Authors: Arthur C Clarke
It was one of those peculiar dreams when you know you're dreaming and can't do anything about it. Everything that had happened to me in the last few weeks was all muddled up together—as well as flashbacks from earlier experiences. Sometimes things were quite the wrong way round. I was down on Earth, but weightless, floating like a cloud over valleys and hills. Or else I was up in the Inner Station—but had to struggle against gravity with every movement I made.
The dream ended in nightmare. I was taking a shortcut through the Inner Station, using an illegal but widely practised method that Norman Powell had shown me. Linking the central part of the Station with its outlying pressurized chambers are ventilating ducts, wide enough to take a man. The air moves through them at quite a speed, and there are places where one can enter and get a free ride. It's an exciting experience, and you have to know just what you're doing or you may miss the exit and have to buck the air stream to find a way back. Well, in this dream I was riding the air stream, and had lost my way. There ahead of me I could see the great blades of the ventilating fan, sucking me down towards them.
And
the protecting grill was gone
—in a few seconds I'd be sliced like a side of bacon…
'He's all right,' I heard someone say. 'He was only out for a minute. Give him another sniff.'
A jet of cold gas played over my face, and I tried to jerk my head out of the way. Then I opened my eyes and realized where I was.
'What happened?' I asked, still feeling rather dazed.
Tim Benton was sitting beside me, an oxygen cylinder in his hand. He didn't look in the least upset.
'We're not quite sure,' he said. 'But it's O.K. now. A change-over valve must have jammed in the oxygen supply when one of the tanks got empty. You were the only one who passed out, and we've managed to clear the trouble by bashing the oxygen distributor with a hammer. Crude, but it usually works. Of course it will have to be stripped down when we get back—someone will have to find out why the alarm didn't work.'
I still felt rather muzzy, and a little ashamed of myself for fainting—though that wasn't the kind of thing anyone could help. And, after all, I
had
acted as a sort of human guinea-pig to warn the others. Or perhaps a better analogy would be one of the canaries the old-time miners took with them to test the air underground.
'Does this sort of thing happen very often?' I asked.
'Hardly ever,' replied Norman Powell. For once he looked serious. 'But there are so many gadgets in a space-ship that you've always got to keep on your toes. In a hundred years we haven't got all the bugs out of space-flight. If it isn't one thing, it's another.'
'Don't be so glum, Norman,' said Tim. 'We've had our share of trouble for this trip. It'll be plain sailing now.'
As it turned out,
that
remark was about the most unfortunate that Tim ever made. I'm sure the others never gave him a chance to forget it.
We were now several miles from the Hospital—far enough away to avoid our jets doing any damage to it. The pilot had set his controls and was waiting for the calculated moment to start firing. Everyone else was lying down in their bunks: the acceleration would be too weak to be anything of a strain, but we were supposed to keep out of the pilot's way at blastoff and there was simply nowhere else to go.
The motors roared for nearly two minutes: at the end of that time the Hospital was a tiny, brilliant toy twenty or thirty miles away. If the pilot had done his job properly, we were now dropping down on a long curve that would take us back to the Inner Station. We had nothing to do but sit and wait for the next three and a half hours, while the Earth grew bigger and bigger until it once more filled almost half the sky.
On the way out, because of our patient, we hadn't been able to talk, but there was nothing to stop us now. There was a curious kind of elation, even light-headedness, about our little party. If I'd stopped to think about it, I should have realized that there was something odd in the way we were all laughing and joking—but at the time it seemed natural enough.
Even the Commander unbent more than I'd ever known him to before—not that he was ever really formidable once you'd got used to him. But he never talked about himself; and back at the Inner Station no one would have dreamed of asking him to tell the story of his part in the first expedition to Mercury. And if they had, he certainly wouldn't have done so—yet he did now. He grumbled for a while, but not very effectively. Then he began to talk.
'Where shall I start?' he mused. 'Well, there's not much to say about the voyage itself—it was just like any other trip. No one else had ever been so near the Sun before, but the mirror-plating of our ship worked perfectly and stopped us getting too hot by bouncing eighty per cent of the Sun's rays straight off again.
'Our instructions were not to attempt a landing unless we were quite sure it would be safe. So we got into an orbit a thousand miles up and began to do a careful survey.
'You know, of course, that Mercury always keeps one face towards the Sun, so that it hasn't days or nights as we have on Earth. One side is in perpetual darkness—the other in blazing light. However, there's a narrow 'twilight' zone between the two hemispheres, where the temperature isn't too extreme. We planned to come down somewhere in this region, if we could find a good landing place.
'We had our first surprise when we looked at the day side of the planet. Somehow everyone had always imagined that it would be very much like the Moon—covered with jagged craters and mountain ranges. But it wasn't. There are no mountains at all on the part of Mercury directly facing the Sun—only a few low hills and great, cracked plains. When we thought about it, the reason was obvious. The temperature down there in that perpetual sunlight is over seven hundred degrees F. That's much too low to melt rock—but it can soften it, and gravity had done the rest. Over millions of years, any mountains that might have existed on the day side of Mercury had slowly collapsed, just as a block of pitch flows on a hot day. Only round the rim of the night land, where the temperature was far lower, were there any real mountains.
'Our second surprise was to discover that there were lakes down there in that blazing inferno. Of course, they weren't lakes of water, but of molten metal. Since no one's been able to reach them yet we don't know what metals they are—probably lead and tin, with other things mixed up with them. Lakes of solder, in fact! They may be pretty valuable one day, if we can discover how to tap them.
'As you'll guess from this, we weren't anxious to land anywhere in the middle of the day side. So when we'd completed a photographic map we had a look at the Night Land.
