THE CHALLENGE OF THE SPACESHIP
by
ARTHUR C. CLARKE


 Books by Arthur C. Clarke

The Challenge of the Spaceship The Exploration of Space Voices from the
Sky

Published by POCKET BOOKS

 ARTHUR C. CLARKE

THE CHALLENGE

OF THE

SPACESHIP

PUBLISHED BY POCKETBOOKS NEW YORK

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Copyright 0 1955, 1957, 1958, 1959 by Arthur C. Clarke Copyright 1953,
1954, 0 1955, 1957, 1958, 1959 by The Curtis Publishing Company
Copyright (D 1958 by The New York Times Company

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Printed in Canada  To Carl Biemiller and Harry Sions,

Chief Instigators of the ensuing pages  Contents

Introduction 9

The Challenge of the Spaceship 13

Vacation in Vacuum 29

Journey by Earthlight 41

So You're Going to Mars?  54

The Planets Are Not Enough 66

Meteors 77

The Star of the Magi 88

Where's Everybody?  98

The Sun 108

What Can We Do About the Weather?  118

Oh for the Wings .. .. .. .128

Across the Sea of Stars 134

Of Mind and Matter 141

Which Way Is Up?  150

Report on Planet Three 161

Question Time 169

Things in the Sky 179

The Men on the Moon 192

The Radio Universe 203

Of Space and the Spirit 210

Envoi 222  Introduction

THE MAIN THEME OF THIS BOOK IS THE IMPACT OF THE coming Space Age upon
our hitherto Earth-bound species.  Looking past the immediate present,
and ignoring both the occasional triumphs and more frequent failures of
today's satellites and rocket probes, it attempts to view the conquest
of space as part of a historical process.  Except where they are
essential to the argument, it is not in the least concerned with
technical matters; it assumes that machines are less important than
what men do with them-or what they do with men.

Though the various examinations of the Man-Space relationship that
follow look at the subject from different angles, some overlapping is
inevitable and some is deliberate.  I have tried to edit out all
unnecessary repetition, but when a thing is really important it is
worth saying more than once.

Interleaved among these philosophical and cultural speculations are
examples of straight science reporting, most of them from the pages
of

Holiday Magazine.  Sometimes, as in the trio of pieces giving helpful
advice to interplanetary tourists, the reporting is not so straight.
However, anyone who reads this book as a whole will be in little danger
of confusing fact with fiction.

THE CHALLENGE

OF THE SPACESHIP

 The Challenge of the Spaceship*

A HISTORIAN OF THE TWENTY-FIRST CENTURY, LOOKing back past our own age
to the beginnings of human civilization, will be conscious of four
great turning points which mark the end of one era and the dawn of a
new and totally different mode of life.  Two of these events are lost,
probably forever, in the primeval night before history began.  The
invention of agriculture led to the founding of settled communities and
gave Man the leisure and social intercourse without which progress is
impossible.  The taming of fire made him virtually independent of
climate and, most important of all, led to the working of metals and so
set him upon the road of technological development-that road which was
to lead, centuries later, to the steam engine, the Industrial
Revolution, and the age of steel and gasoline and surface
transportation through which we are now passing.

* "The Challenge of the Spaceship" is a much revised and updated
version of a talk delivered to the British Interplanetary Society in
1946, during my first term as chairman.  Despite the obvious derivation
of the title, it should not be assumed that I now owe any particular
allegiance to Professor

Toynbee, though at the time of writing I was much taken by a lecture I
had just heard him deliver on "The Unification of the World."

One other historical note: I am still rather proud of the fact that
when I sent the first printed version of this paper to George Bernard
Shaw (then in his ninety-first year), he promptly joined the British
Interplanetary

Society, and remained a member until his death.  The third revolution
began, as all the world knows, in a squash court in

Chicago on December 2, 1942, when the first self-sustaining nuclear
reaction was started by Man.  We are still too close to that
cataclysmic event to see it in its true perspective, but we know that
it will change our world, for better or for worse, almost beyond
recognition.  And we know too that it is linked with the fourth and in
some ways greatest change of all-the crossing of space and the
exploration of the other planets.  For though the first space vehicles
were chemically fueled, only atomic energy is adequate to lift really
large payloads out of the Earth's gravitational field-that invisible
maelstrom whose tug can still be felt a million miles away.

Prophecy is a dangerous and thankless business, frequently fatal to
those who practice it.  We have, however, learned from past experience
that even the most extravagant forecast seldom overtakes the truth.  H.
G. Wells once wrote-and was no doubt laughed to scorn for his
folly-that the airplane might have some influence upon warfare by the
year 1950.  He never dared to imagine that by that date aircraft would
not only have become of supreme importance but would have been
challenged by still newer weapons.

It is certainly not being rash-it may indeed be conservative-to assume
that by the last quarter of this century an efficient and reliable
method of nuclear propulsion for space vehicles will have been
perfected.  Atomic power is hardly likely to advance the conquest of
space by more than ten years, but it may make it practical almost from
the beginning.  It would mean that the whole Solar System, and not
merely the Moon, would be immediately accessible to Man.  As our first
space probes have demonstrated, it requires very little more power to
reach the planets than it does to go to the Moon, but the most
economical voyages involve months or even years of free coasting along
orbits curving halfway round the Sun.  With atomic power these journeys
could be cut to a fraction of the time.  For example, the "cheapest"
journey to Mars-as far as fuel is concerned-lasts 258 days.

With a nuclear-propelled ship, traveling by a more direct route at
quite a moderate speed, it need take only a few weeks.

There are still some scientists who consider that there is no point in
sending men into space, even when it becomes technically possible;
machines, they argue, can do all that is necessary.  Such an outlook is
incredibly shortsighted; worse than that, it is stupid, for it
completely ignores human nature.  Though the specific ideals of
astronautics are new, the motives and impulses underlying them are as
old as the race--and, in the ultimate analysis, they owe as much to
emotion as to reason.  Even if we could learn nothing in space that our
instruments would not already tell us, we should go there just the
same.

Some men compose music or spend their lives trying to catch and hold
forever the last colors of the dying day, or a pattern of clouds that,
through all eternity, will never come again.  Others make voyages of
exploration across the world, while some make equally momentous
journeys in quiet studies with no more equipment than pencil and paper.
If you asked these men the purpose of their music, their painting,
their exploring or their mathematics, they would probably say that they
hoped to increase the beauty or the knowledge in the world.  That
answer would be true, and yet misleading.  Very few indeed would give
the simpler, more fundamental reason that they had no choice in the
matter-that what they did, they did because they had to.

The urge to explore, to discover, to "follow knowledge like a sinking
star," is a primary human impulse which needs, and can receive, no
further justification than its own existence.  The search for
knowledge, said a modern Chinese philosopher, is a form of play.  If
this be true, then the spaceship, when it comes, will be the ultimate
toy that may lead mankind from its cloistered nursery out into the
playground of the stars.

However, it is not hard to think of endless and entirely valid
"practical" reasons why one should wish to cross space, and some of
these we will discuss later.  There is no doubt that eventually sheer
necessity would 15  bring about the conquest of the other planets.  It
may well be impossible to have a virile, steadily advancing culture
limited to a single world, and taking the long term-the very long
term-view, we know that our Earth will one day become uninhabitable.
The Sun is still evolving, growing steadily hotter as its central fires
become banked up beneath their accumulated "ash" of helium.  In the far
future the oceans will boil back into the skies from which they once
condensed, and life must pass from the planet Earth.

But the human race will not wait until it is kicked out.  Long before
the

Sun's radiation has shown any measurable increase, Man will have
explored all the Solar System and, like a cautious bather testing the
temperature of the sea, will be making breathless little forays into
the abyss that separates him from the stars.

The last quarter of this century will be an age of exploration such as
Man has never before known.  By the year 2000.  most of the major
bodies in the

Solar System will probably have been reached, but it will take
centuries to examine them all in any detail.  Those who seem to think
that the Moon is the goal of interplanetary travel should remember that
the Solar System contains eight other planets, at least thirty moons
and some thousands of asteroids.  The total area of the major bodies is
about 250 times that of

Earth, though the four giant planets probably do not possess stable
surfaces on which landings could be made.  Nevertheless, that still
leave-, an area ten times as great as all the continents of Earth.

This, then, is the future which lies before us, if our civilization
survives the diseases of its childhood.  It is a future which some may
find terrifying, as no doubt our ancestors found the hostile emptiness
of the great oceans.  But the men who built our world crossed those
oceans and overcame those fears.  If we fail before the same test, our
race will have begun its slide into decadence.  Remember, too, that
when the great explorers of the past set sail into the unknown they
said good-by for years to their homes and everything they knew.  16
Our children will face no such loneliness.  When they are among the
outermost planets, when Earth is lost in the glare of the Sun and the
Sun itself is no more than the brightest of the stars, they will still
be able to hear its voice and to send their own words in a few hours
back to the world of men.

Let us now consider the effects which interplanetary travel must have
upon human institutions and ideas.  The most obvious and direct result
of the crossing of space will be a revolution in almost all branches of
science.

I will not attempt to list more than a few of the discoveries we may
make when we can set up research stations and observatories upon the
other planets, or in satellite orbits.  One can never predict the
outcome of any scientific investigation, and the greatest discoveries
of all-the ones which will most influence human life-may come from
sciences as yet unborn.

Astronomy and physics will, of course, be the fields of knowledge most
immediately affected.  In both these sciences there are whole areas
where research has come to a dead end, or has never been started,
because our terrestrial environment makes it impossible.

The atmosphere, which on a clear night looks so transparent, is in
reality a colored filter blocking all rays beyond the ultraviolet. Even
in the visible spectrum the light that, finally struggles through the
shifting strata above our heads is so distorted that the images it
carries dance and tremble in the field of the telescope.

An observatory on the Moon, working with quite small instruments, would
be many times as effective as one on Earth.  Far greater magnifications
could be employed, and far longer exposures used.  In addition, the low
gravity would make relatively simple the building of larger telescopes
than have ever been constructed on this planet.

In physics and chemistry, access to vacuums of unlimited extent will
open up quite new fields of investigation.  The electronic scientist
may well look forward to -the day when he can build radio tubes miles
long, if be wishes, merely by setting up his electrodes in the open!
17  It is also interesting to speculate whether we may not learn more
about gravity when we can escape partially or wholly from its
influence.

Artificial satellites have already given dramatic notice of what may be
achieved when we can establish permanent, manned stations in space for
observation and research.  Accurate weather forecasting-which, it has
been estimated" would be worth five billion dollars a year to the
United States alone-will 4)rob ably be impossible until we can hoist
the meteorologists out into space, however reluctant they may be to go
there.  Only from a height of several thousand miles is it possible to
observe the Earth's weather pattern as a whole, and to see literally at
a glance the movement of storms and rain areas.

One application of space stations and satellites, whose importance it
is impossible to overestimate, is their use for communications and TV
relaying.  Many years ago (in the British radio magazine Wireless
World,

October, 1945) I pointed out that satellite-borne transmitters could
provide interference-free reception over the whole Earth, and might
indeed be the only means of establishing a global TV service

Should any one nation establish a satellite relay chain, it would do
more than dominate the world's communications.  The cultural and
political impact of TV news and entertainment broadcast directly to
every home on Earth would be immeasurable.  When one considers the
effect of TV upon ostensibly educated populations, the impact upon the
semiliterate peoples of Africa and Asia may be decisive.  It may well
determine whether English or Russian becomes the leading world language
by the end of this century.

Yet these first direct results of astronautics may be less important,
in the long run, than its indirect consequences.  This has proved true
in the past of most great scientific achievements.  Copernican
astronomy, Darwin's theory of evolution, Freudian psychology * To the
best of my knowledge, this was the first appearance of this now
commonplace idea.  I have since wondered, a little wistfully, if I
could have patented it.  these had few immediate practical results,
but their effect on human thought was tremendous.

We may expect the same of astronautics.  With the expansion of the
world's mental horizons may come one of the greatest outbursts of
creative activity ever known.  The parallel with the Renaissance, with
its great flowering of the arts and sciences, is very suggestive.  "In
human records," wrote the anthropologist J. D. Unwin, "there is no
trace of any display of productive energy which has not been preceded
by a display of expansive energy.

Although the two kinds of energy must be carefully distinguished, in
the past they have been .. . united in the sense that one has developed
out of the other."  Unwin continues with this quotation from Sir James
Frazer:

"Intellectual progress, which reveals itself in the growth of art and
science .. . receives an immense impetus from conquest and empire."
Interplanetary travel is now the only form of "conquest and empire"
compatible with civilization.  Without it, the human mind, compelled to
circle forever in its planetary goldfish bowl, must eventually
stagnate.

We all know the narrow, limited type of mind which is interested in
nothing beyond its town or village, and bases its judgments on those
parochial standards.  We are slowly-perhaps too slowly-evolving from
that mentality toward a world outlook.  Few things will do more to
accelerate that evolution than the conquest of space.  It is not easy
to see how the more extreme forms of nationalism can long survive when
men begin to see the

Earth in its true perspective as a single small globe among the
stars.

There is, of course, the possibility that as soon as space is crossed
all the great powers will join in a race to claim as much territory as
their ships can reach.  Some American writers have even suggested that
for its own protection the United States must occupy the Moon to
prevent its being used as a launching site for atomic rockets.
Fantastic though such remarks may seem today, they represent a danger
which it would be unwise to ignore.  The menace of interplanetary
imperialism 19  can be overcome only by world-wide technical and
political agreements well in advance of the actual event, and these
will require continual pressure and guidance from the organizations
which have studied the subject.

The Solar System is rather a large place, though whether it will be
large enough for so quarrelsome an animal as Homo sapiens remains to be
seen.  But it is surely reasonable to hope that the crossing of space
will have a considerable effect in reducing the psychological pressures
and tensions of our present world.  Much depends, of course, on the
habitability of the other planets.  It is not likely that very large
populations will, at least for many centuries, be able to subsist
outside the Earth.  There may be no worlds in the Solar System upon
which men can live without mechanical aids, and some of the greatest
achievements of future engineering will be concerned with shaping
hostile environments to human needs.

We must not, however, commit the only too common mistake of equating
mere physical expansion, or even increasing scientific knowledge, with
"progress"-however that may be defined.  Only little minds are
impressed by sheer size and number.  There would be no virtue in
possessing the Universe if it brought neither wisdom nor happiness. Yet
possess it we must, at least in spirit, if we are ever to answer the
questions that men have asked in vain since history began.

Perhaps analogy will make my meaning clearer.  Picture a small island
inhabited by a race which has not yet learned the art of making
ships.

Looking out across the ocean this people can see many other islands,
some of them much the same as its own but most of them clearly very
different.

From some of these islands, it is rumored, the smoke of fires has been
seen ascending though whether those fires are the work of men, no one
can say.

Now these islanders are very thoughtful people, and writers of many
books with such resounding titles as The Nature of the Universe, The
Meaning of

Life, Mind and Reality, and so on.  Whilst admiring their 20
enterprise, I do not think we should take their conclusions very
seriously-at least until they have gone a little further afield than
their own coral reef.  As Robert Bridges wrote in "The Testament of
Beauty":

Wisdom will repudiate thee, if thou think to enquire WHY things are as
they are or whence they came: thy task is first to learn WHAT IS ...
That task the human race can scarely begin to undertake while it is
still earthbound.

Every thoughtful man has often asked himself: Is our race the only
intelligence in the Universe, or are there other, perhaps far higher,
forms of life elsewhere?  There can be few questions more important
than this, for upon its outcome may depend all philosophy-yes, and all
religion too.

The first discovery of planets revolving round other suns, which was
made in the United States in 1942, has changed all ideas of the
plurality of worlds.  Planets are far commoner than we had ever
believed: there may be thousands of millions in this Galaxy alone.  Few
men today would care to argue that the Earth must be the only abode of
life in the whole of space.

It is true-it is even likely-that we may encounter no other
intelligence in the Solar System.  That contact may have to wait for
the day, perhaps ages hence, when we can reach the stars.  But sooner
or later it must come.

There have been many portrayals in literature of these fateful
meetings.

Most science-fiction writers, with characteristic lack of imagination,
have used them as an excuse for stories of conflict and violence
indistinguishable from those which stain the pages of our own history.
Such an attitude shows a complete misunderstanding of the factors
involved.

Remember the penny and the postage stamp which Sir James Jeans, in
The

Mysterious Universe, balanced on Cleopatra's Needle.  The obelisk
represented the age of the world, the penny the whole duration of man's
21  existence, and the stamp the length of time in which he has been
slightly civilized.  The period during which life will be possible on
Earth corresponds to a further column of stamps hundreds of
yards-perhaps a milein height.

Thinking of this picture, we see how infinitely improbable it is that
the question of interplanetary warfare can ever arise.  Any races we
encounter will almost certainly be superhuman or subhuman-more likely
the former, since ours must surely be one of the youngest cultures in
the Universe.

Only if we score a bull's-eye on that one stamp in the mile-high column
will we meet a race at a level of technical development sufficiently
near our own for warfare to be possible.  If ships from Earth ever set
out to conquer other worlds they may find themselves, at the end of
their journeys, in the position of painted war canoes drawing slowly
into New

York Harbor.

But if the Universe does hold species so greatly in advance of our own,
then why have they never visited Earth?* There is one very simple
answer to this question.  Let us suppose that such races exist: let us
even suppose that, never having heard of Einstein, they can pass from
one end of the

Galaxy to the other as quickly as they wish.

That will help them less than one might think.  In ten minutes, a man
may walk along a beach-but in his whole lifetime he could not examine
every grain of sand upon it.  For 0 that we know, there may be fleets
of survey ships diligently charting and recharting the Universe.  Even
making the most optimistic assumptions, they could scarcely have
visited our world in the few thousand years of recorded history.

Perhaps, even at this moment, there lies in some rather extensive
filing system a complete report on this planet, with maps which to us
would look distorted but still recognizable.  That report would show
that though Earth was teeming with life, it had no dominant spe* For a
more detailed discussion of this problem, and an updated version of

Jeans' analogy, see "Where's Everybody?"  (page 98).  cics.  However,
certain social insects -showed considerable promise, and the file might
end with the note: "Intelligence may be emerging on this planet.

Suggest that intervals between surveys be reduced to a million
years."

Very well, you may ask-suppose we encounter beings who judge, condemn
and execute us as dispassionately, and with as little effort, as we
spray a pool of mosquito larvae with DDT?  I must admit that the
possibility exists, and the logical answer-that their reasons will no
doubt be excellent-is somewhat lacking in appeal.  However, this
prospect seems remote.  I do not believe that any culture can advance,
for more than a few centuries at a time, on a technological front
alone.  Morals and ethics must not lag behind science, otherwise the
social system will breed poisons which will cause its certain
destruction.  I believe therefore that with superhuman knowledge must
go equally great compassion and tolerance.  In this I may be utterly
wrong: the future may yet belong to forces which we should call cruel
and evil.  Whatever we may hope, we cannot be certain that human
aspirations and ideals have universal validity.  This we can discover
in one way only, and the philosophical mind will be willing to pay the
price of knowledge.

I have mentioned before how limited our picture of the Universe must be
so long as we are confined to this Earth alone.  But the story does not
end there.  Our impressions of reality are determined, perhaps more
than we imagine, by the senses through which we make contact with the
external world.  How utterly different our cosmologies would have been
had Nature economized with us, as she has done with other creatures,
and given us eyes incapable of seeing the stars!  Yet how pitiably
limited are the eyes we do possess, tuned as they are to a single
octave in an endless spectrum!  The world in which we live is drenched
with invisible radiations, from the microwaves which we have just
discovered coming from Sun and stars, to the cosmic rays whose 23
origin is still one of the prime mysteries of modern physics.  These
things we have discovered within the last generation, and we cannot
guess what still lies beneath the threshold of the senses-though recent
discoveries in paranormal psychology hint that the search may be only
beginning.

The races of other worlds will have senses and philosophies very
different from our own.  To recall Plato's famous analogy, we are
prisoners in a cave, gathering our impressions of the outside world
from shadows thrown upon the walls.  We may never escape to reach that
outer reality, but one day we may hope to meet other prisoners in
adjoining caves, where the shadows may be very different and where we
may learn far more than we could ever do by our own unaided efforts.

These are deep waters, and it is time to turn back to the shore, to
leave the distant dream for the present reality of fuels and motors, of
combustion-chamber pressures and servomechanisms.  Yet I make no
apology for discussing these remote vistas at some length, if only to
show the triviality of the viewpoint which regards interplanetary
travel as a schoolboy adventure of no more real value than the scaling
of some hitherto inaccessible mountain.  The adventure is there, it is
true, and that is good in itself-but it is only a small part of a much
greater whole.

Not so shortsighted, but equally false, is the view expressed by
Professor

C. S. Lewis, who has written of would-be astronauts in this
unflattering fashion-"The destruction or enslavement of other species
in the universe, if such there are, is to these minds a welcome
corollary."  * In case there are any to whom this prospect still
appeals, I would point out that empires, like atomic bombs, are
self-liquidating assets.  Dominance by force leads to revolution, which
in the long run, even if indirectly, must be successful.  Humane
government leads eventually to self-determination and equality, as the
classic case of the British Empire has shown.  * Perelandra (voyage to
Venus).  Professor Lewis's more recent views are discussed in "of Space
and the Spirit" (page 210).  Commonwealths alone can be stable and
enduring, but empires must always contain the seeds of their own
dissolution.

The desire to give a comprehensive picture of the outcome of
astronautics has compelled me to range not unwillingly-over an enormous
field.  However,

I do not wish anyone to think that the possibilities we have been
discussing need come in this century, or the next, or the next.  Yet
any of them may arise, at any time, as soon as the first ships begin to
leave the

Earth.  Man's first contact with other intelligent races may lie as far
away in time as the building of the pyramids-or it may be as near as
the discovery of X rays.

Of this, at least, we may be fairly certain.  Barring accidents-the
most obvious of which I need not specify -the exploration of the
planets will be in full swing as this century draws to its close.  To
examine them in any detail, and to exploit their possibilities fully,
will take hundreds of years.  But Man being what he is, when his first
ship circles down into the frozen wastes of Pluto, his mind will
already be bridging the gulf still lying between him and the stars.

Interplanetary distances are a million times as great as those to which
we are accustomed in everyday life, but interstellar distances axe a
millionfold greater still.  Before them even light is a hopeless
laggard, taking years to pass from one star to its neighbor.  How Man
will face this stupendous challenge I do not know; but face it one day
he will.  Professor

J. D. Bernal was, I believe, the first to suggest that one solution
might lie in the use of artificial planets, little self-contained
worlds embarking upon journeys which would last for generations Olaf
Stapledon has expanded this theme in Star Maker, one of the greatest of
his fantasies, but the thought of these tiny bubbles of life, creeping
from star to star on their age-long journeys, carrying whole
populations doomed never to set foot upon any planet, never to know the
passage of the seasons or even the interchange of night and day, is one
from which we

See "The Planets Are Not Enough" (page 66).  might well recoil in
horror.  However, those who would make such journeys would have
outlooks very different from our own and we cannot judge their minds by
our standards.

These speculations, intriguing though they are, will hardly concern
mankind in this century.  We may, I think, confidently expect that it
will be a hundred years at least before confinement to the Solar System
produces very marked signs of claustrophobia.

Our survey is now finished.  We have gone as far as is possible, at
this moment of time, in trying to assess the impact of astronautics
upon human affairs.  I am not unmindful of the fact that fifty years
from now, instead of preparing for the conquest of the outer planets,
our grandchildren may be dispossessed savages clinging to the fertile
oases in a radioactive wilderness.  Yet we must keep the problems of
today in their true proportions.  They are of vital-indeed of supreme
importance since they can destroy our civilization and slay the future
before its birth.  But if we survive them, they will pass into history
and the time will come when they will be as little remembered as the
causes of the Punic Wars.  The crossing of space-even the sense of its
imminent achievement in the years before it comes -may do much to turn
men's minds outward and away from their present tribal squabbles.  In
this sense the rocket, far from being one of the destroyers of
civilization, may provide the safety valve that is needed to preserve
it.  This point may be of the utmost importance.  By proP vi ding an
outlet for man's exuberant and adolescent energies, astronautics may
make a truly vital contribution to the problems of the present world.

Space flight does not even have to be achieved for this to happen.  As
soon as there is a general belief in its possibility, that belief will
begin to color men's psychological outlook.  In many ways, the very
dynamic qualities of astronautics are in tune with the restless,
expansive spirit of our age.  In this essay I have tried to show that
the future development of mankind, on the spiritual no less than the
material plane, is bound up with the conquest of space.  To what may be
called-using the words in the widest possible sense-the liberal
scientific mind, I believe these arguments to be unanswerable.  The
only real criticism that may be raised against them is the quantitative
one that the world is not yet ready for such changes.  It is hard not
to sympathize with this view, which may be correct, but I have given my
reasons for thinking otherwise.

The future of which I have spoken is now being shaped by men working
with slide rules in quiet offices, and by men taking instrument
readings amid the savage roar of harnessed jets.  Some are engineers,
some are dreamers-but many are both.  The time will come when they can
say with T. E. Lawrence: "All men dream; but not equally.  Those who
dream by night in the dusty recesses of their minds wake in the day to
find that it was vanity: but the dreamers of the day are dangerous men,
for they may act their dream with open eyes, to make it possible."

Thus it has always been in the past, for our civilization is no more
than the sum of all the dreams that earlier ages have brought to
fulfillment.

And so it must always be, for if men cease to dream, if they turn their
backs upon the wonder of the Universe, the story of our race will be
coming to an end.

In the following three pieces I have attempted to bring home the
realities of space travel by considering what the tourists of the
twenty-first century will meet when vacationing on the Moon, Mars or a
satellite hotel.

These articles were commissioned, with considerable foresight, by
Holiday

Magazine almost five years before the launching of the first Sputnik,
and

I have reproduced them here with only one alteration-the addition of
the letters USSR.... In attempting to give close-ups of the Moon and

Mars I have, obviously, had to go beyond the limits of known facts; the
best telescopes cannot bring us to with in less than 50,000 miles of
Mars, or 250 miles of the Moon.  My comments on extraterrestrial life
forms are therefore purely speculative, but I have been careful not to
let them conflict with present-day knowledge.

Much of the material in these three articles has been used to provide
the background of Islands in the Sky, Earthlight and The Sands of Mars.
 Vacation in Vacuum

WHEN THE U.S. AND USSR.  STARTFD BUILDING THE first satellite stations,
back in the 1960's, the idea that they would one day become health
resorts and embarkation points for space-bound vacationers would have
seemed slightly fantastic.  Yet it was no more fantastic, of course,
than the fact that since the beginning of the century the human race
had deserted the sea and lifted its commerce into the air.  If anyone
had dared to prophesy that miracle when the Wright Brothers made their
first nervous hop in 1903, he would have been laughed to scorn. And
even fifty years later, though there were many who realized that space
stations might have military and scientific uses, there were very few
who looked beyond these to the day when they would become part of
everyday life.

Well, perhaps that is a slight exaggeration.  Even today, relatively
few people have actually been to a space station, but there can be
nobody who has not seen one with his own eyes.  If you live near the
equator you have a fine selection to choose from: you can see not only
the outer stations but the close refueling satellites that hug the edge
of the atmosphere, and are so near the Earth that the curve of the
planet hides them from observers in high latitudes.  In the daytime
they are bright stars, easily visible when the sky is clear, sweeping
from horizon to horizon in a matter of minutes.  29  And, of course,
they move backward, from west to east, because they race round their
tight little orbits so much more quickly than Earth itself turns on its
axis.

At night, they are the brightest stars in the sky, and you can see them
move even as you watch.  You'll have to look for them low down near the
horizon, for as they rise up they disappear into Earth's vast,
invisible shadow, winking suddenly out of existence as they go into
eclipse and no longer catch the light of the Sun.  Sometimes, if you
are lucky, you may see a star snuffed out for a few seconds as a space
station moves silently across it up there in the emptiness beyond the
atmosphere.  But the stations are so tiny, and the sky so vast, that
you'll have to watch for many nights before you'll see this happen.

Let's go up there into the shining darkness of space, into that
paradoxical world where intense heat and unimaginable cold exist
together, where dawn and dusk are separated by minutes, not by hours.
Yet before we begin the journey, we'll glance back for a moment into
the twentieth century, to remind ourselves how so much we now take for
granted first came into being.

It was around 1925 that scientists first became seriously interested in
space stations as refueling stops for interplanetary rockets.  Back at
that time, of course, there weren't any rockets-interplanetary or
otherwise -and the general public never heard about the idea.  It
didn't hit the headlines until 1948, soon after the end of the Second
World War.  The United States military experts had been studying the
results of German war research, and had been staggered by what they
found.  They were now seriously investigating, the Secretary of Defense
announced, the possibilities of "space platforms" for military use.

Looking at the newspapers of that time, it's amusing to note the
reactions.

Many editors asked sarcastically how such platforms could possibly stay
up there in the sky.  Apparently they'd never bothered to consider how
the Moon "stayed up," and so had not realized that the proposed
artificial satellites would obey exactly the same laws as the natural
ones.  Slowly, during the 1950's and '60's, the idea was accepted by
the general public as well as the military.  As rockets reached greater
speeds and altitudes, the goal-of the Earth satellite vehicle came
nearer to realization, until at last a few instruments were flung out
into space, never to return to the atmosphere.  That was the first
frail rang on the ladder that would lead to the planets.

It was still many years before real man-carrying space stations, and
not mere automatic missiles, were constructed from prefabricated parts
ferried up by rocket and assembled in space.  By the end of the
twentieth 'century there were dozens of military reconnaissance units,
meteorological stations and astronomical observatories circling Earth
at various distances, carrying crews of up to twenty men in conditions
almost as cramped as in the old-time submarines.  They were the first
forerunners of the spacious orbital cities we have today-the nuclei
around which the later satellites were built, just as on Earth itself
great capitals once grew from ancient villages or fortified camps.

The ordinary space traveler sees only the inner station-Space Station

One-as he transfers from the Earth ferry rocket to the liner that's
taking him to Mars or Venus.  It's the nearest of all the satellites, a
mere three hundred miles up-too close, therefore, to give one a really
good view of

Earth.  If you want to see the planet as a whole, you've got to travel
out to one of the more distant stations.  We'll start our tour,
therefore, more than ten thousand miles out, in the most luxurious of
all the satellites-Sky Hotel.

Even today, with all our modern developments in rocketry, it's highly
doubtful if a hotel in space would be a commercial proposition.
However,

Sky Hotel draws its income from many subsidiary sources.  It's not
merely patronized from Earth-the staffs from the other satellites take
their vacations there, as it's cheaper for them to do that than to pay
the fares down to Earth and up again.  Moreover, Sky Hotel has pretty
large shares in the relay stations, which we'll be visiting later in
our trip.  The hotel is in two sections-the part with gravity and the
part without.

When you first see it from your approaching rocket, you'll think you're
about to land on the planet Saturn.  Hanging there in space ahead of
you is a great ball, with a ring surrounding it but not touching it at
any point.

The ball is motionless, while the ring slowly revolves.

When the pilot has jockeyed the rocket over to the ball, you'll realize
just how big the hotel is.  Your ship will seem like a toy when it
couples, itself up to the mooring socket on the axis of the station,
and the air locks are joined together so that you can go aboard: The
hotel staff will collect both you and your luggage, for most people are
pretty helpless under zero gravity for the first few hours.  But,
believe me, it's an experience worth getting used to.

Sky Hotel has, by ingenious design, managed to get the best of both
worlds.

Most vacationers go up there to enjoy the fun and games under
zero-gee-but weightlessness is not so amusing when you want to eat a
meal or take a bath, and some people find it impossible to sleep under
free-fall conditions.  Hence the dual purpose design of the hotel.  The
central ball contains the gymnasiums and that fantastic swimming pool
we'll be visiting presently, while over in the ring are the bedrooms,
lounges and restaurant.

As the ring rotates, centrifugal force gives everyone inside it a
feeling of weight which can't be distinguished from the real thing.
It's not so powerful, though-at the outer rim of the hotel you'll weigh
only half as much as you would on Earth.

And there's one other difference between gravity home on Earth and the
imitation variety in the hotel.  Because "Up" always points to the
center of the ring to the invisible axle on which it turns-all the
floors are curved, like the inside of a drum.  If you could see right
across the hotel-and maybe it's just as well that you can't-you'd see
that the people on the other side were upside down, with their heads
pointing toward you.  It's only in the Sky Grill-the largest room in
the 32  ring-that this effect is at all noticeable.  When you're
dining, your table seems to be at the bottom of a smoothly curving
valley, while everyone else is sitting at improbable angles further up
the slope.  The more distant they are from you, the more canted toward
you they will be, until eventually it seems that they must be glued to
the wall.  It's a fascinating sight watching a waiter come down the
slope with a trayful of beers.  At first you won't be able to believe
your eyes-why don't the glasses spill?  Then as he approaches he'll
veer over to what you-but nobody else-consider to be the vertical, and
you'll breathe a sigh of relief.

Of course, there's nothing mysterious about all this.  Centrifugal
force can produce exactly the same effect down on Earth if you whirl a
bucket at the end of a rope.  But I advise you to do the experiment out
of doors, and to use water rather than beer.

Most of the hotel's residents divide their time more or less equally
between the gee and the zero-gee parts between the ring and the ball,
in other words.  The kids are an exception-it's a job luring them away
from weightlessness, even for meals, so they spend almost all their
time in the ball.  There is a snack-bar over there, where you can get
drinks served in plastic bulbs so that you can squirt the liquid
straight into your mouth.

That's the theory-and it works, too.  But the kids usually prefer less
efficient methods, and promptly empty their bulbs into the air.  It's
quite a sight watching a budding space cadet chasing a ball of Coke as
it drifts slowly from point to point, and eventually splatters messily
on one of the walls.

Traveling between the stationary ball and the spinning ring that
surrounds it is another of the novelties of space-station life.  The
trip's made in a kind of pressurized elevator cage, running round a
track on the inside of the ring.  It's a queer sensation, feeling your
weight ebb away as you move across to the ball and centrifugal force
vanishes.

The hotel is full of ingenious mechanisms and gadgets like this.  Most
of them you'll take for granted and may never even see unless you ga
one of the engineers 33  to take you behind the scenes.  Then you may
be shown round the air purifiers that crack the carbon dioxide, so that
there's very little loss of oxygen to make good by shipments from
Earth.  If they fail, there's a big enough reserve to last until the
hotel can be evacuated -or the plant repaired.

Almost as important is the heat-regulating apparatus.  Out in space, in
direct sunlight, an object can reach a temperature of three or four
hundred degrees F. on its "day" side-while the "night" side can be a
couple of hundred degrees below zero.  By circulating air through the
double walls of the hotel, these temperature extremes are eliminated.

Ignoring such activities as poker and canasta, which are highly
independent of gravity, there are two classes, of recreation aboard the
hotel.  In the ring you can play most of the games that are found on
Earth-with suitable modifications.  The billiard tables, for example,
have to be curved slightly: at first sight it looks as if they dip down
in the middle, but in this radial gravity field, this makes them behave
like flat surfaces.  You very quickly get used to this sort of thing,
though it may throw off your game for a while when you return to
Earth.

However, since there seems little point in going out into space to
indulge in terrestrial-type sports, most of the excess energy in Sky
Hotel is expended in the zero gee rooms aboard the ball.  The one thine
that nobody misses is a chance to do some flying-real flying, of the
kind we've all dreamed about at some time or another.  You may feel a
little foolish as you fasten the triangular wings between your ankles
and wrists and secure the free ends to your belt.  Certainly your first
few strokes will start you turning helplessly over and over in the air.
But in a few hours you'll be flying like a bird and much less
effortlessly.  By the way, the crash helmet that goes with the wings is
not just an ornament.  It may prevent your knocking yourself out if you
get up too much speed and don't notice how near the wall you are.  Some
of the zero-gee ballets with special lighting 34  effects, that the
expert performers can execute are unbelievably beautiful, like
fairyland filmed in slow motion.  Even if you've already seen them on

TV, don't miss an opportunity of attending an actual performance at the
hotel.

When you've earned your wings in the amusing series of tests that
entitles you to your "Spacehound's Certificate," you'll probably want
to take part in such sports as zero-gee basketball or three-dimensional
miniature golf.

Many terrestrial games have been adapted, with interesting variations,
to conditions of weightlessness, but there are also dozens of sports
and tricks that have no counterpart on Earth.

For example, there's the quite exhausting game you can play where
everyone puts on wings and the winner's the one who can collect the
largest number of scattered water drops into a single sphere-and bring
it back to goal before his opponents tear it to pieces.

Talking about water drops leads me, inevitably, to the hotel's most
incredible novelty-its famous swimming pool.  Any resemblance to
similarly described places on Earth is not merely coincidental-it's
nonexistent.

When you go to the "pool" you'll find yourself in a big spherical
chamber about sixty feet across, almost filled by what is
claimed-probably correctly-to be the largest single drop of water in
existence.  You won't be particularly surprised to see people swimming
round and round inside the sphere, but what will astonish you is the
sight of a group in its center talking and laughing together and
perhaps even taking refreshments.  Even in space, you'll say to
yourself, people still have to breathe!

To settle the mystery, dive into the drop and swim through it.  When
you've gone about twenty feet, and are still some distance from the
center, you'll break through another water surface and find yourself in
a hollow space about ten feet across, breathing ordinary air.
Yes-you're inside a bubble!

It can't escape from the inside of the drop, because only when there is
an

"Up" can bubbles rise in a liquid.  So the swimming 35  pool is really
a huge hollow shell of water, and you can sit quietly at the very
center and watch your friends sporting like fish all around you.

I have seen people smoking in the middle of the pool, though that's
against regulations as it's liable to overtax the little air purifier
that floats at the exact center of the bubble.

Incidentally, keeping the water clean presents some headaches, and you
ll notice eight large pipes leading into the giant drop at points
equally spaced over its surface.  Water flows in and out of these at
carefully adjusted rates, so that the shell of liquid always remains
the same size.

When you're tired of swimming, you can spend a good many happy hours in
the observation lounge, simply watching the Earth and stars.  There are
no windows in the ring, because it would be rather disconcerting to see
the heavens around you revolving at such a rate.  So you'll have to do
all your stargazing from the non rotating ball.

From ten thousand miles out, the Earth is just small enough to fill
your field of vision completely, and you can see everything except the
extreme polar regions.  Even to the naked eye, it's a source of endless
enchantment.

In the nine hours that the hotel takes to complete its orbit, you'll
see the Earth change from new to full and back again-going through the
phases that the Moon takes a whole month to complete.  The sight of the
dawn down there, as the Sun comes blasting up through the incandescent
mists at the edge of the atmosphere and Earth grows swiftly from a
hairline crescent to a huge glowing disk, is something no amount of
repetition can ever stale.

When you've had your fill of gazing through the observation windows,
you'll turn to the telescopes.  Some of them can magnify up to a
thousand times, so you'll feel that you're hanging only ten miles above
the surface of the

Earth.  If there's no cloud, it's amazing bow much minute detail you
can see.  Towns and cities are easy; even single large buildings can be
detected under favorable conditions.  But don't believe anyone who 36
tells you that they've been able to see individual men!  That's only
possible from t1le inner satellites, a mere few hundred miles up.

It's interesting to study the effect of these novel surroundings on
your companions.  Human beings are incredibly adaptable, and for most
of the time the guests in Sky Hotel enjoy themselves in the same
uninhibited way as if they were down on Earth.  But from time to time
you'll catch them looking thoughtfully at the stars, realizing that
this is space-this is the

Universe.  They'll have become suddenly aware that the familiar Earth,
with its gravity and its air and its oceans, and its teeming,
multitudinous life, is a freak, an incredible rarity; 99.999999 percent
of the cosmos is emptiness and night.

That realization can affect people in two ways.  It can depress them
when they think how puny Man is against the Universe-or it can
exhilarate them when they consider his courage in attempting to conquer
it.

