structure--its
pattern.  he 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 existence.

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 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 change
immortality 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.)  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.

The 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 obsolescence  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 de sprit 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 intelligent
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 Wohler 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.  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"--whether 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
intelligence  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 techniques 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
thousand fold 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-acti rIg  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 constructed 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 that unless you cheat by altering the direction of your gaze
you 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 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 billion fold 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,  pl ore 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 environments 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 habits, 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 consciousness is free to roam at
will from machine to 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.

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).  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 merely 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
PASt

CabCUUMCATION MATKRLAISB1

DATx TxAxxsoRrA-noer INYoRmAnomMAXVFA~cCHEUMSTRYPHYSICS

Steam angmes Inorganic chem Atomic the" is try

Locomotive

Camera

Babbage calcu- Urea Synthesized lator

Steamship Telegraph Machine tools Spectroscope

Conservation of

Electricity Organic chem-anew is try

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 Quantum a-?

Chrom 1020 Genes

Relativity

Atomic structurs, 2930 Language of bees

Hormones Indeterminacy

TV Wave mechanics

Neutron low jet Radar

Rocket

Helicopter Tape recorders

Electronic oom- MagnesiumSyntheticsUranfurn ass las pute" from
seaAntibioticsAccelerators

Cybernetics Atomic energySiliconesRadio astronomy

Iwo Transistor Automation

Shtellits Maser Fusion bombTranquilizersI.C.Y.

CEM Law Parity ova&vwn  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 machines Efficient 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-ca mining vices weather control Nuclear I 202D
interstellar Logical lan-Control of ~Ysts guages 2D30 probesRobotsSpace
mining heredity

Contact with Bloengmeering extra-taffestri 2M
TransmutationIntelligent-fra

2DSO Crovity control Suspended "Space driver Memory playback
Plimetaryanimation

2M Mechanical edit-engineering cat or S=

Codingofartifacts Artificial lifs 2DTO Climate 2DSO Near-light spcc
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  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
burn 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-white 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 infra reds 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.  I 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.

