Read Clarke, Arthur C - SSC 04 Online
Authors: The Other Side of the Sky
First published in
If
, February 1958
Collected in
The Other Side of the Sky
If you have only lived on Earth, you have
never seen the sun. Of course, we could not look at it directly, but only
through dense filters that cut its rays down to endurable brilliance. It hung
there forever above the low, jagged hills to the west of the Observatory,
neither rising nor setting, yet moving around a small circle in the sky during
the eighty-eight-day year of our little world. For it is not quite true to say
that Mercury keeps the same face always turned toward the sun; it wobbles
slightly on its axis, and there is a narrow twilight belt which knows such
terrestral commonplaces as dawn and sunset.
We were on the edge of the twilight zone, so
that we could take advantage of the cool shadows yet could keep the sun under
continuous surveillance as it hovered there above the hills. It was a full-time
job for fifty astronomers and other assorted scientists; when we’ve kept it up
for a hundred years or so, we may know something about the small star that
brought life to Earth.
There wasn’t a single band of solar
radiation that someone at the Observatory had not made a life’s study and was
watching like a hawk. From the far X rays to the longest of radio waves, we had
set our traps and snares; as soon as the sun thought of something new, we were
ready for it. So we imagined …
The sun’s flaming heart beats in a slow,
eleven-year rhythm, and we were near the peak of the cycle. Two of the greatest
spots ever recorded – each of them large enough to swallow a hundred Earths –
had drifted across the disc like great black funnels piercing deeply into the
turbulent outer layers of the sun. They were black, of course, only by contrast
with the brilliance all around them; even their dark, cool cores were hotter
and brighter than an electric arc. We had just watched the second of them
disappear around the edge of the disc, wondering if it would survive to
reappear two weeks later, when something blew up on the equator.
It was not too spectacular at first, partly
because it was almost exactly beneath us – at the precise centre of the sun’s
disc – and so was merged into all the activity around it. If it had been near
the edge of the sun, and thus projected against the background of space, it
would have been truly awe-inspiring.
Imagine the simultaneous explosion of a
million H-bombs. You can’t? Nor can anyone else – but that was the sort of
thing we were watching climb up toward us at hundreds of miles a second,
straight out of the sun’s spinning equator. At first it formed a narrow jet,
but it was quickly frayed around the edges by the magnetic and gravitational
forces that were fighting against it. The central core kept right on, and it
was soon obvious that it had escaped from the sun completely and was headed out
into space – with us as its first target.
Though this had happened half a dozen times
before, it was always exciting. It meant that we could capture some of the very
substance of the sun as it went hurtling past in a great cloud of electrified
gas. There was no danger; by the time it reached us it would be far too tenuous
to do any damage, and, indeed, it would take sensitive instruments to detect it
at all.
One of those instruments was the
Observatory’s radar, which was in continual use to map the invisible ionised
layers that surround the sun for millions of miles. This was my department; as
soon as there was any hope of picking up the oncoming cloud against the solar
background, I aimed my giant radio mirror toward it.
It came in sharp and clear on the long-range
screen – a vast, luminous island still moving outward from the sun at hundreds
of miles a second. At this distance it was impossible to see its finer details,
for my radar waves were taking minutes to make the round trip and to bring me
back the information they were presenting on the screen. Even at its speed of
not far short of a million miles an hour, it would be almost two days before
the escaping prominence reached the orbit of Mercury and swept past us toward
the outer planets. But neither Venus nor Earth would record its passing, for
they were nowhere near its line of flight.
The hours drifted by; the sun had settled
down after the immense convulsion that had shot so many millions of tons of its
substance into space, never to return. The aftermath of that eruption was now a
slowly twisting and turning cloud a hundred times the size of Earth, and soon
it would be close enough for the short-range radar to reveal its finer
structure.
Despite all the years I have been in the
business, it still gives me a thrill to watch that line of light paint its
picture on the screen as it spins in synchronism with the narrow beam of radio
waves from the transmitter. I sometimes think of myself as a blind man
exploring the space around him with a stick that may be a hundred million miles
in length. For man is truly blind to the things I study; these great clouds of
ionised gas moving far out from the sun are completely invisible to the eye and
even to the most sensitive of photographic plates. They are ghosts that briefly
haunt the solar system during the few hours of their existence; if they did not
reflect our radar waves or disturb our magnetometers, we should never know that
they were there.
The picture on the screen looked not unlike
a photograph of a spiral nebula, for as the cloud slowly rotated it trailed
ragged arms of gas for ten thousand miles around it. Or it might have been a
terrestrial hurricane that I was watching from above as it spun through the
atmosphere of Earth. The internal structure was extremely complicated, and was
changing minute by minute beneath the action of forces which we have never
fully understood. Rivers of fire were flowing in curious paths under what could
only be the influence of electric fields; but why were they appearing from
nowhere and disappearing again as if matter was being created and destroyed?
And what were those gleaming nodules, larger than the moon, that were being
swept along like boulders before a flood?
Now it was less than a million miles away;
it would be upon us in little more than an hour. The automatic cameras were
recording every complete sweep of the radar scan, storing up evidence which was
to keep us arguing for years. The magnetic disturbance riding ahead of the
cloud had already reached us; indeed, there was hardly an instrument in the
Observatory that was not reacting in some way to the onrushing apparition.
I switched to the short-range scanner, and
the image of the cloud expanded so enormously that only its central portion was
on the screen. At the same time I began to change frequency, tuning across the
spectrum to differentiate among the various levels. The shorter the wave
length, the farther you can penetrate into a layer of ionised gas; by this
technique I hoped to get a kind of X-ray picture of the cloud’s interior.