Moving in almost exactly the same orbit as the hotel, but fifty miles
away from it, is the newest and largest of the space hospitals-Haven
IV.  It's often possible to arrange a trip across in one of the
low-powered rocket shuttles that ply between the orbits of the various
stations, and sometimes there are official conducted tours of the
hospital.  Most of the patients on

Haven are heart cases, recuperating under conditions where physical
effort is so much less than on Earth and their weakened hearts haven't
got to pump pounds of blood up and down the body twenty-four hours a
day.  The first rocketeers, crushed in their acceleration couches under
the strain of blast-off, would have been very surprised to know how
soon cardiac sufferers were to make the same trip.  Of course, the
patients all travel under deep anesthesia and don't know a thing about
it.

Haven IV is a single giant disk, slowly turning on its axis so that at
the outer rim "gravity" has the same value as on Earth.  As you go
toward the center and the speed of rotation decreases, the synthetic
gravity weakens as well, until at the very center you have complete
weightlessness.  New patients start their treatment 37  near the axis
of the hospital, in wards where gravity is maybe a tenth as powerful as
it is on Earth, and move outward toward normal weight as their
condition improves.  Sometimes they never recover sufficiently to
return to

Earth-but even these severe cases can settle down on the Moon and get
along happily with a sixth of Earth's gravity.

Besides the heart cases, the space hospitals specialize in polio
victims, as well as people who have lost their legs and would be
virtually helpless down on Earth.  There are quite a number of legless
men working permanently on the space stations.  Often they are more
agile than those who are not disabled-they haven't so much useless
weight to drag around!

Quite recently, Haven IV has started to deal with severe burns.  It
doesn't take much imagination to realize how treatment and recuperation
can be speeded when the patient can float freely in space and no longer
has to lie on his dressings.

No wonder, therefore, that it's been said that the four space hospitals
have already repaid humanity all the billions that the conquest of
space has cost.  And I haven't even mentioned the fundamental medical
research they've made possible, particularly through the studies of
giant microbes that could only be bred under zero-gee conditions.

From the observation lounge of the Sky Hotel you can see all the inner
stations as they pass between you and Earth, moving on their smaller,
swifter orbits far more rapidly than you do.  Sometimes, when you are
looking through a telescope at the lights of some city on the night
side of

Earth, you may be surprised to see a tiny brilliant star explode
against the darkness and start moving purposefully out into space.
You'll have caught one of the interplanetary liners at the moment of
take-off, as it pulls away from its refueling station and begins its
long journey.  And sometimes you may see the glare of one of the big
freighter rockets as it starts the climb up from Earth-that
two-hundred-mile haul that requires so much more effort than all the
millions of miles between the planets.  Down there between you and
Earth are the met stations, charting the weather over the entire planet
so that we know now, nine times out of ten, exactly what's going to
happen during the next forty-eight hours.  (The meteorologists are
still worried about that odd tenth time, but they swear they're going
to get it licked one of these days.) And there are the big space labs,
carrying out all sorts of experiments that could never be done on
Earth, where no amount of money could buy you a perfect vacuum as many
miles across as you cared to specify.  Last, but perhaps most important
of all, are the astronomical observatories with their vast, floating
mirrors, scores of feet across, peering out across the billions of
light-years and no longer half blinded by the murk and haze of the
atmosphere.

You may feel rather superior to these lower satellites as you look down
upon them from your ten-thousand mile-high eyrie.  But if you do, then
remember that the outermost of all Earth's man-made moon lets are
twelve thousand miles beyond you.  I mean, of course, the three relay
stations which now carry all the long-range TV and radio traffic of the
planet.

At this height of twenty-two thousand miles, a satellite takes exactly
twenty-four hours to go round its orbit, so the entire huge triangle of
the relay chain rotates in synchronism with Earth, just as if it was
fixed to it by invisible spokes.  That's why, once you've aimed your TV
antenna at the nearest relay up there in the sky, you need never move
it again.  And you can get your pictures without any interference, and
from any spot in the world-something that would have seemed incredible
when TV was first invented.

Sometimes you can thumb a lift on a shuttle up to one of the relay
stations.  Out there, more than twenty thousand miles above Earth,
you'll really feel you're on the frontier of space.  But don't forget
that this is only a tenth of the distance to our nearest neighbor, the
Moon-and much less than a thousandth of the distance to Mars or Venus,
even at their closest approach.  So when you get back to Earth, don't
be too boastful about your achievements-at least until you've made 39
quite sure that there are no real space hounds in the party.

More seriously, there's one point you must watch when you're home
again.

Take things very easily for the first few days.  Remember, we've got a
little thing called gravity down here, and the tricks you can play in
Sky

Hotel won't work so well back on Earth.  You can't cross Fifth Avenue,
for instance, by stepping out at the two-hundredth floor of Planet
Tower and launching yourself in an easterly direction.  (Take my word
for it-it's been tried.) Even in your own home, you may find yourself
treating the stairs with quite unjustified contempt, so this warning is
by no means as superfluous as it seems.

Finally, I've been asked to deny a canard which has been causing the
hotel management much grief.  Luigi, chef de cuisine, is particularly
upset by the slander which he's convinced has been put out by rival
establishments on

Earth.  It's completely untrue that the guests at the hotel have to
live on compressed foods and vitamin pills, like the first space
pioneers.  The meals are as good as anything you can get on Earth. They
may not actually weigh as much, but I can, assure you, from personal
experience, that they're every bit as satisfying..  .. journey by
Earthlight

JUST A HUNDRED YEARS AGO, BACK IN 1976,* THE FIRST men landed on the
Moon, and the age of space flight began.  During the last few years, it
must be admitted, the glamor of more romantic places like Mars and
Venus has diverted attention from our satellite.  Perhaps it's so close
that we tend to take it for granted, just as no New Yorker ever bothers
to go to the top of

Planet Tower to see what his city looks like from half a mile up.
Moreover, until very recently few people went to the Moon unless they
were scientists or technicians on official business.

Two things have changed this.  Now that the necessary facilities exist,
the

Lunar Commission is encouraging a limited tourist trade, though for the
moment it will be restricted to the Earthward face of the Moon.  The
second factor, of course, is the establishment of Pasteur City, which
is likely to have a profound effect on medical research and even,
ultimately, on human society.

Looking back on it from our vantage point, it is obvious that the first
landing on the Moon was an anticlimax.  Everyone had been expecting it
for almost half a century: it had been the theme of countless books and
movies, and rockets had been getting closer and

* This seemed wildly optimistic in the early 1950's.  Today, 1970 would
be a safer guess.  closer for twenty years before the final touchdown
was made.  Moreover, no one had expected to find very much on the
Moon-and for a while they weren't disappointed.  The general
impression, through most of the twentieth century, was that the Moon
was completely dead and unchanging-a cosmic slag heap of interest only
to geologists and astronomers.  It might be useful as an observatory
and a fueling stop on the road to the planets, but otherwise it was not
a very valuable piece of real estate.

To see how accurate that first impression was, imagine you're aboard
the passenger ship Archimedes as it drops down toward the rugged lunar
landscape.  The journey from Space Station One, just outside Earth's
atmosphere, has taken less than ten hours.  Once, it lasted almost five
days, but now that atomic propulsion has been perfected, fuel economy
is no longer at a premium and the crossing can be made at much higher
speeds.

However many times you do it, a landing on the Moon is an awe-inspiring
experience, totally different from the long glide through the upper
atmosphere.  which brings you down on planets like Earth or Mars.  The
lunar landing must be made by rockets alone, at the end of an
interminable fall which is checked only when you are within a hundred
miles of that jagged, pock-marked landscape.  Then the silence will be
broken as the rockets thunder into life, and your returning weight will
force you down into your seat.  Through the observation window-if
you're lucky enough to be near one-you'll see the white-hot pillar of
flame which is checking your headlong fall.  The squat and stubby
Archimedes will look like a giant spider as it descends, out thrust
landing legs spread to take up the shock of impact.

Touchdown itself will be indicated only by the final cessation of
thrust, and a ringing silence as the rockets die.  Then there will be a
curious, heaving motion as the long hydraulic cylinders in the
undercarriage absorb the ship's momentum.  It will last for less than a
second, but if the landing has been badly off the vertical you'll think
42  for a minute that you're aboard a boat in a choppy sea.  Luckidy
it doesn't last long enough for anyone to be seasick.... The very first
question that everybody asks when they find themselves on the Moon is
"Where are all the mountains?"  For hours they'll have seen those great
peaks coming closer and closer: they'll have watched the crater walls
rise around them until the summits seem to tower above the falling
ship.  And then, when the flurry of dust and flame has died away, the
Archimedes will be standing on a rocky plain, with only a few low hills
in sight.  Though you are in the center of a mountain-fringed plain,
the steep curve of the Moon's surface has hidden the surrounding walls
from view.  It will take you some time to get used to this nearness of
the horizon, caused by the fact that the Moon is only a quarter the
size of the Earth.

The Archimedes will land in the Sinus Medii-a small plain at the exact
center of the Moon's visible face.  This region is of enormous
geological interest, for it is surrounded by crevasses of up to a
hundred miles in length.  Through these gigantic fissures, men have
been able to penetrate far into the crust and hence the area is one of
great mining activity.

Though no sound can exist where there is no atmosphere to carry it,
you'll sometimes feel the ground shake as blasting charges are let off
round the colossal canyon known as the Hyginus Cleft.

Sinus Medii means "Central Bay"; though of course there is no free
water on the Moon, such terms as bay, sea, ocean and lake were used by
the early astronomers and have stuck so thoroughly that no one can
change them now.

To make matters more confusing to newcomers, the Latin and English
versions are used indiscriminately.  It may take you some time to
realize, for example, that Palus Sornnii is the same place as the Marsh
of Sleep.  Though there have been several attempts to tidy up lunar
nomenclature, nothing has come of them and we're stuck with the
five-hundred-year-old names.  Luckily the Moon's other side-which of
course was never seen until the first rockets started to land 43
there-isn't littered with remnants of medieval astrology.  The great
formations there have been named after famous men of modern times, so
don't be surprised to encounter Einstein, Churchill, Rutherford,
Sibelius,

Roosevelt-all of whom have craters more than a hundred miles across

The Sinus Medii is not only the main spaceport on this side of the
Moon, but also the center for surface transport.  All long-distance
travel is by monorail, for the Moon is an absolutely ideal place for
this type of locomotion.  There's no air resistance, so speeds of five
hundred miles an hour can be reached with little difficulty.  And the
low gravity greatly eases the construction problem-the single rail need
only be supported at wide intervals, and bridges can have enormous
spans.

So come aboard the north-bound track to Pasteur City, in the great
walled plain of Plato, and take a ride over the most spectacular
scenery on the

Moon.  We'll leave in darkness, a few hours after the beginning of the
long lunar night.

The monorail car holds about fifty passengers, and is automatically
controlled.  Because its weight is too low to give good traction, the
driving wheels grip the rail horizontally under the pressure of
powerful springs.  The terminus itself might be a station on Earth:
there'll be the usual lines of track, the speakers calling departures
and arrivals.  But when everyone has come aboard, the car will be
sealed and will slide through double doors into a huge air lock. You'll
hear the throb of giant pumps as the chamber is evacuated; then the
outer door will open and there will be a surge of acceleration as the
monorail's electric motors speed you out of the terminus, onto the
surface of the Moon.

If you're lucky, you may see a take-off as you skirt the edge of the
spaceport.  A night launch from the Moon is an unforgettable sight; its
utter soundless ness somehow adds to the effect.  The ship will ascend
in a cloud of dust blasted up from the plain-a cloud within which the
jets will burn like incredibly brilliant suns.  As

* See "The Men on the Moon" (page 192) for a fuller account of lunar
nomenclature.  the dust falls behind, the blue-white glare will flood
the landscape with a light more fierce even than that of noon.  It will
ebb away as the ship dwindles against the stars, and will suddenly wink
out of existence as the departing vessel reaches escape velocity and
cuts its drive.

For the first few hundred miles, the monorail runs over relatively flat
country as it heads northeast.  Though the Sun has set, the landscape
will be brilliantly illuminated by the Earth, just passing its first
quarter but already giving a dozen times as much light as the full Moon
does to the terrestrial scene.  It's a cold light: an arctic radiance
that gives not an atom of heat.  For it's tinged with the blues and
greens of Earth's oceans and clouds; it sparkles from the polar caps
that even across a quarter of a million miles of space are too dazzling
for the unprotected eye.  It's hard to believe that this freezing
luminosity really comes from a world of warmth and life.

There's an observation room at the front of the car, curtained off from
the light of the main cabin.  Unless you're a seasoned, blase traveler,
you'll spend most of your time here, watching the lunar landscape
racing past.

Ahead of you the single rail, supported by pillars disquietingly far
apart, is now running almost due east.  Here's another paradox to
bother you: the way directions on the Moon have been chosen, the Sun
sets in the east, not the west.... The monorail is losing speed as it
climbs up out of the shadowed lowlands.

At any moment now, you'll overtake the Sun.  The line of darkness moves
so slowly here that a running man could almost keep abreast of it, and
could hold the Sun balanced on the horizon as long as he could maintain
his speed.

On your left-that's the north-the broken land falls away in a series of
layers as if, a million years ago, the lava welling up from the Moon's
molten heart had solidified in successive, weakening waves.  It's a
scene that chills the soul, yet there are spots on Earth as bleak as
this.  The

Badlands of Arizona are equally desolate; the upper slopes of Everest
are still more hostile, for 45  though the temperature here is two
hundred degrees below zero, at least there is no eternal ravening
wind.

And then-the cliff on the right comes to a sudden halt as if a
monstrous chisel had sliced it off the surface of the Moon.  You see
clear round to the north: there, marching across the sky in flaming
glory, are the peaks of the Apennines, incandescent in the last rays of
the hidden Sun.  The abrupt blaze of light almost blinds you, and you
have to shield your eyes from the glare until you can safely face it.
When you look again, the transformation is complete.  The stars, which
until a moment ago had filled the sky, have vanished.  Your contracted
pupils can no longer see them: even the glowing Earth now seems no more
than a feeble patch of phosphorescence.

The glare from the sunlit mountains, still fifty miles away, has
eclipsed all other sources of light.

The peaks float in the sky, fantastic pyramids of flame.  They seem to
have no more connection with the ground beneath them than do the clouds
that hover round a sunset on Earth.  The line of shadow is so sharp,
the lower slopes of the mountains so lost in utter darkness, that only
the burning summits have any real existence.  It will be hours yet
before the last of those proud peaks slips back into the shadow of the
Moon and surrenders to the night.

The Apennines are the finest range on this side of the Moon: those
summits tower more than twenty thousand feet above the plain, and seem
an impassable barrier.  But twenty thousand feet on the Moon is
equivalent to less than four thousand feet on Earth, and it is possible
to ascend vertiginous inclines with impunity.  The monorail weaves and
climbs through the spectacular passes, then drops down the northern
slopes into the vast plain of the Mare Imbrium-the Sea of Rains.  As
you descend into the lowlands, the Sun which your speed has magically
conjured up from night sinks again below the edge of the Moon.  There
is little more to see until you reach Pasteur; you might as well go
back into the cabin and join your fellow passengers.

You'll catch your first glimpse of the city as you descend the inner
ramparts of Plato-the superb walled 46  plain on the northern border
of the Mare.  It's strange to think that Man built his first
extraterrestrial cities on distant Mars, not on his nearest neighbor in
space.  But the incentive was greater, the technical problems less. Now
that they have been overcome, we can expect to see many more cities on
the Moon.

The first lunar bases were entirely underground; many of them still
are.  By digging a few feet into the interior one can completely avoid
the four-hundred degree temperature change between day and night.  The
first colonists were also frightened of meteors, and decided to take no
chances against bombardment from space.

We know now that meteors are no more common on the Moon than they are
on

Earth.  For the Moon has an atmosphere: true, it's a billion times less
dense than ours, but because of the lower gravity it extends much
further into space.  As far as breathing it is concerned, you might
just as well be in a vacuum-but this tenuous envelope has two very
important practical uses.  It's a first-class meteor screen-and it
provides an ionosphere like

Earth's, reflecting radio waves round the curve of the planet so that
long-distance communication is possible.

Pasteur City consists of a' dozen pressure domes, linked together by
air locks, a few miles from the north wall of Plato.  One of the domes
is transparent, so that the residents can watch the pageant of the
changing heavens, can see the long dawn break above the mountains-and
can watch the seasons come and go on the world to which they can never
return.

Yet it is quite wrong to think of Pasteur City as a home for
convalescents, like the space-station hospitals circling Earth.  Almost
all its twenty thousand inhabitants live normal, unrestricted lives.
But they could do so only here, where they weigh no more than thirty
pounds and the strain on hearts and muscles is correspondingly
reduced.

Like all great advances in medical science, the founding of Pasteur
City has opened up new and unsuspected frontiers.  If people suffering
from chronic heart diseases 47  can live out their normal span under
the Moon's gravity, what will be the expectation of an ordinary,
healthy man?  No one talks too much about this, but there's an air of
suppressed excitement among the doctors studying the matter.  Some of
them have been heard to say that old age can now be postponed until far
into the second century.  If this is true, and the technical problems
of supporting a large lunar population can be overcome-well, we can
expect some interesting social changes.

Pasteur looks like an ideal center for the tourist trade when it starts
to develop, for the Mare Imbrium is one of the most beautiful regions
of the

Moon.  The city itself is still somewhat deficient in luxuries, since
the effort to become self-supporting has absorbed most of its energy.
Oxygen and water have to be extracted by chemical means from the lunar
rocks-in which, luckily, they are fairly common.  Food is produced
under acres of glass in the huge hydroponic farms, where nutrient
solutions flow through pressurized tubes during the fourteen days of
continuous sunlight.  You'll be surprised to find how tasteful some of
these synthetic foods are, but you'll make yourself unpopular if you
ask for steaks or chops.

In Pasteur City you'll encounter a practical problem that won't have
bothered you greatly elsewhere.  At the spaceport back in the Sinus
Medii, and on the monorail trip, you will have been in fairly cramped
surroundings, and won't have been able to perform those athletic feats
which the earlier writers about the Moon loved to emphasize.  It's not
very practical, for instance, to jump twenty feet high when the ceiling
is only a yard above your head.  But in Pasteur City, under the domes,
you will have your first real opportunity to show off.

Well, take it easy.  Don't go up until you are sure you know how to
come down.  It's all too simple to turn over in flight and land on your
head-which will damage you just as much as it would on Earth.  Should
you wear one of those lead belts which are recommended for visitors
during their first few days on the Moon?  That's up to you; try one, by
all means-it may save 48  you from injury through carelessness.  But
there's a snag, which many people don't realize, about loading yourself
down with lead.  Whereas weight on the

Moon is reduced to a sixth, inertia is exactly the same.  Your hundred
pounds of lead will help keep you on the ground and will be no burden
when you are standing still.  But as soon as you start or stop, or try
to change direction, it will feel exactly what it is-a hundred pounds
of lead!

Personally, I think the best thing to do is to accept your weight for
what it is, and learn to reduce muscular effort accordingly.  Your
first attempts to take strides of normal length will look somewhat
prissy and mincing, but you'll soon get used to it.

Since you won't have come all the way to the Moon to look at other
human beings, you'll want to spend as much time as you can outside the
city.

Short-range lunar transport is carried out by tractors-pressurized
vehicles with large balloon tires and caterpillar treads that can
negotiate any ground that isn't actually vertical.  (Even that's an
unfair restriction; tractors have often hauled themselves up cliffs
with their power winches.)

They are virtually spaceships on wheels, and prospectors live in the
larger ones for weeks at a time.

Because rockets are hardly practical for this kind of.  work, the
detailed examination of the Moon has depended almost entirely on these
tough little vehicles.  Some have now been turned into observation
cars, and are already operating around Plato, carrying sightseers from
Pasteur City.  The most popular trips are those along the foothills of
the Alps, and over the Pole to the hidden face of the Moon.

The Alpine excursion runs south from Plato to the great mountain of
Pico, rearing itself to a height of eight thousand feet above the
plain.  It now stands in splendid isolation, but was once part of a
mighty crater wall destroyed by volcanic action when the Moon was
young.

Then the tractor will swing west for two hundred miles until it comes
to Mount Blanc, the great sentinel standing guard at the entrance to
the extraordinary Al pine Valley.  This weird formation, eighty miles
long, slices through the

Alps like a railroad cutting, and even now we do not know exactly how
it was caused.  Entering it is like driving into the Grand
Canyon-except that this valley is almost perfectly straight and was
certainly not produced by the action of water.

If you are a really expert mountaineer, and are prepared to sign the
necessary waivers, you may be allowed to try your skill on some of
the

Alpine peaks.  At first sight, your reduced weight will seem a great
advantage-and so it is, since you can easily lift yourself with one
arm.  But low gravity can also induce carelessness; a sixty-foot fall
on the Moon is as dangerous as a ten-foot one on Earth-more dangerous,
in fact, since there is always the risk of damaging your space suit.
Although these suits have now reached a high degree of perfection-they
are practically foolproof, and can keep a man alive for twenty-four
hours-no one claims that they are exactly comfortable, and they prevent
free and unimpeded movement.  With all your equipment, your Earth
weight when you start climbing will be about fifty pounds.

One surprising fact about lunar slopes and mountains is that, on the
whole, they are not as steep as on Earth.  Because of the absence of
weathering, however, they are angular and jagged-there have been no
winds or rains to soften their contours.  The complete absence of snow
or ice removes one major obstacle to climbing, and, when all factors
are taken into account, lunar mountaineering, despite its risks, is no
more suicidal a pursuit than its terrestrial equivalent.

From the region round Pasteur City, the Earth hangs low in the southern
sky, its continents clearly visible and its blanket of atmosphere
forming a luminous haze around its edge.  It is so near the mountains
that you expect it to set at any moment, and it will be a long time
before you get used to the idea that it will always be there, fixed in
the lunar sky.  The

Sun and stars rise and set, taking two weeks of Earth time to cross
from horizon to horizon; but Earth remains forever motionless, apart
from a slight swaying back and forth caused by 50  the fact that the
Moon's orbital motion is not perfectly regular.  The only change that
Earth shows is that of phase, as it waxes to full and wanes to a
threadlike crescent.  After a while, you will be able to tell the time
by the great clock hanging there against the stars..  ..

The stars-yes, they will give you another surprise.  Even today, people
will tell you that on the Moon you can see Sun and stars in the sky at
once.

It's a statement which is both true and false.  If you look directly at
the

Sun, you won't see anything else for a long time, and you'll be lucky
not to damage your eyes.  During daytime on the Moon, if you are out in
the open, the glare from the rocks demands the use of sun filters and
your pupils will be fully contracted.  Consequently, though the stars
are shining up there in the sky, you won't be able to see them and it
will be perfectly black overhead.  It you want to look at the stars,
step into the shadow of a convenient rock and shield your eyes from all
the glare around you.

Then, as your vision adapts itself and your pupils enlarge, you'll see
the stars come out.  First there will be the bright, familiar
constellations, then the legions of their faint companions, until at
last the whole sky seems packed with glowing dust.  All those countless
points of light will be shining with a steady, unvarying radiance: none
will twinkle or scintillate as they do in the clearest nights on Earth.
Now you will understand why all the great observatories are on the
Moon: you will realize that, until he had climbed above the atmosphere
of his own planet, no man had ever really seen the stars..  ..

Though it was known long before the first landings that the conquest of
the

Moon would revolutionize astronomy, few people believed that biologists
would find anything of interest on our satellite.  Yet, as far back as
the beginning of the twentieth century, evidence, had been accumulating
that plant life existed around certain craters, such as Aristarchus
and

Eratosthenes.  There had been curious changes of shading and variable
patches of darkness that were hard to explain in any other way.  The
explanation was correct.  Where the mistake was made was in assuming
that any lunar plants would be primitive, when a little thought would
have shown that the reverse must be the case.  Conditions on the Moon
are so severe that only very advanced and sophisticated types of plants
exist there-the primitive, unspecialized forms died out aeons ago. Most
of the' existing vegetation is found in the neighborhood of the great
lunar clefts, such as the Herodotus Valley, for traces of carbon
dioxide, water vapor and sulphur dioxide occasionally gush out of these
fissures-sometimes producing short-lived mists which are visible from
Earth.  These precious gases are eagerly trapped by the slender, cactus
like plants.  They are absorbed through systems of pores and tubes
which are virtually air compressors; you can cause great excitement
among the plants by deliberately spilling some air from your suit, when
the multitudes of pores will start frantically opening and closing.

The lunar plants have another ingenious trick which allows them to trap
sunlight without losing water vapor.  Their upper parts are studded
with tiny "windows" of horny material, transparent to light but
impenetrable to gases.  Oddly enough, exactly the same technique has
been worked out independently by certain plants in the dry African
deserts, where in some respects conditions are not so very different
from those on the Moon.

Incidentally, no one has yet found any practical use for these
plants.

Their chemistry contains too much sulphur for them to be edible, but
when we have learned more about them they may teach us how to grow our
own crops on the unprotected lunar surface-obviously a matter of great
practical importance.

The question -is often asked: "Is there any evidence for aninwl, as
opposed to plant, life on the Moon?"  It's true that much of the Moon's
twelve million square miles of highly contorted terrain is still
unexplored, and there may yet be some surprises in store for us.  But
it's most unlikely that animal life will be among them.  Though
biologists have had a lot of fun imagining 52  creatures that could
live under lunar conditions, none of them has so far obliged by making
an appearance.

One must not be greedy.  The Moon has already turned out to be a much
more valuable and interesting place than the first pioneers expected.
The millions that have been sunk into it are beginning to pay off in
terms of knowledge-from the observatories and vacuum labs; of raw
materials-from the mines and refueling stations; and of human
happiness-from Pasteur City.

There were some who feared that when we reached the Queen of Night, her
romance and mystery would be destroyed.  They need not have worried. We
may roof the lunar craters, spread our cities across the dusty seas,
build our farms on the Sunward-facing slopes of the mountains.  We will
not change the essential nature of the Moon.  She watched life emerge
from the steaming oceans of the dawn; she saw Man embark on the
conquest of his own world-and, a little later, the conquest of space
itself.

She will still be watching, drawing the tides beneath her, when our
descendants have spread so far from home that few could say in what
region of the sky lies the ancestral planet Earth....  So You're Going
to Mars?

SO YOU'RE GOING TO MARS?  THAT'S STILL QUITE AN ADventure-though I
suppose that in another ten years no one will think twice about it.
Sometimes it's hard to remember that the first ships reached Mars
scarcely more than half a century ago, and that our colony on the
planet is less than thirty years old.  (By the way, don't use that word
when you get there.  Base, settlement, or whatever you like-but not
colony, unless you want to hear the ice tinkling all around you.)

I suppose you've read all the forms and tourist literature they gave
you at the Department of Extraterrestrial Affairs.  But there's a lot
you won't learn just by reading, so here are some pointers and
background information that may make your trip more enjoyable.  I won't
say it's right up to date-things change so rapidly and it's a year
since I got back from Mars myself-but on the whole you'll find it
pretty reliable.

Presumably you're going just for curiosity and excitement-because you
want to see what life is like out on the new frontier.  It's only fair,
therefore, to point out that most of your fellow passengers will be
engineers, scientists or administrators traveling to Mars-some of them
not for the first time-because they've got a job of work to do.  So
whatever your achievements here on Earth, it's advisable not to talk
too much about them, as you'll be among people who've had to tackle
much 54  tougher propositions.  I won't say that you'll find them
boastful: it's simply that they've got a lot to be proud of, and they
don't mind who knows it.

If you haven't booked your passage yet, remember that the cost of the
ticket varies considerably according to the relative positions of Mars
and

Earth.  That's a complication we don't have to worry about when we're
traveling from country to country on our own globe, but Mars can be six
times further away at one time than at another.  Oddly enough, the
shortest trips are the most expensive, since they involve the greatest
changes of speed as you hop from one orbit to the other.  And in space,
speed, not distance, is what costs money.

Incidentally, I'd like to know how you've managed it.  I believe the
cheapest round trip comes to about $30,000, and unless the firm is
backing you or you've got a very elastic expense account-oh, all right,
if you don't want to talk about it.... I take it you're O.K. on the
medical side.  That examination isn't for fun, nor is it intended to
scare anyone off.  The physical strain involved in space flight is
negligible-but you'll be spending at least two months on the trip, and
it would be a pity if your teeth or your appendix started to misbehave.
See what I mean?

You're probably wondering how you can possibly manage on the weight
allowance you've got.  Well, it can be done.  The first thing to
remember is that you don't need to take any suits.  There's no weather
inside a spaceship-the temperature never varies more than a couple of
degrees over the whole trip, and it's held at a fairly high value so
that all you'll want is an ultra lightweight tropical kit.  When you
get to Mars you'll buy what you need there, and dump it when you
return. The great thing to remember is-only carry the stujff you
actually need on the trip.  I strongly advise you to buy one of the
complete travel kits-most of the big stores like Abercrombie & Fitch
can supply the approved outfits.  They're expensive, but will save you
money on excess baggage charges.  Take a camera by all means-there 9 s
a chance of 55 some unforgettable shots as you leave Earth and when you
approach Mars. But there's nothing to photograph on the voyage itself,
and I'd advise you to take all your pictures on the outward trip.  You
can sell a good camera on

Mars for five times its price here-and save yourself the cost of
freighting it home.  They don't mention that in the official
handouts.

Now that we've brought up the subject of money, I'd better remind you
that the Martian economy is quite different from anything you'll meet
on Earth.

Down here, it doesn't cost you anything to breathe, even though you've
got to pay to eat.  But on Mars the very air has to be synthesized-they
break down the oxides in the ground to do this-so every time you fill
your lungs someone has to foot the bill.  Food production is planned in
the same way-each of the cities, remember, is a carefully balanced
ecological system, Eke a well organized aquarium.  No parasites can be
allowed, so everyone has to pay a basic tax which entitles him to air,
food and the shelter of the domes.  The tax varies from city to city,
but averages about ten dollars a day.  Since everyone earns at least
ten times as much as this, they can all afford to go on breathing.

You'll have to pay this tax, of course-and you'll find it rather hard
to spend much more money than this.  Once the basic needs for life are
taken care of, there aren't many luxuries on Mars.  When they've got
used to the idea of having tourists around, no doubt they'll get
organized, but as things are now you'll find that most reasonable
requests won't cost you anything.  However, I should make arrangements
to transfer a substantial credit balance to the Bank of Mars-if you've
still got anything left.  You can do that by radio, of course, before
you leave Earth.

So much for the preliminaries; now some points about the trip itself.
The ferry rocket will probably leave from the New Guinea field, which
is about two miles above sea level on the top of the Orange Range.
People sometimes wonder why they chose such an out-of-the-way spot.
That's simple; it's on the equator, so a ship gets the full
thousand-mile-an-hour boost of the

Earth's spin 56  as it takes off-and there's the whole width of the
Pacific for jettisoned fuel tanks to fall into.  And if you've ever
heard a spaceship taking off, you'll understand why the launching sites
have to be a few hundred miles from civilization..  ..

Don't be alarmed by anything you've been told about the strain of
blast-off.  There's really nothing to it, if you're in good health-and
you won't be allowed inside a spaceship unless you are.  You just lie
down on the acceleration couch, put in your earplugs and relax.  It
takes over a minute for the full thrust to build up, and by that time
you're quite accustomed to it.  You'll have some difficulty in
breathing, perhaps-it's never bothered me-but if you don't attempt to
move you'll hardly feel the increase of weight.  What you will notice
is the noise, which is slightly unbelievable.  Still, it only lasts
five minutes, and by the end of that time you'll be up in the orbit and
the Motors will cut out.  Don't worry about your hearing; it will get
back to normal in 4 couple of hours.

You won't see a great deal until you get aboard the space station,
because there are no viewing ports on the ferry rockets and passengers
aren't encouraged to wander around.  It usually takes about thirty
minutes to make the necessary steering corrections and to match speed
with the station; you'll know when that's happened from the rather
alarming "clang" as the air locks make contact.  Then you can undo your
safety belt, and of course you'll want to see what it's like being
weightless.

Now, take your time-and do exactly what you're told.  Hang onto the
guide rope through the air lock and don't try to go flying around like
a bird.

There'll be plenty of time for that later: there's not enough room in
the ferry and if you attempt any of the usual tricks you'll not only
injure yourself but may damage the equipment as well.

Space Station One-which is where the ferries and the liners meet to
transfer their cargoes-takes just two hours to make one circuit of
the

Earth.  You'll spend all your time in the observation lounge:
everyone' does no 57  matter how many times they've been out into
space.  I won't attempt to describe that incredible view; I'll merely
remind you that in the hundred and twenty minutes it takes the station
to complete its orbit you'll see the

Earth wax from a thin crescent to a gigantic, multicolored disk-and
then shrink again to a black shield eclipsing the stars.  As you pass
over the night side you'll see the lights of cities down there in the
darkness, like patches of phosphorescence.  And the stars!  You'll
realize that you've never really seen them before in your life.

But enough of these purple passages; let's stick to business.  You'll
probably remain on Space Station One for about twelve hours, which will
give you plenty of opportunity to see how you like weightlessness.  It
doesn't take long to learn how to move around; the main secret is to
avoid all violent motions-otherwise you may crack your head on the
ceiling.

Except, of course, that there isn't a ceiling, since there's no up or
down any more.  At first you'll find that confusing: you'll have to
stop and decide which direction you want to move in, and then adjust
your personal reference system to fit.  After a few days in space it
will be second nature to you.

Don't forget that the station is your last link with Earth.  If you
want to make any final purchases, or leave something to be sent home-do
it then.

You won't have another chance for a good many million miles.  But
beware of buying items that the station shop assures you are "just the
thing on

Mars."

You'll go aboard the liner when you've had your final medical check,
and the steward will show you to the little cabin that will be your
home for the next few months.  Don't be upset because you can touch all
the walls without moving from one spot.  You'll only have to sleep
there, after all, and you've got the rest of the ship to stretch your
legs in.

If you're on one of the larger liners, there'll be about a hundred
other passengers and a crew of perhaps twenty.  You'll get to know them
all by the end of the voyage.  There's nothing on Earth quite like the
atmo2 58  sphere in a spaceship.  You're a little, self-contained
community floating in vacuum millions of miles from anywhere, kept
alive in a bubble of plastic and metal.  If you're a good mixer, you'll
find the experience very stimulating.  But it has its disadvantages.
The one great danger of space flight is that some prize bore may get on
the passenger list-and short of pushing him out of the air lock there's
nothing anyone can do about it.

It won't take you long to find your way around the ship and to get used
to its gadgets.  Handling liquids is the main skill you'll have to
acquire: your first attempts at drinking are apt to be messy.  Oddly
enough, taking a shower is quite simple.  You do it in a sort of
plastic cocoon, and a circulating air current carries the water out at
the bottom.

At first the absence of gravity may make sleeping difficult-you'll miss
your accustomed weight.  That's why the sheets over the, bunks have
spring tensioning.  They'll prevent you drifting out while you sleep,
and their pressure will give you a spurious sensation of weight.

But learning to live under zero gravity is something one can't be
taught in advance: you have to find out by experience and practical
demonstration.  I believe you'll enjoy it, and when the novelty's worn
off you'll take it completely for granted.  Then the problem will be
getting used to gravity again when you reach Mars!

Unlike the take-off of the ferry rocket from Earth, the breakaway of
the liner from its satellite orbit is so gentle and protracted that it
lacks all drama.  When the loading and instrument checks have been
completed, the ship will uncouple from the, space station and drift a
few miles away.

You'll hardly notice it when the atomic drive goes on-there will be the
faintest of vibrations and a feeble sensation of weight.  The ship's
acceleration is so small, in fact, that you'll weigh only a few ounces,
which will scarcely interfere with your freedom of movement at all. Its
only effect will be to make things drift slowly to one end of the cabin
if they're left lying around.  Although the liner's acceleration is so
small that it 59  will take hours to break away from Earth and head out
into space, after a week of continuous drive the ship will have built
up a colossal speed.  Then the motors will be cut out and you'll carry
on under your own momentum until you reach the orbit of Mars and have
to start thinking about slowing down.

Whether your weeks in space are boring or not depends very much on you
and your fellow passengers.  Quite a number of entertainments get
organized on the voyage, and a good deal of money is liable to change
hands before the end of the trip.  (It's a curious fact, but the crew
usually seems to come out on top.) You'll have plenty of time for
reading, and the ship will have a good library of micro books  There
will be radio and TV contact with Earth and Mars for the whole voyage,
so you'll be able to keep in touch with things-if you want to.

On my first trip, I spent a lot of my time learning my way around the
stars and looking at clusters and nebulae through a small telescope I
borrowed from the navigation officer.  Even if you've never felt the
slightest interest in astronomy before, you'll probably be a keen
observer before the end of the voyage.  Having the stars all around
you-and not merely overhead-is an experience you'll never forget.

As far as outside events are concerned, you realize of course that
absolutely nothing can happen during the voyage.  Once the drive has
cut out, you'll seem to be hanging motionless in space: you'll be no
more conscious of your speed than you are of the Earth's seventy
thousand miles an hour round the Sun right now.  The only evidence of
your velocity will be the slow movement of the nearer planets against
the background of the stars-and you'll have to watch carefully for a
good many hours before you can detect even this.

By the way, I hope you aren't one of those foolish people who are still
frightened about meteors.  They see that enormous chunk of nickel-steel
in

New York's American Museum of Natural History and imagine that's the
sort of thing you'll run smack into as soon 60  as you leave the
atmosphere-forgetting that there's rather a lot of room in space and
that even the biggest.  ship is a mighty small target.  You'd have to
sit out there and wait a good many centuries before a meteor big enough
to puncture the hull came along-it hasn't happened to a spaceship
yet.

One of the big moments of the trip will come when you realize that Mars
has begun to show a visible disk.  The first feature you'll be able to
see with the naked eye will be one of the polar caps, glittering like a
tiny star on the edge of the planet.  A few days later the dark
areas-the so-called seas-will begin to appear, and presently you'll
glimpse the prominent triangle of the Syrtis Major.  In the week before
landing, as the planet swims nearer and nearer, you'll get to know its
geography pretty thoroughly.

The braking period doesn't last very long, as the ship has lost a good
deal of its speed in the climb outward from the Sun.  When it's over
you'll be dropping down onto Phobos, the inner moon of Mars-which acts
as a natural space station about four thousand miles above the surface
of the planet.

Though Phobos is only a jagged lump of rock not much bigger than some
terrestrial mountains, it's reassuring to be in contact with something
solid again after so many weeks in space.

When the ship has settled down into the landing cradle, the air lock
will be coupled up and you'll go through a connecting tube into the
port.  Since

Phobos is much too small to have an appreciable gravity, you'll still
be effectively weightless.  While the ship's being unloaded the
immigration officials will check your papers.  I don't know the point
of this; I've never heard of anyone being sent all the way back to
Earth after having got this far!

There are two things you mustn't miss at Port Phobos.  The restaurant
there is quite good; it's very small, and only goes into action when a
liner docks, but it does its best to give you a fine welcome to Mars.
And after a couple of months you'll have got rather tired of the
shipboard menu.  The other item is the centrifuge; I believe that's 61
compulsory now.  You go inside and it will spin you up to half a
gravity, or rather more than the weight Mars will give you when you
land.  It's simply a little cabin on a rotating arm, and there's room
to walk around inside so that you can practice using your legs again.
You probably won't Eke the feeling; life in a spaceship can make you
lazy.

The ferry rockets that will take you down to Mars will be waiting when
the ship docks.  If you're unlucky you'll hang around at the port for
some hours, because they can't carry more than twenty passengers and
there are only two ferries in service.  The actual descent to the
planet takes about three hours-and it's the only time when you'll get
any impression of speed.

Those ferries enter the atmosphere at over five thousand miles an hour,
and go halfway round Mars before they lose enough speed through air
resistance to land like ordinary aircraft.

