by Isaac Asimov
The thinner air of Mars scarcely softened them, but left them hard and gem-bright. There was no moon, of course, not one such as Earth knew. Mars's two satellites, Phobos and Deimos, were tiny things only five or ten miles across, simply mountains flying loose in space. Even though they were much closer to Mars than the Moon was to Earth, they would show no disk and be only two more stars.
He searched for them, even though he realized they might easily both be on the other side of Mars. Low on the western horizon he caught something else. Slowly he turned to it. It was by far the brightest object in the sky, with a faint blue-green tinge to it that was matched for beauty by nothing else in the heavens he watched. Separated from it by about the width of Mars's shrunken sun was another object, yellower, bright in itself but dwarfed by the much greater brillance of its neighbor.
David needed no star map to identify the double object. They were the Earth and the Moon, the double "evening star" of Mars.
He tore his eyes away, turned toward the low outcropping of rock visible in the light of his pencil flash, and began walking. Bigman had told him to use those rocks as a guide. It was cold in the Martian night, and David was regretfully aware of the heating powers of even the Martian sun, one hundred and thirty million miles away.
The sand-car was invisible, or nearly so, in the weak starlight, and he heard the low, even purr of its engines long before he saw it.
He called, "Bigman!" and the little fellow popped out of it.
"Space!" said Bigman. "I was beginning to think you were lost."
"Why is the engine running?"
"That's easy. How else do I keep from freezing to death? We won't be heard, though. I know this place."
"Do you have the films?"
"Do I? Listen, I don't know what you had in the message you sent but they had five or six scholars circling me like satellites. It was 'Mr. Jones this' and "Mr. Jones that.' I said, 'My name's Bigman,' I said. And then it was 'Mr. Bigman, if you please.' Anyway"-Bigman ticked items off on his fingers-"before the day was gone, they had four films for me, two viewers, a box as big as myself which I haven't opened, and the loan (or maybe the gift for all I know) of a sand-car to carry it all in."
David smiled but made no answer. He entered Into the welcome warmth of the car and quickly, in a race to outrun the fleet night, adjusted the viewers for projection and inserted a film in each. Direct viewing would have been quicker, more preferable, but even in the warm interior of the sand-car his nosepiece was still a necessity, and the bulbous transparent covering of his eyes made direct viewing impossible.
Slowly the sand-car lurched forward through the night, repeating almost exactly the route of Griswold's subsection on the day of the checkup.
"I don't get it," said Bigman. He had been muttering under his breath uselessly for fifteen minutes and now he had to repeat his louder statement twice before the brooding David would respond.
"Don't get what?"
"What you're doing. Where you're going. I figure this is my business because I'm going to stay with you from here on. I've been thinking today, Mr. St- Williams, thinking a lot. Mr. Makian's been in a kind of biting temper for months now, and he wasn't a bad joe at all before that. Hermes came in at that time, with a new shuffle for all hands. And Schoolboy Benson gets his licks in all of a sudden. Before it all started he was nobody, and now he's real pally with the big shots. Then, to top it off, you're here, with the Council of Science ready to put up anything you want. It's something big, I know, and I want to be in on it"
"Do you?" said David. "Did you see the maps I was viewing?"
"Sure. Just old maps of Mars. I've seen them a million times."
"How about the ones with the crosshatched areas? Do you know what those areas stood for?"
"Any farmboy can tell you that. There are supposed to be caverns underneath, except that I don't believe it. My point is this. How in Space can anyone tell there are holes two miles underneath the ground if no one's been down there to see? Tell me that."
David did not bother to describe the science of seismography to Bigman. Instead, he said, "Ever hear of Martians?" Bigman began, "Sure. What kind of a question____________________ " and then the sand-car screeched and trembled as the little fellow's hands moved convulsively on the wheels. "You mean real Martians? Mars Martians; not people Martians Eke us? Martians living here before people came?"
His thin laugh rattled piercingly inside the car and when he caught his breath again (it is difficult to laugh and breathe at the same time with a nosepiece on), he said, "You've been talking to that guy Benson."
David remained gravely unruffled at the other's glee. "Why do you say that, Bigman?"
"We once caught him reading some kind of book about it, and we ribbed the pants off him. Jumping Asteroids, he got sore. He called us all ignorant peasants, and I looked up the word in the dictionary and told the boys what it meant. There was talk of mayhem for a while, and he got shoved around sort of by accident, if you know what I mean, for a while after that. He never mentioned anything about Martians to ms after that; wouldn't have had the nerve. I guess, though, he figured you were an Earthman and would fall for that kind of comet gas."
"Are you sure it's comet gas?"
"Sure. What else can it be? People have been on Mars for hundreds and hundreds of years. No one's ever seen Martians."
"Suppose they're down in the caverns two miles underneath."
"No one's seen the caverns either. Besides, how would the Martians get there in the first place? People have been over every inch of Mars and there sure aren't staircases going down anywhere. Or elevators, either."
"Are you certain? I saw one the other day."
"What?" Bigman looked back over his shoulder. He said, "Kidding me?"
"It wasn't a staircase, but it was a hole. And it was at least two miles deep."
"Oh, you mean the fissure. Nuts, that doesn't mean anything. Mars if full of fissures."
"Exactly, Bigman. And I've got detailed maps of the fissures on Mars too. Right here. There's a funny thing about them which, as nearly as I can tell from the geography you brought me, hasn't been noticed before. Not a single fissure crosses a single cavern."
"What does that prove?"