It seemed to change before my eyes as I
sliced down through the tenuous outer envelope with its trailing arms, and
approached the denser core. ‘Denser’, of course, was a purely relative word; by
terrestrial standards even its most closely packed regions were still a fairly
good vacuum. I had almost reached the limit of my frequency band, and could
shorten the wave length no farther, when I noticed the curious, tight little
echo not far from the centre of the screen.
It was oval, and much more sharp-edged than
the knots of gas we had watched adrift in the cloud’s fiery streams. Even in
that first glimpse, I knew that here was something very strange and outside all
previous records of solar phenomena. I watched it for a dozen scans of the
radar beam, then called my assistant away from the radio-spectrograph, with
which he was analysing the velocities of the swirling gas as it spun toward us.
‘Look, Don,’ I asked him, ‘have you ever
seen anything like that?’
‘No,’ he answered after a careful
examination. ‘What holds it together? It hasn’t changed its shape for the last
two minutes.’
‘That’s what puzzles me. Whatever it is, it
should have started to break up by now, with all that disturbance going on
around it. But it seems as stable as ever.’
‘How big would you say it is?’
I switched on the calibration grid and took
a quick reading.
‘It’s about five hundred miles long, and
half that in width.’
‘Is this the largest picture you can get?’
‘I’m afraid so. We’ll have to wait until
it’s closer before we can see what makes it tick.’
Don gave a nervous little laugh.
‘This is crazy,’ he said, ‘but do you know
something? I feel as if I’m looking at an amoeba under a microscope.’
I did not answer; for, with what I can only
describe as a sensation of intellectual vertigo, exactly the same thought had
entered my mind.
We forgot about the rest of the cloud, but
luckily the automatic cameras kept up their work and no important observations
were lost. From now on we had eyes only for that sharp-edged lens of gas that
was growing minute by minute as it raced towards us. When it was no farther
away than is the moon from Earth, it began to show the first signs of its
internal structure, revealing a curious mottled appearance that was never quite
the same on two successive sweeps of the scanner.
By now, half the Observatory staff had
joined us in the radar room, yet there was complete silence as the oncoming
enigma grew swiftly across the screen. It was coming straight toward us; in a
few minutes it would hit Mercury somewhere in the centre of the daylight side,
and that would be the end of it – whatever it was. From the moment we obtained
our first really detailed view until the screen became blank again could not
have been more than five minutes; for every one of us, that five minutes will
haunt us all our lives.
We were looking at what seemed to be a
translucent oval, its interior laced with a network of almost invisible lines.
Where the lines crossed there appeared to be tiny, pulsing nodes of light; we
could never be quite sure of their existence because the radar took almost a
minute to paint the complete picture on the screen – and between each sweep the
object moved several thousand miles. There was no doubt, however, that the
network itself existed; the cameras settled any arguments about that.
So strong was the impression that we were
looking at a solid object that I took a few moments off from the radar screen
and hastily focused one of the optical telescopes on the sky. Of course, there
was nothing to be seen – no sign of anything silhouetted against the sun’s
pock-marked disc. This was a case where vision failed completely and only the
electrical senses of the radar were of any use. The thing that was coming
toward us out of the sun was as transparent as air – and far more tenuous.
As those last moments ebbed away, I am quite
sure that every one of us had reached the same conclusion – and was waiting for
someone to say it first. What we were seeing was impossible, yet the evidence
was there before our eyes. We were looking at life, where no life could exist …
The eruption had hurled the thing out of its
normal environment, deep down in the flaming atmosphere of the sun. It was a
miracle that it had survived its journey through space; already it must be
dying, as the forces that controlled its huge, invisible body lost their hold
over the electrified gas which was the only substance it possessed.
Today, now that I have run through those
films a hundred times, the idea no longer seems so strange to me. For what is
life but organised energy? Does it matter
what
form that energy takes –
whether it is chemical, as we know it on Earth, or purely electrical, as it
seemed to be here? Only the pattern is important; the substance itself is of no
significance. But at the time I did not think of this; I was conscious only of
a vast and overwhelming wonder as I watched this creature of the sun live out
the final moments of its existence.
Was it intelligent? Could it understand the
strange doom that had befallen it? There are a thousand such questions that may
never be answered. It is hard to see how a creature born in the fires of the
sun itself could know anything of the external universe, or could even sense
the existence of something as unutterably cold as rigid nongaseous matter. The
living island that was falling upon us from space could never have conceived,
however intelligent it might be, of the world it was so swiftly approaching.
Now it filled our sky – and perhaps, in
those last few seconds, it knew that something strange was ahead of it. It may
have sensed the far-flung magnetic field of Mercury, or felt the tug of our
little world’s gravitational pull. For it had begun to change; the luminous
lines that must have been what passed for its nervous system were clumping
together in new patterns, and I would have given much to know their meaning. It
may be that I was looking into the brain of a mindless beast in its last
convulsion of fear – or of a godlike being making its peace with the universe.
Then the radar screen was empty, wiped clean
during a single scan of the beam. The creature had fallen below our horizon,
and was hidden from us now by the curve of the planet. Far out in the burning
dayside of Mercury, in the inferno where only a dozen men have ever ventured and
fewer still come back alive, it smashed silently and invisibly against the seas
of molten metal, the hills of slowly moving lava. The mere impact could have
meant nothing to such an entity; what it could not endure was its first contact
wih the inconceivable cold of solid matter.