You'll land, of course, at Port Lowell: besides being the largest
settlement on Mars it's still the only place that has the facilities
for handling spaceships.  From the air the plastic pressure domes look
like a cluster of bubbles-a very pretty sight when the Sun catches
them.  Don't be alarmed if one of them is deflated.  That doesn't mean
that there's been an accident.  The domes are let down at fairly
frequent intervals so that the envelopes can be checked for leaks.  If
you're lucky you may see one being pumped up-it's quite impressive.

After two months in a spaceship, even Port Lowell will seem a mighty
metropolis.  (Actually, I believe its population is now well over
twenty thousand.) You'll find the people energetic, inquisitive,
forthrigbt-and very friendly, unless they think you're trying to be
superior.

It's a good working rule never to criticize anything you see on Mars.
As I said before, they're very proud of their achievements-and after
all you are a guest, even if a paying one.

Port Lowell has practically everything you'll find in a city on Earth,
though of course on 'a smaller scale.  62  You'll come across many
reminders of "home."  For example, the main street in the city is Fifth
Avenuebut surprisingly enough you'll find Piccadilly

Circus where it crosses Broadway.

The port, like all the major settlements, lies in the dark belt of
vegetation that roughly follows the Equator and occupies about half the
southern hemisphere.  The northern hemisphere is almost all desert-the
red oxides that give the planet its ruddy color.  Some of these desert
regions are very beautiful; they're far older than anything on the
surface of our

Earth, because there's been little weathering on Mars to wear down the
rocks -at least since the seas dried up, more than five hundred million
years ago.

You shouldn't attempt to leave the city until you've become quite
accustomed to living in an oxygen-rich, low-pressure atmosphere. You'll
have grown fairly well acclimatized on the trip, because the air in the
spaceship will have been slowly adjusted to conditions on Mars. Outside
the domes, the pressure of the natural Martian atmosphere is about
equal to that on the top of Mount Everest-and it contains practically
no oxygen.  So when you go out you'll have to wear a helmet, or travel
in one of those pressurized jeeps they call "sand fleas."

Wearing a helmet, by the way, is nothing like the nuisance you'd expect
it to be.  The equipment is very light and compact, and as long as you
don't do anything silly is quite foolproof.  As it's most unlikely that
you'll ever go out without an experienced guide, you'll have no need to
worry.  Thanks to the low gravity, enough oxygen for twelve hours'
normal working can be carried quite easily-and you'll never be away
from shelter as long as that.

Don't attempt to imitate any of the locals you may see walking around
without oxygen gear.  They're second-generation colonists and are used
to the low pressure.  They can't breathe the Martian atmosphere any
more than you can, but like the old-time native pearl divers they can
make one lungful last for several minutes when necessary.  Even so,
it's a silly sort of trick and they're not supposed to do it.

As you know, the other great obstacle to life on Mars is the low
temperature.  The highest thermometer reading ever recorded is
somewhere in the eighties, but that's quite exceptional.  In the long
winters, and during the night in summer or winter, it never rises above
freezing.  And I believe the record low is minus one hundred and
ninety!

Well, you won't be outdoors at night, and for the sort of excursions
you'll be doing, all that's needed is a simple thermosuit.  It's very
light, and traps the body heat so effectively that no other source of
warmth is needed.

No doubt you'll want to see as much of Mars as you can during your
stay.

There are only two methods of transport outside the cities-sand fleas
for short ranges and aircraft for longer distances.  Don't
misunderstand me when

I say "short ranges"-a sand flea with a full charge of power cells is
good for a couple of thousand miles, and it can do eighty miles an hour
over good ground.  Mars could never have been explored without them-you
can survey a planet from space, but in the end someone with a pick and
shovel has to do the dirty work filling in the map.

One thing that few visitors realize is just how big Mars is.  Although
it seems small beside the Earth, its land area is almost as great
because so much of our planet is covered with oceans.  So it's hardly
surprising that there are vast regions that have never been properly
explored-particularly around the poles.  Those stubborn people who
still believe that there was once an indigenous Martian civilization
pin their hopes on these great blanks.  Every so often you hear rumors
of some wonderful archaeological discovery in the wastelands but
nothing ever comes of it.

Personally, I don't believe there ever were any Martians-but the planet
is interesting enough for its own sake.  You'll be fascinated by the
plant life and the queer animals that manage to live without oxygen,
migrating each year from hemisphere to hemisphere, 64  across the
ancient seabeds, to avoid the ferocious winter.  The fight for survival
on "Mars has been fierce, and evolution has produced some pretty odd
results.  Don't go investigating any Martian life forms unless you have
a guide, or you may get some unpleasant surprises.

Well, that's all I've got to say, except to wish you a pleasant trip.
Oh, there is one other thing.  My boy collects stamps, and I rather let
him down when I was on Mars.  If you could drop me a few letters while
you're there-there's no need to put anything in them if you're too
busy-I'd be much obliged.  He's trying to collect a set of space-mail
covers postmarked from each of the principal Martian cities, and if you
could help~---thanks a lot!  The Planets Are Not Enough

ALTOGETHER APART FROM ITS SCIENTIFIC VALUE, SPACE travel has one
justification which transcends all others.  It is probably the only way
in which we can hope to answer one of the supreme questions of
philosophy: Is

Man alone in the Universe?  It -seems 'incredible that ours should be
the only inhabited planet among the millions of worlds that must exist
among the stars, but we cannot solve this problem by speculating about
it.  If it can be solved at all, it will be by visiting other planets
to see for ourselves.

The Solar System, comprising the nine known worlds of our Sun and their
numerous satellites, is a relatively compact structure, a snug little
celestial oasis in an endless desert.  It is true that millions of
miles separate Earth from its neighbors, but such distances are
cosmically trivial.  They will even be trivial in terms of human
engineering before another hundred years-a mere moment in historical
time-have elapsed.  However, the distances which sunder us from the
possible worlds of other stars are of a totally different order of
magnitude, and there are fundamental reasons for thinking that
nothing-no scientific discovery or technical achievement-will ever make
them trivial.

When today's chemical fuels have been developed to the ultimate, and
such tricks as refueling in space have been fully exploited, we will
have spaceships 66  which can attain speeds of about ten miles a
second.  That means that the

Moon will be reached in two or three days and the nearer planets in
about half a year.  (I am deliberately rounding these numbers off, and
anyone who tries to check my arithmetic had better remember that
spaceships will never travel in straight lines or at uniform speeds.)
The remoter planets, such as

Jupiter and Saturn, could be reached only after many years of travel,
and so the trio Moon-Mars-Venus marks the practical limit of
exploration for chemically propelled spaceships.  Even for these cases,
it is all too easy to demonstrate that hundreds of tons of fuel would
be needed for each ton of payload that would make the round trip.  This
situation, which used to depress the preatomic energy astronauts, will
not last for long.  Since we are not concerned here with engineering
details, we can take it for granted that eventually nuclear power, in
some form or other, will be harnessed for the purposes of space flight.
With energies a millionfold greater than those available from chemical
fuels, speeds of hundreds, and ultimately thousands, of miles a second
will be attainable.

Against such speeds, the Solar System will.  shrink until the inner
planets are no more than a few hours apart, "and even Pluto will be
only a week or two from Earth.  Moreover, there should be no reasonable
limit to the amount of equipment and material that could be taken on an
interplanetary expedition.  Anyaone who doubts this may ponder the fact
that the energy released by a single H-bomb is sufficient to carry
about a million tons to

Mars.  It is true that we cannot as yet tap even a fraction of that
energy for such a purpose, but there are already hints of how this may
be done.

The short-lived Uranium Age will see the dawn of space flight; the
succeeding era of fusion power will witness its fulfillment.  But even
when we can travel among the planets as freely as we now travel over
this Earth, it seems that we will be no nearer to solving the problem
of Man's place in the Universe.  That is a secret that will still lie
hidden in the stars.  All the evidence indicates that we are alone in
the Solar System.  True, there is almost certainly some kind of life on
Mars, and possibly on

Venus-perhaps even on the Moon.  (The slight evidence for lunar
vegetation comes from the amateur observers who actually look at the
Moon, and is regarded skeptically by professional astronomers, who
could hardly care less about a small slag heap little more than a
light-second away.) Vegetation, however, can provide little
intellectual companionship.  Mars may be a paradise for the botanist,
but it may have little to interest the zoologist-and nothing at all to
lure the anthropologist and his colleagues across some scores of
millions of miles of space.

This is likely to disappoint a great many people and to take much of
the zest out of space travel.  Yet it would be unreasonable to expect
anything else; the planet shave been in existence for several billion
years, and only during the last .0001 per cent of that time has the
human race been slightly civilized.  Even if Mars and Venus have been
(or will be) suitable for higher forms of life, the chances are wildly
against our encountering beings anywhere near our cultural or
intellectual level at this particular moment of time.  If rational
creatures exist on the planets, they will be millions of years ahead of
us in development-or millions of years behind us.  We may expect to
meet apes or angels, but never men.

The angels can probably be ruled out at once.  If they existed, then
surely they would already have come here to have a look at us.  Some
people, of course, think that this is just what they are doing.  I can
only say that they are going about it in a very odd manner.

We had better assume, therefore, that neither on Mars nor Venus, nor on
any other of the planets, will explorers from Earth encounter
intelligent life.

We are the only castaways upon the tiny raft of the Solar System, as it
drifts forever along the Gulf Streams of the Galaxy.

This, then, is the challenge that sooner or later the human spirit must
face, when the planets have been conquered and all their secrets
brought home to Earth.  The nearest of the stars is a million times
farther away than the closest of the planets.  The spaceships we may
expect to see a generation from now would take about a hundred thousand
years to reach Proxima Centauri, our nearest stellar neighbor.  Even
the hypothetical nuclear-powered spaceships which a full century of
atomic engineering may produce could hardly make the journey in less
than a thousand years.

The expressive term "God's quarantine regulations" has been used to
describe this state of affairs.  At first sight, it appears that they
are rigorously enforced.  There may be millions of inhabited worlds
circling other suns, harboring beings who to us would seem godlike,
with civilizations and cultures beyond our wildest dreams.  But we
shall never meet them, and they for their part will never know of our
existence.

So run the conclusions of most astronomers, even those who are quite
convinced that mere common or garden interplanetary flight is just
around the corner.  But it is always dangerous to make negative
predictions, and though the difficulties of interstellar travel are
stupendous, they are not insuperable.  It is by no means certain that
Man must remain trapped in the

Solar System for eternity, never to know if he is a lonely freak of no
cosmic significance.

There are two ways in which we might gain direct knowledge of other
stellar systems without ever leaving our own.  Rather surprisingly, it
can be shown that radio communication would be perfectly feasible
across, interstellar space, if very slow speed telegraphy were
employed.  However, we can hardly assume that anyone would be listening
in at the precise frequency with a receiver tuned to the extremely
narrow band which would have to be employed.  And even if they were, it
would be extremely tedious learning to talk to them with no initial
knowledge of their language-and having, to wait many years for any
acknowledgment of our own signals, as the radio waves came limping back
across the light-years.  If we sent a question to

Proxima Centauri, it would be almost nine years before any answer could
reach Earth.  , A more practical, though at first sight more
startling, solution would be to send a survey ship-unmanned.  This
would be a gigantic extrapolation of existing techniques, but it would
not involve anything fundamentally new.

Imagine an automatic vessel, crammed with every type of recording
instrument and controlled by an electronic brain with preset
instructions.  It would be launched out across space aimed at a target
it might not reach for a thousand years.  But at last one of the stars
ahead would begin to dominate the sky, and a century or so later, it
would have grown into a sun, perhaps with planets circling round it.
Sleeping instruments would wake to life, the tiny ship would check its
speed, and its sense organs would start to record their impressions. It
would circle world after world, follow Jug a program set up to cover
all possible contingencies by men who had died a thousand years before.
Then, with the priceless knowledge it had gained, it would begin the
long voyage home.

This type of proxy exploration of the universe would be slow and
uncertain, and would demand long-range planning beyond the capacity of
our age.  Yet if there is no other way of contacting the stars, this is
how it might be done.  One millennium would make the investment in
technical skill so that the next would reap the benefit.  It would be
as if Archimedes were to start a research project which could produce
no results before the time of

Einstein.

If men, and not merely their machines, are ever to reach the planets of
other suns, problems of much greater difficulty will have to be
solved.

Stated in its simplest form, the question is this: How can men survive
a journey which may last for several thousand years?  It is rather
surprising to find that there are at least five different answers which
must be regarded as theoretical possibilities-however far they may be
beyond the scope of today's science.

Medicine may provide two rather obvious solutions.  There appears to be
no fundamental reason why men should die when they do.  It is certainly
not a matter of the body "wearing out" in the sense that an inanimate
70  piece of machinery does, for in the course of a single year almost
the entire fabric of the body is replaced by new material.  When we
have discovered the details of this process, it may be possible to
extend the life span indefinitely if so desired.  Whether a crew of
immortals, however well-balanced and psychologically adjusted, could
tolerate each other's company for several centuries in rather cramped
quarters is an interesting subject for speculation.

Perhaps a better answer is that suggested by the story of Rip Van
Winkle.

Suspended animation (or, more accurately, a drastic slowing down of the
body's metabolism) for periods of a few hours is now, of course, a
medical commonplace.  It requires no great stretch of the imagination
to suppose that, with the aid of low temperatures and drugs, men may be
able to hibernate for virtually unlimited periods.  We can -picture an
automatic ship with its oblivious crew making the long journey across
the interstellar night until, when a new sun was looming up, the signal
was sent out to trigger the mechanisms which would revive the sleepers.
When their survey was completed, they would head back to Earth and
slumber again until the time-came to awake once more, and to greet a
world which would regard them as survivors from the distant past.

The third solution was, to the best of my knowledge, suggested over
thirty years ago by Professor J. D. Bernal in a long-out-of print
essay, The

World, the Flesh, and the Devil, which must rank as one of the most
outstanding feats of scientific imagination in literature.  Even today,
many of the ideas propounded in this little book have never been fully
developed, either in or out of science fiction.  (Any requests from
fellow authors to borrow my copy will be flatly ignored.)

Bernal imagined entire societies launched across space, in gigantic
arks which would be closed, ecologically balanced systems.  They would,
in fact, be miniature planets, upon which generations of men would live
and die so that one day their remote descendants would return to Earth
with the record of their celestial odyssey.  The engineering,
biological and sociological problems involved in such an enterprise
would be of fascinating complexity.  The artificial planets (at least
several miles in diameter) would have to be completely self-contained
and self-supporting, and no material of any kind could be wasted.

Commenting on the implications of such closed systems, Time magazine's
able, erudite science editor Jonathan Leonard once hinted that
cannibalism would be compulsory among interstellar travelers.  This
would be a matter of definition; we crew members of the two-billion-man
spaceship Earth do not consider ourselves cannibals, despite the fact
that every one of us must have absorbed atoms which once formed part of
Caesar and Socrates,

Shakespeare and Solomon.

One cannot help feeling that the interstellar ark on its thousand-year
voyages would be a cumbersome way of solving the problem, even if all
the social and psychological difficulties could be overcome.  (Would
the fiftieth generation still share the aspirations of their Pilgrim
Fathers who set out from Earth so long ago?) There are, however, more
sophisticated ways of getting men to the stars than the crude,
brute-force methods outlined above.  After the hard-headed engineering
of the last few paragraphs, what follows may appear to verge upon
fantasy.  It involves, in the most fundamental sense of the word, the
storage of human beings.  And by that I do not mean anything as naive
as suspended animation.

A few months ago, in an Australian laboratory, I was watching what
appeared to be perfectly normal spermatozoa wriggling across the
microscope field.

They were perfectly normal, but- their history was not.  For three
years, they had been utterly immobile in a deep freeze, and there
seemed little doubt that they could be kept fertile for centuries by
the same technique.

What was still more surprising, there had been enough successes with
the far larger and more delicate ova to indicate that they too might
survive the same treatment.  If this proves to be the case,
reproduction will eventually become independent of time.  The social
implications of this make anything in Brave New World seem like child's
play, but I am not concerned here with the interesting results which
might have been obtained by, for example, uniting the genes of

Cleopatra and Newton, had this technique been available earlier in
history.  (When such experiments are started, however, it would be as
well to remember Shaw's famous rejection of a similar proposal: "But
suppose, my dear, it turns out to have my beauty and your brains?") *

The cumbersome interstellar ark, with its generations of travelers
doomed to spend their entire lives in empty space, was merely a device
to carry germ cells, knowledge and culture from one sun to another. How
much more efficient to send only the cells, to fertilize them
automatically some twenty years before the voyage was due to end, to
carry the embryos through to birth by techniques already foreshadowed
in today's biology labs, and to bring up the babies under the tutelage
of cybernetic nurses who would teach them their inheritance and their
destiny when they were capable of understanding it.

These children, knowing no parents, or indeed any one of a different
age from themselves, would grow up in the strange artificial world of
their speeding ship, reaching maturity in time to explore the planets
ahead of them-perhaps to be the ambassadors of humanity among alien
races, or perhaps to find, too late, that there was no home for them
there.  If their mission succeeded, it would be.  their duty (or that
of their descendants, if the first generation could not complete the
task) to see that the knowledge they had gained was someday carried
back to Earth.

Would any society be morally justified, we may well ask, in planning so
onerous and uncertain a future for its unborn-indeed un
conceived-children?

That is a question which different ages may answer in different ways.
What to one era would seem a cold-blooded sacrifice might to another
appear a great and glorious, We have Shaw's word for it that the
would-be geneticist was a complete stranger and not, as -frequently
stated, Isadora Duncan.  adventure.  There are complex problems here
which cannot be settled by instinctive, emotional answers.

So far, we have assumed that all interstellar voyages must of necessity
last for many hundreds or even thousands of years.  The nearest star is
more than four light-years away; the Galaxy itself-the island universe
of which our Sun is one insignificant member-is hundreds of thousands
of light-years across; and the distances between the galaxies are of
the order of a million light-years.  The speed of light appears to be a
fundamental limit to velocity; in this sense it is quite different from
the now outmoded "sound barrier," which is merely an attribute of the
particular gases which happen to constitute our atmosphere.

Even if we could reach the speed of light, therefore, interstellar
journeys would still require many years of travel, and only in the case
of the very nearest stars would it appear possible for a voyager to
make the round trip in a single lifetime, without resort to such
techniques as suspended animation.  However, as we shall see, the
actual situation is a good deal more complex than this.

First of all, is it even theoretically possible to build spaceships
capable of approaching the speed of light?  (That is, 186,000 miles a
second or 670,000,000 mph.) The problem is that of finding a sufficient
source of energy and applying it.  Einstein's famous equation E = MC2
gives an answer-on paper-which a few centuries of technology may be
able to realize in terms of engineering.  If we can achieve the total
annihilation of matter-not the conversion of a mere fraction of a per
cent of it into energy-we can approach as near to the speed of light as
we please.  We can never reach it, but a journey at 99.9 per cent of
the speed of light would, after all, take very little longer than one
at exactly the speed of light, so the difference would hardly seem of
practical importance.

Complete annihilation of matter is still as much a dream as atomic
energy itself was twenty years ago.  However, the discovery of the
anti-proton (which engages in mutual suicide on meeting a normal
proton) may be the first step on the road to its realization.

Traveling at speeds approaching that of light, however, involves us at
once in one of the most baffling paradoxes which spring from the theory
of relativity the so-called "time dilation effect."  It is impossible
to explain why this effect occurs without delving into very elementary
yet extremely subtle mathematics.  (There is nothing difficult about
basic relativity math: most of it is simple algebra.  The difficulty
lies in the underlying concepts Nevertheless, even if the explanation
must be skipped, the results of the time-dilation effect can be stated
readily enough in nontechnical language.

Time itself is a variable quantity; the rate at which it flows depends
upon the speed of the observer.  The difference is infinitesimal at the
velocities of everyday life, and even at the velocities of normal
astronomical bodies.  It is all-important as we approach to within a
few per cent of the speed of light.  To put it crudely, the faster one
travels, the more slowly time will pass.  At the speed of light, time
would cease to exist; the moment "Now" would last forever.

Let us take an extreme example to show what this implies.  If a
spaceship left Earth for Proxima Centauri at the speed of light, and
came back at once at the same velocity, it would have been gone for
some eight and one half years according to all the clocks and calendars
of Earth.  But the people in the ship, and all their clocks, would have
recorded no lapsed time at all.

At a physically attainable speed, say ninety-five per cent of the
velocity of light, the inhabitants of the ship would think that the
round trip had lasted about three years.  At ninety-nine per cent, it
would have seemed little more than a year to them.  In each case,
however, they would return more than eight years-Earth time after they
had departed.  (No allowance has been made here for stopping and
starting, which would require additional time.)

If we imagine a more extensive trip, we get still more surprising
results.

The travelers might be gone 75  for a thousand years, from the point
of view of Earth, having set out for a star five hundred light-years
away.  If their ship had averaged 99.9 per cent of the speed of light,
they would be fifty years older when they returned to an Earth-where
ten centuries had passed away

It should be emphasized that this effect, incredible though it appears
to be, is one of the natural consequences of Einstein's theory.  The
equation connecting mass and energy once appeared to be equally
fantastic and remote from any practical application.  It would be very
unwise, therefore, to assume that the equation linking time and
velocity will never be of more than theoretical interest.  Anything
which does not violate natural laws must be considered a
possibility-and the events of the last few decades have shown clearly
enough that things which are possible will always be achieved if the
incentive is sufficiently great.

Whether the incentive will be sufficient here is a question which only
the future can answer.  The men of five hundred or a thousand years
from now will have motivations very different from ours, but if they
are men at all they will still burn with that restless curiosity which
has driven us over this world and which is about to take us into space.
Sooner or later we will come to the edge of the Solar System and will
be looking out across the ultimate abyss.  Then we must choose whether
we reach the stars-or whether we wait until the stars reach us.

The physical reality of the time dilation effect has been the subject
of unusually acrimonious debate in recent years.  Very few scientists
now have any doubt of its existence, but its magnitude may not have the
values quoted above.  My figures are based on Special Relativity, which
is too unsophisticated to deal with the complexities of an actual
ftht.  Meteors

IF YOU GO OUT OF DOORS ON A CLEAR, MOONLESS NIGHT and look up at the
sky, you will seldom have to wait for more than a few minutes before
you see a meteor slide through the stars.  These faint streaks of
light, vanishing almost as soon as born, were a complete mystery to
mankind for thousands of years.  Until quite recent times, indeed, it
was not even realized that they had any connection with the other
heavenly bodies; they were considered to be purely atmospheric
phenomena, perhaps something akin to lightning.  The very word
"meteor," with its obvious kinship to "meteorology," is a survival of
this ancient belief.

Ours is an age in which subjects which once seemed of no interest to
anyone except a few ivory-tower scientists have suddenly become of
overwhelming practical (and, alas, all too often military) importance.
So it is with the transient lines of fire in the night sky.  Within the
last few years, the study of meteors has become the concern of research
teams all over the world; and tomorrow it may determine the very
survival of great nations.

The fact that meteor trails are caused by fragments of matter from
outer space entering the Earth's atmosphere at enormous velocities is
now known to almost everybody.  Yet it was not until the beginning of
the last century that astronomers accepted this fact, and 77  then
only after a determined rear guard action.  Science (if there is such a
thing as Science with a capital S!) is often accused of being orthodox
and unwilling to give heed to new ideas, and there are times when the
charge has some truth in it.  The argument over the origin of meteors
provides a perfect example of this.

Though there had been reports in all times and from all lands of stones
falling from the sky, the scientists of the French Academy, in the
closing years of the eighteenth century-when it was confidently
believed that the

Age of Reason had dawned-dismissed all such tales as superstitious
nonsense.  They reacted, in fact, much as an astronomer of today would
do when confronted with a typical flying saucer report-though it by no
means follows that the sequel will be similar.  And then, in 1803,
almost as if

Nature had determined to teach the skeptical scientists a lesson, a
great shower of meteoric stones fell in Normandy-geographically
speaking, on the

Academy's doorstep.  Thereafter no one doubted the fact that objects
from outer space entered Earth's atmosphere and occasionally reached
the surface.

It was another thirty years before meteors attracted much further
attention; then they did so with a spectacle the like of which has
seldom been matched before or since.  Listen to the words of a South
Carolina planter, describing what happened on the night of November 11,
1833:

I was suddenly awakened by the most distressing cries that ever fell on
my ears.  Shrieks of horror and cries of mercy I could hear from most
of the negroes of the three plantations.... While earnestly listening
for the cause I heard a faint voice near the door, calling my name.  I
arose and, taking my sword, stood at the door.  At this moment I heard
the same voice still beseeching me to rise and saying, "Oh my God, the
world is on fire!"

I then opened the door, and it is difficult to say which excited me
most-the awfulness of the scene, or the distressing cries of the
negroes.  Upwards of a hundred lay prostrate on the ground, some
speechless, and some with the bitterest cries, but with their hands
raised, imploring God to save the world and them.  The scene was truly
awful: for never did rain fall much thicker than the meteors fell
toward Earth: East, West, North and

South it was the same.

Such was the great shower of 1833, which dramatically demonstrated that
meteors could occur not only as sporadic wanderers but also in enormous
clusters or streams.  As a result of many years of observation, large
numbers of these meteor showers have been identified and their dates of
arrival noted.  For example, around the twelfth of August every year,
meteors will be seen streaking from the heart of the constellation
Perseus at the rate of about one a minute.  And between the fourteenth
and sixteenth of November, in the constellation of Leo, the shower
which caused such alarm over the southern states in 1833 still puts on
an annual display-though in most years it is so feeble that one would
never notice it unless one was on the lookout.  Until the close of the
Second World War, the study of meteors was a somewhat neglected branch
of astronomy.  Since they are so transient and unpredictable, they
cannot be watched through telescopes-except by pure chance-and hence
almost all observations until recently were naked-eye ones made by
amateur astonomers with no equipment but a notebook, a watch, a
thorough knowledge of the constellations, unlimited patience and a
complete indifference to cold and fatigue.  These devoted souls would
spend their nights watching the stars, and every time a meteor flashed
across the sky would note its duration and would pinpoint the beginning
and end of its track.  It may seem surprising, to those who think that
astronomers have to work with huge and expensive instruments, that
anything useful could be discovered by such simple means.  Yet it was
from thousands of such naked-eye observations that almost all our
knowledge of meteors was derived, until 79  the invention of radar
gave astronomy a new and unexpected weapon of tremendous power.

Behind this there is a story of war and science that is still largely
untold.  During the late thirties, Britain began to build the chain of
radar stations without which the Royal Air Force could never have held
the Luftwaffe at bay.  The men who designed and constructed the
three-hundred-foot-high towers, along the east coast of England changed
the history of the world, by defeating Goering's bombers in the Battle
of Britain.

Three years later, in 1944, they were called upon again to fight the
weapon which made those bombers obsolete.

The V2 rockets which the radar chain now had to detect traveled ten
times as fast as any bomber, and twenty times as high.  Nevertheless,
the hastily modified radar picked them up.  It also picked up something
else -something that produced strange echoes seventy or eighty miles
above the earth.

These echoes, it was soon discovered, were due to meteors-or, to be
more accurate, to the trails of intensely heated gas which meteors
leave in their wakes as they plunge into the upper atmosphere at speeds
often exceeding 100,000 miles an hour.  It was obviously a matter of
great importance to distinguish between the echoes caused by meteors
and those produced by rockets.  And it is even more important now that
those rockets can carry a million tons of explosive power instead of
the miserable one ton of the quaint, oldfashioned V2..  ..

After the war, when radar apparatus was available for more peaceful
uses, a regular watch was kept for meteors at "radio observatories"
throughout the world.  The enormous advantage of radar for this work
lies in the fact that it is independent of weather conditions and can
operate just as well during daylight as at night.  Previously, there
had been no way of observing meteors except after darkness-and even
then only when there was no Moon to flood the sky with light.

It is hardly surprising, therefore, that some remarkable discoveries
were very quickly made.  The most 80  spectacular of these was
undoubtedly the detection, by the group of radio astronomers at
Manchester, England, of great meteor showers that occur during the
hours of daylight and so are quite invisible to the eye.  Every summer,
showers take place which if they occurred after nightfall would produce
a display almost as dramatic as the one of 1833.  Between June and

August, vast belts of meteors are sweeping unseen, and until today
unsuspected, across the daylight skies of Earth.

Continuous watches are now being kept by automatic equipment which, as
soon as a meteor is located, photographs its radar echo on a
cathode-ray tube.

From this it is possible to calculate the mew or height and velocity,
and thus the orbit it was following through space before it met its
doom.  This radar watch has already settled one question concerning
which astronomers had been fighting furiously for more than a
generation.

One school of thought maintained that a substantial proportion of
meteors did not belong to the Solar System at all, but came from
interstellar space-that there were, in other words, vast streams of
meteoric matter flowing between the stars.  The evidence for this
startling theory was quite strong-indeed, at first sight overwhelming.
When the velocities of meteors were measured by the indirect methods
which were the only ones available before radar, many were found to be
traveling so fast that they could not possibly be revolving around the
Sun.  In Earth's neighborhood, any object moving at more than 94,000
miles an hour could only be a visitor to the

Solar System, not a permanent resident.  This is the limiting speed
above which the Sun can no longer keep a body under its gravitational
control.

Anything moving faster than this, accordingly, must have fallen into
the

Solar System from outside-and would shoot out of it again after doing a
tight turn round the Sun.  "The more accurate radar methods proved
conclusively that meteors traveling faster than this solar speed limit
did not exist; all meteors, therefore, are as much 81  captives of the
Sun as are Earth and other planets, and revolve around it in similar
closed orbits.

Although meteors do not travel faster than 94,000 miles an hour with
respect to the Sun in' our part of the Solar System, the velocities
with which they hit our atmosphere can be far higher than this, since
Earth itself is racing along its orbit at 66,000 miles an hour.  When
Earth and meteor hit head on, therefore, their combined speed may be as
much as 160,000 miles an hour-a velocity which would take one to the
Moon in ninety minutes.

On the other hand, when a meteor catches up to the Earth from the rear
its speed of approach is relatively low, and this sometimes produces a
remarkable effect.  Though most meteor trails flash out and vanish in a
second, when one of these "slow" meteors enters the atmosphere it may
make a sedate and dignified-not to say impressive-progress across the
sky.  There have even been occasions when an entire procession of
meteors has put on such a display, apparently for the express purpose
of adding to the flying-saucer mythos.  (I'm sorry to raise that
subject again, but it's never far away where meteors are concerned.)

It is very important to draw a clear distinction between meteors
themselves and the trails they produce in the sky when they happen to
hit Earth's atmosphere.  It is these trails that are observed both by
the eye and by the electronic senses of the radar telescope; the
meteors are far too small to be detected.  There is a close analogy
here with something we have all witnessed when a jet plane passes high
overhead.  Often the vapor trail can be seen stretching.  for miles
across the deep blue of the stratosphere-but of the plane itself there
is no sign.

In the case of meteors, the disparity between the size of the trail and
the object causing it is far more extreme.  Even a very bright
meteor-one producing a burst of light outshining all the stars put
together-is only about half an inch in diameter.  Such a giant is quite
rare; perhaps a thousand hit the entire earth every hour.  Anyone who
considers that this makes 82  them hardly uncommon should remember
that Earth is a rather large object, and that in an hour it carves out
a tunnel through space 8,000 miles in diameter and 66,000 miles long.

The total number of meteors, of all sizes, that hit Earth every hour is
enormous-probably in the billions.  But the vast majority of these are
smaller than grains of sand; most, indeed, are specks of dust that
would be invisible to the eye.

Ever since space travel and artificial satellites began to be
considered seriously, a good deal of attention has been paid to the
possible hazard that meteors might represent.  As long ago as 1946 the
Rand Corporation concerned itself with this problem on behalf of the
Air Force, and made public its findings in an unclassified report.  The
results were reassuring and have since been confirmed by satellite
observations; meteors are very much less of a danger- to space
travelers than automobiles are to practically everybody.  You would die
of old age on an interplanetary journey before you met a meteor large
enough to do any serious damage-though it is possible-that there may be
enough meteoric dust around in space to "sandblast" windows and optical
surfaces after a few years of continuous operations.  Meteors may be a
nuisance, but they will certainly not be a menace.

About ten times a day Earth encounters a meteor which is sufficiently
large not to be consumed by the friction of its passage through the
atmosphere, and which manages to reach the surface intact.  It is then
termed a meteorite, passing from the jurisdiction of astronomy to that
of meteoritics (studied, heaven help them, by meteoriticists.  Try to
say that quickly after the fourth or fifth martini).  Since these
falling bodies are the only samples we have of matter from outside
Earth, they are of great interest to science and nowadays any report of
a falling meteorite sparks off something like a gold rush.

The average meteorite is an unprepossessing lump of stone or
nickel-iron which looks as if it had been picked up from a slag heap.
In a sense, indeed, it is a lump of 83  cosmic slag-possibly part of
the debris left over when the planets were formed, at least five
billion years ago.  Once or twice every century, really large
meteorites hit Earth; it happened in Siberia in IW8 and again.  in
1947.  Several hundred tons of iron and stone plunging down through the
atmosphere at ten or more times the speed of an artillery shell can
produce a blast wave greater than that of an atomic bomb; the 1908
meteorite felled a forest, snapping off tree trunks for miles around so
that they lay like matchsticks pointing away from the impact area.

During the course of geological time, there must have been thousands of
such collisions, but the effect of weather and vegetation have
obliterated the evidence and it should also be remembered that most
meteorites must come down in the sea.  Until recently, the famous
Meteor Crater in Arizona was the largest-known survival of one of these
prehistoric catastrophes; with a diameter of over four thousand feet,
it is a very impressive object, especially from the air.

During the war, United States and Canadian Air Force pilots noticed a
curious circular lake in the frozen wastes of Northern Quebec, and this
has now been found to mark the site of a meteor crater more than eleven
thousand feet in diameter.  The Ungava Crater, as it has been named.
has certainly been there for many thousands of years.  for the glaciers
of the last Ice Age have ground their way across it and retreated aLan.
lea vine unTnistnknble marks of their nassaae.  So, thouLyh the Ungava
Crater is more than twice as large as its Arizona rival.  it is not in
the same pristine condition and much of the evidence of its formation
has previously been erased.

There is little doubt that air surveys will reveal many mo-e formations
of this type.  some of them in roinulated areas.  At the villaee of

Cabrerolles in southern France.  for instance.  lies a group of craters
which no one had ever noticed because they had been comnletely
overgrown with vegetation-one of them, indeed, is occupied by a
vineyard.  It is not yet certain that they were caused by meteorites,
and anyone who knows 84  much about the French peasantry will realize
that the scientists may have to do some hard bargaining before they can
start digging for nickel-iron fragments.

It is always possible that a large meteorite may fall on a city-and one
can guess the consequences if, by doubly bad luck, this should happen
during a period of international tension.  In the whole of recorded
history, however, there are less than half a dozen cases of deaths from
falling meteorites, and a recent statistical analysis showed that there
is only about one chance in three that a single member of the human
race will be hit by a meteorite during the entire twentieth century. An
insurance company wishing to make the headlines, therefore, would not
be taking much of a risk if it offered ten billion dollars compensation
to any client meeting this unusual mishap.  It the phrase "almost
unique" can be justified in strict logic, here is a case for employing
it.  *

Yet, though the chance of a personal encounter with a meteorite is so
remote, these visitors from outer space now affect the lives of every
one of us.  Today, the problem which first confronted the British radar
experts during the closing months of the war has become of vital
importance.  How is one to distinguish between an intercontinental
ballistic missile and a meteor which may be traveling at the same speed
and at the same height?  A few minutes' wait will give the answer, of
course; but then it may be a little too late.

There is considerable evidence that without meteors we would have no
long-range radio communication.  The only way that radio waves can get
round the curve of the earth is by bouncing off the ionized layers in
the upper atmosphere, some seventy miles above our heads.  Why the air
in this region should act as a kind of radio mirror is still something
of a mystery; during the day Despite the statistics, this incredible
event occurred almost at the time these words were written.  in
December, 1954, Mrs.  Hewlitt Hodges of

Sylacauga, Alabama, was grazed by a ten-pound meteorite that came
through the roof of her house!

The first, and probably only, case of a meteorite hitting an automobile
also occurred in the United States-at Berild, Illinois, in September,
1938.  time, it is true, the Sun',s rays are able to keep it
electrically charged, but that does not explain how it persists at
night.  It is now fairly certain that the continuous gentle rain of
meteor dust from space is responsible for at least one of the
electrified layers which enable us to send our voices round the
world.

Some recent research, started in Australia, has shown that meteors may,
after all, have some association with meteorology.  The link is a most
unexpected one but if it can be established will be of very great
practical importance.  It appears that our small-scale attempts to
produce rain by "seeding" clouds with dry ice and other.  substances
have been anticipated by Nature; the ceaseless shower of meteoric dust
filtering down from the stars may have the same effect.  Long-range
weather prediction, therefore, will have to take account of the meteor
streams which the Earth encounters in its passage through space.

It would be hard to find a better example of the way in which
apparently unrelated branches of science prove to be closely connected.
Though the laws which govern the Universe may be simple, the effects
which they produce can be exceedingly complex.  One of the giant
planets may deflect a meteor stream half a billion miles from Earth, so
that ages later our world encounters an abnormally high concentration
of dust as it sweeps along its orbit.  And so an event far off in space
and time can cause rains and floods which may destroy many lives and
undo the work of generations of men.

A hundred years ago the greatest poet of the Victorian.  Age wrote
these words:

Now sleeps the crimson petal, now the white;

Nor waves the cypress in the palace walk;

Nor winks the gold fin in the porphyry font

The fire-fly wakens; waken thou with me.

Now droops the milk white peacock like a ghost,

And like a ghost she glimmers on to me.

Now lies the Earth all Dana6 to the stars, And all thy heart lies open
unto me.  86  Now slides the silent meteor on, and leaves A shining
furrow, as thy thoughts in me.

A different description, perhaps, from the one that science gives, and
perhaps some may prefer it.  Yet both are equally valid-and why should
we not appreciate the beauty of that "shining furrow" all the more, now
that we are beginning to uncover its secrets?

 The Star of the Magi

Where is he that is born King of the Jews?  for we have seen his star
in the east, and are come to worship him.

Go out of doors any morning this December,* and look up at the eastern
sky an hour or so before dawn.  You will see there one of the most
beautiful sights in all the heavens-a blazing, blue-white beacon, many
times brighter than Sirius, the most brilliant of the stars.  Apart
from the Moon itself, it will be the brightest object you will ever see
in the night sky.  It will still be visible even when the Sun rises;
indeed, you will be able to find it at midday if you know exactly where
to look.

It is the planet Venus, our sister world, reflecting across the gulfs
of space the sunlight glancing from her unbroken cloud shield.  Every
nineteen months she appears in the morning sky, rising shortly before
the Sun, and all who see this brilliant herald of the Christmas dawn
will inevitably be reminded of the star that led the Magi to
Bethlehem.

What was that star, assuming that it had some natural explanation?
Could it, in fact, have been Venus?  At * This article was written to
appear in December, 1954, but as the statement is correct for
approximately one Christmas in three, I have left the opening
unchanged.  least one book has been written to prove this theory, but
it will not stand up to serious examination.  To all the peoples of the
Eastern world, Venus was one of the most familiar objects in the sky.
Even today, she serves as a kind of alarm clock to the Arab nomads.
When she rises, it is time to start moving, to make as much progress as
possible before the Sun begins to blast the desert with its heat.  For
thousands of years, shining more brilliantly than we ever see her in
our cloudy northern skies, she has watched the camps struck and the
caravans begin to move.

Even to the orrFnarv, uneducated Jews of Herod's kingdom, there could
have been nothing in the least remarkable about Venus.  And the Magi
were no ordinary men; they were certainly ex nerts on astronomy, and
must have known the movements of the planets better than do ninety-nine
neonle out of a hundred today.  To explain the Star of Bethlehem we
must look elsewhere.

The Bible gives us very.  few clues; all that we can do is to consider
some possibilities which at this distance in time can be neither proved
nor disproved.  One of these possibilities-the most spectacular and
awe-inspiring of all-has been discovered only in the last few years,
but let us first look at some of the earlier theories.

