Collected Stories Of Arthur C. Clarke (90 page)

The ‘conventional’ theory of Culture X was that it had originally come from one of the smaller planets or satellites, had made peaceful contact with the Martians – the only other intelligent race in the known history of the System – and had died out at the same time as the Martian civilisation. But Professor Forster had more ambitious ideas: he was convinced that Culture X had entered the Solar System from intersteller space. The fact that no one else believed this annoyed him, though not very much, for he is one of those people who are happy only when in a minority.

From where I was sitting, I could see Jupiter through the cabin porthole as Professor Forster unfolded his plan. It was a beautiful sight: I could just make out the equatorial cloud belts, and three of the satellites were visible as little stars close to the planet. I wondered which was Ganymede, our first port of call.

‘If Jack will condescend to pay attention,’ the Professor continued, ‘I’ll tell you why we’re going such a long way from home. You know that last year I spent a good deal of time poking among the ruins in the twilight belt of Mercury. Perhaps you read the paper I gave on the subject at the London School of Economics. You may even have been there – I do remember a disturbance at the back of the hall.

‘What I didn’t tell anyone then was that while I was on Mercury I discovered an important clue to the origin of Culture X. I’ve kept quiet about it, although I’ve been sorely tempted when fools like Dr Haughton have tried to be funny at my expense. But I wasn’t going to risk letting someone else get here before I could organise this expedition.

‘One of the things I found on Mercury was a rather well preserved bas-relief of the Solar System. It’s not the first that’s been discovered – as you know, astronomical motifs are common in true Martian and Culture X art. But there were certain peculiar symbols against various planets, including Mars and Mercury. I think the pattern had some historic significance, and the most curious thing about it is that little Jupiter Five – one of the least important of all the satellites – seemed to have the most attention drawn to it. I’m convinced that there’s something on Five which is the key to the whole problem of Culture X, and I’m going there to discover what it is.’

As far as I can remember now, neither Bill nor I was particularly impressed by the Professor’s story. Maybe the people of Culture X had left some artifacts on Five for obscure reasons of their own. It would be interesting to unearth them, but hardly likely that they would be as important as the Professor thought. I guess he was rather disappointed at our lack of enthusiasm. If so it was his fault since, as we discovered later, he was still holding out on us.

We landed on Ganymede, the largest moon, about a week later. Ganymede is the only one of the satellites with a permanent base on it; there’s an observatory and a geophysical station with a staff of about fifty scientists. They were rather glad to see visitors, but we didn’t stay long as the Professor was anxious to refuel and set off again. The fact that we were heading for Five naturally aroused a good deal of interest, but the Professor wouldn’t talk and we couldn’t; he kept too close an eye on us.

Ganymede, by the way, is quite an interesting place and we managed to see rather more of it on the return journey. But as I’ve promised to write an article for another magazine about that, I’d better not say anything else here. (You might like to keep your eyes on the
National Astrographic
Magazine next Spring.)

The hop from Ganymede to Five took just over a day and a half, and it gave us an uncomfortable feeling to see Jupiter expanding hour by hour until it seemed as if he was going to fill the sky. I don’t know much about astronomy, but I couldn’t help thinking of the tremendous gravity field into which we were falling. All sorts of things could go wrong so easily. If we ran out of fuel we’d never be able to get back to Ganymede, and we might even drop into Jupiter himself.

I wish I could describe what it was like seeing that colossal globe, with its raging storm belts spinning in the sky ahead of us. As a matter of fact I
did
make the attempt, but some literary friends who have read this MS advised me to cut out the result. (They also gave me a lot of other advice which I don’t think they could have meant seriously, because if I’d followed it there would have been no story at all.)

Luckily there have been so many colour close-ups of Jupiter published by now that you’re bound to have seen some of them. You may even have seen the one which, as I’ll explain later, was the cause of all our trouble.

At last Jupiter stopped growing: we’d swung into the orbit of Five and would soon catch up with the tiny moon as it raced around the planet. We were all squeezed in the control room waiting for our first glimpse of our target. At least, all of us who could get in were doing so. Bill and I were crowded out into the corridor and could only crane over the other people’s shoulders. Kingsley Searle, our pilot, was in the control seat looking as unruffled as ever: Eric Fulton, the engineer, was thoughtfully chewing his moustache and watching the fuel gauges, and Tony Groves was doing complicated things with his navigation tables.

And the Professor appeared to be rigidly attached to the eyepiece of the teleperiscope. Suddenly he gave a start and we heard a whistle of indrawn breath. After a minute, without a word, he beckoned to Searle, who took his place at the eyepiece. Exactly the same thing happened, and then Searle handed over to Fulton. It got a bit monotonous by the time Groves had reacted identically, so we wormed our way in and took over after a bit of opposition.

I don’t know quite what I’d expected to see, so that’s probably why I was disappointed. Hanging there in space was a tiny gibbous moon, its ‘night’ sector lit up faintly by the reflected glory of Jupiter. And that seemed to be all.

Then I began to make out additional markings, in the way that you do if you look through a telescope for long enough. There were faint crisscrossing lines on the surface of the satellite, and suddenly my eye grasped their full pattern. For it
was
a pattern: those lines covered Five with the same geometrical accuracy as the lines of latitude and longitude divide up a globe of the Earth. I suppose I gave my whistle of amazement, for then Bill pushed me out of the way and had his turn to look.

The next thing I remember is Professor Forster looking very smug while we bombarded him with questions.

‘Of course,’ he explained, ‘this isn’t as much a surprise to me as it it to you. Besides the evidence I’d found on Mercury, there were other clues. I’ve a friend at the Ganymede Observatory whom I’ve sworn to secrecy and who’s been under quite a strain this last few weeks. It’s rather surprising to anyone who’s not an astronomer that the Observatory has never bothered much about the satellites. The big instruments are used on extra-galactic nebulae, and the little ones spend all their time looking at Jupiter.