'The only way we could do that was to illuminate it with flares. We went as close as we dared—less than a hundred miles up—and shot off billion-candle-power markers one after another, taking photographs as we did so. The flares, of course, shared our speed and travelled along with us until they burned out.
'It was a strange experience, knowing that we were shedding light on a land that had never seen the Sun—a land where the only light for maybe millions of years had been that of the stars. If there was any life down there—which seemed about as unlikely as anything could be—it must be having quite a surprise! At least, that was my first thought as I watched our flares blasting that hidden land with their brilliance. Then I decided that any creatures of the Night Land would probably be completely blind, like the fish of our own ocean depths. Still, all this was fantasy:
nothing
could possibly live down there in that perpetual darkness, at a temperature of almost four hundred degrees below freezing point. We know better now, of course…
'It was nearly a week before we risked a landing, and by that time we'd mapped the surface of the planet pretty thoroughly. The Night Land, and much of the Twilight Zone, is fairly mountainous, but there were plenty of flat regions that looked promising. We finally chose a large shallow bowl on the edge of the Day Side.
'There's a trace of atmosphere on Mercury, but not enough for wings or parachutes to be of any use. So we had to land by rocket braking, just as you do on the Moon. However often you do it, a rocket touchdown is always a bit unnerving—especially on a new world where you can't be perfectly sure that what looks like rock is anything of the sort.
'Well, it
was
rock, not one of those treacherous dust-drifts they have on the Moon. The landing gear took up the impact so thoroughly that we hardly noticed it in the cabin. Then the motors cut out automatically and we were down—the first men to land on Mercury. The first living creatures, probably, ever to touch the planet.
'I said that we'd come down at the frontiers of the Day Side. That meant that the Sun was a great, blinding disc right on the horizon. It was strange, seeing it almost fixed there, never rising or setting—though because Mercury's got a very eccentric orbit, the Sun does wobble to and fro through a considerable arc in the sky. Still, it never
dropped
below the horizon, and I always had the feeling that it was late afternoon and that night would fall shortly. It was hard to realize that "night" and "day" didn't mean anything here…
'Exploring a new world sounds exciting, and so it is, I suppose. But it's also darned hard work—and dangerous, especially on a planet like Mercury. Our first job was to see that the ship couldn't get overheated: we'd brought along some protective awnings for this purpose. Our "sunshades", as we called them. They looked peculiar—but they did the job properly. We even had portable ones, like flimsy tents, to protect us if we stayed out in the open for any length of time. They were made of white nylon and reflected most of the sunlight, though they let through enough to provide all the warmth and light we wanted.
'We spent several weeks reconnoitring the Day Side, travelling up to twenty miles from the ship. That may not sound very far, but it's quite a distance when you've got to wear a space-suit and carry all your supplies. We collected hundreds of mineral specimens and took thousands of readings with our instruments, sending back all the results we could by tight-beam radio to Earth. It was impossible to go far enough into the Day Side to reach the lakes we'd seen—the nearest was over eight hundred miles away, and we couldn't afford the rocket fuel to go hopping around the planet. In any case it would have been far too dangerous to go into that blazing furnace with our present, untried equipment.'
The Commander paused, staring thoughtfully into space as if he could see beyond our cramped little cabin to the burning deserts of that distant world.
'Yes,' he continued at last, 'Mercury's
quite
a challenge. We can deal with cold easily enough, but heat's another problem. Yet I suppose I shouldn't say that, because it was the cold that got me, not the heat…
'The one thing we never expected to find on Mercury was life, though the Moon should have taught us a lesson. No one had expected to find it
there,
either. And if anyone had said to me, "Assuming that there
is
life on Mercury, where would you hope to find it?" I'd have replied, "Why, in the Twilight Zone, of course." I'd have been wrong again…
'Though no one was very keen on the idea, we decided we ought to have at least one good look at the Night Land. We had to move the ship about a hundred miles to get clear of the Twilight one, and we landed on a low, flat hill a few miles from an interesting-looking range of mountains. We spent an anxious twenty-four hours before we were sure that it was safe to stay. The rock on which the ship was standing had a temperature of minus three hundred and fifty degrees, but our heaters could handle the situation. Even without them on, the temperature in the ship dropped very slowly, because of course there was a near vacuum round us and our silvered walls reflected back most of the heat we'd lose by radiation. We were living, in fact, inside a large Thermos flask—and our bodies were also generating quite a bit of heat.
'Still, we couldn't learn much merely by sitting inside the ship: we had to put on our space-suits and go out into the open. The suits we were using had been tested pretty thoroughly on the Moon during the lunar night, which is almost as cold as it is on Mercury. But no test is ever quite like the real thing. That was why three of us went out. If one man got into trouble, the other two could get him back to the ship we hoped.
'I was in that first party: we walked slowly round for about thirty minutes, taking things easily and reporting to the ship by radio. It wasn't as dark as we'd expected, thanks to Venus. She was hanging up there against the stars, incredibly brilliant, and casting easily visible shadows. Indeed, she was too bright to look at directly for more than a few seconds: using a filter to cut down the glare, one could easily see the tiny disc of the planet.
'The Earth and Moon were also visible, forming a beautiful double star just above the horizon. They also gave quite a lot of light so we were never in complete darkness. But, of course, neither Venus nor Earth gave the slightest heat to this frozen land.
'We couldn't lose the ship, because it was the most prominent object for miles around and we'd also fixed a powerful beacon on its nose. With some difficulty we broke off a few small specimens of rock and carried them back with us. As soon as we took them into the air-lock, an extraordinary thing happened. They became instantly covered with frost, and drops of liquid began to form on them, dripping off to the floor and evaporating again. It was the air in the ship condensing on the bitterly cold fragments of stone. We had to wait half an hour before they had become sufficiently warm to handle.