In addition to Venus, there are four other planets visible to the naked
eye-Mercury, Mars, Jupiter and Saturn.  During their movements across
the sky, two planets may sometimes appear to oass very close to one
another-though in reality, of course, they are actually millions of
miles apart.

Such occurrences are called "conjunctions"; on occasion they may be so
close that the planets cannot be separated by the naked eye.  This
happened for Mars and Venus on October 4, 1953, when for a short while
the two planets appeared to be fused together to give a single star.
Such a spectacle is rare enough to be very striking, and the great
astronomer

Johannes Kepler devoted much time to proving that the Star of Bethlehem
89  was a special conjunction of Jupiter and Saturn.  The planets
passed very close together (once again, remember, this was purely from
the Earth's point of view-in reality they were half a billion miles
apart!) in May, 7 B.c.

This is quite near the date of Christ's birth, which probably took
place in the spring of 7 or 6 i3.c. (This still surprises most people,
but as Herod is known to have died early in 4 B.c."  Christ must have
been born before 5

B.c. We should add six years to the calendar for A.D. to mean what it
says.)

Kepler's proposal, however, is as unconvincing as the Venus theory.
Better calculations than those he was able to make in the seventeenth
century have shown that this particular conjunction was not a very
close one, and the planets were always far enough apart to be easily
separated by the eye.

Moreover, there was a closer conjunction in 66 i3x."  which on Kepler's
theory should have brought a delegation of wise men to Bethlehem sixty
years too soon!

In any case, the Magi could be expected to be as familiar with such
events as with all other planetary movements, and the Biblical account
also indicates that the Star of Bethlehem was visible over a period of
weeks (it must have taken the Magi a considerable time to reach Judea,
have their interview with Herod and then go on to Bethlehem).  The
conjunction of two planets lasts only a very few days, since they soon
separate in the sky and go once more upon their individual ways.

We can get over the difficulty if we assume that the Magi were
astrologers ("Magi" and "magician" have a common root) and had somehow
deduced the birth of a Messiah from a particular configuration of the
planets, which to them, if to no one else, had a unique significance.
It is an interesting fact that the Jupiter-Saturn conjunction of 7 B.c.
occurred in the constellation Pisces, the Fish.  Now though the ancient
Jews were too sensible to believe in astrology, the constellation
Pisces was supposed to be connected with them.  Anything  peculiar
happening in Pisces would, naturally, direct the attention of

Oriental astrologers toward Jerusalem.*

This theory is simple and plausible, but a little disappointing.  One
would like to think that the Star of Bethlehem was something more
dramatic, and not anything to do with the familiar planets whose
behavior had been perfectly well known for thousands of years before
the birth of Christ.  Of course, if one accepts as literally true the
statement that "the star, which they saw in the east, went before them,
till it came and stood over where the young Child was," no natural
explanation is possible.  Any heavenly body-star, planet, comet or
whatever-must share in the normal movement of the sky, rising in the
east and setting some hours later in the west.  Only the Pole Star,
because it lies on the invisible axis of the turning Earth, appears
unmoving in the sky and can act as a fixed and constant guide.

But the phrase, "went before them," like so much else in-the Bible, can
be interpreted in many ways.  It may be that the star-whatever it might
have been was so close to the Sun that it could be seen only for a
short period near dawn, and so would never have been visible except in
the eastern sky.

Like Venus when she is a morning star, it might have risen shortly
before the Sun, then been lost in the glare of the new day before it
could climb very far up the sky.  The wise men would thus have seen it
ahead of them at the beginning of each day, and then lost it in the
dawn before it had veered round to the south.  Many other readings are
equally possible.

Very well, then-can we discover some astronomical phenomenon,
sufficiently startling to surprise men com * Since writing the above, I
have come across a most informative little brochure, "The Star of
Bethiel-em," by Roy K. Marshall, available from the

American Museum's Hayden Planetarium (and doubtless from other
planetariums elsewl-ere).  Dr.  Marshall discusses at some length the
actual date of the

Nativity and points out that the Magi were probably Persian
priests-followers of Zoroaster.  He gives a very full account of the

Saturn-Jupiter "triple conjunction" of 7 B.c."  and adds the
thought-provoking comment that the same phenomenon occurred in 1940 and
1941.  pletely familiar with the movements of the stars and planets,
which fits the

Bible text?

Let's see if a comet would answer the specification.  There have been
no really spectacular comets this century-though there were several in
the eighteen hundreds-and most people do not know what they look like
or how they behave.  They even confuse them with meteors, which any
observer i s bound to see if he goes out on a clear night and watches
the sky for half an hour.

No two classes of object could be more different.  A meteor is a speck
of matter, usually smaller than a grain of sand, which burns itself up
by friction as it tears through the outer layers of Earth's atmosphere.
But a comet may be millions of times larger than the entire Earth, and
may dominate the night sky for weeks on end.  A really great comet may
look like a searchlight shining across the stars, and it is not
surprising that such a portentous object always caused alarm when it
appeared in the heavens.  As

Calpurnia said to Caesar:

When beggars die, there are no comets seen; The heavens themselves
blaze forth the death of princes.

Most comets have a bright, starlike core or nucleus, which is
completely dwarfed by their enormous tail-a luminous appendage which
may be in the shape of a narrow beam or a broad, diffuse fan.  At first
sight it would seem very unlikely that anyone would call such an object
a star, but as a matter of fact in old records -comets are sometimes
referred to, not in aptly as "hairy stars."

Comets are unpredictable: the great ones appear without warning, come
racing in through the planets, bank sharply round the Sun, and then
head out toward the stars-not to be seen again for hundreds or even
millions of years.  Only a few large comets-such as Halley's-have
relatively short periods and have been observed on many occasions.
Halley's comet, which 92  takes seventy-five years to go round its
orbit.  has managed to put in an appearance at several historic events.
It was visible just before the sack of Jerusalem in A.D. 66, and before
the Norman invasion of England in A.D. 1066.  Of course, in ancient
times (or modern ones, for that matter) it was never very difficult to
find a suitable disaster to attribute to any given comet. It is not
surprising, therefore, that their reputation as portents of evil lasted
for so long.

It is perfectly possible that a comet appeared just before the birth
of

Christ.  Attempts have been made, without success, to see if any of the
known comets were visible around that date.  (Halley's, as will be seen
from the figures above, was just a few years too early on its
appearance before the fall of Jerusalem.) But the number of comets
whose paths and periods we do know is very small compared with the
colossal number that undoubtedly exists.  If a comet did shine over
Bethlehem, it may not be seen again from

Earth for a hundred thousand years.

We can picture it in that Oriental dawn-a band of light streaming up
from the eastern horizon, perhaps stretching vertically toward the
zenith.  The tail of a comet always points away from the Sun; the comet
would appear, therefore, like a great arrow, aimed at the east.  As the
Sun rose, it would fade into invisibility; but the next morning, it
would be in almost the same place, still directing the travelers to
their goal.  It might be visible for weeks before it disappeared once
more into the depths of space.

The picture is a dramatic and attractive one.  It may even be the
correct explanation; one day, perhaps, we shall know.

But there is yet another theory, and this is the one which most
astronomers would probably accept today.  It makes the other
explanations look very trivial and commonplace indeed, for it leads us
to contemplate one of the most astonishing-and terrifying-events yet
discovered in the whole realm of

Nature.

We will forget now about planets and comets and the other denizens of
our own tight little Solar Systen-L 93  Let us go out across real
space, right out to the stars those other suns, many far greater than
our own, which sheer distance has dwarfed to dimensionless points of
light.

Most of the stars shine with unwavering brilliance, century after
century.

Sirius appears now exactly as it did to Moses, as it did to
Neanderthal

Man, as it did to the dinosaurs-if they ever bothered to look at the
night sky.  Its brilliance has changed little during the entire history
of our

Earth, and will be the same a billion years from now.

But there are some stars-the so-called "novae" or new stars-which
through internal causes suddenly become celestial atomic bombs.  Such a
star may explode so violently that it leaps a hundred-thousand-fold in
brilliance within a few hours.  One night it may be invisible to the
naked eye, on the next, it may dominate the sky.  If our Sun became
such a nova, Earth would melt to slag and puff into vapor in a matter
of minutes, and only the outermost of the planets would survive.

Novae are not uncommon; many are observed every year, though few are
near enough to be visible except through telescopes.  They are the
routine, everyday disasters of the Universe.

Two or three times in every thousand years, however, there occurs
something which makes a mere nova about as inconspicuous as a firefly
at noon.  When a star becomes a supernova, its brilliance may increase
not by a hundred thousand but by a billion in the course of a few
hours.  The last time such an event was witnessed by human eyes was in
A.D. 1604; there was another supernova in A.D. 1572 (so brilliant that
it was visible in broad daylight); and the Chinese astronomers recorded
one in A.D. 1054.  It is quite possible that the Bethlehem star was
such a supernova, and if so one can draw some very surprising
conclusions.

We'll assume that Supernova Betblebem.  was about as bright as the
supernova

Of A.D. 1572-often called "Tycho's star," after the great astronomer
who observed it at the time.  Since this star could be seen by day, it
must have been as brilliant as Venus.  As we also 94  know that a
supernova is, in reality, at least a hundred million times more
brilliant than our own Sun, a very simple calculation tells us bow far
away it must have been, for its apparent brightness to equal that of
Venus.

It turns out that Supernova Bethlehem was more than three thousand
light-years-or, if you prefer, 18,000,000,000,000,000 miles-away.  That
means that its light had been traveling for at least three thousand
years before it reached Earth and Bethlehem, so that the awesome
cataclysm of which it was the symbol took place five thousand years
ago, when the great pyramid was still fresh from the builders.

Let us, in imagination, cross the gulfs of space and time and go back
to the moment of the catastrophe.  We might find ourselves watching an
ordinary star-a sun, perhaps, no different from our own.  There may
have been planets circling it; we do not know how common planets are in
the scheme of the

Universe, and how many suns have such small companions.  But there is
no reason to think that they are rare, and many novae must be the
funeral pyres of worlds, and perhaps races, greater than ours.

There is no warning at all-only a steadily rising intensity of the
sun's light.  Within minutes the change is noticeable; within an hour,
the nearer worlds are burning.  The star is expanding like a balloon,
blasting off shells of gas at a million miles an hour as it blows its
outer layers into space.  Within a day, it is shining with such
supernal brilliance that it gives off more light than all the other
suns in the Universe combined.  If it had planets, they are now no more
than flecks of flame in the still-expanding shells of fire.  The
conflagration will burn for weeks before the dying star collapses back
into quiescence.

But let us consider what happens to the light of the nova, which moves
a thousand times more swiftly than the blast wave of the explosion.  It
will spread out into space, and after four or five years it will reach
the next star.  If there are planets circling that star, they will
suddenly be illuminated by a second sun.  It.  will give them no
appreciable heat, but will be bright enough to, banish night
completely, for it will be more than a thousand times more luminous
than our full Moon.  All that light will come from a single blazing
point, since even from its nearest neighbor Supernova Bethlehem would
appear too small to show a disk.

Century after century, the shell of light will continue to expand
around its source.  It will flash past countless suns and flare briefly
in the skies of their planets.  Indeed, on the most conservative
estimate, this great new star must have shone over thousands of worlds
before its light reached Earth-and to all those worlds it appeared far,
far brighter than it did to the men it led to Judea.  for as the shell
of light expanded, it faded also.  Remember, by the time it reached
Bethlehem it was spread over the surface of a sphere six thousand light
years across.  A thousand years earlier, when Homer was singing the
song of Troy, the nova would have appeared twice as brilliant to any
watchers further upstream, as it were, to the time and place of the
explosion.

That is a strange thought; there is a stranger one to come.  For the
light of Supernova Bethlehem is still flooding out through space; it
has left

Earth far behind in the twenty centuries that have elapsed since men
saw it for the first and last time.  Now that light is spread over a
sphere ten thousand light-years across, and must be correspondingly
fainter.  It is simple to calculate bow bright the supernova must be to
any beings who may be seeing it now as a new star in their skies.  To
them, it will still be far more brilliant than any other star in the
entire heavens, for its brightness will have fallen only by 50 percent
on its extra two thousand years of travel.

I At this very moment, therefore, the Star of Bethlehem may still be
shining in the skies of countless worlds, circling far suns.  Any
watchers on those worlds will see its sudden appearance and its, slow
fading, just as the Magi did two thousand years ago when the expanding
shell of light swept past Earth.  And for thousands of years to come,
as its radiance ebbs out toward

Ole frontiers of the Universe, Supernova Bethlehem will 96  still have
power to startle all who see it, wherever-and whatever-they may be.

Astronomy, as nothing else can do, teaches men humility.  We know now
that our Sun is merely one undistinguished member of a vast family of
stars, and no longer think of ourselves as being at the center of
creation.  Yet it is strange to think that before its light fades away
below the limits of vision, we may have shared the Star of Bethlehem
with the beings of perhaps a million worlds-and that to many of them,
nearer to the source of the explosion, it must have been a far more
wonderful sight than ever it was to any human eyes.

What did they make of it-and did it bring them good tidings, or ill?

POSTSCRIPT

Many planetariums put on a special display at Christmas in which the
possible explanations of the Star of the Nativity are discussed and
demonstrated.  New York's Hayden Planetarium, for example, has a
particularly impressive and moving program "The Christmas Sky" every
December, which should not be missed by anyone who has an opportunity
to see it.  Where's Everybody?

AT THIS MOMENT OF TIME, WHEN HUMANITY STANDS upon the threshold of
space and has already launched its first vehicles beyond the
atmosphere, there is a centuries-old question which presses more and
more urgently for an answer.

In almost any astronomy book you will find a chapter devoted to the
subject

"Is There Life on Other Worlds?"-the answer given depending upon the
optimism of the author and the period in which he is writing (for there
are fashions in astronomy as in everything else).

Today, that question needs to be reframed and brought up to date. There
must be very few astronomers now who are conceited enough to suppose
that only the Earth is the abode of life, or even that it is the only
home of intelligence.  Assuming this to be the case, we have an
interesting problem on our hands.  How are we to explain the peculiar
behavior of the other intelligent races which share our Universe?  '

What peculiar behavior, Holmes?  Assuming that such races exist, they
have done absolutely nothing about us.

Precisely, my dear Watson.

Having stated the problem, let's look at it as scientifically and
dispassionately as we can.  It falls into three distinct
sections-astronomical, biological and technical' and we'll deal with
them in that order.  On a clear, moonless night the sky seems so packed
98  with stars that it is hard to believe that they could ever be
counted.  Yet in reality the unaided eye can see only a couple of
thousand stars at any one time; even a small telescope shows millions,
and the photographic plate billions.  All those stars are suns, many of
them larger than ours, most of them smaller.  Unfortunately, there is
no way in which we can tell if any of them possess planets, except in
cases so unusual that only a couple of examples are known.

However, even these examples are enough to suggest that planets are not
so rare as they were once thought to be; it may in fact turn out that
most stars have small, cold bodies circling them.  And if no more than
one in a hundred does, that would still be some billion planetary
systems in our

Galaxy alone.

By the laws of probability, we should expect at least one planet
capable of supporting life to exist within ten light-years of Earth.
(The nearest star, Proxima Centauri, is just over four light-years
away; ten light years is the approximate distance of the brightest
star, Sirius.) On the cosmic scale, such distances are completely
trivial. Our Galaxy-the island

Universe of which the Sun is a not particularly outstanding member -is
about a hundred thousand light-years from end to end.  And the remotest
of the myriads of other galaxies we have so far detected lies more than
a billion light years away (6,000,000,000,000,000,000,000 miles, if
anyone prefers it that way

Given a suitable planet.  the next question is: Will life evolve upon
it?  It used to be thought that life was a very improbable phenomenon,
requiring such a fantastic chain of events for it to come about that it
would occur only on a very, very few planets-perhaps, indeed, only upon
Earth.  This argument is a relic of the medieval belief in the
uniqueness of Man; it never had much scientific basis, and now it has
none.

Though we are still very far from a full understanding of the mechanism
of life-and may not achieve that for centuries yet-it is certainly not
mysterious.  Mar

The latest evidence indicates that the distance is at least five times
as great.  velo us if you like; but no more so in principle than a
continent-spanning telephone system, or the complex of factories which
makes up a great chemical combine.  For a living creature is both
chemical factory and telephone exchange, and obeys the same fundamental
laws.

Quite recently, it has been shown that surprisingly complicated
chemicals are produced by purely natural forces-such as lightning and
ultraviolet rays-acting on the substances which would be found in the
primitive seas of any planet.  Some of these chemicals are the basic
building blocks of living organisms, and biologists have been able to
construct rather convincing schemes to show how, in the lengths of time
available, life could arise from nonliving materials In a few hundred
million years, even more unlikely events are bound to happen, and one
of the things that Nature possesses in large quantities is time.

It seems, therefore, that life is virtually certain to arise wherever
conditions are at all favorable.  That is a lesson we might have
learned from a study of our own planet.  There is hardly a spot of
Earth, from the highest mountains to the ultimate depths of the sea,
which some creature has not been able to conquer by suitable
adaptation.  Life may be found frozen eleven months out of twelve in
the Antarctic wastes--or flourishing a few degrees below boiling point
in sulphur springs.

Yet even if life is common throughout the Universe, intelligence may
still be rare.  There are millions of different types of living
creature on this

Earth, but only one with the power of abstract thought-and he hasn't
been round for very long.  Just how late Man has appeared on the cosmic
stage can best be realized by this analogy borrowed, with improvements,
from Sir

James Jeans.

Let the height of the Empire State Building represent the age of Earth;
on this scale, a foot is about two million years.  Now (if the wind
will let you) stand an average-sized book upright on the TV tower.  It
won't look very conspicuous from ground level-but its * For a more
detailed discussion, see "Of Space and the Spirit" (Page 210).  few
inches of height correspond roughly to the entire existence of Homo
sapiens.

However, we haven't finished yet.  Now place a slightly worn.  dime on
top of the book.  The thickness of the coin corresponds to the whole of
man's civilization, right back to the building of the pyramids.  And if
you want to represent the era of modern science and technology-that is
about as thick as a postage stamp.

The postage stamp on the top of the Empire State Building is a picture
we should bear in mind; it shows how extremely unlikely it is that, on
any particular world, intelligence should exist at our own level of
development.  Even assuming that evolution takes similar roads on all
suitable planets, only upon one world in millions could we expect to
find a civilization that had discovered steam power a couple of
centuries ago, and which now dreams of the conquest of space as it
passes into its Atomic Age.

No--it is far more likely that if other intelligent races exist, the
vast majority of them will be at stages of development corresponding to
points millions of years in our past-or in our future.  The latter,
indeed, seems more likely, for our own history is so short that we must
surely be among the youngest peoples in the Universe.

This leads us to an inescapable conclusion.  Scattered around us in
space, at distances which cannot be more than a few scores of
light-years, there must be not a few civilizations far in advance of
ours-and there may be dozens of them.  Which brings us back to our
opening question: If they are so advanced, why haven't they come
here?

At this point, I have to pause briefly to deal with the hordes of
flying-saucer believers who have suddenly appeared on the horizon,
waving affidavits and smudgy photographs.  To dispose of them would
need another article a good deal longer than this one, not all of it
printable in a book intended for general circulation.  So I'll merely
state my views on this agitated subject, without giving the reasons
that have led me to them after several years of thought, reading,
interviewing and 101  personal observations I think -there may be
"Unidentified Flying Obiects" which are exactly what their name
implies, and which may turn out to be quite interesting and exciting
when we discover their cause.  At the same time I am pretty sure that
they're not, repeat, not, spaceships; if they were, so many
consequences would have arisen which, in fact, have not done so.  (The
most obvious one-we and the Russians would be the best of friends.)

If I'm wroniz, that still proves the main point of my thesis, so I
can't lose anyway.  -Assuming, therefore, that during modern times
there have been no visitors from space, we have to look for an
explanation. It may well be arpu-d (and indeed has been by many eminent
scientists) that our an parent isolation can be exolained ve-v simply. 
Travel from planet to planet inside the Solar

System may be possible in the relatively near future, so that we shall
visit neighboring worlds such as Mars and Venus.  But travel to the
planets of other suns-interstellar travel-may be totally impossible
because of the sheer distances involved.  On this theory, the Universe
may be full of intelligent races, but they must forever exist in total
ignorance of each other, quarantined by space itself.

This is a serious and plausible argument, and, must be dealt with
before we proceed any further.  First of all, let us get clearly into
our minds the important-the fundamental-distinction between the
d;stances of interplanetary space, which our c1lildren will he
challenging, and the immensely greater distances which separate us from
the stars.

Planetary distances are about a millionfold greater than those of
ordinary, everyday life.  (For example Venus at its closest, 26 million
miles; Mars at its closest, 35 million miles.) The stars, however, are
about a million times further away still (e.g."  Proxima Centauri, 25
million million miles.) When we get to the remotest planet, therefore,
we will be little nearer the stars than we are today.

But distance itself means nothing; all that really

I have given them in "Things in the Sky" (page 179).  matters is the
length of time any particular journey requires.  In the last hundred
years we have seen the world shrink beyond the wildest imagination of
our forefathers.  Jules Verne was laughed at when he dared to suggest
that one might circumnavigate the Earth in eighty days, but now it has
been done in two-and the IGY satellites, the harbingers of the Space
Age, go round the globe in almost as many minutes as Phileas Fogg
required days.

This steady increase in speed shows no sign of slackening; indeed, in
the last decade the development of the jet and the rocket has given the
curve an even steeper upward trend.  We already know how long the first
interplanetary journeys will take, with the fuels and techniques that
exist today.  Mars and Venus are both much less than a year's flight
away with chemical fuels; when atomic propulsion becomes available, a
few decades from now, the journeys will be measured in weeks, and
ultimately in days.

This state of affairs will arise nearer the beginning of the next
century than its end.  It is partly because interplanetary travel must
become possible quite early in the history of any technically minded
race that I think it most unlikely that there is intelligent life
elsewhere in the

Solar System.  It is much more likely that we have missed the Martians
by a few million years, and that the Venusians may miss us by even
more.

So we must look beyond the Sun's other planets for life-at least
intelligent life, for there are good grounds for thinking that there is
vegetation on Mars-and pin our hopes upon the distant stars.  Can we-or
any other race-ever hope to attain such velocities that the
interstellar gulfs will be bridged in reasonably short periods of
time?

I'll now go out on a limb by saying that this is one question that we
can answer, even today.  And the answer is "Yes, but-"

To put the matter in the right perspective, let's look at the entire
gamut of speed, past, present and future.  The past can be dealt with
very briefly; from the dawn of history until the beginning of the
nineteenth century, 103  no man had ever traveled much faster than ten
miles an hour.

There are men still alive who can remember when 100 mph.  was reached;
yet 1,000 mph.  was attained and doubled-during the last decade. Manned
flight at 10,000 mph will be achieved in the 1960's; unmanned rockets
have already~ passed this speed, and the satellites and space probes
far exceed it.

You'll notice that we are going up in steps of ten.  Each jump seemed
enormous when it was made-and nothing much to boast about when it had
become history.  The next surge forward-to 100,000 mph.-will take place
when atomic energy is harnessed to rocket propulsion, and today's
chemical fuels join the wax candles and kerosene lamps in the museums.
(This may be sooner than we think.  Almost every aviation company is
now working on "ion" and "plasma-jet" rockets, which produce thrust by
electrical means and which, incidentally, can only be used for driving
spaceships, not airplanes.)

A not very efficient atomic propulsion system, such as might reasonably
be developed, round the turn of this century, would enable us to attain
speeds in the 1,000,000 mph.  category.  This would mean Mars in less
than two days-and Venus in one (though starting and stopping would
extend these times somewhat)!

A million miles an hour is such a nice round figure that one is tempted
to see what impression it would make on interstellar distances-since it
certainly deflates interplanetary ones.  The result is startling; even
the very nearest of the stars would be almost three thousand years
away.

We want a few more zeroes on our speedometer.  What about 10,000,000
mph.?

Well, there's no theoretical reason why it should be impossible in the
frictionless vacuum of space.  The atom contains enough energy, if we
are smart enough to apply it in the right way.  And when a thing is
possible in theory, it's always done in practice sooner or later.
So-Proxima Centauri in only three hundred years.  One -hundred million
mph.?  Yes, even that's still 104  not asking too much of atomic
energy.  However, we'll need to learn a few new tricks, such as the
total conversion of matter into energy, not the annihilation of the
miserable fraction of a percent which is all that our present atomic
devices achieve.  That would take us to the nearest star in thirty
years; still too long, but the figures are beginning to look reasonable
at last.  One more jump and we're nearly there.

One billion mph.?  I'm sorry-no.  A new factor has come into the
picture.

On our way to that extra zero, we've passed the speed limit of the

Universe.  It happens to be 670,000,000 mph.  and is a limit that's
rigorously enforced.  It is the velocity of light-more usually quoted
as 186,000 miles a second.

If the theory of relativity is correct-and all the evidence of the past
fifty years indicates that it is-nothing can ever surpass this speed,
and it would require an infinite amount of energy merely to reach it.
Why this should be so is a complicated story which I have no intention
of going into here; all that matters at the moment is that the velocity
of light is not just an arbitrary figure, but is bound up with the very
structure of the

Universe.  Even if you could, in theory, exceed it, you wouldn't be in
our space and time any longer; you'd be somewhere else-if there is
somewhere else.

The velocity of light, therefore, appears to set a limit to the speed
with which any object can move through space.  That speed may be
approached more and more closely as propulsion systems improve, but it
can never be reached, still less exceeded.  If this is the case, time
of travel between even the closest star systems can never be less than
four or five years; between inhabited star systems, in our fairly
crowded corner of the Galaxy, we might not be far out if we fix the
lower limit of travel time as ten years.

This is a good deal longer than we would like, especially as the return
trip still has to be considered.  But can anyone seriously argue that
it is an absolutely insuperable objection to interstellar flight?  Of
course not; as soon as the propulsion problems were solved, there would
be members even of our ephemeral species who 105  would be prepared to
devote a quarter of their lives to the supreme adventure of contacting
new races, new civilizations on the other side of the stellar abyss.

Recent progress in medical science may be of assistance here. Suspended
animation-the deliberate production of a trancelike state in which the
subject is unaware of the progress of time-is no longer a fantasy.  It
can be induced for short periods by drugs or cold, and it does not
require much imagination to suppose that what the dormouse can do men
may also be able to achieve.  The distances between the stars will no
longer seem so terrifying if we can sleep our way across them.

In any event, there is no need to assume that exploring vessels
designed to cross interstellar space would carry living crews; it is
much more likely that the first ones would not.  All the rockets we
have so far launched beyond the atmosphere carried recording
instruments; spaceships which set out on journeys of indefinite
duration and uncertain goal would be purely automatic, controlled by
elaborate electronic brains which had been conditioned to perform one
task-to gather all the information they could, and to bring it safely
home.  Since we will be able to build such robot scouts ourselves in
the near future, other races must have had them for ages, and sooner or
later they will come sniffing round our Earth.

Sooner or later.  That, perhaps, is the crux of the whole matter.
Visitors from space may have landed on our planet dozens-hundreds-of
times during the long, empty ages while Man was still a dream of the
distant future.

Indeed, they could have landed on 90 per cent of the Earth as recently
as two or three hundred years ago-and we would never have heard of it.
If one searches through old newspapers and local records, one can find
large numbers of curious incidents that could be interpreted as
visitations from space.  That stimulating if eccentric writer Charles
Fort made a collection of such occurrences in his book Lo!  and one is
inclined to give them more weight than any comparable modern reports,
for the simple reason that they happened long 106  before anyone had
ever thought of space travel.  Yet at the same time one cannot take
them too seriously, be cause before scientific education was widespread
even the commonest celestial phenomena-meteors, comets, auroras and so
on-gave rise to the most incredible stories.  As they still do, in
fact.

Going further back in time, it has been suggested that some of the
legends and myths of prehistory, perhaps even the weird entities of
many pagan religions, may have been inspired by glimpses of beings from
other worlds.

But this is pure and unprofitable speculation-unprofitable for the
reason that it can never be proved or disproved, but only argued
endlessly.

Do we have to wait ten years or a thousand years before the next ship
calls?  Or if none has ever called before, when will our Earth's
billions of years of isolation be ended?  It may be that our first
meeting with alien intelligences is already far nearer to us in time
than Columbus' landing in the New World.

One would like to think that we will be the discoverers, not the
discovered.  Yet perhaps when we leave the snug little confines of the
Solar

System, we may meet a bored reception committee which greets us with
the words: "Taken your time, haven't you?  Welcome to the Galactic
Federation; here's the book of rules."

Or-and this is the most depressing thought of all perhaps we have
already been blacklisted.  It provides a very simple, and horribly
plausible, explanation for our apparent lack of visitors to date.

The neighbors may already know everything about us; who can blame them,
therefore, if they've kept a few light-years away?  The Sun

IF DR.  GALLUP WERE TO ASK A FAIR SAMPLE OF THE public the
straightforward question: "What is the nearest star?"  the replies
would probably run something like this:

95%-"How's that again?"  3 %-"Alpha Centauri" 2% -"Proxima Centauri"

They would all be wrong, even the erudite 2 per cent who knew that
Proxima was a fraction of a light-year closer to Earth than its
companion, Alpha.

For the nearest star is-the Sun.

It took the human race quite a few thousand years to discover this
fact, for no two classes of object could be more unlike than the
dazzling, burning Sun and the coldly scintillating stars.  But remove
the Sun to a million times its present distance, and it would become an
undistinguished though still easily visible star.  It is merely the
Sun's extreme closeness-a trifling 93,000,000 miles-that gives it such
overwhelming importance in terrestrial affairs.

The true nature of the Sun was a complete mystery until very recent
times, and indeed it was only about twenty years ago that astronomers
began to have some idea of what makes it function.  Today, thanks to
the 108  patient detective work of generations of scientists, we have
not only learned the secret of the Sun, but in the achievement of
nuclear fusion we have ignited its fires here on Earth, with awesome
consequences for the future of mankind.

To the ancients, the possibility c~f ever learning anything definite
about the Sun must have seemed not only vain, but presumptuous.
However, it is most unwise to set limits to knowledge and discovery, as
is proved by the sad example of the eighteenth-century philosopher who
remarked: "If one thing is certain, it is that we shall never know what
the stars are made of."  But today, thanks to the spectroscope, we have
more accurate knowledge of the composition of stars trillions of miles
away than we have of the earth beneath our feet.

All atoms, when they are sufficiently heated, become tiny transmitting
stations-but they broadcast light, not radio waves.  What is more, the
wave length of that light is as characteristic of the particular atom
involved as is a fingerprint of an individual man.  The spectroscope
can.  take the light of the Sun and spread it out into a colored band
yards in length-a band crossed with thousands of lines which betray the
Sun's composition as clearly as if the astronomer could grab a sample
of it for chemical analysis.  All the ordinary elements.  are present
in the Sun, but two of them-hydrogen and helium-are vastly more
abundant than all the others put together.  The composition of the Sun,
therefore, is quite different from that of the Earth, which is mostly
made of oxygen and silicon.  This was rather a blow to the theory that
the Earth was once part of the Sun, but it has been able to survive
thanks to some skillful footwork.

As soon as fairly accurate measurements of the Sun's distance and size
(diameter 864,000 miles-or a hundred times that of Earth) became
available about three centuries ago, astronomers had a major problem on
their hands, though just how major it was they didn't realize for
another century.  The amount of energy which Earth receives from the
Sun is enormous; it is roughly equivalent to a one-kilowatt electric
heater on 109  every square yard of our planet's surface.  But Earth
itself intercepts only a minute fraction of the Sun's rays; most of the
energy goes rushing past into space and is, from our admittedly rather
self-centered point of view, completely wasted.  The total waste, if
you like nice round figures, is approximately half a million, million,
million, million horsepower.

Where does all that energy come from?  Even more important, how long is
it going to last?

In the Victorian era, scientists began to ask these questions more and
more insistently, and a splendid fight developed between the
astronomers and the geologists.  The problem was this-no source of
energy known to science could possibly keep the Sun as a going concern
for the periods of time that the geologists demanded.  If the Sun was
made of the best-quality coal, for example, it would have burned itself
out in a couple of thousand years.  It was obvious, therefore, that
chemical energy was quite insufficient to power the Sun.

The astronomers racked their brains to think of an alternative, and at
last they thoueht they had found one.  The Sun, they decided, obtained
its energy from its slow contraction under gravity.  But if the Sun was
contracting, it must once have been bigger, and it was not hard to
calculate how long ago it had been since it had engulfed Earth.  The
answer came to approximately fifty million years-which obviously set an
upper limit to the age of Earth.

At the beginning of the Victorian age, fifty million years seemed long
enough to satisfy everyone, even those infidels who did not agree
with

Archbishop Ussher that the world was created in 4004 B.c. Then the
evidence of geology began to accumulate, and it was soon obvious that
fifty, a hundred-even five hundred million years was simply not long
enough to have allowed for all the changes which our planet has seen.
The geologists pointed to the mountains that had been worn away, the
chalk beds miles thick that had been laid down on the beds of vanished
seas-and told the astronomers to go and look for a few more zeros.  The
110  argument was quite acrimonious, but the geologists always won
because fossils are heavier than slide rules.

Not until the discovery of radioactivity was the paradox resolved, as
the astronomers realized that there were gigantic stores of energy
locked up in the atoms themselves.  There could be no doubt that the
Sun was able to tap that energy, which was sufficient to keep it
shinning steadily for thousands of millions of years.  That took care
of the past-and of the future too, as far ahead as anyone cared to
look.

For several decades there was much speculation about the precise means
by which the Sun released the energy of matter.  Some elements-radium,
for example-are naturally unstable and continuously give out energy,
until they have decayed into less spendthrift substances, such as lead.
But even if the Sun was made of radium-a highly unlikely
assumption-that could not account for so vast a generation of power
over so long a period of time.

The Sun must have learned the secret of releasing energy from
"ordinary" matter.

In the history of the world, there has been no more momentous quest
than the search for that secret-uncannily foreshadowed in the legend
of

Prometheus, who brought fire from heaven to earth at the price of
having his own body continually devoured.  The first major clue came as
long ago as 1868, when the spectroscope revealed in the Sun the lines
of an element not yet discovered on Earth.  The new element was given
the appropriate name of "helium," and, after an intensive search, was
found to be present in our atmosphere in minute quantities.

Helium, though it aroused a great deal of interest because of the
unusual way in which it was found, seemed no more than a scientific
novelty, and nothing could have appeared of less practical importance.
But it was a major milestone on the road which was to lead, eighty-four
years later, to the hundred-mile-long cloud above Eniwetok Atoll, and,
beyond that, to the promise of eternal power for all the machines that
Man would ever build.

We now know that helium is the ash which is left  when hydrogen is
burnt in the atomic furnace of the Sun.  But the type of "burning" that
takes place in the Sun is as much fiercer than ordinary combustion as
the flame of a blowtorch is warmer than the pale glow of a firefly.  It
is an atomic, not a chemical, process, and takes place at temperatures
of millions instead of thousands of degrees.  the Sun's interior, in
fact, is far too hot for fire, as we know it, to exist.

The solar transmutation of hydrogen to helium, with its accompanying
enormous release of energy, is a complex process involving several
intermediate stages, and is quite different in detail from the
reactions which take place in the H-bomb-though the final result is the
same.  The Sun also operates on a slightly larger scale; every second
of time, some four million tons of matter are converted into raw
energy.  As the Department of

Defense has unaccountably failed to answer my courteous letter asking
for precise details of the H-bomb's composition, the following figure
is only approximate, but will not be more than a zero astray in either
direction.

We would have to explode ten billion H-bombs every second if we wanted
to equal the energy output of the Sun.

Deep down in the solar core, under the influence of pressures and
temperatures beyond all imagination, the atoms of hydrogen are fused
together to form helium, and the released energy batters its way up to
the surface of the Sun, hundreds of thousands of miles above.  Then, in
the form of light, heat and other radiations, it spreads out into space
to be lost in the uttermost limits of the Universe-apart from the tiny
fraction which is intercepted by Earth and the other planets, and which
makes life possible on at least one of them.

No man has ever seen the Sun, or ever will.  Only a small part of its
radiation-the narrow band of visible light-leaks down through our
atmosphere, which acts as a filter eliminating most of the ultraviolet
and

X rays which without its protection would continually bombard us.  When
men leave the atmosphere and enter the direct solar rays, they will
have to be shielded by the v;aUs and windows of their spaceships.  An
un112  protected man out in space-even assuming that he could still
breathe-would die in a few minutes from acute sunburn.

Much of the effort now going into the building of satellite rockets is
concerned with attempts to measure the Sun's radiations before they
enter the atmosphere, so that we can get a true picture of what the Sun
"looks like" when all its rays are taken into account.  This work will
have two immediate practical consequences, as well as endless indirect
ones.  The solar rays absorbed in the upper atmosphere have a great,
though still unknown, effect on the weather, and also on short-wave
radio communication.

There are times when the Sun sends out sudden spurts of ultraviolet
light that cause such intense electrification of the upper air that all
long-distance radio circuits are disrupted.

In the last few years it has also been discovered that the Sun itself
is a powerful though erratic radio transmitter.  The outer layers of
the Sun-its atmosphere, if one can use that term in connection with a
body which is entirely gaseous-are convulsed by great storms which are
often many times as large as our world, and which are visible in
telescopes as black areas on the Sun's shining surface.  Occasionally
these areas, known as sunspots, are large enough to be seen by the
naked eye, and for some reason which is still unknown they act as
intense generators of radio waves.  So also, on a smaller scale, does
the Sun's, beautiful and mysterious envelope, the corona, which can be
seen in its full glory only during the magic moments of a total
eclipse.

If we could "see" the Sun by its radio waves instead of its light waves
we would not recognize it as the same object.  It would appear much
larger, and not even circular in shape.  Normally it would be an
irregular oval, slowly changing its shape from week to week.  The
brilliance of its surface would be very uneven; to the radio eye, the
sunspots and corona would, be the brightest portions, and the rest
would be relatively dark.  At rare intervals, for a few minutes at a
tie, a tiny portion -of the disk would erupt in a blaze of radio
brilliance so fierce that the Sun might shine for a little while with
hundreds of times its, normal intensity.  This outburst would be a
"flare," one of the most spectacular and least understood items in
the

Sun's extensive repertory of curious phenomena.

In recent years it has been possible to make motion picture films of
events on the surface of the Sun, and by speeding them up several
hundred times to project on the screen the entire life story of
cataclysmic solar events which may occupy hours of time and
quadrillions-not millions-of cubic miles of space.  Some of these films
are awe-inspiring: they show immense fountains of flame spurting to
heights of a hundred thousand miles from the

Sun's edge; bridges of fire which could span a dozen earths forming and
crumbling; exact replicas of A-bomb bursts-but a thousand times as
large-shooting up into space.

But some of the occurrences that have been filmed on the Sun are not
merely awe-inspiring; they are inexplicable, and when watching them one
is acutely aware that one is seeing the action of forces completely
beyond our understanding.  Sometimes, for example, a slanting jet of
incandescent gas will shoot out on a long, flat trajectory, reach its
apex, and then whip back along its original path-just as if a shell at
the peak of its flight decided to return to the gun.  And sometimes,
thousands of miles above the

Sun's surface, cascades of glowing matter will start pouring down from
no apparent source, as if they were created high in the solar
atmosphere.

No one has yet been able to explain these events, which sometimes give
the impression that time itself is running backward.  Perhaps what we
are seeing is not the actual movement of matter, but something
analogous to electrical discharges-lightning flashes half a million
miles in length.

In view of the fact that the Sun is purely gaseous, it is rather
surprising that it has such a sharply defined surface, except in the
areas disturbed by sunspots or sporadic eruptions.  In the telescope,
the edge of the 114  Sun is such a geometrically perfect circle that
it is much easier to imagine it composed of liquid than of gas.  One
reason for the "flatness" of the

Sun's surface is its intense gravity, twenty-six times that of Earth.
On the

Sun, a 160-pound man would weigh almost two tons, but that would be the
least of his worries.