‘The only thing the Observatory had ever done to Five was to measure its diameter and take a few photographs. They weren’t quite good enough to show the markings we’ve just observed, otherwise there would have been an investigation before. But my friend Lawton detected them through the hundred-centimetre reflector when I asked him to look, and he also noticed something else that should have been spotted before. Five is only thirty kilometres in diameter, but it’s much brighter than it should be for its size. When you compare its reflecting power – its aldeb – its—’

‘Its albedo.’

‘Thanks, Tony – its albedo with that of the other Moons, you find that it’s a much better reflector than it should be. In fact, it behaves more like polished metal than rock.’

‘So that explains it!’ I said. ‘The people of Culture X must have covered Five with an outer shell – like the domes they built on Mercury, but on a bigger scale.’

The Professor looked at me rather pityingly.

‘So you still haven’t guessed!’ he said.

I don’t think this was quite fair. Frankly, would you have done any better in the same circumstances?

We landed three hours later on an enormous metal plain. As I looked through the portholes, I felt completely dwarfed by my surroundings. An ant crawling on the top of an oil-storage tank might have had much the same feelings – and the looming bulk of Jupiter up there in the sky didn’t help. Even the Professor’s usual cockiness now seemed to be overlaid by a kind of reverent awe.

The plain wasn’t quite devoid of features. Running across it in various directions were broad bands where the stupendous metal plates had been joined together. These bands, or the crisscross pattern they formed, were what we had seen from space.

About a quarter of a kilometre away was a low hill – at least, what would have been a hill on a natural world. We had spotted it on our way in after making a careful survey of the little satellite from space. It was one of six such projections, four arranged equidistantly around the equator and the other two at the Poles. The assumption was pretty obvious that they would be entrances to the world below the metal shell.

I know that some people think it must be very entertaining to walk around on an airless, low-gravity planet in spacesuits. Well, it isn’t. There are so many points to think about, so many checks to make and precautions to observe, that the mental strain outweighs the glamour – at least as far as I’m concerned. But I must admit that this time, as we climbed out of the airlock, I was so excited that for once these things didn’t worry me.

The gravity of Five was so microscopic that walking was completely out of the question. We were all roped together like mountaineers and blew ourselves across the metal plain with gentle bursts from our recoil pistols. The experienced astronauts, Fulton and Groves, were at the two ends of the chain so that any unwise eagerness on the part of the people in the middle was restrained.

It took us only a few minutes to reach our objective, which we discovered to be a broad, low dome at least a kilometre in circumference. I wondered if it was a gigantic airlock, large enough to permit the entrance of whole spaceships. Unless we were very lucky, we might be unable to find a way in, since the controlling mechanisms would no longer be functioning, and even if they were, we would not know how to operate them. It would be difficult to imagine anything more tantalising than being locked out, unable to get at the greatest archaeological find in all history.

We had made a quarter circuit of the dome when we found an opening in the metal shell. It was quite small – only about two metres across – and it was so nearly circular that for a moment we did not realise what it was. Then Tony’s voice came over the radio.

‘That’s not artificial. We’ve got a meteor to thank for it.’

‘Impossible!’ protested Professor Forster. ‘It’s much too regular.’

Tony was stubborn.

‘Big meteors always produce circular holes, unless they strike very glancing blows. And look at the edges; you can see there’s been an explosion of some kind. Probably the meteor and the shell were vaporised; we won’t find any fragments.’

‘You’d expect this sort of thing to happen,’ put in Kingsley. ‘How long has this been here? Five million years? I’m surprised we haven’t found any other craters.’

‘Maybe you’re right,’ said the Professor, too pleased to argue. ‘Anyway, I’m going in first.’

‘Right,’ said Kingsley, who as captain has the last say in all such matters. ‘I’ll give you twenty metres of rope and will sit in the hole so that we can keep radio contact. Otherwise this shell will blanket your signals.’

So Professor Forster was the first man to enter Five, as he deserved to be. We crowded close to Kingsley so that he could relay news of the Professor’s progress.

He didn’t get very far. There was another shell just inside the outer one, as we might have expected. The Professor had room to stand upright between them, and as far as his torch could throw its beam he could see avenues of supporting struts and girders, but that was about all.

It took us about twenty-four exasperating hours before we got any further. Near the end of that time I remember asking the Professor why he hadn’t thought of bringing any explosives. He gave me a very hurt look.

‘There’s enough aboard the ship to blow us all to glory,’ he said. ‘But I’m not going to risk doing any damage if I can find another way.’

That’s what I call patience, but I could see his point of view. After all, what was another few days in a search that had already taken him twenty years?

It was Bill Hawkins, of all people, who found the way in when we had abandoned our first line of approach. Near the North Pole of the little world he discovered a really giant meteor hole – about a hundred metres across and cutting through both the outer shells surrounding Five. It had revealed still another shell below those, and by one of those chances that must happen if one waits enough eons, a second, smaller, meteor had come down inside the crater and penetrated the innermost skin. The hole was just big enough to allow entrance for a man in a spacesuit. We went through head first, one at a time.

I don’t suppose I’ll ever have a weirder experience than hanging from that tremendous vault, like a spider suspended beneath the dome of St Peter’s. We only knew that the space in which we floated was vast. Just
how
big it was we could not tell, for our torches gave us no sense of distance. In this airless, dustless cavern the beams were, of course, totally invisible and when we shone them on the roof above, we could see the ovals of light dancing away into the distance until they were too diffuse to be visible. If we pointed them ‘downward’ we could see a pale smudge of illumination so far below that it revealed nothing.