Though there are many stars that wax and wane in brilliance,
fortunately for us the Sun is not one of these so-called variables. Its
output of heat and light has not changed by more than a few per cent
during the course of human history, and perhaps not during the whole
progress of geological time.  (Though the suggestion has been made that
solar changes were responsible for the Ice Ages,* this theory is not
very popular today.) The sunlight which warms us now has not altered
its intensity since the first man walked the earth.

Yet in the early days of Earth's history, even though the Sun was
unchanged, the light that reached the surface of our planet was a
fierce, searing flood of radiation that would have been fatal to all
the life forms of our age.  The atmospheric filters which protect us
now had not then formed, and the raw sunlight that today exists only in
space a hundred miles up could pour down almost unhindered upon the
seas and continents of the ancient Earth.

And what of the future?  Despite its size and the inconceivable stores
of hydrogen still untapped within it, the Sun cannot maintain its
present output forever, though it is still good for many billion years.
In the present state of world affairs, what will happen when the Sun
starts to run out of fuel around the year A.D. 10,000,000,000, give or
take a few billion, seems something which no sensible person would
worry about.  So we will do just that.

The obvious assumption is that the Sun will gradually cool down to a
dull red and finally gutter out into extinction; the wonderful closing
chapter of H. G. Wells' masterpiece, The Time Machine, gives a
description of the dying Sun based on this hypothesis.  But as is so
often the case in science, the obvious assumption is 115  not the
correct one.  The Sun is not cooling down; it is warming up.

The effect on the weather will not be noticeable for about ten thousand
million years, but then things will start to happen in a hurry.  As the
Sun uses up its hydrogen fuel and the helium "ash" begins to accumulate
around its core, the solar furnace will burn hotter and hotter.  It may
seem strange that the Sun should do this as it runs out of fuel; the
reason is that the thickening blanket of helium will bank up the
central fires, and so increase the rate of burning, if we may continue
to use our analogy from ordinary combustion.  So, like a gambler who
squanders his resources more and more frantically as he comes to their
end, the Sun will go out in a final blaze of glory.  Within a span of a
mere five million years it will increase its brilliance a hundredfold,
melting down the Earth and the inner planets into balls of glowing
lava.  Then it will collapse swiftly to a tiny star only a few thousand
miles in diameter, becoming one of the fantastically dense "white
dwarfs" in which the mass of an entire sun is packed into the volume of
a planet.

It will still be very bright, but from the orbit of the Earth it will
be so small that it will show no visible disk and will appear to give
little more heat than the full Moon does today.  The minute star which
finally gutters to extinction amid the corpses of the planets will not
be anything which we of today would recognize as the Sun.

So, at least, runs the current theory of solar evolution, but to claim
that this is an accurate description of what must happen to the Sun
would be very rash indeed.  We are learning all the time, and with new
knowledge our picture of the Sun is continually becoming more
complicated.  And even when we have attained a complete understanding
of the processes taking place inside the Sun, we cannot be sure that
external factors-clouds of interstellar dust into which it may run, for
example-may not write new and unexpected chapters in its history.  A
lot may happen to the Sun, and to the Earth, in the millions of
centuries that lie ahead.  Certainly we need have no fear of the Sun
misbehaving in the next few thousand years.  And after that, it won't
matter.  If it gets uncomfortable here on Earth, we'll go somewhere
else.  What Can We Do About the Weather?

THERE IS NO MAN WHO HAS NOT CURSED THE WEATHER at some time in his
life.  He may be a holiday maker watching the storm clouds cover the
Sun; a farmer, fighting to save his parched crops-or an emperor,
listening to the blizzard that is burying his armies and his dreams
beneath a blanket of white.  Each will have felt, in varying degree,
the same helpless frustration; each will have wondered if someday,
somehow, the apparently arbitrary pattern of rain and sun might be
influenced by human needs and wishes.

Until a decade ago, this seemed as futile a hope as any in the
extensive category of Man's aspirations."  Today, it is no longer
completely vain.

There is still not a great deal that we can do about the weather-but it
is at least beginning to take some notice of our activities.

The component of weather which is of the most direct importance to
mankind is, of course, rainfall.  Without the continual circulation of
fresh water from sea to cloud to land and back to sea, most of the
world would be a barren desert.  Though there are many fortunate
regions which have ample rain for their needs, vast and zones exist
which would be fertile if only rain could be induced to fall upon
them.

Many primitive, and some not-so-primitive, peoples have tried their
hands at attracting rain.  The Zufti Indians of New Mexico, for
example, were famous for 118  their rain dances.  These usually began
at the summer solstice, when the rays of the rising Sun struck the same
place five mornings in succession.  At the beginning of the ceremony, a
boy impersonating the fire god would light a cedar branch and set fire
to dry grass, on the theory that the smoke clouds would attract rain
clouds.  So, by applying the principles of sympathetic magic, the
Indians arrived at much the same position as our modern rainmakers, who
try to seed clouds with their silver-iodide smoke generators.  It would
be quite a difficult feat to explain to a Zuhi medicine man why our
technique is scientific and his was merely superstition.

The Zufri dancers, painted with yellow mud and carrying live tortoises,
who probably did not enjoy the proceedings, would dance all night and
then the rest of the next day, watching the sky for the first clouds to
arrive.  If no rain fell, they would know that they'd done something
wrong and would try again, continuing their dances as long as
necessary.  That is one beauty of rainmaking; it always works
eventually, though sometimes you may have to wait a few weeks or months
for the pay-off.

It is hard for most of us, who take ample supplies of water for
granted, to realize what rain means to people living in and lands.  It
dominates their thoughts, their religion, their art.  One of the Zufti
songs, chanted while the men danced and the women ground corn,
symbolizes this preoccupation in these naive yet moving words:

Lovely!  See the cloud, the cloud appear!  Lovely!  See the rain, the
rain draw nearl Who spoke?  "Twas the little corn-ear

High on the tip of the stalk

Saying while it looked at me

Talking aloft there

Ah, perchance the floods

Hither moving,

Ah, may the floods come this wayl Curiously enough, other tribes who
lived in well watered regions such as

Mississippi, and therefore had no need to evoke rain, evolved dances to
drive storms away.  To them, storms were symbols of war, and bad
weather was a disaster if a peace ceremony was in progress.  After
heeding a Zufti chant like the one above, a timid and uncertain rain
cloud might well be badly coniused by such an incantation as this:

Away, away dark clouds, away!  Leave the sky!

Go far away, dark clouds, today,

Leave the skyl

Yet perhaps with New Mexico pulling, and Mississippi pushing, something
ought to happen in the general area of Texas.

More sophisticated peoples, feeling that Nature might not respond to
invocations, have tried action by shooting cannon or rockets into rain
clouds.  The argument seems to have been that a shock or concussion
might cause a cloud to drop its burden of water, and this idea is not
completely absurd.  A shock wave produces compression and, after it has
passed, expansion of the air; this expansion, in turn, causes local
cooling, which in theory could produce condensation in moisture-laden
air.  Today, everyone has seen this effect with his own eyes; the vapor
trail behind a high-flying jet is caused in precisely this manner.  And
in some of the

Pacific A-bomb tests, intense local rainfall was produced around the
point of explosion; in movies that have been released, clouds can be
seen forming like magic along the expanding front of the shock wave.

However, it is most unlikely that gunfire has ever produced any
appreciable rainfall, for an explosion at ground level would have spent
all its force by the time it reached an altitude where it might
conceivably have some effect.  After the First World War there was a
widespread popular belief-remmniseent of the recent H-bomb debate-that
the Fiandeis bombardments had produced abnormally bad weather.  We can
now look 120 back with supercilious amusement upon such presumption,
for today we have the doubtful privilege of being able to release, in a
single explosion, more energy than was liberated by all the guns and
shells and bombs of World War I.

During the Second World War, the Royal Air Force made a rather
determined effort to Do Something About the Weather, if only on a local
basis.  All too often, a bomber squadron would take off to Germany only
to discover, when it had completed its mission and returned to England,
that its base had been closed down by fog.  Many planes and crews were
lost for this reason, and the "boffins"-as the R.A.F. affectionately
christened its civilian scientists-were called upon to produce an
answer.

That answer was FIDO (Fog, Intense, Dispersal Of), one of the war's
most spectacular yet least publicized secret weapons.  I was fortunate
enough to be associated with the tests of the biggest FIDO installation
ever built, on a large airfield in Cornwall, not far from Land's End.
The runway was lined on either side with a double row of pipes-four or
five miles of them in all-which conveyed gasoline to long rows of
burners.  When they were in action, they consumed fuel at the awesome
rate of 100,000 gallons an hour (I trust that this figure is no longer
a well-kept secret from the British taxpayer) and formed multiple walls
of flame the full length of the runway.

At night, with the fog rolling in from the Atlantic, a FIDO operation
was like a scene from Dante's Inferno.  The roar of the flames filled
the air and made speech difficult; they created such an updraft that
small stones on the edge of the runway were picked up and tossed around
by the air currents.  As far as the eye could see, the yellow walls of
fire, taller than a man, stretched away into the foggy night.  The
miles of burners were pumping heat into the air at the rate of
10,000,000 horsepower, cutting a long, narrow trench through the fog,
down which the returning bombers could find their way to the ground.  I
have known nights when the fog was so thick that 121  visibility was
less than ten feet-but standing in the middle of the runway, with the
flames roaring on either side, one could see the stars shining
overhead.  FIDO worked by brute force, and the development of radar
made it obsolete; but it did show what could be done if the incentive
was sufficiently great-and expense was no object.

It was not until 1946 that, for the first time, a method of affecting
weather without the use of, enormous amounts of energy appeared on the
scene, and rainmaking changed from a superstition into a science.  In
that year Vincent Schaefer, at the General Electric Laboratories,
discovered that "dry ice"-solid carbon dioxide-could cause the
precipitation of myriads of minute ice crystals in water-laden,
supercooled air.  Further experiments showed conclusively that in the
right circumstances solid carbon dioxide was so effective a "seeding"
agent that a few pounds of it could trigger off the precipitation of
millions of times its own weight of rain.

The process works because the water vapor in the atmosphere does not
normally condense directly into rain, but first forms ice crystals
which melt before they reach the ground.  In turn each crystal of ice
must have a dust particle, or something equivalent, to act as its
foundation-very much as a pearl grows around an almost invisible speck
of irritant in an oyster.

If the atmosphere is sufficiently cold, and contains enough water
vapor, then the particles of solid Co2 can start the chain reaction
which may make a cloud release its precious burden.

"Dry ice" has now been largely superseded by silver iodide, the
crystals of which are very similar in shape to the basic hexagonal unit
from which all snowflakes are built up.  When a smoke of invisibly
small silver iodide crystals is released into a cloud, ice forms
rapidly around them and snow starts to fall.  A small spoonful of
silver iodide, costing a couple of cents, can produce
10,000,000,000,000,000 snowflakes under favorable conditions.  That
last phrase is the key to all rainmaking experiments.  No cloud
seeding, or any other technique, can produce rain out of a dry
atmosphere-or even out of a wet one, if the temperature in the cloud is
too high to permit condensation.

There is still a great deal of argument among meteorologists about the
effectiveness of rainmaking, and some early optimistic promises have
been rather drastically scaled down.  But there seems little doubt that
scientific cloud seeding can increase the rainfall by 10 or 15 per
cent-and there are circumstances where such percentages are very much
worth while.

Such cities as Dallas, Fort Worth and Oklahoma City have recently
signed rainmaking contracts which appear to have netted them several
million dollars' worth of extra water.

There is also some evidence that the number of destructive tornadoes
has decreased in areas where cloud seeding has taken place.  Possibly,
continued "milking" of rain clouds prevents the build-up of unstable
conditions which could lead to tornadoes, and if this fact can be
definitely established it will be an important step forward in weather
control.  However, it is extremely difficult to prove anything in this
elusive field, where so many variables are involved.  Skeptical
meteorologists can always argue that any behavior of the weather,
however freakish, is due entirely to natural causes.  Only by the
accumulating of statistics over long periods of time is it possible to
detect the results of human intervention.

Before we can hope to achieve anything more impressive than the
premature puncturing of overladen clouds, we will need not only more
power but also more knowledge.  As far as the latter is concerned, we
are rapidly accumulating it, and there is no doubt that artificial
satellites will make possible an enormous advance in meteorology.  For
the first time we are able to study our Earth from outside, and can
measure the radiations falling upon it from space-radiations hidden
from our view until now by the thick screen of the atmosphere itself.
"Weather" is, in fact, no more than the local behavior of the
atmosphere, as it perpetually adjusts to influences both cosmic and
terrestrial.  The human race lives inside a steam engine eight thousand
miles across, operated by sun power, and with oceans for boilers and
mountain ranges for condensers.  The entire machine rotates on its axis
every twenty-four hours, and its parts are more irregularly shaped-so
it is hardly surprising that we have not yet been able to figure
accurately what will happen next at any given spot.

The total energy involved in the circulation of the atmosphere is
enormous; to keep all the winds of the world on the move would require
the energy of a million atom bombs a day.  We can hardly expect,
therefore, that a single atom bomb would have an appreciable effect on
the general weather picture; one might as well imagine that, if the
entire population of Washington or

Cleveland were shouting at once, the voice of one extra man would be
noticed.

Yet one man's voice can start an avalanche thundering down a
mountainside, its infinitesimal energy triggering the fall of millions
of tons of snow.

It is, therefore, by no means impossible that a strategically detonated
bomb could produce large-scale alterations, just as the few grams of
silver iodide dropped upon a cloud can initiate a downpour.
Unfortunately, we know far too little about the causes of weather to
calculate exactly where to apply the "push" which may lead perhaps days
later and half the globe away-to some desired result.  The consequences
of error here could be so serious that one hopes that no attempt is
made to alter the weather on a large scale until we know enough to be
able to make forecasts with complete accuracy.

The widespread popular belief that A- and H-bomb tests have been
responsible for recent abnormal weather is not supported by the facts.
The

National Academy of Science now has a "Committee on Meteorological
Aspects of Atomic Radiation," which after studying the available
evidence has come to the conclusion that there has been nothing unusual
about the weather of the last few years.  One need not go back very
far into the Pre-Atomic Age to match everything in the way of droughts
or floods, hurricanes or tornadoes, that the current decade has
produced.

Strangely enough, it is a much homelier and less terrifying of Man's
activities which may have already produced a noticeable effect upon the
weather-indeed, upon the climate itself.  For the last fifty years, the
globe has been warming up.  It is true that the average temperature
rise is oruy about two degrees, but that has been enough to start the
glaciers receding in many parts of the world.

A rise of one degree per generation is a fantastic rate of increase;
Nature seldom moves as swiftly as this.  We may have been helping her.
To a very large extent, the temperature of the Earth is determined by
the amount of solar heat which the atmosphere Can retain.  The air
above us acts like the glass in a greenhouse, trapping many of the heat
waves which would otherwise bounce right back into space.  And the
constituent of the air which is most responsible for this "greenhouse
effect" is carbon dioxide, the gas produced by all our countless fires,
furnaces and internal combustion engines.

Every year we put not millions but billions of tons Of Co2 into the
air.

Most of it is promptly taken out again by growing pi ants as they mix
it with water, sunlight and chlorophyll to produce starch and oxygen. 
Yet there may be a net gain, and that gain may have been sufficient to
explain the upward temperature trend of the last half century.

The end of the short-lived age of fossil fuels is al ready in sight;
soon-in one or two centuries at the most-we will have squandered the
world's resources of oil and coal, accumulated over so many geological
aeons.  This no longer means disaster, for atomic energy has arrived in
time to save our civilization from perishing through lack of power. We
are moving into a brighter and cleaner age, as the smoke of a myriad
fires and blast furnaces and automobiles ceases to stain the skies.
But for that very reason, it may also be a colder age.

This suggests that, paradoxically enough, it may be easier to affect
climate-the long-range pattern of temperature and moisture-than to_,
control the behavior of the weather, which is a local, short-term
phenomenon, possibly subject to random and therefore unpredictable
influences.

The climate of Earth is determined to no small extent by the immense
quantities of ice locked up at the poles, and that ice remains
perpetually frozen, despite the twenty-four-hour-long summer days,
because the Sun's heat is reflected off the blinding white wastes and
has no chance of being absorbed.  If that ice could once be removed, it
would never re-form on the same scale.  The darker, exposed soil would
collect and keep so much of the

Sun's warmth now lost to us that Earth would balance off its incoming
and outgoing radiation at a higher temperature level.

If such a melting of the polar ice could be achieved, we would gain a
fifth continent; the Antarctic, with its unknown wealth of minerals,
might be the home of new nations and new civilizations.

In a few decades, as fission gives way to fusion and hydrogen energy
replaces the costly and poisonous power of uranium, we may be able to
thaw out the ancient ice that sheets the poles.  But there may be a
better way; why not let the Sun itself do the work?

On a bright winter's day, spread a sheet of any black material across a
snowdrift-and watch how quickly it sinks as it melts its way downward.
The trapped sunlight is burning a way into the snow, now that it is
absorbed and no longer reflected back into the sky.  Even at the South
Pole, the radiation received from the Sun at Midsummer's Day equals the
heat from a network of one-kilowatt electric fires, spaced five feet
apart.

Catch that energy for a few years, perhaps by dusting the snows with
carbon black in some form that would not be easily dispersed, and we
might be able to make a permanent impression upon our planet's polar
caps.  However, the price of Antarctica might be higher than 126  we
would care to pay, for the sea level over the whole Earth would rise at
least a hundred feet.

The pros and cons of such a scheme would, therefore, have to be very
carefully weighed-though there is something rather attractive about the
idea of New York as a semitropical Venice, with gondola-buses letting
off the passengers at the tenth floor.... It will be a long time before
we attempt to interfere with the climate of our planet on such a scale
as this; we are more likely to content ourselves, for a few centuries
to come, with air-conditioning on an ever increasing scale.  The first
air-conditioned business and shopping centers, covering several blocks,
are now being planned; soon entire cities will follow suit.  After all,
if we can control our living conditions inside our homes and offices,
and can predict what will happen outside with sufficient accuracy to
make our vacation arrangements, what more do we really need?

Well, one day we will need a great deal more.  We lie between two Ice
Ages, and we do not know when the next one is due.  Sooner or later,
the glaciers will start to move once more, grinding down from the poles
to reconquer the land they relinquished little more than fifteen
thousand years ago.

Our ancestors met that challenge in the only way they could.  They
retreated; but we will stand and fight.  Oh for the Wings .... THE
RAPID DEVELOPMENT OF AUTOMATION NOW MAKES it virtually certain that
there can be no escape from an age of compulsory leisure in the
not-too-mdistant future.  It is also equally certain that most of
mankind won't be content to occupy its spare time exclusively with
painting, ballet dancing, orchestral composition, poetry recital,
monumental sculpting and similar aesthetic activities.  Which leads us
to conclude that one of the greatest benefactors of the human race in
the years ahead will be the man who can invent a new sport.

A completely new and original sport is a very rare invention indeed. We
are lucky enough to have witnessed the birth of a major one-skin
diving-during the last decade.  It now seems quite possible that an
even more spectacular and unexpected recreation will arrive in the
quite near future.  That new sport may be -flying.

Before you ask indignantly where I've been hiding since 1903, let me
make clear exactly what I mean.  The flying I refer to is one of man's
most ancient dreams, forgotten since the internal-combustion engine
gave us (at a price) the freedom of the air.  It is flight by muscle
power alone-the practical achievement of the legend of Daedalus, the
conversion into reality of Leonardo da Vinci's sketches.  We are go
accustomed to the roar of thousands and 128  tens of thousands of
horsepower in the sky that we have taken it for granted that
muscle-powered flight is an aerodynamic impossibility as far as human
beings are concerned.  Our bodies, it has been generally assumed, are
far too heavy and underpowered for the job.  And anyway-who cares?

Let's deal with the last point first.  A great many people would care,
if they had the slightest idea that such a feat as man-powered flight
was even theoretically possible.  There is always a sense of
achievement in doing something without mechanical aid, and discovering
the Emits of the human body's ability.  Only the most torpid and
unimaginative of men can fail to feel some sense of excitement at the
idea of competing with the birds in their own element, on their own
terms.

The development of aerodynamics as an exact science now allows us to
analyze the problem of manned flight as a straightforward engineering
proposition.  There is a certain whimsical interest in the fact that
the subject is now being studied by a group of young "British
aerodynamicists at the College of Aerodynamics, Cranfield-in the
intervals between calculating what happens to vehicles re-entering the
Earth's atmosphere from outer space at twenty times the speed of
sound.

The crux of the problem is how much power a man can develop.  For very
short periods (say a couple of seconds) this may be as much as 11/2
hp."  if legs and arms are used simultaneously.  This is equivalent to
lifting one's own weight through five feet every second -a sort of
high-jump performance, in fact.  It obviously has no relevance to
sustained, steady operating conditions, but may be of importance in
connection with take-offs.

The continuous power which a man can produce for prolonged periods-up
to an hour-is just under half a horsepower, and a little more if arms
as well as legs are used.  (.45 hp.  16-gs alone; .6 hp.  all limbs
working.) When one looks at the disparity in size between a horse and a
man, this figure is quite surprising.  However, the definition of a
horsepower-a rate of working of 550 feet pounds per second-was laid
down 129  at the beginning of the steam-engine age by James Watt, and
we can be quite sure that he chose a small and skinny horse for his
standard so that the performance of his engines would appear
correspondingly impressive.  Even then, he probably cooked the
figures.

The basic problem of manned flight, therefore, is that of building an
aircraft that can fly on a half-horsepower engine.  This would be a
considerable feat of aeronautical skill, and it is not certain that it
is possible.  What does appear to be possible, however, is to build a
twonwn machine that could be sustained in the air by muscle power
alone.  The point is that an aircraft carrying two men would have
double the power, but much less than double the drag and weight, of a
single engined one, and would be correspondingly more efficient.  It
might be even better to have a still larger crew, all but one of its
members pedaling furiously with hands and feet while the odd man out
steered the machine and provided power with legs alone.

To concentrate on the minimum-sized, two-man machine, calculations made
by

B. "S.  Shenstone indicate that it would have to weigh about five
hundred pounds (more than half that being the weight of the crew) and
would have a wingspan of about sixty feet.  The very large wingspan
arises from the fact that the aircraft must have the extremely low wing
loading-the amount of dead weight each square foot of wing area has to
support-of about two pounds per square foot, as compared with the fifty
or more pounds per square foot of a modern airliner (not to mention the
hundred pounds per square foot and up of a supersonic fighter).

Incidentally, it might be mentioned that Mr.  Shell-w stone is the
Chief

Engineer of British European Airways.  I-Es interest in this particular
problem should cause no alarm to B.E.A. passengers; it is a purely
private one and doesn't indicate that the company fears that its
customers will ever have to get out and push.

The airframe would have to be extremely "clean," since no power could
be wasted overcoming unnecessary drag, even at the low speed of 30
mph., which is about the limit to be expected from such a vehicle. To
130  obtain the required low drag, what is known as "boundary-layer
control" would be needed.  This involves sucking air from the wing
through slots placed at strategic locations, thus preventing the
build-up of turbulent eddies.

One of the most difficult engineering problems in the design would be
getting the power out of the men and into the airscrew without too much
loss through gears, chains or bearings.  A very efficient 'transmission
system would be required, as the crew would be at the front or center
of the aircraft, and the propeller would probably be at the rear.

Without going into too many details which still remain for the experts
on sub-subsonic flight to work out, we can get a fairly clear idea of
the two-man aerial bicycle of the near future.  It would look very much
like one of today's gliders, and would be built from similar materials.
The wing would be excessively long and thin-only about five feet wide
at the roots, but with a total span of sixty feet.  There would be no
undercarriage, a spring-mounted skid serving for landing gear.

To keep frontal area to a minimum, the crew would sit-or even lie in a
reclining position, like bobsled riders.  The pilot would pedal with
his feet and use his hands for control; the rear man would be working
flat out with all his limbs.

There is one slight difficulty we haven't mentioned yet.  Such an
underpowered aircraft could fly, but it couldn't take off.  It would
have to be launched into the air like a glider by winch, catapult or
rockets.

The take-off could be purely man-powered if the vehicle contained some
energy-storing device which would be revved up by the crew while they
were still on the ground, and then coupled to the propeller to give a
brief burst of power.  A spinning flywheel is the obvious example of
such a device, but would be far too heavy tct be practical.  Perhaps a
compressed-air system might do the trick and would also solve the
transmission problem.  The crew could pedal away until they had built
up starting pressure in a cylinder, and at the right moment this would
be connected to a tiny piston engine driving the airscrew.  The use of
compressed-air lines instead of shafts or chains would simplify the
engineering problems, but the increased weight and complexity of the
system might make it impracticable.

In any event, it is clear that the air cycle will be a fairly expensive
piece of machinery-at least as expensive as a glider, though of course
the cost of production would fall sharply if the demand was
sufficiently large.

The two-man machines would certainly be within the reach of most sports
clubs, colleges and athletic organizations.  And as for the larger
ones, it is obvious what their destiny would be.

It's about time that Harvard and Yale, not to mention Oxford and
Cambridge, moved ahead with the times.  Can't you picture the
excitement as the beautifully streamlined aircraft, fragile and
delicate as dragonflies, are brought out of their (ivy-covered)
hangars?  The crews-representing the highest weight-to-power ratio,
their colleges can muster-file into the long, slim fuselages and take
their places in line astern.  They won't see much of the race; but then
they never did.  Only the coxes under their tiny perspex blisters will
know what is happening and will control the flight of the graceful,
man-powered birds.

The propellers spin into invisibility, the rudders and ailerons swing
back and forth as the controls are tested.  The elastic launching
cables have been attached; the two aircraft are lined up side by side,
waiting for the starting signal.

They're off!  Leaping from the ground under the smooth yet steady tug
of the catapults, the two machines rise steeply into the sky.  At the
same instant the launching cables drop away; they're on their own now,
as they head toward the starting line, at all of forty miles an hour,
on the first lap of the unforgettable race of 19-.

What date shall we fill in there As far as technical considerations are
concerned, the aircraft could be ready in five or ten years at the
most, and if anyone has a large fraction of a megabuck which they would
132  Eke to donate to a spectacular but completely useless cause this
time scale might be compressed.

Useless?  That, it seems to me, is one of its chief virtues.  A feeble
and far-fetched case might be made out for some military applications,
but only the dimmest of generals would be convinced by it-perhaps one
who was still pining for the days of cavalry.  Though the glider has
been turned into a weapon of war, the man-powered airplane appears to
have about as promising a military future as the crossbow.

Perhaps for this very reason we won't develop it.  We may be so busy
building rockets and starting on the conquest of space that we'll leave
it to the twenty-first century to complete the conquest of the air.

POSTSCRIPT

There have been further developments in this field since the above
article was written.  In England, the Royal Aeronautical Society has
formed a Man

Power Flight Group, and the Russians (here we go again!) have also set
up a "Muscle Powered Flight Committee."  The Aero Club de.  France is
organizing a competition for such aircraft, and the startling fact has
emerged that it might have been won in 1936 by Haessler and Villinger
in Germany, who made several officially observed single-seat
man-powered flights of over two hundred yards at heights of between
three and fifteen feet.

Anyone who is interested in technical details will find a paper of
great value by T. Nonweiler in the October, 1958, issue of the Journal
of the

Royal Aeronautical Society.  Across the Sea of Stars

AT SOME TIME OR OTHER, AND NOT NECESSARILY IN moments of depression or
illness, most men have known that sudden spasm of unreality which makes
them ask, "What am I doing here?"  Poets and mystics all down the ages
have been acutely aware of this feeling, and have often expressed the
belief that we are strangers in a world which is not really ours.

This vague and disturbing premonition is perfectly accurate.  We don't
belong here, and we're on our way to somewhere else.

The journey began a billion years ago, when one of our forgotten
ancestors crawled up out of the sea and so started life's invasion of
the land.  That great adventure was Nature's most spectacular triumph,
but it was achieved at a heavy price in biological hardshipa price
which every one of us continues to pay to this day.

We are so accustomed to our terrestrial existence that it is very hard
for us to realize the problems that had to be overcome before life
emerged from the sea.  The shallow, sun-drenched water of the primitive
oceans was an almost ideal environment for living creatures.  It
buffered them from extremes of temperature, and provided them with both
food and oxygen.  Above all, it sustained them, so that they were
untouched by the crippling, crushing influence of gravity.  With such
ad134  vantages, it seems incredible that life ever invaded so hostile
an environment as the land.

Hostile?  Yes, though that is an adjective few people would apply to
it.

Certainly I would not have done so before I took up skin diving and
discovered-as have so many thousands of men in the past few years-that
only when cruising underwater, sight-seeing among the myriad strange
and lovely creatures of the sea, did I, feel completely happy and
beyond the cares and worries of everyday life.

No one who has experienced this sensation can ever forget it, or can
resist succumbing to its lure once more when the chance arises. Indeed,
there are some creatures-the whales and porpoises, for example-who have
heeded this call so completely that they have abandoned the land which
their remote ancestors conquered long ago.

But we cannot turn back the clock of evolution.  The sea is far behind
us; though its memories have never ceased to stir our minds, and the
chemical echo of its waters still flows in our veins, we can never
return to our ancient home.  We creatures of the land are exiles
-displaced organisms on the way from one element to another.  We are
still in the transit camp, waiting for our visas to come through.  Yet
there is no need for us to regret our lost home, for we are on the way
to one of infinitely greater promise and possibility.  We are on our
way to space; and there, surprisingly enough, we may regain much that
we lost when we left the sea.

The conquest of the land was achieved by blind biological forces; that
of space will be the deliberate product of will and intelligence.  But
otherwise the parallels are striking; each event-the one ages ago, the
other a few decades ahead of us-represents a break with the past, and a
massive thrust forward into a new realm of opportunity, of experience
and of promise.

Even before the launching of the Earth satellites, no competent expert
had any doubts that the conquest of space would be technically feasible
within another

135 .  I

 generation, or that the new science of astronautics now was standing
roughly where that of aeronautics was at the close of the last century.
The first men to land on the Moon have already been born; today we are
much nearer in time to the moment when a man-carrying spaceship
descends upon the lunar plains than we are to that day at Kitty Hawk
when the Wright Brothers gave us the freedom of the sky.

So let us blithely take for granted the greatest technical achievement
in human history (one which, by the way, has already cost far more than
the project which made the atom bomb) and consider some of its
consequences to mankind.  Even over short periods they may be
impressive; over intervals long enough to produce evolutionary changes
they may be staggering.

The most important of these changes will be the result of living in
gravitational fields lower than Earth's.  On Mars, for example, a
180-pound man would weigh about 70 pounds; on the Moon, less than 30.
And on a space station or artificial satellite he would weigh nothing
at all.  He would have gone full circuit, having gained-and indeed
surpassed-the freedom of movement his remote ancestors enjoyed in the
weightless ocean.

To see what that may imply, consider what the never relenting force of
gravity does to our bodies on the surface of Earth.  We spend our
entire lives fighting it -and in the end, often enough, it kills us.
Remember the energy that has to be exerted pumping the blood round and
round the endless circuit of veins and arteries.  It is true that some
of the heart's work is done against frictional resistance-but how much
longer we might live if the weight of the blood, and of our whole
bodies, was abolished!

There is certainly a close connection between weight and the
expectation of life, and this is a fact which may be of vast importance
before many more decades have passed * The political and social
consequences which may follow if it turns out that men can live
substantially longer on Mars or the Moon may be revolutionary.  Even
taking the most conservative viewpoint, the study 136  of living
organisms under varying gravitational fields will be a potent new tool
of biological and medical science.

Of course, it may be argued that reduced or zero gravity will produce
undesirable side effects, but the rapidly growing science of space
medicine-not to mention the experience of all the creatures in the
sea-suggests that such effects will be temporary and not serious.
Perhaps our balance organs and some of our muscles might atrophy after
many generations in a weightless environment, but what would that
matter since they would no longer be needed?  It would be a fair
exchange for fallen arches, pendulous paunches, and the other defects
and diseases of gravity.

But mere extension of the life span, and even improved health and
efficiency, are not important in themselves.  We all know people who
have done more in forty years than others have done in eighty.  What is
really significant is richness and diversity of experience, and the use
to which that is put by men and the societies they constitute.  It is
here that the conquest of space will produce an advance in complexity
of stimulus even greater than that which occurred when life moved from
water to land.

In the sea, every creature exists at the center of a little universe
which is seldom more than a hundred feet in radius, and is usually much
smaller.

This is the limit set by underwater visibility, and though some
information comes from greater distances by sound vibrations, the world
of the fish is a very tiny place.

That of a land animal is thousands of times larger.  It can see out to
the horizon, miles away.  And at night it can look up to the stars,
those piercing points of light whose incredible explanation was
discovered by Man himself more recently than the time of Shakespeare.

In space, there will be no horizon this side of infinity.  There will
be suns and planets without end, no two the same, many of them teeming
with strange life forms and perhaps stranger civilizations.  The sea
which beats against the coasts of Earth, which seems so endless and so
eternal, is as the drop of water on the slide of a 137  microscope
compared with the shoreless sea of space.  And our pause here, between
one ocean and the next, may be only a moment in the history of the

Universe.

When one contemplates this awe-inspiring fact, one sees how glib,
superficial and indeed downright childish are the conceptions of those
science-fiction writers who merely transfer their cultures and
societies to other planets.  Whatever civilizations we may build on
distant worlds will differ from ours more widely than mid
twentieth-century America differs from

Renaissance Italy or, for that matter, from the Egypt of the Pharaohs.
And the differences, as we have seen, will not merely be cultural; in
the long run they will be organic as well.  In a few thousand years of
forced evolution, many of our descendants will be sundered from us by
psychological and biological gulfs far greater than those between the
Eskimo and the African pygmy.

The frozen wilderness of Greenland and the steaming forests of the
Congo represent the two extremes of the climatic range that Man has
been able to master without the use of advanced technology.  There are
much stranger environments among the stars, and one day we shall pit
ourselves against them, employing the tools of future science to change
atmospheres, temperatures and perhaps even orbits.  Not many worlds can
exist upon which an unprotected man could survive, but the men who
challenge space will not be unprotected.  They will remold other
planets as we today bulldoze forests and divert rivers.  Yet, in
changing worlds, they will also change themselves.

What will be the thoughts of a man who lives on one of the inner moons
of

Saturn, where the Sun is a fierce but heatless point of light and the
great golden orange of the giant planet dominates the sky, passing
swiftly through its phases from new to full while it floats within the
circle of its incomparable rings?  It is hard for us to imagine his
outlook on life, his hopes and fears-yet he may be nearer to us than we
are to the men who signed the Declaration of Independence.

Go further afield to the worlds of other suns (yes, one day, we shall f
each them, though that may not be 138  for ages yet), and picture a
planet where the word "night" is meaningless, for with the setting of
one sun there rises another-and perhaps a third or fourth-of totally
different hue.  Try to visualize what must surely be the weirdest sky
of all-that of a planet near the center of one of those close-packed
star clusters that glow like distant swarms of fireflies in the fields
of our telescopes.  How strange to stand beneath a sky that is a solid
shield of stars, so that there is no darkness between them through
which one may look out into the Universe beyond.... Such worlds exist,
and one day men will live upon them.  But why, it may reasonably be
asked, should we worry about such remote and alien places when there is
enough work to keep us busy here on Earth for centuries?

Let us face the facts; we do not have centuries ahead of us.  We have
aeons, barring accidents and the consequences of our own folly.  A
hundred million yea is will be but a small fraction of the future
history of Earth.  This is about the length of time that the dinosaurs
reigned as masters of this planet.  If we last a tenth as long as the
great reptiles which we sometimes speak of disparagingly as one of
Nature's failures, we will have time enough to make our mark on
countless worlds and suns.

Yet one final question remains.  If we have never felt wholly at home
here on Earth, which has mothered us for so many ages, what hope is
there that we shall find greater happiness or satisfaction on the
strange worlds of foreign suns?

The answer lies in the distinction between the race and the individual.
For a man "home" is the place of his birth and childhood-whether that
be

Siberian steppe, coral island, Alpine valley, Brooklyn tenement,
Martian desert, lunar crater, or mile-long interstellar ark.  But for
Man, home can never be a single country, a single world, a single Solar
System, a single star cluster.  While the race endures in recognizably
human form, it can have no one abiding place short of the Universe
itself.  This divine discontent is part of our destiny.  It is one
more, and perhaps the greatest, of the gifts we inherited from the sea
that rolls so restlessly around the world.

It will be driving our descendants on toward a myriad unimaginable
goals when the sea is stilled forever, and Earth itself a fading legend
lost among the stars.  Of Mind and Matter

FOR THOUSANDS OF YEARS THE HUMAN RACE HAS debated, with singular lack
of agreement, such questions as the existence of the soul, the meaning
of personality, the relationship between the mind and the.  body and
above all-the possibility of survival after death.  The fact that the
debate is still just as heated as when it began in the Late Neolithic
Period strongly suggests that the wrong questions have been asked-, and
certain spectkcular developments of the last decade indicate, with
equal force, that now is a good time to recast them into g form that
makes sense.

Those developments -are purely scientific-a fact which will upset a
great many people with vested interests in some of the pseudo-answers
now current.  They lie almost entirely in the fields of biophysics,
neurology and electronics, and at first sight it may seem improbable
that such areas of modern technology could have any conceivable
relation to the great questions of philosophy and religion.

But four centuries ago, it would have seemed equally unlikely that
several thousand years of cosmological speculation, culminating in the
poetic fantasies of Paradise Lost, could have been swept away in a few
decades by a couple of leAses in a tube.  Today, we are witnessing
another scientific breakthrough, in an area that affects 141  us much
more personally than any astronomical discovery could possibly do.

It is now obvious that we are approaching, more closely than anyone
would have dared to hope a few years ago, the basic secrets of life.
Such fabulous tools as the electron microscope, which has given us
clear pictures of the very building blocks of living organisms, are
showing us how the bridge was crossed between the world of inorganic
materials and the richer world of life.  It is only a matter of time
before that bridge is crossed again in some laboratory; whether that
moment is ten or a hundred years from now is not in itself important.
Many details of the fantastically complex electro-chemistry of life
will elude us for generations yet, but it cannot be doubted now that
there is nothing inherently mysterious, or fundamentally unknowable, in
the processes that build and power our bodies.  That makes them none
the less marvelous; real knowledge, when it dispels superstition,
seldom diminishes awe.  (For can the petty cosmos of Milton compare
with the grandeur of the Universe we know today?)

It seems possible that the brain will hold its secrets longer than the
body, but even here remarkable advances have been made toward an
understanding of the processes of memory and reason-all the complex of
phenomena which we group under the term "thought."  In this case the
scientific breakthrough has occurred at two distinct points: on the one
hand the mechanism of the brain itself has been investigated, and on
the other electronic devices have been built which show--often with
startling realism-many of the behavior patterns of sentient creatures.
And perhaps most significant of all, the large-scale development of
giant computers has done much to destroy the illusion that there is
something transcendental about the brain, beyond all possibility of
duplication or imitation by machine.

Almost all the basic activities of the mind have now been reproduced,
more or less successfully, by electronic means.  Memory, purposeful
reaction to the environment, ability to draw logical or mathematical
conclusions-these are now commonplace features of machines being
mass-prqduced for the commercial market.  The ability to learn from
past experience-to profit from mistakes so that they will not be made
again-has also been demonstrated on the laboratory scale.  Even the
all-too-human attribute of total unpredictability can be incorporated
in a machine if desired; and sometimes it is desirable, in carefully
regulated amounts.  (For there are problems that can drive both men and
machines crazy if they try to solve them, and then the only thing to do
is to make a random choice.)

The situation has been somewhat confused by the determination of the
computer designer's not to let the popular name "electronic brains" be
applied to their offspring.  For once, however, the public, and not the
experts, is right.  Today's computers are electronic brains by any
reasonable definition of the phrase.  It is true that they have the
intelligence of single-minded tapeworms (though they usually possess
much better memories), but this does not alter the basic situation.

Important though electronic computers will be (and indeed already are)
in science, business and technology, it is their profound philosophical
implications which we are concerned with here.  For they have shown-in
principle at least-that though Mind needs a vehicle, that vehicle can
be of many forms.

Before we see where this leads us, it is necessary to deal with a
persistent red herring.  Many people have been so impressed by the gulf
betweefi even the most advanced electronic computer and the most
moronic human mind that they have denied the possibility of bridging
it.  The brain of a man, it has been pointed out, contains
approximately ten billion fundamental switching units, capable of
cross-connection in an almost infinite number of ways.  A much quoted
"proof" that no electronic equivalent of the brain is possible states
that such a machine would have to be as large as the Empire State
Building and would need as much water as flows over Niagara to keep its
billions of vacuum tubes cool.

It is amusing to see how quickly this has become an argument that such
a machine is perfectly possible.  Since the first computers were built,
the bulky heat143  generating vacuum tube has been largely replaced by
the rice-grain-sized transistor.  We no longer need the whole Empire
State Building; one floor will do, and the existing plumbing will
provide all the cooling water required.  But even this reduction in
scale has now been surpassed; the transistor itself is challenged by
the yet tinier and still more efficient cryotron (a switch literally as
big as a hair, operating on the principle of superconductivity).  It is
believed that one of today's giant computers could be packed into a
small suitcase if it were redesigned with cryotrons as its fundamental
circuit elements.  So much, then, for the Empire State school of
criticism.

All this does not mean that we will be able to build electronic
equivalents of the human brain in the near or even remote future.  But
the feat is not intrinsically impossible, and when one looks back at
the progress of technology during the past hundred years one would be
very foolish indeed to declare categorically that this will never be
achieved.  Most top-rank computer scientists, if they let their hair
down, would probably agree that sooner or later we will find ourselves
dealing with mechanical entities which will pass every conceivable test
for intelligence and self-awareness which we might apply to another
human being.  They will contain fewer units than many electronic
systems already in existence -the telephone network of the United
States, for example-though they will be a great deal more
complicated.

A good many people find it somehow degrading to realize that the human
brain, Eke the human body, is 4conly" an electro-chemical machine and
flatly refuse to admit it.  This attitude is completely absurd.  The
Taj

Mahal is "only" a mass of stones; the roof of the Sistine Chapel only
plaster and paint.  The material is unimportant; the pattern is all
that matters.  Should an athlete feel that sport is worthless because
of the undeniable fact that his body is an elaborate artifice of pumps,
levers and elastic fibers?  Of course not; indeed, it adds zest and
interest to his performance.  (It is no 144  coincidence that the
first man to run a mile in four minutes was a doctor.)

It may well be that we will learn to think properly and effectively
only when we know how we think.

We must not commit the elementary error of supposing that the mechanism
of the human brain is necessarily similar in detail to that of today's
(or tomorrow's) electronic computers.  It is certainly not so, if only
because of the different structural elements involved.  This, however,
is quite unimportant; what matters is that memory, personality-all the
components which make up every human being and distinguish him from all
other men who have ever lived-are ( ) the byproduct of data storage and
processing in an extremely complex computer of some kind.  (That blank
parenthesis, by the way, is to allow you to insert the word "merely" if
it helps your feelings.

It will affect the situation just about as much as the actions of
Kipling's

"Village That Voted the Earth Was Flat.")

It may be no serious oversimplification to say that a man is the sum of
his-abilities (the circuit networks through which he observes the
external world and decides what to do about it) and his memories (the
storage banks holding his accumulated experience).  There may be other
components, but these are the basic ones which between them largely,
and perhaps completely, account for the personality and behavior of
every one of us.

The storage of information can be carried out in many, ways-by marks on
paper, by grooves in wax, by holes punched in cards-or, as

Nature appears to do it, by coding based upon molecular structures like
immensely elongated Yale keys.  The physical basis is immaterial; as we
have said before, only the pattern itself matters.  And from this
simple fact, the most awe-inspiring results follow.  Even those readers
who have found nothing -surprising or controversial in what has gone
before had better fasten their seat belts at this point.

One characteristic of a pattern is that it can be reproduced; a good
example is the way in which endless 145  indistinguishable copies of a
symphony can be stamped out from a master recording.
(Indistinguishable?  Not strictly speaking, but the differences can be
made so small that they are of no practical importance.) Now the
duplication of a human personality would be an immensely more difficult
problem-but it is not a fundamentally different one.  We cannot at this
primitive stage of our technology begin to guess how it could be
achieved, any more than Beethoven could have imagined how a performance
of the Ninth

Symphony could be snatched out of time and saved for eternity.

The basic problem is that of recording and playing back-using those
terms in a general sense-the vast quantity of information involved in
defining personality and memory.  Yet the actual storage space required
is quite small.  If Nature manages to compress the pattern of a human
body into a couple of cells invisible to the eye, and the memories of a
lifetime into a lump of jelly six inches across, is it expecting too
much to suppose that

Man may one day perform the same feat with a few cubic yards of
electronics?  After all we could now pack the Library of Congress into
a shoe box if we had to, and the amount of information there must be
comparable with that defining an individual human being.

It therefore follows that, in a strictly scientific sense,
reincarnation is theoretically possible.  If one could reproduce the
physical pattern of an individual down to the molecular fine-structure
which is the library of the mind, there would be no way of
distinguishing between the original and the duplicate.  It would be
totally meaningless to ask, "Which is really John

Doe?"  They would both be.

If you think that this is absurd fantasy, of no practical importance,
you have a surprise coming.  For it happened to you during the last few
months; it will have happened to me by the time you read these words.
This is a simple statement of fact-though a fact that could never have
been imagined before the tools of modern science were turned upon the
mechanism of life.  The atoms in our bodies are in a state of constant
flux, being replaced so rapidly by others from the food we eat that we
are completely rebuilt every few weeks.  Even the bones are involved in
this ceaseless ebb and flow of matter.  Every one of us moves through
the world like a flame, seeking fuel from his environment, assembling
it into a momentary pattern, then rejecting the smoke and ash.  Only
the flame is-relatively-unchanging, until it gutters to extinction at
the end of life.

It has been said that no man ever steps twice into the same river; it
is almost equally true that no man ever looks at his face twice in the
mirror.

The flow of flesh may be slower than the movement of water to the sea,
but it is no I ess inexorable.

We are involved, therefore, in a kind of continuous reincarnation
almost as marvelous as any other type that has ever been postulated. At
the same time, we can see that another popular idea of the
mystics-transmigration through lower animals-can have no logical basis.
The personality and memory of a human being could no more be squeezed
into the limited storage capacity of any other vertebrate (still less
invertebrate) than could the, entire musical heritage of mankind be
recorded on a six-inch disk.

The above argument now enables us to give a definite and somewhat
unexpected answer to the ancient question of immortality.  What happens
to us when we die can differ in no significant way from what happens to
the information punched on an IBM.  card-when the card is burned.  But
suppose the information is also stored elsewhere (in what manner is
immaterial) and is used to prepare a fresh card.  There would then be
no way of distinguishing between the old card and the new.

Some people may console themselves with the thought that such "master
cards" (using the term in a completely general sense to mean any
suitable storage device) may exist somehow, somewhere; others will
consider such an attitude slightly egocentric.  Yet even if no records
are in existence from which anyone alive today could be recreated, this
may not always be the 147  case.  If it seems absurd to talk of
storing a human being on a few miles of tape, that is only because we
cannot yet build the input and output devices which could perform the
feat.  If the day should ever come when this is possible, death will
have lost its power over the minds of men.

I have little doubt that a great many people will consider these
speculations naively mechanistic, because they cannot reconcile such
imponderables as personality, intelligence-even the soul, if one cares
to use the word-with the concepts of electronics or information theory.
Such an attitude is a hangover from nineteenth-century
materialism-though this charge will make many critics doubly indignant.
By the word "machine," far too many otherwise educated people still
envisage a contraption of cogs and cranks and levers; they are still
mentally in the steam-engine era.  They cannot imagine the subtlety and
sophistication of the great computers which are now leaving the
laboratory, some of which may comprise a million circuit elements and
be as large as a house-yet contain practically no moving parts, though
they may carry out a hundred thousand operations a second.  The
machines we are building now differ in kind as well as degree from all
that mankind has ever seen before-and their evolution is barely
beginning.

No one can say where it will lead, but glimpsed vaguely in the mists of
the future is a dr earn-I will not say a possibility-which has long
been hinted at in most of the religions of the world.  Since pattern
alone is important, can mind and intelligence exist without matter?  In
the relationship between, for example, purely electrical entities or
packages of radiation?

There is some evidence that space itself has a fundamental structure,
and could therefore in principle be used as a medium for storing and
processing information.

And thus, intelligence, which arose from the inter actions of matter
and has used it as a vehicle for so many ages, may at last break loose
from its origin, as a butterfly from the prison of its chrysalis.  And
like the butterfly climbing into the summer sky, it may go on to
orders of experience completely beyond the reach of its earlier
metamorphoses.

Where are we today in the hierarchy which, ages hence, may culminate in
something which only the word "spirit" can describe?  Are we the
chrysalis, the larva-or merely the unhatched egg?  Which Way Is Up?

WHEN I BECAME AMPHIBIOUS, I N~EVER EXPECTED THAT it would cause such
confusion among my friends.  Yet I can understand their feelings; when
one has been writing and talking about space flight for the best part
of twenty years, a sudden switch of interest from the other side of the
stratosphere to the depths of the sea does seem peculiar.  It might be
regarded as a serious failure to keep to the point-even a demonstration
of a certain lack of stability.  So, to put the record straight, I'd
like to explain just why it is that I've traded in my space suit for an
Aqua-Lung, my telescope for an underwater camera.

The first excuse I give to baffled journalists and lecture chairmen
agonizing over their introductions is the economic one; submarine
exploration is so much cheaper than space flight.  The first round-trip
ticket to the Moon is going to cost at least $10 billion if you include
research and development.  By the end of this century it will be down
to a few million-but the complete basic kit needed for skin diving
(flippers, face mask and snorkel tube) can be bought for twenty
dollars.  Which, it can hardly be denied, is a very modest price to pay
for admission to a new element.

My second argument is more philosophical: the ocean, surprisingly
enough, has many points of similarity to space.  Some of these I had
guessed even before I first went underwater; others I did not discover
until I had been diving for several years, though I do my best to claim
that I had anticipated them all.

In their different ways, both sea and space are equally hostile to Man.
If we wish to survive in either for any length of time, we have to
employ mechanical aids.  The diving dress was the prototype of the
space suit;.  the sensations and emotions of a man beneath the sea will
have much in common with those of a man beyond the atmosphere.

One of those sensations is weightlessness, and it was this fact, as
much as any other, that first got me interested in underwater swimming.
Here on the surface of the Earth, it is never possible to escape from
gravity.  All our lives, we creatures of the land must drag the weight
of our bodies around with us, envying the freedom of the birds and
clouds.

In a spaceship, however, once the thrust of the rockets has ceased, all
weight vanishes, and the effect that this will have upon the human
organism has long been the subject of debate among medical men.  It has
been suggested that "space-sickness" and perhaps total incapacity might
result when there is no longer any way of distinguishing between up and
down, because both conceptions have lost all meaning.

Something rather Eke this happens underwater, for gravity plays little
part in the lives of fish and other marine creatures.  Looking at the
matter scientifically, it occurred to me that, if I imitated them, I
might discover what it felt like to be a spaceman.

There is no doubt that one of the greatest attractions of skin diving
is the sense of freedom in three dimensions that it gives; when your
buoyancy is properly neutralized by lead weights, you can float without
any effort at any level.  If you push against a rock or kick off from
the seabed, you will drift slowly until the friction of the water
destroys your momentum.

Until the first manned satellite is established, this is the nearest we
shall know to the conditions that prevail inside a spaceship.  I soon
discovered, however, that the analogy was not 151  exact.  Though you
possess no weight when you are submerged, up and down still exist. Even
when the other senses fail, your eyes can give you all the orientation
you need.  Unless you are swimming after sunset, or in -very dirty
water, you can always tell the direction from which the light is
cQming.  It may be no more than a vague glow like the first hint of
dawn but it is an unmistakable signpost to the surface.

Well-almost unmistakable, for there are exceptions even to this rule. I
was once diving in a somewhat gloomy coral cave whose floor was covered
with light sand when I was surprised to see that most of the fish
around me were swimming upside down.  All the light came from below-and
they'd been fooled into thinking that this direction was up.

Men are, on the whole, more intelligent than fish, but here is a case
where what counts is instinct, not intelligence.  It would seem that as
long as the cabin of a space vehicle looked normally oriented to the
eye, the danger of vertigo would be greatly reduced, even in the
complete absence of gravity.  However, if chairs and tables were bolted
indiscriminately to all six walls, that would be asking for trouble.
Even the most hardened astronaut might soon feel unhappy unless there
was a general agreement that a certain direction would be up, and the
cabin was designed and used accordingly.  (One can picture the warning
notices: PLEASE DO NOT SIT ON THE

CEILING.) Once the eye had been satisfied, its signals would override
any messages from other sense organs which were frantically telling the
brain that gravity had ceased to exist.

It was Cousteatf who coined the phrase "Silent World" to describe the
sea, but the description is even more applicable to space.  There are a
few sounds underwater: porpoises squeak, whales groan, shrimps snap
their claws.  In the vacuum of space, however, no sounds can exist, for
there is nothing to transmit them.  The only noises that a space
traveler will normally hear are those created inside his ship-the
whirring of electric motors, the hiss of air pumps, the clank of metal
upon metal.  These sounds would echo round and 152  round the little
world of the ship and would form a continuous background which would be
noticed only when there was some change in it.  In the same way, an
Aqua-Lunger is seldom consciously aware of the bubbling of his exhaust
valve-but when it stops he reacts at once, even before he feels the
alteration in the airflow.

Very occasionally, a space traveler might hear a noise from the outer
world.  From time to time particles of meteor dust would hit the hull
with enough impact to make an audible sound; on still rarer occasions,
when the meteor was a really large one, that sound might be the last
thing that the voyager would ever hear.

In space there are no horizons; the questiDg eye reaches out forever,
in all directions, and finds no fixed point at which to rest.  For this
reason there is also no real sense of distance; in the absence of
perspective, it is impossible to judge the remoteness of the stars.
They could be pinpoints of light a few miies away, as indeed the
ancients thought they were.  The truth is so incredible that the
instinct rejects it, and a man midway between the planets might feel
that he could reach out and grasp the gleaming sparks around him.

This sense of floating in a void which is not infinite, but merely
indefinite, is one that can be captured in the sea under certain
conditions.  If you dive into deep water and head quickly downward, you
can lose all sight of the surface before there is any trace of the
bottom.  You will then be suspended in a completely featureless
blue-green void, and if there are no fish within your field of vision
is it quite impossible to judge how far you can see.  Visibility may be
a hundred feet yet you can delude yourself into thinking that you
cannot see more than a yard.

This is not a pleasant sensation, and more than once I have been glad
to reassure myself, simply by stretching out my hand and looking at my
fingers, that I could see farther than my nose.  Whether a similar
illusion will arise in space we will not know until we can get a few
million miles away from Earth; if it does, then the 153  ocean is one
place where we can prepare men to meet it.  Another lesson for space
which I have learned from the sea is that the human body is much
tougher and more adaptable than anyone could reasonably have expected.
Although- it is necessary, in a vehicle traveling beyond the
atmosphere, to provide complete protection against the vacuum of space
by the use of a pressure cabin, I, believe that the achievements of
today's skin divers have demonstrated that men could withstand even
exposure to airless space for appreciable periods of time-a fact which
might make all the difference between life and death in an emergency.

This statement will certainly astonish a good many people, especially
those who have read science-fiction stories containing gruesome
accounts of what happens to space travelers when their ship springs a
leak, or is punctured by a meteor.  Yet in either of these cases, it
would normally take several seconds for the air pressure to- drop to
zero, and a skin diver coming up quickly from a depth of only ten feet
experiences a greater pressure drop, in a far shorter time, than the
occupants of a spaceship would undergo if their vessel was suddenly
holed.

Skin diving has also shown what an extraordinarily long period of time
men can exist without breathing, if they have suitable training and
preparation.  The first time I went underwater, I stayed down all of
ten seconds.  But as I became more confident, and learned the tricks of
the trade, I was able to push my endurance up to three and a half
minutes; though this sounds impressive, it is nothing compared with the
record, which is now over thirteen minutes.

This has convinced me that trained men, given sufficient warning so
that they could prepare themselves, would be able to stand exposures of
a minute or so even to the vacuum of space.  Recently I had a chance of
arguing this point with Major David Simons, the only man who has so far
spent more than a day beyond the effective limits of the atmosphere.
(During his famous balloon ascent in 1957, he had more than 99 per cent
154  of the atmosphere below him, so that for most physiological
purposes he was out in space.) Major Simons was willing to grant me
fifteen seconds of consciousness on exposure to vacuum, but considered
that death would then follow swiftly because the brain would be
deprived of oxygen.

Well, fifteen seconds is a very long time in an emergency-long enough
to get into the next cabin and slam the airtight doors.  And I have a
hunch that the margin of safety may be better than fifteen seconds, for
the human body has so often surprised us in the past by its unexpected
powers of adaptation.  Not long ago, doctors proved conclusively that a
naked diver could not possibly descend a hundred feet without having
his lungs crushed by the pressure.  Yet the skin-diving record is now
140 feet without breathing gear, and there is evidence that some divers
have been down 200 feet-a depth at which the pressure on every square
foot of the body is over five tons.  Yes-the human frame can take a lot
of punishment if it has to, and there are occasions when a space pilot
may be tougher than his ship.

In the exploration of a new element, psychology is as important as
physiology.  From my own experience, I'm convinced that underwater
exploring inculcates the kind of mental outlook which we shall need in
space.  It may be summed up as a sense of alertness a realization that
almost anything can happen, and that when it does you've got to be
ready for it.  This is not a question of being nervous or apprehensive,
so much as being prepared, so that you react properly and don't panic.
In the sea, panic can be the deadliest of killers, and it needs so
little to bring it on-a strange movement glimpsed out of the corner of
the eye, a slight malfunctioning of equipment, a shadow crossing the
seabed when you know there are no clouds in the sky, a sound in a world
which is normally silent.  And, above all, an unexpected, purposeful
contact when you think you are floating alone in mid-ocean.... There is
a test that the Australian Navy used on its frogmen to separate, not
the men from the boys, but the men from the supermen.  (Readers prone
to night155  mares had better skip the next two paragraphs.) It
consisted of sending a trainee down into the water, at night, with his
face mask blacked out so that he was totally blind.  A second diver
with a sealed-beam searchlight would be in the neighborhood to keep an
eye on the victim, who had been instructed to swim back to the surface.
This is not difficult, even when you cannot see your way, because it is
a simple matter to increase buoyancy and thus go up like a balloon. In
this case, however, there was a fiendish complication of which the
victim was unaware.

He had been released in the middle of an underwater jungle-a dense
forest of kelp.  The thin fronds, scores of yards long, formed a
close-packed wall around him, and the current carried him steadily
toward it.  Without the slightest warning, he would hit this floating
barrier-and at once the tons of unstable vegetation would collapse,
engulfing him (in utter darkness, remember) beneath an animated
avalanche of twining tendrils.  By the time he had been dug out of this
and brought back to the surface, his instructors would know if he'd
made the grade.

Anyone who could pass a test like this would be a useful man to have
around in one of those typical space emergencies where the atomic pile
is about to go out of control, the captain is down with the D.T."s, the
last of the oxygen is leaking through a meteor puncture, and the Thing
has broken loose from its cage in the hold.

Talking of Things leads us to another, and some what speculative, link
between sea and space.  Sooner or later, during our exploration of the
Universe, we are going to encounter utterly alien forms of life.  It
does not se em likely that we will meet them on the Moon when we get
there in the 1970's, but the first contact may occur on Mars a decade
or so later.

There is absolutely no way of guessing what shape extraterrestrial life
forms may take; even if we had perfect knowledge of conditions on Mars
and

Venus (the only planets where protoplasmic life could exist), we would
be no nearer to picturing the creatures, that might live there.  If
anyone doubts this, let him ask him156  self if he could have
predicted the elephant, the duck billed platypus, the giraffe, or Homo
sapiens from a geophysical survey of the planet Earth.

Until we reach them-or they reach us-we shall remain in complete
ignorance about the creatures which may exist on other planets. Perhaps
we may find no more than a few lichens on Mars; perhaps our first
encounter with extraterrestrial animals or intelligences may still lie
centuries in the future.  Yet even now, by sinking down into the sea,
we can capture many of the sensations our descendants will know when
they set foot upon other planets.  Certainly nothing that they will
ever meet there can be more fantastic than some of the creatures which
inhabit the waters of this world.

This is another reason why underwater exploring is, psychologically, a
good preparation for Man's adventure in space-and why, incidentally, it
can be a good corrective to the psychotic horror movies which depict
all extraterrestrial beings as hideous monsters bent on destruction.
Monsters do not exist in Nature, but only in men's minds.  I learned
this lesson the first time I met a giant manta ray, and I have never
forgotten it.

Sometimes known as the devilfish, because of its grotesque batlike
shape and the two horns or pal ps extending on either side of its
mouth, the manta is one of the weirdest looking beasts in the sea. 
When, long before I had dreamed of doing any underwater exploring
myself, I saw some of Hans Haas' photos of this strange creature (which
can grow up to thirty feet across) I thought I had never seen anything
so hideous; its head reminded me strongly of the gargoyles on

Notre Dame.  Yet five years later, when I encountered one of the great
beasts peacefully browsing over a coral reef off the Queensland coast,
that initial feeling of repulsion vanished completely.  Here, it was
true, was something strange and beyond ordinary experience, but it was
no longer hideous-it was not even alien.  Its fitness of purpose and
the grace of its movements as it flapped along the reef, keeping a wary
eye on the human invaders of its territory, left little room in my mind
for anything except admiration~ and a furious rage against those
fishermen (above or below the water) who sometimes spear these huge,
harmlesg beasts for their amusement.

To most people, perhaps the most ghastly inhabitant of the sea-the
ultimate in creeping, malevolent horror -is the octopus.  The very
thought of contact with its slimy, sucker-studded tentacles is enough
to make them feel physically sick, yet once again this is a reaction
founded on ignorance or inspired by stories put out by divers who want
to make their job sound even more dangerous than it is.  I would not go
so far as to say that the octopus is a friendly, at1ractive beast which
no home should be without, but I would claim that almost all one's
original revulsion vanishes when one gets to know this talented
mollusk.  In real life, and not when seen frozen in menace by an
imaginative illustrator, the octopus is quite fascinating to watch as
it jets across the seabed or slithers briskly from rock to rock, only
too anxious to keep out of your way.  And its rapid color changes, when
it is excited or nervous, are really beautiful.

These examples should be sufficient to prove my point-that there is
nothing in the natural world, however strange it may be, that one
cannot grow accustomed to.  Albert Schweitzer must have had this in
mind when he formulated his doctrine of "reverence for life"; it is a
creed that a man of sensitivity can learn in the sea as nowhere
else-and it is one which mankind must master before it makes contact
with other intelligent races in the Universe.  I have never been
convinced that intelligence comes only in one model-and that that model
has two legs, two arms, two eyes and one mouth.

Someday we may encounter representatives of far higher civilizations
than ours, who may differ from us as greatly as we differ from the
manta or the octopus..  And as we have had to overcome color prejudice,
so our descendants may have to overcome a much more fundamental shape
prejudice.

The time may come when no well-bred person would dream of remarking
that the ambassador from Riger looks like a cross between a jellyfish
and a tarantula (even if he does) or is particularly upset because the
members of the Sirian trade del gation have not only three heads but
also four sexes.

Fantasy?  Of course; the reality of our Universe is fantastic.  We live
in an age when we can keep up with tomorrow---or even today-only by
letting our imaginations free wheel anywhere they care to travel, as
long as they keep within the bounds of logic and the known laws of
Nature.

Yet if we hope to reach the stars, we shall need more than imagination,
more than scientific skill.  These alone would be useless without the
spirit of adventure which conquered our own world in the days when much
of this

Earth was as mysterious and remote as the planets seem today..

That spirit is not lacking; along all the coasts of the world, boys
(and girls) barely in their teens are setting off on subaqueous
journeys which would have seemed utterly incredible to their
grandparents, and which must often terrify their parents.  Among those
youthful skin divers, the men who will make up the space crews of
tomorrow are already learning courage, judgment, selfconfidence and
those less definable qualities needed by all great explorers.

I began this apologia on a personal note; I would like to end it on
one.

The parallels between sea and space are sufficiently clear, and there
is no need to say any more to prove that underwater exploration has a
perfectly logical tie-in with astonautics.  Yet logic is never enough;
it was Bertrand

Russell-somewhat surprisingly-who remarked that the purpose of reason
is to give us excuses for doing the things we want to.

In the final analysis, I went undersea because I liked it there,
because it opened up to me a new, strange world as fantastic and
magical as the one which Alice discovered behind the looking glass. And
perhaps I did it because, after hearing people call me a space travel
expert for twenty years, I felt I was getting into a rut. As Hollywood
stars know very well, it is fatal to become typed; if you want to
progress, to continue your mental and emotional growth, every so often
you 159  must surprise yourself (and your friends) by changing the
pattern of your life and interests.

Once you are neatly classified and pigeonholed, incapable of any
further development, your life is over.  You might as well be a stuffed
specimen in a museum, completely described by the label tied to your
ankle.  When there's nothing more to say about you, you're already
dead.

I feel very happy to have avoided that fate, but there's one problem
that sometimes worries me.  What new track do I switch to in 19752
Report on Planet Three

(THE FOLLOWING DOCUMENT, WIHCH HAS JUST BEEN deciphered for the

Interplanetary Archaeological Commission, is one of the most remarkable
that has yet been discovered on Mars, and throws a vivid light upon the
scientific knowledge and mental processes of our vanished neighbors. It
dates from the Late Uranium [i.e. final] Age of the Martian
civilization, and thus was written little more than a thousand years
before the birth of

Christ.

The translation is believed to be reasonably accurate, though a few
conjectural passages have been indicated.  Where necessary, Martian
terms and units have been converted into their terrestrial equivalents
for ease of understanding.-Translator.)

The recent close approach of the planet Earth has once again revived
speculations about the possibility of life upon our nearest neighbor in
space.  This is a question which has been debated for centuries,
without conclusive results.  In the last few years, however, the
development of new astronomical instruments has given us much more
accurate information about the other planets.  Though we cannot yet
confirm or deny the existence of terrestrial life, we now have much
more precise knowledge of conditions on

Earth, and can base our discussions on a firm scientific foundation.
One of the most tantalizing things about Earth is that 161  we cannot
see it when it is closest, since it is then between us and the Sun and
its dark side is therefore turned toward us.  We have to wait until it
is a morning or evening star, and thus a hundred million or more miles
away from us, before we can see much of its illuminated surface.  In
the telescope, it then appears as a brilliant crescent, with its single
giant

Moon hanging beside it.  The contrast in color between the two bodies
is striking; the Moon is a pure silvery-white, but the Earth is a
sickly blue-green.  [The exact force of the adjective is uncertain; it
is definitely unflattering.  "Hideous" and "virulent" have been
suggested as alternatives.  -Translator.)

As the Earth turns on its axis-its day is just half an hour shorter
than ours-different areas of the planet swing out of darkness and
appear on the illuminated crescent.  By carrying out observations over
a period of weeks, it is possible to construct maps of the entire
surface, and these have revealed the astonishing fact that more than
two-thirds of the planet Earth is covered with liquid.

Despite the violent controversy which has raged over this matter for
some centuries, there is no longer any reasonable doubt that this
liquid is water.  Rare though water now is upon Mars, we have good
evidence that in the remote past much of our planet was submerged
beneath vast quantities of this peculiar compound; it appears,
therefore, that Earth is in a state corresponding to our own world
several billion years ago.  We have no way of telling how deep the
terrestrial oceans" to give them their scientific name-may be, but some
astronomers have suggested that they are as much as a thousand feet in
thickness.

The planet also has a very much more abundant atmosphere than ours;
calculations indicate that it is at least ten times as dense.  Until
quite recently, we had no way of guessing the composition of that
atmosphere, but the spectroscope has now solved this problem with
surprising results.  The thick gaseous envelope surrounding the Earth
contains large amounts of the poisonous and very reactive element
oxygen, of which scarcely a trace exists in our own air.  Earth's
atmo~ sphere also holds considerable quantities of nitrogen and water
vapor, which forms huge clouds, often persisting for many days and
obscuring large areas of the planet.

Being some 25 per cent nearer the Sun than Mars, Earth is at a
considerably higher temperature than our world.  Readings taken by
thermocouples attached to our largest telescopes reveal intolerable
temperatures on its Equator; at higher latitudes, however, conditions
are much less extreme and the presence of extensive icecaps at both
poles indicates that temperatures there are often quite comfortable.
These polar icecaps never melt completely, as do ours during the
summer, so they must be of immense thickness.

As Earth is a much larger planet than Mars (having twice our diameter),
its gravity is a good deal more powerful.  It is, indeed, no less than
three times as great, so that a 170-pound man would weigh a quarter of
a ton on

Earth.  This high gravity must have many important consequences, not
all of which we can foresee.  It would rule out any large forms of
life, since they would be crushed under their own weight.  It is
something of a paradox, however, that Earth possesses mountains far
higher than any that exist on

Mars; this is probably another proof that it is a young and primitive
planet, whose original surface features have not yet eroded away.

Looking at these well-established facts, we can now weigh the prospects
for life on Earth.  It must be said at once that they appear extremely
poor; however, let us be open-minded and prepared to accept even the,
most unlikely possibilities, as long as they do not conflict with
scientific laws.

The first great objection to terrestrial life-which many experts
consider conclusive-is the intensely poisonous atmosphere.  The
presence of such large quantities of gaseous oxygen poses a major
scientific problem, which we are still far from solving.  Oxygen is so
reactive that it cannot normally exist in the free state; on our own
planet, for example, it is combined with iron to form the beautiful
red deserts that cover so much of the world.

It is the absence of these areas which gives Earth its unpleasant
greenish hue.

Some unknown process must be taking place on Earth which liberates
immense quantities of this gas.  Certain speculative writers have
suggested that terrestrial life forms may actually release oxygen
during the course of their metabolism.  Before we dismiss this idea as
being too fanciful, it is worth noting that several primitive and now
extinct forms of Martian vegetation did precisely this.  Nevertheless,
it is very hard to believe that plants of this type can exist on Earth
in the inconceivably vast quantities which would be needed to provide
so much free oxygen.  [We know better, of course.  All the Earth's
oxygen is a by-product of vegetation; our planet's original atmosphere,
like that of Mars today, was oxygen-free.-Translator.]

Even if we assume that creatures exist on Earth which can survive in so
poisonous and chemically reactive an atmosphere, the presence of these
immense amounts of oxygen has two other effects.  The first is rather
subtle, and has only recently been discovered by a brilliant piece of
theoretical research, now fully confirmed by observations.

It appears that at a great altitude in Earth's atmosphere-some twenty
or thirty miles-the oxygen forms a gas known as ozone, containing three
atoms of oxygen as compared with the normal molecule's two.  This gas,
though it exists in very small quantities so far from the ground, has
an overwhelmingly important effect upon terrestrial conditions.  It
almost completely blocks the ultraviolet rays of the Sun, preventing
them from reaching the surface of the planet.

This fact alone would make it impossible for the life forms we know to
exist on Earth.  The Sun's ultraviolet radiation, which reaches the
surface of Mars almost unhindered, is essential to our well-being and
provides our bodies with much of their energy.  Even if we could
withstand the corrosive atmosphere of Earth, we should soon perish
owing to this lack of vital radiation.  The second result of the high
oxygen concentration is even more catastrophic.  It involves a
terrifying phenomenon, fortunately known only in the laboratory, which
scientists have christened "fire."

Many ordinary substances, when immersed in an atmosphere like that of

Earth's and heated to quite modest temperatures, begin a violent and
continuous chemical reaction which does not cease until they are
completely consumed.  During the process, intolerable quantities of
heat and light are generated, together with clouds of noxious gases.
Those who have witnessed this phenomenon under controlled laboratory
conditions describe it as quite awe-inspiring; it is certainly
fortunate for us that it can never occur on

Mars.

Yet it must be quite common on Earth-and no possible form of life could
exist in its presence.  Observations of the night side of Earth have
often revealed bright glowing areas where fire is raging; though some
students of the planet have tried, optimistically, to explain these
glows as the lights of cities, this theory must be rejected.  The
glowing regions are much too variable; with few exceptions, they are
quite short-lived, and they are not fixed in location.  [These
observations were doubtless due to forest fires and volcanoes-the
latter unknown on Mars.  It is a tragic irony of fate that had the
Martian astronomers survived a few more thousand years, they would have
seen the lights of Man's cities.  We missed each other in time by less
than a millionth of the age of our planets.-Translator.]

Its dense, moisture-laden atmosphere, high gravity and closeness to the
Sun make Earth a world of violent climatic extremes.  Storms of
unimaginable intensity have been observed raging over vast areas of the
planet, some of them accompanied by spectacular electrical
disturbances, easily detected by sensitive radio receivers here on
Mars.  It is hard to believe that any form of life could withstand
these natural convulsions, from which the planet is seldom completely
free.

Although the range of temperatures between the terrestrial winter and
summer is not so great as on our world, this is slight compensation for
other handicaps.  On Mars, all mobile life forms can easily escape the
winter by migration.

There are no mountains or seas to bar the way; the small size of our
world-as compared with Earth-and the greater length of the year make,
such seasonable movements a simple matter, requiring an average speed
of only some ten miles a day.  There is no need for us to endure the
winter, and few

Martian creatures do so.

It must be quite otherwise on Earth.  The sheer size of the planet,
coupled with the shortness of the year (which only lasts about six of
our months), means that any terrestrial beings would have to migrate at
a speed of about fifty miles a day in order to escape from the rigors
of winter.  Even if such a rate could be achieved (and the powerful
gravity makes this appear most unlikely) mountains and oceans would
create insuperable barriers.

Some writers of "science fiction" have tried to get over this
difficulty by suggesting that life forms capable of aerial locomotion
may have evolved on

Earth.  In support of this rather farfetched idea they argue that the
dense atmosphere would make flying relatively easy; however, they gloss
over the fact that the high gravity would have just the reverse effect.
The conception of flying animals, though a charming one, is not taken
seriously by any competent biologist.

More firmly based, however, is the theory that if any terrestrial
animals exist, they will be found in the extensive oceans which cover
so much of the planet.  It is believed that life on our own world
originally evolved in the ancient Martian seas, so there is nothing at
all fantastic about this idea.  In the oceans, moreover, the animals of
Earth would no longer have to fight the fierce gravity of their planet.
Strange though it is for us to imagine creatures which could live in
water, it would seem that the seas of

Earth may provide a less hostile environment than the land.

Quite recently, this interesting idea has received a setback through
the work of the mathematical physicists.  Earth, as is well known, has
a single enormous Moon, which must be one of the most conspicuous 166
objects in its sky.  It is some two hundred times the diameter of even
the larger of our two satellites, and though it is at a much greater
distance its attraction must produce powerful effects on the planet
beneath it.  In particular, what are known as "tidal forces" must cause
great movements in the waters of the terrestrial oceans, making them
rise and fall through distances of mapy feet.  As a result, all
low-lying areas of Earth 'must be subjected to twice-daily flooding; in
such conditions, it is difficult to believe that any creatures could
exist either in land or sea, since the two would be constantly
interchanging.

To sum up, therefore, it appears that our neighbor Earth is a
forbidding world of raw, violent energies, certainly quite unfitted for
any type of life which now exists on Mars.  That some form of
vegetation may flourish beneath that rain-burdened, storm-tossed
atmosphere is quite possible; indeed, many astronomers claim to have
detected color changes in certain areas which they attribute to the
seasonal growth of plants.

As for animals-this is pure speculation, all the evidence being against
them.  If they exist at all, they must be extremely powerful and
massively built to resist the high gravity, probably possessing many
pairs of legs and capable only of slow movement.  Their clumsy bodies
must be covered with thick layers of protective armor to shield them
from the many dangers they must face, such as storms, fire and the
corrosive atmosphere.  In view of these facts, the question of
intelligent life on Earth must be regarded as settled.  We must resign
ourselves to the idea that we are the only rational beings in the Solar
System.

For those romantics who still hope for a more optimistic answer, it may
not be long before Planet Three reveals its last secrets to us. Current
work on rocket propulsion has shown that it is quite possible to build
a space craft which can escape from Mars and head across the cosmic
gulf toward our mysterious neighbor.  Though its powerful gravity would
preclude a landing (except by radio-controlled robot vehicles) we could
orbit Earth at a low altitude and thus observe every 167  detail of
its surface from little more than a millionth of our present
distance.

Now that we have at last released the limitless energy of the atomic
nucleus, we may soon use this tremendous new power to escape the bonds
of our native world.  Earth and its giant satellite will be merely the
first celestial bodies our future explorers will survey.  Beyond them
lie .. . [Unfortunately, the manuscript ends here.  The remainder has
been charred beyond decipherment, apparently by the thermonuclear blast
that destroyed the Imperial Library, together with the rest of Oasis
City.  It is a curious coincidence that the missiles which ended
Martian civilization were launched at a classic moment in human
history.  Forty million miles away, with slightly less advanced
weapons, the Greeks were storming Troy.  -Translator.]

 Question Time

WHEN I STARTED LECTURING IN THE UNITED STATES I solemnly vowed that
here, for a change, would be one visiting Englishman who would not
write a book about his attempts to bring culture and learning to
darkest America.  That promise still stands, if only for the reason
that after a hundred appearances in every part of the country I can't
always remember where I've been.  (Indeed, not long ago I flatly denied
ever visiting one large city in which I'd lectured just three weeks
before.) But like the young lady who shrugged off an inexplicable baby
on the grounds that, after all, it was only a very small one, I hope I
can be permitted this brief relapse.

It is more than twenty years, I am somewhat horrified to discover,
since I began lecturing on space flight.  In my 1958 season, thanks to
the unexpected co-operation of the Kremlin, I started my tour not
merely one up but two up on my audiences.  Both Sputniks were circling
Earth when I delivered my first talk on satellites; gone forever,
consequently, was the opinionated little man in the front row who was
quite sure that space travel was impossible-because no one had ever
done it before.  Sometimes I miss him; it used to be more fun when
there was at least one person in the audience who thought I was crazy,
and didn't hesitate to say so.  The organizations I've addressed
during my tours cover almost the entire spectrum of American life
-universities, women's clubs, businessmen's associations"

YMCA's, synagogues, public libraries.  The qualifying "almost" is
inserted because there is one type of audience I have not so far met.
I'm still awaiting an invitation from the warden of Sing Sing to
address his charges; but perhaps the subject of space flight is
considered too escapist.  I

Such varying audiences naturally react in very different ways to the
prospect of being shot out into the cosmic void.  My younger hearers,
not surprisingly, are the more enthusiastic; older groups manage to
restrain their enthusiasm and often regard the coming Age of Space as
something to be endured rather than enjoyed.

The first platform peril which every speaker has to face is, of course,
the chairman, whose introduction can all too often be the kiss of
death.  (As per the fine example quoted, in its entirety, by Stephen
Potter: "It's often said that Englishmen have no sense of humor.  Just
wait until you have heard Mr.  Potter.") On the whole I have been
fortunate; at least I have never yet been introduced as someone else.
But several times the.  chairman has got my name partly wrong; on one
occasion I was introduced to a surprised audience as "Mr.  Adam
Clarke," and spent the first ten minutes of my lecture in a somewhat
distracted mood, wondering whose Freudian slip was showing.

Though audience reactions vary greatly, the questions I am asked after
the lecture do not.  I can usually tell, before my interrogator has
spoken more than a dozen words, just what problem is worrying him, and
automatically switch the appropriate sound track into place.  There are
times when I have grown so tired of such hoary old faithfuls as "What
about meteors?"  "Are cosmic rays dangerous?"  that I've felt like
giving a prize to anyone who can think of a new question about space
flight.  For a really good one, I might even waive my lecture fee.
[Important!  Mr.  Clarke is, of course, only joking-W.  Colston Leigh,
Inc.] The problem which still seems to worry many people, 170  is the
one which is basic to the whole conception of space flight.  How, they
often ask, can a rocket work out there in the vacuum of space, where
there is nothing for it to push against?

After trying various answers over the past couple of decades, I've
finally settled on this one, which has the merit (unlike many
scientific "explanations") of not being simplified to the point of
inaccuracy.  It's quite correct, I start by admitting, that any
propulsive device has to have something to push on.  A ship pushes on
the sea, an automobile pushes on the land.  If you were out in space,
surrounded by light-years of nothingness, you could not move an inch
without having some material substance to thrust against.  You have,
therefore, to carry such a substance with you.

It could be any material whatsoever; one day it may be something as
cheap and simple as water.  At the moment, however, it happens to be
the rocket fuel itself -the scores or hundreds of tons of liquids which
comprise more than 90 percent of the mass of any space vehicle.  This
is what the rocket pushes against; the tremendously violent combustion
(someone once described a rocket launching as a "controlled
catastrophe") blasts the heavy fuel in one direction, and the much
lighter vehicle therefore builds up an even greater speed in the
other.

The emptiness of space-a conception which appears to be universally
appreciated, even though its implications are not always
understood-sometimes prompts another query, from those who do not grasp
the fundamental difference between radio and sound waves.  Since sound
cannot pass through a vacuum, I am occasionally asked how it is
possible for a spaceship to communicate with Earth.

Perhaps the best answer to this question is given by the Sun.  The rays
bringing its light and heat to us differ from radio waves only by being
very much shorter, and they reach us without difficulty across
93,000,000 miles of empty space.  The recent development of radio
astronomy (that is, the observation of the heavenly bodies by means of
the radio waves they emit) has given an even clearer proof that radio
can span not merely interplanetary but interstellar gulfs.  Indeed, it
now appears that our radio telescopes can see further into space than
our optical ones, for the waves they operate with are less easily
absorbed in the great dust and gas clouds-the debris of creation which
swirl between the stars.  For as long as we can foresee, men will be
able to send their messages far ahead of their ships.  the two
questions I have just repeated have this in common: they are quite
sensible ones, but they could not have been asked by anyone with even
an elementary understanding of science.  The principle of action and
reaction was enunciated by Newton three hundred years ago; the fact
that radio waves could pass through a vacuum was understood even before
Hertz first produced them in 1888.  At the risk of laboring a point
which has been somewhat heavily plugged since S-day burst bleeping upon
the world, we have now reached the stage when some knowledge of basic
science is as necessary for everyday life as the ability to read and
write.  The commonly heard cry, "We need more scientists!"  is an
oversimplification, and perhaps a dangerous one.  What we really need
are more educated men-and in the future anyone who is totally ignorant
of science is, frankly, uneducated.  And if, like some people today, he
boasts about his ignorance, he will be in precisely the same position
as those illiterate medieval barons who proudly claimed that figuring
and copying were jobs they left to their clerks.

It by no means follows, however, that people who, have never had a
formal scientific education cannot hope to understand how satellites
and spaceships work.  Astronautics is based on familiar physical
principles; the behavior of rockets and space vehicles can be related
in a direct and simple fashion to the movements of objects in everyday
life.  They don't defy common sense in the lighthearted manner of
neutrinos, mesons, electrons and the other particles of the subatomic
world.

If s an interesting challenge to the lecturer to put across the basic
principles of space flight to an entirely 172  nontechnical audience,
and a matter of great satisfaction to watch the dawning comprehension
on the faces of people who were convinced that they couldn't understand
what it was all about.  (Not that I can always claim to have succeeded;
at least twice I've been deflated by: "Thank you for such a fascinating
talk, Mr.  Clarke.  Of course, it was right over my head.") -The most
interesting and stimulating questions I am asked by my audiences are
not, however, scientific or technical ones.  They concern matters of
philosophy, politics and religion, and often reveal very clearly the
climate of opinion on the subject of space travel.  It is hardly
surprising that from October 4, 1957, until the first American
satellite was launched on February 1, 1958, one of the commonest
questions was an anguished, "Why didn't we do it first?"

I don't want to get involved here with the answers, to that cri de
coeur, and will make a swift detour round it to deal with a closely
allied subject.  Whenever the comparison between U.S. and Russian
rocketry comes up, someone will inevitably bring up the argument that
the Russians received great (perhaps decisive) help from German rocket
scientists.  This pathetic apology still dies hard; I find it
particularly exasperating because it is based not upon ignorance (which
can be excused) but upon stupidity (which cannot).

One would have thought that even before Dr.  Wernher von Braun's team
launched Explorer I most people who read the newspapers would have
known that the leading German rocket experts had come to the United
States, which should have given this country a decided advantage over
the Russians.  And in fact the Russians never obtained more than a very
small handful of top rocket scientists, all of whom have now returned
to Germany and none of whom had any direct part in the Sputnik program.
The Russians, like everyone else, learned all that they could from
wartime German research; thereafter their own very competent scientists
did the rest.  The fact that they achieved so much without the German
talent available (and, some would argue, frustrated) in the United
States makes their accomptishments all the more remarkable.

It is an interesting-and possibly significant-fact that nowhere have I
come across any religious opposition to the idea of space travel.  To
one questioner who asked me, "Does space flight agree with God's plan
for Man?"

I had to confess that I was not privy to the details of this
fascinating thesis.  I could merely point out that there seemed no
fundamental difference between exploring the Universe and exploring the
Earth.  No doubt there were people in the past who believed it was
impious to discover new lands, on the grounds that what was good enough
for their grandfathers, etc.  But I could not imagine any citizen of so
recently settled a country as the United States supporting this
argument; if he believed in it, he had no right to be alive.

As far as Catholics are concerned this matter is presumably settled.
Pope

Pius XII, in the course of a brilliant address to the 1956
International

Astronautical Congress in Rome, made the point that now that Man has
discovered the means of getting into space, he would be failing to
fulfill his God-given potentialities if he did not do so.  It is hard
to believe that anyone, whatever his religious faith, can seriously
disagree with this argument.

At the same time, is is quite clear that many people realize-if only
subconsciously-that space travel is going to give the human race some
considerable shocks in the psyche.  It will complete the process of
shrinking the Earth to insignificance-a process which has been under
way since the invention of the telescope and the rise of modern
astronomy.  But until today, appreciation of our planet's place in the
hierarchy of the

Universe has been purely intellectual, not emotional.  I well remember
the slightly stunned reaction of a Dallas audience to a rocket photo
showing the whole of Texas; this will be nothing to the feelings of all
mankind when, through space-borne TV eyes, it watches the entire Earth
dwindle among the stars-and at last looks for it in vain.  That this
immense revolution in thought and outlook will be upon us in little
more than a decade-certainly no more than a generation-was the main
theme of my talks.  We are living, I told audiences from New Hampshire
to

New Mexico, in a moment unique in all history-the last days of Man's
existence as a citizen of a single planet.  What is happening now is
nothing less than the next stage in evolution, comparable to the time,
perhaps a billion years ago, when life came out of the sea and
conquered the land.

This was an analogy which I used even in Tennessee, conscious enough
though

I was there of the disapproving ghost of William Jennings Bryan.

Unfortunately I did not know at the time that this idea had been most
beautifully expressed half a century ago by Tsiolkovsky, the great
Russian pioneer of astronautics: "The Earth is the cradle of
Mankind-but you cannot live in a cradle forever."

That so many of my listeners accepted this challenge with zest I found
very encouraging.  Indeed, not a few were somewhat upset because I
limited my modest speculations to the other eight planets of this sun.
The thought of being confined to the Solar System-a mere 7,400,000,000
miles in diameter-appeared to give them acute claustrophobia and they
wanted to know what hope there was of reaching the planetary systems of
other stars-and, in particular, of exceeding the speed of light so that
such journeys could be carried out in a reasonable length of time.  My
reply to this question (which cropped up in about 50 per cent of my
lectures) was that it appeared virtually certain that neither we nor
anything else could ever travel faster than light-but that this doesn't
rule out interstellar exploration.

It will merely make it time-consuming.

One of the most difficult problems which any lecturer on astronautics
has to face is that of giving good advice to eager youngsters anxious
to build and shoot rockets.  It is necessary to tell them-disappointing
though it may be-that under no circumstances should they set up private
proving grounds.  Such activities can be fatal as well as illegal. 
Studying hard to earn a degree in engineering or physics is rather less
glamorous, than producing spectacular explosions or launching reluctant
mice into the empyrean, but in the long run it gets you much further. 
The first man to step out upon the surface of the Moon will have a
master's degree in at least one science.

This fact is certainly not realized by the thousands of hopefuls who
have--more or less seriously-volunteered for flights into space.  At
the

Army Ballistic Missiles Agency, Huntsville, Alabama, where the
Redstone,

Jupiter C and Jupiter rockets were built, I was told that such
applications frequently conclude with the P.S.: "Please do not let my
wife know I have written to you."  The general who passed this
top-secret piece of information on to me also gave some other news
which I consider an even more significant sign of the times.
Volunteering for space travel seemed safe enough a few years ago-but
now quite a few people are writing in, with every sign of anxiety, to
withdraw their earlier applications..  ..

One frankly disturbing feature of my question periods, was the interest
still shown in flying saucers.  I had been optimistic enough to suppose
that this subject had now died a natural death; yet it cropped up at
almost every session.  Since dealing adequately with Unidentified
Flying Objects would have required an entire lecture in itself, I
usually confined myself to describing some of the half dozen I've seen,
and then giving their ridiculously simple explanations My pleas for
sanity and skepticism in this matter, however, were often not well
received by the devotees of this new religion.  On one occasion a lady
from the audience asked me if I believed that those who claimed to have
met men from flying saucers were liars.  She sat down rather abruptly
when I replied, "Yes, madam"; not until a little later did the chairman
gleefully inform me that her husband had authored one of the best known
of the sacred writings.

Lecturing is not a one-way process; a good audience gives as well as
takes, and often a remark will come,

See "Things in the Sky" (page 179).  from the floor which may throw a
completely new light upon some idea which the speaker thought he had
fully examined.  This is an unexpected and welcome bonus to be added to
the satisfaction of establishing rapport with a body of interested
listeners.  The last time this happened to me I had been describing how
future generations would first explore the planets and then shape them
with the tools of nuclear power so that they would become homes for
civilizations as unimagined today as the United States would have been
to the men of the Middle Ages.  The picture I had painted of our
descendants spreading out from their parent world clearly made a deep
impression on one young lady in my audience, for during the question
period she rose to ask if

I thought that Earth would ever become a kind of ghost town..  ..
Somehow this remark has haunted me ever since-perhaps because I have a
feeling that one day it may come perfectly true.

Quite a different-though in its way equally memorable-reaction was
provoked in a New England college by the remark with which I usually
conclude my addresses to younger audiences.  After giving them a
provisional timetable for the rate of interplanetary exploration, I try
to bring home to them what it will mean by this prophecy: "Many of you
here in this room may have grandchildren who will not be born on
Earth."

This exit line usually produces the desired impact, but in at least one
case it failed completely.  One young aristocrat in the audience was
heard to remark to his neighbor, with Olympian self-assurance, "My
grandchildren will be born in Boston."

This, needless to say, is not a typical response to the challenge of
the future; I would soon have to shut up shop if it were-and so, for
that matter, would the

United States.  I am sure that it is more than counter balanced by The
positive reactions of those forward looking youngsters upon whom all
our tomorrows depend  Sometimes one can recognize them, but those I
should really like to meet I shall probably never know, even though
they may have sat in the front row (and probably did).

By this time I must have lectured to some tens of thousands of
teenagers and the laws of chance make it virtually certain that many of
them will play important roles in the conquest of space.  More than a
few will one day walk upon the dusty surface of the Moon, or later
still hear the whistle of the thin Martian atmosphere building up
outside the walls of their descending ship.  And sometimes I wonder how
many times my words may have started men along paths that, twenty or
thirty years from now, will lead them to strange and lonely deaths, far
from their native world.

For the freedom of the Universe is the greatest prize which human hands
have ever reached out to grasp; and like all prizes, money alone is not
enough to purchase it.  Perhaps it is well that I cannot see the
futures of those young explorers I unknowingly meet, and must scan
their eager faces as vainly as did the poet at Ludlow Fair.  Like those
Shropshire Lads of a vanished century, many will never grow old, but
will "carry back bright to the coiner the mintage of Man."  They are
the ones who will pay the price for the conquest of space-the price
that will be remembered when the billions of dollars and rubles are
meaningless entries in dusty ledgers.  Things in the Sky

DURING A RECENT LECTURE TOUR OF THE UNITED States I was astonished (and
disturbed) by the continuing extreme interest in "flying saucers."  I
had been optimistic enough to assume that everyone was as bored with
them as I was-but no; they cropped up in at least 50 per cent of the
question periods.

And although enthusiasm for aerial crockery rises to a sharp peak in
the region of California, it is still rampant on both sides of the
Atlantic.

Indeed, on my last transit through England I recklessly jeopardized my
place on future Honours Lists by getting into a brisk argument on the
subject with

Royalty.

The reason why I don't believe in flying saucers (few of which are
saucer-shaped, anyway) is that I've seen far too many.  And so will any
person of normal eyesight during the course of a few years, if he
bothers to look at the sky at all.

Perhaps I had better amplify that statement, and it might also be a
good idea to replace the emotion laden term "flying saucer" with the
less controversial one, "unidentified flying object" (U.F.O.). The
point I wish to make is that the sky contains an almost endless variety
of peculiar sights and objects, only a few of which any one person is
ever likely to encounter in a lifetime.  Yet any averagely observant
person is bound to see some of them, and not knowing their 179
explanation may be misled into thinking he's seen something
incredible-instead of merely unfamiliar.

Let me give an example which may seem a little farfetched, but which
makes my point perfectly.  Suppose you are completely ignorant of
meteorological phenomena, and live in a country where it never rains.
Then one day you step out of doors-and there is a huge semicircular
arch spanning half the sky.  It is so geometrically perfect that you
feel it must be artificial, yet it is obviously miles across, and it is
beautifully colored in reds, blues, yellows, greens.

Well, if you had never seen one before, what would you make of a
rainbow?

It no longer creates the slightest surprise, because it is so familiar;
and we, unlike our ancestors, have no need to invent supernatural
explanations for it.  Reason has told us what it is, and there would be
many fewer

UFOs around today if reason-or even common sense-was in better
supply..

To demonstrate this, I'll describe some of the odd sights I've seen in
the heavens, all of them during daylight and under conditions of good
visibility.  The first was over London on a bright Sunday afternoon,
more than twenty years ago.  It must have been a Sunday, for that was
the only time I had for long walks through the city.

Somewhere north of Oxford Street, I came across a group of people
staring at the sky.  Following their gaze, I was surprised to see two
tiny black dots or disks, very close together, at a great but quite
unguessable height above the city.  Balloons?  I asked myself.  No-they
don't travel in pairs.

And these dots were motionless, despite the fact that a strong wind was
blowing.  I, looked at them for a long time without being able to
resolve the mystery; then, having nothing better to do, I started to
walk in the general direction of the zoo, above which the objects were
floating.  (This, by the way, is what the detective-story writers call
a Misleading Clue; the

London Zoological Gardens had nothing to do with the matter.)

Before you read any further, I would like you to make a determined
attempt at explaining this incident.  And when I give the simple
answer, please don't say in disgust, "Is that all there was to it?"
Remember Sherlock Holmes' sour remark to Dr.  Watson, when that paragon
of unsocialized medicine commented on the obviousness of some mystery
which Holmes had just solved.  Not being a member of the Baker Street

Irregulars, I can't quote chapter and verse, but the reprimand ran
somewhat in this fashion: "It's always obvious to you, Watson, after
I've explained it."

Well, the twin disks floating high above London turned out to be not
two objects, but one-a box kite at an altitude which must have been at
least a mile.  It was so high that its shape was quite unrecognizable;
the framework could not be seen at all, while the silk covered ends had
lost all squareness and appeared as disks or spheres.  Never before or
since have I seen a kite at such an altitude; the elderly gentleman who
was controlling it from Regent's Park was operating a reel like a
big-game fisherman's, and when he finally brought the thing to Earth it
looked like a half-scale model of the Wright biplane.

If you think that one was too easy, let us move on to number two.  This
was on the other side of the world-in Brisbane, state capital of
Queensland.  I was in an office overlooking the city (arguing, if I
remember correctly, with a customs inspector about import licenses) and
it was late in the afternoon.  The sun was low on the horizon-and
moving slowly above it from north to south was a line of brilliant
silver disks.  They looked like metallic mirrors, and they were
oscillating or flip-flopping with a regular seesaw motion.  Once again,
I could not guess their size or distance; they were so bright and tiny
against the darkening sky that it was also impossible to decide their
shape, but they gave the impression of being ellipses.  I don't mind
admitting that in the few minutes before they came closer I felt myself
wondering if the Martian invasion had started; this was the only time I
have seen a fleet of textbook flying saucers.

In this case, the explanation turned out to be something I already
knew-and didn't believe.  Many U.F.O. 181  sightings (including one
which is the subject of a celebrated and authentic film) were due, I'd
read, to birds reflecting sunlight under unusual conditions of
illumination.  This theory seemed so absurd that I had dismissed it
contemptuously; but it is perfectly correct.  The lights I saw flipping
across Brisbane were nothing more than seagulls, the under surfaces of
their wings acting like mirrors.  Though I have lived beside the sea
for a quarter of my life, and am doing so now, this is the only time I
have ever witnessed this phenomenon, and I should never have credited
it without the evidence of my own eyes.  The effect of oscillating
metallic disks was absolutely realistic; it would have fooled anyone.

The only U.F.O. that has ever given me the queasy, yet at the same time
exhilarating, sensation of being in the presence of the unknown and the
inexplicable also occurred in Australia.  Perhaps the spectacular
surroundings contributed to the impact, for I was standing in Sydney
Harbour, immediately beneath the piers of the world's most impressive
bridge.  (Sorry, San Francisco: size and grace, I'll grant you, but for
monumental, built-for-eternity grandeur, nothing can touch Sydney's
steel rainbow.)

It was a beautiful, sunny day, and I was looking across the waters of
the harbor toward the city, most of which lay framed within that
tremendous arch.  A strong breeze was sending half a dozen sailing
boats scudding over the blue waters, and was also driving a few clouds
low across the city.  But suddenly I realized, with a distinct
prickling at the back of the neck, that there was one exception.  A
single cloud, darker and more compact than its fellows, was floating
completely motionless, and quite isolated from any buildings, a hundred
feet or so above the roof tops.

It was a couple of miles away, and though I stared at it for a good ten
minutes it refused to give up its secret.  It simply sat in the sky,
defying the wind, while all the other clouds went racing past it. There
was nothing to do but to hurry back to the apartment and collect a pair
of binoculars, hoping that the apparition wouldn't vanish during my
absence.  Luckily, it was still there when I returned; through the
glasses I could see that it was a hundred feet or so downwind of a tall
smokestack, and though there was no visible connection between the two,
it was obviously produced by material streaming from this chimney, and
condensing as it cooled off.  Everyone is familiar with the way in
which hot steam leaves the spout of a kettle as an invisible gas, and
appears a fraction of an inch away in a mist of water droplets.  This
must have been a similar phenomenon, on a slightly larger scale.  The
gas, vapor or whatever it was pouring from the chimney condensed for a
few seconds as it flowed along the wind, then dispersed again to
produce the illusion of an unmoving cloud.  In the binoculars it looked
rather like a banner flying without benefit of flagpole--or, rather,"
mysteriously separated from it by a hundred feet of space.  Even after
I'd worked out the explanation, it was a distinctly uncanny sight.

This strange cloud in the Antipodes brings me naturally to another
which I once saw much nearer home, above the farm in the west of
England where I spent most of my childhood.  On this occasion the
explanation was immediate and obvious, if you knew the answer and
utterly unguessable if you did not.

That many people don't is proved by the fact that one book on flying
saucers has made great play of an identical sighting.

Across twenty or thirty years, some of the details are now blurred in
my memory, but I am fairly sure that it was early on a bright spring
morning, with the dew fresh upon the ground.  A gentle wind was
blowing, and it was carrying overhead something which I can best
describe as an aerial jellyfish.  Sometimes it was almost invisible as
it turned and twisted in the breeze; at other times the sunlight
glanced from its translucent material, so that it looked like a
milk-white ghost as it drifted down the sky, being torn apart by the
winds even as it moved.  I never saw its like again, though it is one
of Nature's commoner marvels, familiar enough to those who do not spend
their lives locked up in cities.  This silken cloud is something that
has baffled man183  kind for centuries, and even within the last few
years it has given rise to the most absurd speculations about the
physiology of extraterrestrial visitors.  But it is actually the
product of a very humble terrestrial creature-the spider.  Most young
spiders begin their careers as aeronauts, spinning out long threads
known as gossamer, which drag them up into the sky on rising air
currents.  (There is no such thing, incidentally, as a specific
gossamer spider; almost all spiders emigrate by air.) On rare
occasions, usually in the late summer, the countless threads intertwine
to form evanescent clouds, which assume the most extraordinary
appearances as the sunlight catches them; when the spiders eventually
descend, acres of ground may be covered with their discarded
parachutes.

Of all my UFOs, the most beautiful occurred during the war.  The time
was the summer of 1942, the place a radar station on the east coast
of

England.  It was a perfect, cloudless afternoon-and extremely peaceful,
for the blitz was over and the V-weapons had yet to come.  If you
searched carefully, you could see the pale crescent of the Moon,
nearing its first quarter, looking lost and lonely in the daylight
sky.

And once you had found the Moon, you could hardly miss what was close
beside it-a brilliant, pure white point of light, shining steadily as a
star, where no star could be in the sun-drenched sky.  Compared with
the pallid lunar crescent, it was almost dazzlingly bright, a fraction
of a degree away from the Moon, and apparently motionless with respect
to it.

However, after you had been watching for about ten minutes, you would
have noticed that it was moving very slowly toward the Moon-until at
last, an hour or so after the first sighting, it finally reached the
edge of the chalky lunar disk and merged into it.

The whole sequence of events occupied most of the afternoon, and, as I
had an astronomical telescope with me on the station, the conduct of
the war was suspended while all the operators and radar mechanics had a
closeup view of something which I do not think they will ever
forget-and which, if they had seen it for the first 184  time a few
years later, they would very likely have interpreted as a flying saucer
making a landing on the Moon.

This U.F.O. brings us into the realm of astronomy.  When I used the
phrase "shining steadily as a star where no star could be" I was
technically correct, but deliberately misleading.  No stars are bright
enough to be seen in the daylight sky, but there is one planet
brilliant enough to challenge the Sun.  This is Venus, who is easily
visible during daytime for the greater part of every year, if you know
exactly where to look for her.  All down the centuries people ignorant
of astronomy have suddenly spotted her in daylight and raised a great
hullabaloo, unaware of the fact that they were seeing as commonplace a
celestial object as the Moon.  (Incidentally, a surprising number of
people don't realize that the Moon is visible during the day-still less
Venus!)

The sight I observed from the radar station was one of the most
striking of astronomical phenomena, and not a particularly rare one.
(It occurred twice in 1958.) In the course of its movement round the
Earth, the Moon is continually getting between us and the other
heavenly bodies, partially or wholly hiding them from us.  When this
occurs with respect to the Sun, we call it a solar eclipse; when the
Moon passes in front of a planet or star, it is known as an
occultation.

What I have described was an occultation of Venus, seen during the
daytime.

Though both bodies were moving, most of the apparent motion was due to
the

Moon in its path around the Earth.  About an hour later, Venus emerged
from the other side of the Moon and was shining just as brightly as
before.

At this point, I would like to pause for a summing up.  Even these few
examples collected by one not-very observant sky gazer over a period of
some twenty years show how extremely easy it is to misinterpret quite
ordinary objects when they are seen under unusual conditions.  And
unless one can arrive at an explanation at the time, there is often no
hope of settling the matter at a later date; it remains an unsolved and
un185  solvable mystery.  A perfect example of this was provided a few
years ago when an agitated gentleman phoned the police late one night
with the news that a flying saucer was racing round his back garden,
spitting sparks and flames.  When the skeptical cops arrived it was
still performing, and after a brief chase they managed to capture it.
In a million years, no one-but no one-would guess what it turned out to
be.  Somebody had been burning trash in a nearby garden, and in the
rubbish was an old golf ball.  Now a golf ball is highly combustible,
and its tightly wound rubber bands contain a great deal of energy-all
of which comes out when they start to burn, with the result that the
thing takes off like a rocket.  Try it one night if you want to scare
the neighbors.

Nothing that has so far been said either proves or disproves the
existence of genuine, 100 per cent flying saucers from outer space; it
merely indicates the need for extreme care in coming to conclusions
about peculiar objects seen in the sky.  Many UFOs have been reported
by apparently reliable observers which are quite inexplicable in terms
of current knowledge-but even this does not prove that they are
necessarily the products of intelligence, terrestrial or otherwise. For
there is now no doubt that when Nature really tries, she can produce
"spaceships" that would satisfy the most exacting requirements.

Here is the proof: I am quoting from the May, 1916, issue of The

Observatory, a scientific journal published by the world's leading
astronomical organization, the Royal Astronomical Society.  The
date-1916-is important, but the description is of an event which
occurred more than thirty years before, on the night of November 17,
1882.

The writer was a well-known British astronomer, Walter Maunder, then on
the staff of the Greenwich Observatory.  He had been asked to describe
the most remarkable sight he had ever seen during his many years of
observing the heavens, and he recalled that soon after sunset on that
November night in 1882 he 186  had been on the roof of the
observatory, looking across London, when:

A great circular disc of greenish light suddenly appeared low down in
the

East-North-East, as though it had just risen, and moved across the sky,
as smoothly and steadily as the Sun, Moon, stars and planets move, but
nearly a thousand times as quickly.  The circularity of its shape was
merely the effect of foreshortening, for as it moved it lengthened out,
and when it crossed the meridian and passed just above the Moon its
form was almost that of a very elongated ellipse, and various observers
spoke of it as "cigar-shaped," "like a torpedo" .. . had the incident
occurred a third of a century later, beyond doubt everyone would have
selected the same simile-it would have been "just like a Zeppelin." LMY
italics]

Remember that Maunder was writing this in 1916, when Zeppelins were
very much in the news-even more so than spaceships are today!

Since hundreds of observers all over England and Europe witnessed
this

Object, reasonably accurate figures for its height, size and speed were
obtained.  It was 133 miles above Earth, moving at 10 miles a second
-and must have been at least 50 miles in length.

What was it?  No one could have given a full answer to that question in
1882, but today we can do so with complete confidence.  The solution
follows from a clue which I have deliberately omitted; the object was
seen during a violent auroral display, and was undoubtedly part of
it.

We now know that auroras are caused by streams of electrified particles
shot out of the Sun, which cross space and eventually enter Earth's
atmosphere.  Here they produce a type of fluorescence much like that
which lights up our neon tubes and gas-discharge lamps.  Billions of
years before

Broadway, Nature was hanging her illuminated signs in the polar skies.
Though the Sun is the original source of the energy, our planet is
responsible for the strange shapes which the aurora assumes-its
ever-changing streamers, curtains and rays.  For the Earth's weak but
far-ranging magnetic field, extending thousands of miles out into
space, has a focusing effect on these streams of particles
concentrating them at the poles.  It makes them paint pictures on the
sky, as very similar beams and magnetic fields produce images on the
screens of our

TV sets.

And sometimes, surprising though it seems, Nature with her
93,000,000-mile-long TV tube can create apparently symmetrical,
sharp-edged objects moving steadily across the heavens.  (Maunder
specifically states that the phenomenon he observed "appeared to be a
definite body.") This seems much more remarkable to me than any mere
spaceship, but the facts are beyond dispute.  Observations of the
"torpedo" through the spectroscope proved its auroral nature, and as it
passed across Europe it slowly began to break up.  The cosmic TV tube
went out of focus.

It may be argued that this weird-possibly unique event cannot account
for the hard core of unexplained UFOs, many of which have been observed
in the daytime, when the faint light of the aurora is invisible."  Yet
I have a hunch that there is a remote connection, and this hunch is
based upon a new science which has developed during the last few years,
largely under the impetus of missile and nuclear research.

This science-take a deep breath-is magneto hydrodynamics  You'll be
hearing a lot more of it in the future, for it's one of the keys to
space exploration as well as atomic power.  But it concerns us here
only because iL deals with the movement of electrified gases in
magnetic fields-with the sort of thing, in fact, which startled Mr. 
Maunder and a few thousand other people in 1882.

Today we call these objects "plasmoids."  (A lovely word, that; can't
you see the title from some he-man's magazine of the Space Age: "I Was
Pu.Tsued by Plutonian Plasmoids"?) They've been known for quite a
while, in the form of one of the most baffling phenomena in the whole
of Nature-ball lightning, which is something no one would believe
without overwhelming evidence.  During thunderstorms, brilliantly
glowing spheres are sometimes seen rolling along the ground or moving
slowly through the air.  Occasionally they explode with great violence,
and so until recently have all the theories put forward to explain
them.  But now we have been able to make small versions-baby
plasmoids-in the laboratory; and there have been horrid rumors that the
Russians are trying to develop them as weapons.

I have never seen ball lightning and am by no means sure that I want
to, at least at close quarters.  However, with this example of the
fantastic tricks natural forces can play, it would be very unwise to
argue that even, the most impressive U.F.O. must be artificial.  In
fact, a good working rule for

U.F.O. observers is: It's not a spaceship unless you can read the Mars
registration plate.

Of course, some people claim to have done a good deal better than this,
but luckily I am not concerned here with the more extreme aberrations
of the human mind.  The saucer mania of our age will provide a
fascinating study for future psychologists; I find it not amusing but
saddening.  I could hardly' raise a smile when a good lady in
Pennsylvania recently attacked me for disbelieving in flying saucers,
giving as evidence the fact that they were continually landing in her
garden.  They made, she added, quite a lot of noise-though the only
sound she had definitely identified was "a beautiful, long-drawn-out
hallelujah..  .."

Since one can never rule out all possibilities, there must always
remain the faint chance that some UFOs are visitors from elsewhere,
though the evidence against this is so overwhelming that it would
require an article much longer than this to give it in detail.  And if
this verdict disappoints you, I can offer what seems to me very
adequate compensation.  If you keep looking at the sky, before much
longer you will see a genuine spaceship.

But it will be one of ours.

POSTSCRIPT

Since writing the above, I have seen, the finest-and most
"classical"-flying saucer of my life.  On October 17, 1958, I was
aboard KLM

Flight 826, coming up the coast of Italy on a bright but somewhat hazy
afternoon.  We were at about 10,000 feet, en route for Geneva, and the
ground was clearly visible at the time (around 2 P.m.).

I was looking down at the coastline almost immediately beneath us,
waiting for Naples and Vesuvius to come into view, when I became aware
that a brilliant, oval of light was keeping pace with the aircraft a
few thousand feet below.  It appeared to be quite solid, though its
edges were hazy and seemed to pulsate slightly; they also had a bluish
tinge rather like that of a mercury arc.  It was impossible to judge
its size or distance, but I had the impression that the object was
halfway between the aircraft and the ground.  Sometimes it was so
brilliant that it hurt the eye to look at it directly.

It was in view for a good ten minutes, keeping station beneath us, and
for long periods of time it was remarkably constant both in shape and
size.

Apart from the occasional quivering of its edge, there was no way of
telling that it was not a solid disk; it completely masked the ground
beneath.  Several of my fellow passengers were busy photographing it,
and I am quite sure that they are now proudly showing genuine flying
saucer photos to their friends.

I must confess that had I caught only a glimpse of this apparition I
should have been quite baffled; as it was, I was able to keep it in
sight until it disintegrated and slowly faded from view, like a cloud
breaking up beneath the Sun.  By that time there was no question of its
identity.  It was a mock sun, or "sun dog," caused by the 190 
presence of an invisible layer of ice crystals between the aircraft and
the ground.  They are fairly common, though this is the first I have
ever seen.

The ice crystals act as tiny mirrors, each reflecting an image of the
Sun; the combination of myriads forms the brilliant disk which, being a
reflection, appeared to follow the aircraft.  Dr.  D. H. Menzel's book
Flying

Saucers has a fine photograph of a mock sun as its frontispiece; the
one I observed was more sharp-edged and must have been formed in an
unusually stable layer of air, in which the vast majority of ice
crystals had almost the same orientation.  The Men on the Moon

THOUGH WHOLE BOOKS HAVE BEEN WRITTEN ABOUT the practical problems
involved in colonizinc, the Moon, there is one aspect of life on our
satellite which has been largely overlooked, perhaps because everyone
has taken it for granted.  It is an aspect which will, in fact, became
important long before the first lunar landings take place, for as
high-definition photographs accumulate from our rocket probes, millions
of square miles of hitherto unknown territory will be lumped into the
laps of geographers, scientists-and UN delegates.  Sometime in the
1960's, the cartographers will be faced with the biggest job of map
making since exploration began.

Now when virgin territory is opened up, it must not only be mapped but
its surface features must be named.  This task has already been
performed for the visible side of the Moon, thanks to the labors of
scores of astronomers (mostly amateurs) during the last three
centuries.  In a way that they could scarcely have imagined, they are
about to make a mark on history.  For the names they gave to the lunar
plains and mountains will soon pass into the vocabulary of mankind, as
they blaze forth in the headlines of the future.

It is unfortunate, therefore, that so many of these names are fanciful,
cumbersome or downright inappropriate.  Since all the major formations
on this side of the Moon have already been labeled, it is probably too
192  late to do much about them except in the most extreme cases.
(Future lunar colonists may take violent objection to living in Hell,
the Marsh of

Putridity or the Lake of Death.) The least we can do, however, is to
make sure that the maps of the other side are less medieval and
inconvenient.

The man who created the pattern of lunar nomenclature we are stuck with
today was a Jesuit astronomer, Joannes Riccioli, of Bologna, Italy, who
published his map of the Moon in 1651.  This was some forty years
after

Galileo had made his first telescope and astonished the world with the
news that the Moon was not, as Aristotle had taught, a perfectly smooth
sphere, but was even more mountainous than Earth.

Father Riccioli's scheme for naming the new world that had been
revealed in his lifetime was a consistent one, based on the fact that
there are three main types of lunar formation-the dark, almost level
plains, the mountain ranges and the craters.  The plains are easily
visible to the naked eye, and their patterns have given rise to
countless myths and legends-such as that of the angry warrior mentioned
in Hiawatha who:

Seized his grandmother, and threw her Up into the sky at midnight;

Pight against the moon he threw her; "Tis her body that you see
there.

In a low-powered telescope, the dark regions look very much like areas
of water, and they are also at a considerably lower elevation than the
brighter parts of the Moon.  Though Riccioli knew perfectly well that
they were dry plains, he christened them seas (mare, plural maria),
oceans, lakes, bays and so on.  In the actual naming he really let his
imagination go, being strongly influenced by astrological ideas and the
notion that the

Moon's first quarter promotes good weather while its last quarter
brings storms and rain.  Here are some of the more picturesque names
which survive to this day on all maps of the Moon: Ocean of Storms
(Oceanus Procellarum);

Sea of Tranquillity; Sea of Nectar; Sea 193  of Crises; Sea of Spring
(Mare Veris); Sea of Rains (Mare Imbrium); Sea of

Clouds (Mare Nubium); Bay of Rainbows (Sinus Iridum); Marsh of Dreams
(Palus

Somnii).  We can be slightly thankful that, somewhere in the last three
centuries, Riccioli's Bay of Epidemics and Peninsula of Delirium have
dropped by the wayside.

Skirting many of these dark areas are magnificent mountain ranges, some
of them as high as the Himalayas, and here Riccioli took the easy way
out.

Following the suggestion of the astronomer Hevelius, he simply
transposed terrestrial names to the Moon.  So today we have the lunar
Alps, Apennines,

Urals, Carpathians and Pyrenees.

The problem of finding names for the Moon's relatively few seas, lakes,
bays and mountain ranges is as nothing to that of identifying the
innumerable craters.  The largest map so far produced-a
300-inch-diameter chart made by the British observer Dr.  H. P.
Wilkinsshows about 90,000 craters, ranging from walled plains big
enough to enclose Vermont or

Maryland, down to tiny pits a fraction of a mile across.

Even the first crude telescopes could show at least a thousand craters,
but

Riccioli did not attempt to name them all.  He contented himself with
about two hundred, which was quite enough to start with, and the names
he chose were those of great astronomers, philosophers or scientists.
The precedent thus established has, with very few exceptions, lasted to
this day.

It is amusing to note how Father Riccioh's personal prejudices colored
his map making.  An extraordinarily large number of craters bear the
names of fellow Jesuits, but it is only fair to point out that they
were mostly men of scientific distinction.  (Even today, any large
gathering of astronomers will contain a substantial number of Jesuits;
the order has practically monopolized certain departments of
geophysics.) When Riccioli published his map, the historic debate as to
whether

Earth was the center of the Universe, or merely another planet circling
the Sun, was still in full swing.  Galileo had been haled up before the
Inquisition only eighteen years earlier and forced to recant his
belief in a moving Earth, and

Copernicus' great book, The Revolution of the Celestial Orbs, which
founded modern astronomy, was still on the Index Expurgatorius, where
it remained until well into the nineteenth century.

Though Riccioli could hardly ignore Galileo, the most outstanding
scientist of his age, he attached his name to a small and insignificant
crater tucked away near the western edge of the Moon.  The conspicuous
craters he reserved for the orthodox, party-line astronomers, with the
result that some of the mightiest formations on the Moon are now named
after long-forgotten philosophers and theologians.

Father Riccioli did, however, make a few concessions which he must have
found difficult to reconcile with his conscience.  Though as a faithful
son of the Church he believed that the Copernican doctrine of the
moving Earth was a heresy, his personal admiration for Copernicus was
so great that he gave him what is perhaps the most splendid, though not
the largest, crater on the face of the Moon.  The most conspicuous one
of all easily visible to the naked eye-he gave to Tycho.  Brahe, the
last great astronomer to cling to the outmoded, earth-centered model of
the Universe.

In the three centuries since Riccioli, generations of later
selenograpilers have followed his system and given personal names to
craters.  The result is that the' Moon has become, in Descartes'
phrase, "a graveyard of astronomers."  The term "graveyard" is not
altogether accurate, for there are some sixty individuals alive today
who have lunar craters named after them.

At the last count, thirteen were Americans, the majority of the
remainder

British and Spanish.  There are also French, Italian, Japanese, German
and

Finnish representatives on the Moon, but--curiously enough-not a single
living Russian, and only three dead ones.  (I suspect that
contemporary

Soviet moon maps may show a different state of affairs.)

The right to christen a crater goes only to someone who has made a
serious contribution to lunar studies, and even then the name has to be
approved by the International Astronomical Union to make it official. 
At the moment slightly more than seven hundred lunar formations have
personal names attached to them, and a study of the list is a
fascinating occupation which not only produces some surprises but may
also give useful hints for the future.

Altogether, more than thirty craters possess American names; the most
celebrated ig undoubtedly Benjamin Franklin, who owns a small crater
(well, small for the Moon, since it's only thirty-four miles across)
not far from the Sea of Serenity.  And it must be admitted (Pravda
please copy) that two

United States citizens purchased their lunar immortality with hard
cash, not with the imponderable currency of scientific knowledge.  Yet
considering the services they rendered to astronomy, i; is not likely
that many will grudge the financiers Lick and Yerkes their place on the
Moon.

Let us wander through the directory of lunar craters and stop at
interesting or familiar names.  The very first one listed is an old
friend from English literatureAbenezra, or "Rabbi ben Ezra" of
Browning's poem.

What's he doing on the Moon?  Well, he was a distinguished Jewish
astronomer of the twelfth century and so has a perfect right to his
position.

One cannot really say the same for Alexander the Great, who was put on
the

Moon merely to keep company with Julius Caesar.  Julius, however, has a
good claim, having earned it by his reform of the calendar.4 And while
we are on the subject of military men, it is somewhat startling to meet
Field Marshal

Graf von Moltke owning a tiny crater, rather inappropriately close to
the

Sea of Tranquillity.  Moltke's place on the' Moon was given to him (by
a

German astronomer, needless to, say) in recognition of the fact that he
persuaded the Prussian government to print an important lunar map.
There is no reason to suppose that this was inspired by any early ideas
of interplanetary imperialism; Moltke was himself an energetic explorer
and map maker who surveyed remote parts of Asia which no European had
ever visited.  Famous explorers are well represented on the Moon; 196
among those of the past are Colombo (Columbus), Cook, Marco Polo,
Pytheas,

Magelhaens (Magellan) and Vasco da Gama.  Coming up to more modern
times,

Nansen, Shackleton, Peary, Amundsen and Scott may be found clustering
round the lunar poles.

Scattered across the face of the Moon will be found the names of some
of history's supreme intellects.  Here is a brief listing:
Archimedes,

Aristotle, Darwin, Descartes, da Vinci, Einstein, Euclid, Kant,
Kepler,

Leibnitz, Newton, Plato, Pythagoras.  Unfortunately, but inevitably,
the later scientists and philosophers have had a raw deal, being fobbed
off with very second-rate formations.  The sad case of Einstein is a
good example; he has been given a sorry little crater less than thirty
miles across, so near the edge of the Moon that it is almost impossible
to see and might just as well be on the other side.

In contrast, the names attached to many fine craters are so obscure
that only devoted historical research can uncover their origins. Others
look fairly straightforward, but are quite misleading.  The crater
Hell, for example, was not named because of any supposed satanic
associations; it commemorates Father Maximilian Hell, S.J."  once
Director of Vienna

Observatory.  Luther is not Martin, but a much later German-a
nineteenth-century astronomer.  The crater Pallas is not named after
the

Greek Goddess (who already claims a minor planet) but a German
explorer.

Beer, disappointingly, turns out to be a Berlin banker celebrated for
his astronomical studies but much less well-known to the world at large
than his brother, the composer Meyerbeer.  And though one of the
Americans enshrined on the Moon is Holden, he got there via Lick
Observatory, not

Hollywood.  There are as yet no film stars on the Moon, though probably
this is only a matter of time.

Many of the people with lunar holdings had highly checkered careers
on

Earth, and not a few met violent ends.  Several (Lavoisier, the great
chemist; Condorcet, the philosopher; Bailly, astronomer and mayor of
Paris) made their exits with the aid of that highly scientific device,
the guillotine.  One-Cichus-was burned at the 197  stake for
necromancy, in the days when astronomy and, astrology were still
confused even by the intelligent.

This confusion brought disaster to the tenant of a small crater on the
extreme eastern edge of the Moon.  Ulug-Beg, grandson of Tamerlane, was
a great patron of the sciences, and founded a splendid observatory near
his capital, Samarkand.  Unfortunately, when he took the natural
precaution of casting the horoscope of his eldest son, he was perturbed
to find that the boy was destined to kill him.

Unlike most Oriental potentates, who knew how to deal with this
standard situation, Ulug-Beg did not beat the young man to the draw but
merely exiled him.  Needless to say, he returned at the head of an
invading army and, like a dutiful son, fulfilled his father's
prediction.  Thereafter, the historians record with a fine sense of
restraint, "astronomy was no longer cultivated in Samarkand."

Another obscure name, near the south pole of the, Moon, is associated
with my favorite story of scientific, hard luck.  In the days when a
journey to the Far East was a major undertaking, the French astronomer
Legentil sailed to India to observe the transit of Venus across the
Sun.  It took place on

June 6, 1761, but Legentil couldn't make the appointment; he had been
delayed on the high seas by the current Anglo-French war, and when he
arrived at Pondich6ry the show was over.  However, another transit was
due in almost exactly eight years, so the stubborn astronomer decided
to sit it out.

And so, in 1769, he was in the right place at the right time-but, alas
the transit was completely obscured by clouds.  Legentil couldn't see a
thing; this, however, was not the end of his bad luck.

As the next performance was not due for a hundred and five years, he
packed his things and sadly sailed for France.  And when he got there,
he discovered that all his property had been sold, his family having
assumed that by this time he must be dead.... That is enough for this
side of the Moon; though one could spend a lifetime exploring it-as
many have-that 198  other hemisphere is beckoning.  Yet before we
cross to it, it may be well to mention briefly why there is an "other
side" which we have never been able to observe.  The facts are simple,
but it is astonishing how poorly they are understood.  One sign of the
popular confusion is the expression "the dark side of the Moon."  There
is no such place; the Moon turns under the Sun in 29V2 days, and each
face is equally illuminated during this period.  Any darkness is purely
temporary, as an rain; the interchange of night and day is merely more
leisurely.

Earth and Moon perform a kind of celestial dance together, and in most
dances you cannot see the back of your partner's head.  But imagine
that the male partner, in addition to performing the dance movement, is
also spinning round and round, as in some of the more energetic
ballets.  You then have an accurate analogy of the present Earth-Moon
situation.  The female partner _' the Moon-sees each side of the male
partner-Earth.  But Earth sees only the face of the Moon, not the back
of her head.

You will not be surprised to hear that this is a temporary state of
affairs, and that Earth will be unable to keep it up forever.  The
performance is too exhausting, and in a few billion years the dance
will have settled down to a sedate and stately waltz, each partner
content to stare perpetually into the other's face.  When that time
comes, one side of

Earth will never see the Moon, as today one side of the Moon never
sees

Earth.

There is not the slightest reason to suppose that the Moon's hidden
side differs in any way from the one we can see.  In fact, we can
observe a small portion of it, because the Moon rocks slightly on her
axis during the course of her revolution round Earth, .  and this
enables us to peer a little way over the edge.  This border region is
so badly foreshortened that it cannot be accurately mapped, but because
of its existence we can see about 60 per cent of the Moon, not merely
50 per cent.

We must assume that, as soon as we can observe the far side of the
Moon, we will be confronted with some 199  scores of mountain ranges
and "seas," and at least a hundred thousand craters-all totally
anonymous, all waiting to be named.

As far as the still-to-be-discovered mountain ranges are concerned,
there is no problem.  Earth's greatest peaks were unknown when the Moon
was first mapped; there are no lunar Himalayas, Rockies or Andes. These
evocative names are crying out for mountains to match them, and we can
be sure that they will be forthcoming.  Also available as lunar
candidates are the

Appalachians, the Sierras, the Pamirs and dozens of individual peaks
such as Everest, Kilimanjaro, Whitney, Popocateped, Kanchenjunga, Nanda
Devi.... The new plains-the dusky, and possibly dusty, lunar
lowlands-pose some difficulties.  Shall we continue to name them after
bodies of water7 There seems no harm in continuing the custom; it is
not likely that anyone will ever be misled by it and pack skin-diving
equipment on a trip to the Moon.

But if the practice is continued, then the astrological and occult
associations win certainly be discarded, though we need not abandon the
poetic touch which gives such charm to so many lunar place names.  It
may be simplest to transpose terrestrial lakes and seas; the supply is
certainly adequate, and when we consider how the Moon controls the
tides, the idea of loaning it our oceans seems highly appropriate.

It is when we come to the craters that matters start getting
complicated.

Finding a hundred thousand names in a hurry would be no easy task,
though luckily the, problem is not quite so bad as that.  Once a few
hundred major formations have been named, the smaller ones can be
referred to-as postal districts are in a large city-by adding letters
or numbers as suffixes.

This has long been standard procedure for the visible face of the Moon;
thus a small crater inside the ninety mile-diameter walled plain of

Ptoleinaeus might be referred to as Ptolemaeus B, or Ptolemaeus 123.
(In this single case, incidentally, there are over three hundred sub
craters

Through sheer inertia, if for no other reason, we will probably
continue to give the lunar craters personal 200  names.  But whose
names?  The practice of honoring great scientists and philosophers is
obviously worth continuing, and we might start by redressing some of
the present injustices.  Galileo, Newton and Einstein should be
relocated in the most splendid of the far-side craters, and their
current substandard residences handed over to less important people.
And Maxwell,

Hertz, Roentgen, Becquerel, Curie, Rutherford, Planck and the other
makers of modern science should also be suitably rewarded.

The men who paved the way to the actual conquest of space-the great
pioneers of astronautics, such as Tsiolkovsky, Oberth and Goddard-most
certainly deserve conspicuous lunar landmarks, and though there have so
far been no nonhuman names on the Moon, surely a modest crater can be
dedicated to Laika, the, first space traveler.

It would not be difficult to find sufficient scientists, living or
dead, to label the major features on both sides of the Moon.  However,
now that the matter is no longer of interest only to a handful of
specialists, there will be claims from other quarters.  Some of these
will be well grounded; it is a slight scandal that there are no
artists, composers or poets on the

Moon, despite all the attention they have paid to our satellite.  (One
exception: Leonardo has a small crater in the Moon's westerni.e.
first-quadrant, but he is there because of his scientific interests,
not his artistic attainments.  And though there is a Wagner tucked away
in the

Carpathian Mountains, he turns out to be a nineteenth-century
Germanphysiologist!) Surely Dante, Homer, Michelangelo, Bach,
Shakespeare,

Milton, Goethe, Beethoven, to mention only the first who come to mind,
will not be blacklisted if their names are proposed.

A slightly more controversial suggestion would be the names of the
great religious leaders and reformers who have shaped the thoughts and
lives not of mere millions, but of billions.  Moses, Akhenaton, Asoka,
Mohammed,

Lao-tse, Confucius and Gautama certainly merit apotheosis.  The last
three would probably have reached the Moon centuries ago, had it not
been for 201  the unexplained omission of the Chinese to invent the
telescope.

The real trouble will start when the politicians and statesmen try to
climb aboard the lunar bandwagon.  The few already there got in by the
back door; and are in any event sufficiently remote not to arouse
prejudices.  No one today objects violently to Alexander or Caesar, and
there would probably be few protests against the nominations of
Washington, Napoleon or Lincoln.

But as we approach our own time, universal agreement would become more
difficult.  Though millions would approve of Lenin, Roosevelt or
Churchill, millions more would take a dim view of granting them lunar
franchises.

The obvious solution is to allow no one on the Moon until he has been
dead for a safe period-say fifty years.  That is long enough, in most
cases, for greatness to be established, and for contemporary passions
to evaporate.  It would also eliminate the celebrities whose fame looms
large in their own generation, but are unknown to posterity.

If this rule is followed, then the Moon can indeed become a Roll of
Honor for all mankind.  Let us hope that the cartographers and
photo-reconnaissance experts who must now undertake the task of naming
a world do so in the spirit of responsibility and dignity it demands.
We do not want to wake up one morning, to find that the job has been
done in top secrecy by a Pentagon general who happens to be a baseball
fan, or an unimaginative bureaucrat who has stuck pins at random into
the Vladivostok telephone directory.

For the names we are about to write upon those unknown plains and peaks
and craters will be more than chapter headings in the history of the
future.

They will be the words many of our grandchildren will utter when they
speak of home.  The Radio Universe

FOR THOUSANDS OF YEARS MEN HAVE LOOKED UP AT the Sun, "Moon and
stars-and believed that they saw the Universe.  Within the last decade,
we have discovered that they saw only one Universe, and that another
exists, invisible to the eye.  This is the Universe revealed not by
light, but by the millionfold longer waves of radio.  It has been a
revelation indeed; today's astronomers are like blind men who have
suddenly been granted the gift of sight.  It will be years before they
can fully interpret what they see-or, rather, what their wonderful new
instrument, the radio telescope sees for them.

The discovery of radio waves themselves is still less than a century
old; it was as recently as 1873 that the great physicist James
Clerk-Maxwell predicted their existence theoretically, and not until
1888 that Hertz first generated them in the laboratory.  The swift rise
of radio communication in the 1900's is one of the romances of modern
technology, but for a long time it never occurred to scientists that
Nature, as well as

Man, could produce radio waves.  It was true that brief bursts of
"static" or interference accompanied lightning flashes -as everyone
knows who has ever listened to a radio program during a
thunderstorm-----but this was not considered to be of very great
scientific importance, though 203  it gave the meteorologists a useful
tool for tracking distant storms.

The first man to suspect that we might be missing something was a
Bell

Telephone Laboratories engineer named Karl Jansky, who was trying to
hunt down the source of the background noise which can be heard in any
radio receiver when the volume is turned full up.  Some of this
familiar hissing or frying sound originates in the set itself, but part
of it is picked up by the antenna.  In 1931 Jansky made the surprising
discovery that part of this radio noise came from outer space, from the
general direction of the

Milky Way.  This discovery would have earned Jansky a Nobel Prize if
anyone had appreciated its significance at the time; but like some of
the results of psychical research-it could not be fitted into the
general pattern of accepted science.  So, for almost fifteen years, it
was virtually forgotten.

It took the radar developments of the Second World War to bring the
facts of radio-astronomy so forcibly to the attention of scientists
that they could no longer be overlooked.  Early in 1942 the British
army's anti-aircraft radar was suddenly and inexplicably jammed by a
new type of interference.  Naturally, the Germans got the blame, but it
did not take long to discover that the trouble was a good deal further
away.  The "jamming" was coming from the Sun.

At the time, this was a well-kept secret, but immediately after the war
the scientists concerned-mostly British and Australian-started
following up this new line of investigation with great energy.  They
were much helped by the fact that large quantities of surplus radar
equipment could be picked up for a song, and most of the first
radio-astronomy equipment was built round converted radar sets.  It is,
however, important to distinguish between the two techniques, similar
though they are.  In radar proper, a pulse of radio energy is sent out
into space and the returning echo is received a fraction of a second
later.  In this way, it is possible to range the Moon and to detect
meteors invisible by any other means.  Most of radio-astronomy,
however, is concerned with detecting radio waves produced by distant
natural sources, not echoing back from man-made transmitters.

These natural sources fall into several very different categories, and
there are certainly many others still to be discovered.  One of them,
as the

British army's radar experts found to their discomfort, is the Sun.

However, the greater part of the time the Sun is not a very powerful
source of radio waves; if you listen to it on a sensitive receiver you
will usually hear only a gentle sizzling.  But occasionally, when the
enormous dark blemishes known as sunspots cross the solar disk, the
output of radio waves increases by many millionfold.  Other potent
sources of radio emissions are flares-sudden eruptions of incandescent
gas from the Sun's surface, on a scale which makes our most violent
H-bomb explosion about as impressive as the popping of a paper bag.

Precisely how these torrents and whirlpools of flaming gas, at
temperatures of thousands of degrees, and moving at hundreds of miles a
second, act as generators of radio waves is still being investigated by
scientists.  Their work will lead to a much better understanding of the
Sun, and it is also linked with research which before long may
transform life here on Earth.

For the study of such electrified gases is an essential step on the
road to thermonuclear power-the release of the sea's infinite energy
for the use of all mankind.  The Sun started fusing hydrogen several
billion years ago; now we are learning from its example.

That the Sun was a source of radio waves did not surprise the
astronomers greatly, though they were rather taken aback by the
strength of its most violent transmissions.  What no one could have
foreseen, however, was that radio waves would also be received from far
colder bodies, such as the planets Venus and Jupiter.

In the case of Venus, Earth's perpetually cloud covered twin, the
intermittent radio disturbances may come from something analogous to
thunderstorms.  Being nearer the Sun, Venus is a good deal hotter than
Earth and its weather must be-to put it mildly tropical  In any event,
the bursts of radio noise em erg205  ing from beneath the eternal
clouds may give us our first definite information concerning conditions
on the hidden surface of the planet.

The case of Jupiter is much more mysterious.  This giant planet, ten
times the diameter of Earth, is a hundren degrees colder than the most
frigid

Antarctic night -so cold, indeed, that most ordinary gases are
liquified.

Yet from somewhere deep down in the turbulent, half-frozen slush of
methane, ammonia and hydrogen, through which move floating islands
bigger than our planet, are radio sources of immense power, generating
millions of times more energy than terrestrial thunderstorms.

Very feeble radio waves have also been detected from the Moon and
Mars.

These, however, are merely the waves that are produced by any object
not at the absolute zero of temperature, simply through the heat
vibrations of its molecules.  The radio waves which come from Jupiter
and the Sun are vastly more powerful than can be explained by this
"thermal" effect, and must have a completely different origin.

But the greatest of all radio transmitters in the Universe are far more
remote than Sun and planets, and their investigation leads us back to

Jansky's original discovery.  If our eyes could see radio waves as they
now see light waves, most of the sky would appear covered with a
faintly glowing mist.  The glow would concentrate into a bright band
closely matching the position of the Milky Way, but scattered over the
heavens would also be hundreds of individual points of radio "light,"
some of them extremely brilliant.  These were originally, and rather
naturally, given the name "radio stars"-but it was soon found that most
of them did not coincide with any outstanding visible stars.  The
astronomers were suddenly confronted with an entirely new picture of
the sky, and the attempt to find the origin of the radio stars (or
discrete sources, as they are now more noncommittally called) has been
one of the most fascinating scientific detective stories, of the past
decade.  Some of these radio sources-millions of millions of 206
millions of times more powerful than any transmitters built by Man-are
filaments of heated gas, expanding and twisting through space with
great velocity.  They may be the debris of exploding stars; indeed,
this is known to be the case for one of the most powerful radio sources
(the Crab

Nebula-remnant of a cosmic catastrophe which the Chinese astronomers
observed as a brilliant but short-lived new star in A.D. 1054).

These swirling gas clouds, calling attention to their existence by the
roar of their radio voices, are merely local eddies in that whirlpool
of stars, the Galaxy.  Though they are far larger than the Solar
System, being many light-years across, they are still very small on the
cosmic scale.  And as radio transmitters, they cannot be compared with
the most stupendous source of radio energy yet discovered.

This lies in the heart of the constellation Cygnus, but it is a million
times further away than the cross-shaped group of stars which outlines
the figure of the flying swan.  It is pouring out radio waves at the
unimaginable rate of 1,000,000,000"000,000,000,000,000,000,000
megawatts; for comparison, a high-powered radio station may broadcast
one megawatt.

When this intense source was discovered, barely ten years ago, the
astronomers were baffled because the best telescopes could find nothing
visible to account for it.  Eventually, photographs taken at Mount
Palomar by Baade and Minkowski revealed a tiny smudge of light which
has now been interpreted as one of the most awe-inspiring phenomena yet
discovered.  It is nothing less than the headon collision of two
galaxies.

This is indeed a phrase worth savoring with the mind, but the word
"collision" is a little misleading.  It will take millions of years for
the two great systems of stars to sweep through each other, and it is
most unlikely that even a single pair of stars will actually come into
contact, so vast are the distances between them.  It is the violent
interaction between the tenuous gas clouds between the stars which
generates this tremendous pulse of power.  Even from 270,000,000 light
years away, it dominates the radio sky; our present 207  crude
instruments could detect it at a far greater range than the
two-hundred-inch telescope can observe.

Conditions must be very peculiar in a region so drenched with radiation
as the Cygnus radio source."  One could probably draw sparks off any
piece of bare metal, and radio communication would be as impossible as
a quiet conversation in a jet-engine test cell.  It is difficult to see
how the inhabitants of any planets in these colliding galaxies could
even discover the laws of electromagnetism, in the presence of such a
roaring background of power.

And this leads us naturally to a question which many people would like
to ask, but which the astronomers are chary of answering.  Is there any
evidence at all of signals due to intelligence among the barrage of
radio noise pouring down from space?

Not yet; nor could it reasonably be expected in the present early stage
of this new science.  The natural radio transmitters scattered round
the sky are quadrillions of times more powerful than any that even the
most advanced civilizations could possibly build; against the cosmic
cacophony, the voice of intelligence could be only the faintest of
whispers.  Our own radio signals now fill an expanding sphere of space
more than a hundred light-years across; Marconi's first transmissions
are already fifteen times further away than the nearest star.  But long
before they left the Solar

System, our most powerful broadcasts will have faded so far below the
background of interstellar noise that they are as undetectable as words
that were spoken yesterday.  No receiver, however sensitive, can pick
up signals once they have sunk below the noise level.  And if we ever
do detect intelligent signals from space, the beings that produced them
may no longer exist-such is the slowness of radio waves, compared with
the immensity of the Universe.  That soundless thunderclap from the
colliding galaxies in

Cygnus started on its way before the great reptiles trampled Earth.

Yet, though they may deny it with some indignation, many radio
astronomers must cherish the secret hope that someday they will detect
signals which do not 208  have a natural origin.  The telescopes
already built such as the 250-foot-diameter giant at Jodrell Bank,
Manchester, famous for its Sputnik and moon-rocket tracking-are the
products of the very first decade of radio-astronomy.  One day they
will be superseded by far larger instruments, possibly miles across.

These will not be built on the Earth's surface, but will be assembled
in satellite orbits, where the absence of gravity will permit the use
of paper-thin materials and ultralight construction techniques.  Clear
of the man-made interference which now drenches our planet, they will
be able to gather far more energy than today's antenna systems and,
what is equally important, will be able to focus with much greater
precision upon selected small regions of space.  We can be certain that
these vast instruments will bring us much nearer to a true
understanding of our Universe; and we can hope that, one day, they will
tell us that we are not alone in its immensity.  Of Space and the
Spirit

ASTRONOMY IS THE OLDEST OF THE SCIENCES, AND THE

one which has not only the widest popular appeal but also the most
profound philosophical implications.  This was never more true than at
the present time, when the horizons of human knowledge are not so much
expanding as explodin g. New discoveries and techniques-such as the
development of electronic instruments, the launching of artificial
satellites, the detection of radio waves from space-have invigorated
the whole science and shed new light on problems over which men have
argued in vain for centuries.

Yet what has already happened is merely the prelude to far more
startling events.  In a period which will be very short by the
standards of history-perhaps a century at the most-we may have
established physical contact with all the major solid bodies in the
Solar System.  A landing on the remotest of the Sun's planets may now
be nearer to us in time than the

Battle of Gettysburg.

The shadow of these coming events already lies across our age, stirring
the thoughts of all men who have ever stared at the night sky and
wondered what part our race is destined to play in the unfolding drama
of the Universe.

Many of the great questions of religion and philosophy must now be
reformulated, and there 210  is more than a possibility that some
which seemed forever beyond hope of solution may soon be answered.

Whether intelligent life exists outside Earth is, perhaps, unique among
these problems in its intellectual and emotional appeal.  The only type
of life which we can imagine without losing ourselves in biological
fantasies must be planet-based, and until a short time ago astronomers
felt reluctantly certain that planets were exceedingly rare phenomena.
Indeed, they were regarded as the results of cosmic accidents that
could occur only a very few times in the entire history of any
well-conducted universe.

Today we are fairly confident that the exact reverse is true; modern
theories of the formation of the Solar System suggest that many, if not
most, stars must have planets revolving around them.  This outlook was
given considerable support by the detection, in 1942, of a hitherto
unknown body-much too small to be a Sunin the double-star system 61
Cygni.  This binary star is one of our closest neighbors; it would be a
most remarkable coincidence, if planets were indeed rare, to find a
specimen practically on our doorsteps.  If we eliminate systems which,
through the instability of the central sun or for some other reason,
seem unpromising as the abodes of life, we may not be far from the
truth if we guess that one star in ten possesses at least one planet
upon which life could theoretically exist.

This leads us to the second and equally remarkable transformation which
the last ten or fifteen years has brought.  As recently as 1947 it was
possible for du NoUy, in his widely read book Human Destiny, to
maintain that living things could 'not possibly arise from "dead"
inorganic matter by the operation of purely natural forces.  The
complexity of even the simplest single-celled organism was so enormous
that to expect atoms of carbon, hydrogen, oxygen and the rest to form
it by spontaneous aggregation was much less probable than that
Eddington's famous army of simian typists should produce the entire
works of Shakespeare at the first attempt.  Life's appearance on Earth
(or elsewhere) must therefore have been consciously directed and
controlled by some organizing force, which it was tempting to identify
as the hand of God.

We now know, thanks to, the work of such biologists as Bernal and
Oparin, that this apparently convincing argument is wholly fallacious,
and that life can probably evolve from nonliving matter in the
circumstances that must exist upon many primitive, newly formed
planets.  The process may, indeed, be inevitable when we are dealing
with astronomical time periods; the idea that life on this planet is
some kind of freak or special creation has vanished with the belief in
the uniqueness of the Solar System.  Stanley

Miller's famous experiment at the University of Chicago in 1952, when a
complex organic soup was produced by the action of electrical
discharges upon simple solutions of carbon dioxide, ammonia, methane
and other gases, suggests how the first steps in the evolution of life
may have taken place.  (For an entertaining and not-too-technical
account of the way in which the chemicals of life may build themselves
up from elementary substances, see the essay "The Unblind Workings of
Chance" in Dr.  Isaac Asimov's book Only a Trillion.)

That both planets and living creatures are common throughout the
Universe must, therefore, now be taken as highly probable, though it
cannot yet be proved beyond doubt.  We may be hopelessly conservative
if we guess that life may be associated with one star in every hundred.
Dr.  Harlow Shapely, in his book Of Stars and Men, reduces the figure
to one in a trillion by being deliberately ultra pessimistic he
considers a more reasonable estimate to be one in a million.  But any
figure is, at the present stage of our semi-ignorance, pure guesswork;
let us for the sake of argument settle on that one in a hundred, and
see where it leads us.

It implies the existence of a billion life-bearing worlds in our
single

Galaxy-the whirlpool of stars of which our Sun is an undistinguished
out-of-town member, lying in one of the remoter spiral arms.  And
within the range of our telescopes there are approximately a billion
other galaxies.  Now a billion is a number all too familiar in today's
212  budgets and military estimates, but this does not mean that
anyone can visualize it.  Should you feel like trying, I recommend this
simple and highly instructive experiment.

Go down to the nearest beach and collect a bucketful of sand; then
bring it home and empty it on the table.  You now have in front of
you-assuming that the sand is of reasonable fineness-something like a
billion separate particles.  Sift them through your fingers; each is a
distinct entity, different from all its companions.  How long would it
take you to examine every clearly visible individual in the quite small
pile before you?

Devoting one minute to each, and working eight hours a day, it would
keep you busy for almost six thousand years-the whole span of human
history.

That is what a billion means; and now try to imagine that every one of
those grains of sand is itself a world, perhaps teeming with life, and
perhaps bearing rational creatures who measure their history not in
thousands but in millions of years.  If you succeed, you have a faint
mental picture of our Galaxy; if you wish to visualize the whole
observed

Universe, however, the operation must be repeated with each grain of
sand now representing an entire galaxy.

There is a temptation, when brainwashed by such numbers, to argue that
these astronomical vistas are of no practical importance, since we can
never have direct knowledge of more than a small-indeed, relatively
submicroscopic-portion of the Universe.  A similar policy was adopted
by those followers of Aristotle who refused to look through Galileo's
telescope and to see for themselves that Jupiter, as well as Earth, had
moons revolving round it.  If they could not be seen by the naked eye,
these gentlemen argued, the heretical satellites did not really
exist.

However, we cannot pretend that the Universe isn't there, for our own
children will be starting to explore it, and even their first modest
voyages will completely transform our view of the cosmos.  Once we can
climb the mere hundred miles or so which separate us from space, and
thus establish satellite observatories beyond 213  the murk and haze
of the atmosphere, it will be like emerging from a fog into the light
of day.  Without traveling any further from Earth than

Washington is from New York, we will have broken through the vision
barrier and will be able to view Mars, for example, from an apparent
distance of only a few thousand miles.  With the telescopes which we
will be able to construct and operate under the perfect seeing
conditions in space, we may even be able to look for the planets of
other suns.

It is obviously impossible to anticipate the discoveries which will be
made when we succeed in escaping from Earth; indeed, one characteristic
of most really important discoveries is their unexpectedness.  At* the
moment the astronomical evidence suggests that we will find some sort
of life in the

Solar System (on Mars, almost certainly; on Venus, just possibly) but
that we will not encounter intelligence.  It would be rather too much
to hope that two intelligent races should exist in the same small
region of space and at the same moment of time.

The discovery of any form of life, however humble, on the planets would
greatly affect our outlook upon the Universe by changing what is now a
surmise into a certainty.  Even a few lichens on Mars or a few amoebae
in the (still hypothetical) seas of Venus would prove that life is not
a rare disease that happens to have attacked the planet Earth.  And
with that settled, it would be illogical to deny the existence of
higher forms elsewhere.

It is just possible that we may find direct proof of this on Mars; even
if we have missed the Martians by a few million years, their records
will still be written in the rocks of an and world which knows none of
the erosion or the interchange of land and sea which has obliterated so
much of our own planet's remote past.  But all this is pare, unfounded
speculation; until we have reason to believe the contrary, it would be
safest to assume that H. sapiens is the only intelligent creature yet
to have evolved in the

Solar System.  To find 214  our equals or our peers, we must go
further afield to the planets of other suns.

This, to put it mildly, presents problems.  Though we are now about to
challenge interplanetary distances, the gulfs separating us from the
stars are a million times greater, and light itself takes years to span
them.

Nevertheless, there are good reasons for thinking that interstellar
travel will ultimately be possible.  When we have developed really
efficient nuclear-propulsion devices, speeds comparable to that of
light should be attainable, and round trips to the nearest stars would
take about ten years.  Though tedious, this would not be out of the
question even for manned vessels; such techniques as suspended
animation, or the use of purely automatic exploring vessels, would
extend this range indefinitely.

Nor need physical transportation be necessary.  With today's electronic
techniques stretched to the utmost, we could just about get a readable
Morse signal to the nearest star.  It might therefore be worth while,
as soon as we can establish satelli;e listening posts well away from
the radio racket and electrical interference of Earth, to begin a
search for i - ritelligently modulated signals from space.  If we can
tackle interstellar communication only sixty years after we have
invented radio, it is not unreasonable to assume that there may be
transmitters within a few light-years of us far more powerful than any
we have yet built.  Even today, many of our radars must far outrange
the Solar System -though we can be thankful that all our commercial
radio programs will have faded far below the level of cosmic noise
before they can affront any stellar neighbors

By one means or another, therefore, we may hope to establish the
existence of extraterrestrial intelligences before many more
decades--or at most centuries have passed.  If anyone still feels
doubtful of this, I would remind him of the unfortunate error of
Auguste Comte, who rashly proclaimed our eternal ignorance concerning
the composition of the stars.  The speed and thoroughness with which
the spectroscope refuted him 215  is a good reminder that there are no
apparently fundamental limits to knowledge which may not be transcended
by new techniques or inventions.

Keeping this in mind, it is not premature, and it is certainly
stimulating, to consider what effect these undoubted but still unknown
revelations will have upon the minds of men.  They will certainly
accelerate a process which has been gaining momentum since Copernicus
dethroned Earth from the center of creation and started it upon its
still-continuing journey to the periphery of the Universe.  Today, it
is difficult for us to believe that as recently as the time of
Shakespeare no one knew that other worlds existed; though the Greeks
had surmised it, there was no direct proof until the invention of the
telescope circa 1608, and so to almost all educated men up to a dozen
generations ago, our planet was the Universe.  One might even say that
this was still true, for 90 per cent of the human race, until the
morning of October 4, 1957.

The expansion of the time scale has had equally striking effects on
human thought.  Until well into the last century much of the Western
world believed in the literal truth of Archbishop Ussher's date for
Genesis4004

B.c.-which may still be found printed in sonde Bibles.  It is indeed
curious that so many devout men, during the three hundred years between
Galileo and

Darwin, stubbornly refused to recognize the grandeur of the Universe in
space and time-almost as if determined to disparage the power of God.
The

Eastern religions avoided this mistake, which has done so much to
weaken the prestige of Christianity; the Hindus, for example, take it
for granted that the world's history stretches back through aeons of
time that quite dwarf the few billions demanded by the astronomers.

As mankind's modest place in the scheme of the Universe is more and
more widely recognized-on the emotional as well as the intellectual
level-the effects on our racial pride will certainly be profound.  To
the Psalmist's question, "What is Man, that Thou are mindful of him?"
the future may well give the ironic answer, "What, indeed?"  Our
species has come into 216  existence in the last five-thousandth of
the Earth's history, and the entire span of human civilization extends
for barely a millionth of that time.

Unless we exhibit a conceit which can be aptly termed astronomical, we
must assume that there are many, many races in the Universe far more
advanced than ours intellectually as well as spiritually.  Indeed, the
extreme youth of Homo sapiens on any cosmic time scale makes it likely
that the vast majority of rational extraterrestrial creatures may be
superior to us by millions of years of development.

This prospect has been viewed with some alarm by many Christians, who
find it hard to reconcile the existence of other intelligent races with
the doctrines, of Incarnation and Redemption.  If God made Man in I-Es
own image, what of all the other creatures who; must be made in
different images, if they are to survive on alien worlds?  And if
Christ has saved us alone, what have we done to merit such special
treatment?

During the last few years these problems-which once seemed quite as
abstract as the classic question of the number of angels who could
dance on a pin-have engaged several theologians.  In his book Existence
and the

Christ, Professor Paul Tillich points out that the Incarnation preached
by

Christianity is for mankind only, and that other races may have other
incarnations.  (An idea expressed many years ago by Alice Meynell in
her poem "Christ in the Universe": .  in the eternities Doubtless we
shall compare together, hear A million alien Gospels, in what guise He
trod the Pleiades, the Lyre, the Bear.)

Tillich goes on to conclude: "The manifestation of saving power in one
place implies that saving power is operating in all places.  The
expectation of the Messiah as the bearer of the New Being presupposes
that God loves the universe, even though in the appearance of the
Christ he actualises his love for historical man alone."  Undoubtedly
the most stimulating writer on these matters is C. S. Lewis, professor
of literature at Magdalene College, Cambridge University.  In two
famous novels, Out of the Silent Planet and Voyage to Venus
(Perelandra),

Lewis has developed the theme that only humanity has fallen, and that
the creatures on other planets are free from the guilt which requires
our redemption.  This view of mankind's peculiar depravity, well
justified by a glance at the daily papers, implies that our planet is
under quarantine; in a recent issue of the Christian Herald (April,
1958) Professor Lewis makes it clear that he regards with some disfavor
our current attempts to evade this quarantine.  "Let us," he remarks,
"thank God that we are still very far from travel to other worlds."
Unless one considers twenty five years a very long time, this statement
must now be modified to read "travel to other worlds inhabited by
intelligent beings."

Another possibility, but one so flattering to our racial pride that it
is hard to believe it can be true, is that the redemption of other
races will proceed through us that we, in fact, may one day take
salvation to the stars.  Remembering how "gun and gospel" have been
combined in the past, and the manner in which so many missionaries have
attempted to "civilize the' natives Lewis is not at all happy about
this prospect.  "Would our missionaries," he asks, "recognise an un
fallen race if they met it?  Would they continue to press upon
creatures that did not need to be saved that plan of Salvation which
God has appointed for Man?  Would they denounce as sins mere
differences of behavior which the spiritual and biological history of
these strange creatures fully justified?"

Anyone who has read accounts of past mission activities (Bradford
Smith's

Yankees in Paradise is an excellent example) will appreciate the force
of these questions, and Lewis argues nobly: "We must stand firm against
all exploitation and all theological imperialism..  .. Our loyalty.  is
due not to our species but to God.  Those who are, or can become, His
sons, are our real brothers even if they have shells or tusks.  218 It
is spiritual, not biological, kinship that counts."  In applauding
these sentiments, one can also wish that they were better applied on
Earth.

The Catholic Church has already accepted and welcomed the coming of the
space age.  (Perhaps the outstanding role that Jesuit scientists have
played in astrophysics has something to do with this.) In 1956, the
International

Astronautical Federation held a congress in Rome and heard a lengthy
and learned address from Pope Pius XII in which he expressed the view
that now that Man has discovered the means of exploring the Universe,
God clearly intends him to use it.  This is a ruling which most men,
whatever their beliefs, will surely accept.  Any path to knowledge is a
path to God -or to

Reality, whichever word one prefers to use.

We may conclude, therefore, that any fears that space exploration will
shatter the bases of existing religions are unfounded.  Nevertheless,
the tremendous flood of new knowledge which will accrue from space
travel (and which indeed is already flowing down from today's
satellites) will in due course profoundly modify our philosophical and
religious beliefs.  Anyone who doubts this need only glance at the
overwhelming impact of science upon faith during the past few
centuries; the now settled controversies over

Earth's movement round the Sun and the evolution of Man are the classic
examples.  Even in the last hundred years, many beliefs passionately
held by the leaders of the great religions have ceased to be accepted
by their equally devout successors.  It would be absurd to imagine that
this process will come to an end, just at the moment when science is
about, to make the greatest breakthrough in all history.

At this moment in time, at the very beginning of the centuries-long
gold rush into ever richer, ever expanding fields of knowledge, we must
realize that there is no hope of understanding our Universe until we
have examined a fairly large sample of it-certainly a good deal more
than one small planet out of billions.  Though this cautious attitude
may disappoint many who are hot for certainties, any other policy
would be utterly n0ve.  It would put us in the same position as Pacific
islanders who have never yet had any contact with the world beyond
their coral reef, yet who attempt to construct a picture of the whole
Earth and its peoples from the view they get from the top of their
highest palm tree.

Harlow Shapley, in the already-mentioned Of Stars and Men, looks
forward to our present "anthropomorphic religions and philosophies,
which have so often been conspicuously earth-bound and much tangled up
with the human mind and human behavior" expanding to embrace these new
revelations of science, adding that it a one-planet deity has for me
little appeal."  The

British astronomer Fred Hoyle, in the controversial series of radio
talks which became the well-known book The Nature of the Universe, took
an uncompromisingly materialist view which caused much heart burning
and ink-slinging among his listeners.  He concluded that there is no
evidence for the existence of God in the Universe around us, religion
presumably being an illusion of the human mind.

On this view, it must be assumed that when we contact superior
extraterrestrial intelligences we shall find that belief in a
supernatural order of things marks an early stage of development
amongst most rational creatures, and perishes with the rise of science.
Most disconcerting of all would be the discovery that Man alone is a
myth-making animal, forever impelled to fill the gaps in his knowledge
by fantasies.  (Yet if this be the price we have had to pay for the
whole realm of art, which is always an attempt to create the
nonexistent, we need not be ashamed.  We will be better off than beings
who possess all knowledge, but know nothing of poetry and music.)

Whatever the outcome of our discoveries and adventures in space, the
fact will remain that the real Universe is more miraculous than any
miracle.  And even if every man now alive, seen from a century hence,
appears no more than "a savage suckled in an outworn creed," that will
leave God precisely where He has always been, if He is anywhere-back at
the be i nmig 220  of creation, X billion years ago.  (As of today, X
= 5. But remember

Archbishop Ussher.) Perhaps when God reached zero of the cosmic
countdown,

He turned His attention elsewhere, knowing that His work with us was
done.

It will certainly not diminish His glory rather the reverse-if we
discover that, in all the ages since time began, He has never tinkered
with the mechanism of the Universe.  Only an unskilled craftsman is
forced to make perpetual adjustments to his handiwork; the real expert
packs his tools and walks away when the job is done.... Let us,
therefore, wait in a spirit of expectant humility for whatever light
the future may throw upon these great questions, remembering that our
intellectual sincerity may well be judged by our lack of apprehension.
No honest man was ever afraid of the truth.

Faiths come and go, but Truth abides.  Out there among the stars lie
such truths as we may understand, whether we learn them by our own
efforts, or from the strange teachers who are waiting for us along the
infinite road on which our feet are now irrevocably set.

 Envoi

Across the gulf of centuries, the blind smile of Homer is turned upon
our age.  Along the echoing corridors of time, the roar of the rockets
merges now with the creak of the wind-taut rigging.  For somewhere in
the world today, still unconscious of his destiny, walks the boy who
will be the first Odysseus of the Age of Space....