"It makes sense. If you were building airtight caverns, would you want a hole in the roof? And there's another coincidence. Each fissure cuts close to a cavern, but without ever touching, as though the Martians used them as points of entrance into the caverns they were building."
The sand-car stopped suddenly. In the dim light of the viewers, which were still focused on two maps projected simultaneously upon the flat white surface of the built-in screens, Bigman's face blinked somberly at David in the back seat.
He said, "Wait a minute. Wait a jumping minute. Where are we going?"
"To the fissure, Bigman, About two miles past the place where Griswold went over. That's where it gets nearest the cavern under the Makian farms."
"And once we get there?"
David said calmly, "Once we get there, why, I'll climb down into it."
9. Into the Fissure
"Are you serious?" asked Bigman.
"Quite serious," said David.
"You mean"-he tried to smile-"there really are Martians?"
"Would you believe me if I said there were?"
"No. He came to a sudden decision. "But that doesn't matter. I said I wanted to be in this, and I don't back out." Once again the car moved forward.
The feeble dawn of the Martian heavens was beginning to light the grim landscape when the car approached the fissure. It had been creeping for half an hour previous, its powerful headlights probing the darkness, lest, as Bigman had put it, they find the fissure a little too quickly.
David climbed out of the car and approached the giant crack. No light penetrated it as yet. It was a black and ominous hole in the ground, stretching out of sight in either direction, with the opposing lip a featureless gray prominence. He pointed his flash downward a
nd the beam of light faded into nothing.
Bigman came up behind him. "Are you sure this is the right place?"
David looked about him. "According to the maps, this is the closest approach to a cavern. How far are we from the nearest farm section?"
"Two miles easy."
The Earthman nodded. Farmboys were unlikely to touch this spot except possibly during checkup.
He said, "No use waiting then."
Bigman said, "How are you going to do it, anyway?"
David had already lifted the box which Bigman had obtained in Wingrad City out of the car. He tore it open and took out the contents. "Ever see one of these?" he asked.
Bigman shook his head. He twiddled a piece of It between gloved thumb and forefinger. It consisted of a pair of long ropes with a silky sheen connected at twelve-inch intervals by crosspieces.
"It's a rope ladder, I suppose," he said.
"Yes," said David, "but not rope. This is spun silicone, lighter than magnesium, stronger than steel, and barely affected by any temperatures we're likely to meet on Mars. Mostly, it's used on the Moon, where the gravity is really, low and the mountains really high. On Mars, there's not much use for it because it's a rather flat world. In fact, it was a stroke of luck that the Council could locate one in the city."
"What good will this do you?" Bigman was running the length of it through his hands until the ladder ended in a thick bulb of metal.
"Careful," said David. "If the safety catch isn't on, you can damage yourself pretty badly.".
He took it gently out of Bigman's hand, encircled the metal bulb with his own strong hands, and twisted each hand In opposing directions. There was a sharp little click, but when he released his hold, the bulb seemed unchanged.
"Now look." The soil of Mars thinned and vanished at the approaches of the fissure, and the cliff edge was naked rock. David bent and, with a light pressure, touched the bulb end of the ladder to the crag, faintly ruddy in the flushing sky of morning. He took his hand away, and it remained there, balanced at an odd angle.
"Lift it up," he said..
Bigman looked at him, bent, and lifted. For a moment he looked puzzled as the bulb remained where it was; then he yanked with all his might and still nothing happened.
He looked up angrily. "What did you do?"
David smiled. "When the safety is released, any pressure at the tip of the bulb releases a thin force-field about twelve inches long that cuts right into the rock. The end of the field then expands outward in each direction about six inches, to make a 'T' of force. The limits of the field are blunt, not sharp, so you can't loosen it by yanking it from side to side. The only way you can pull out the bulb is to break the rock clean off."
"How do you release it?"
David ran the hundred-foot length of ladder through his hands and came up with a similar bulb at the other end. He twisted it, then pushed it at the rock. It remained there, and after some fifteen seconds the first bulb fell on its side.
"If you activate one bulb," he said, "the other is automatically deactivated. Or, of course, if you adjust the safety catch of an activated bulb"-he bent down and did so-"it is deactivated"-he lifted it up-"and the other remains unaffected."
Bigman squatted. Where the two bulbs had been there were now narrow cuts about four inches long in the living rock. They were too narrow for him to insert his fingernail.
David Star was speaking. He said, "I've got water and food for a week. I'm afraid my oxygen won't last more than two days, but you wait a week anyway. If I'm not back then, this is the letter you're to deliver to the Council headquarters."
"Hold on. You don't really think these fairy-tale
Martians____________________ "
"I mean lots of things. I mean I may slip. The rope ladder may be faulty. I may accidentally anchor it to a point at which there is a fault in the rock. Anything. So can I rely on you?"
Bigman looked disappointed. "But that's a fine situation. Am I supposed to sit around up here while you take all the risks?"
"It's the way a team works, Bigman. You know that."
He was stooping at the lip of the fissure. The sun was edging over the horizon before them and the sky had faded from black to purple. The fissure, however, remained a forbidding dusky abyss. The sparse atmosphere of Mars did not scatter light very well, and only when the sun was directly overhead was the eternal night of the fissure dispelled.
Stolidly David tossed the ladder into the fissure. Its fiber made no noise as it swung against the rock, upheld by the knob which held tightly to the stony lip. A hundred feet below they could hear the other knob thump once or twice.
David yanked at the rope to test its hold, then, seizing the topmost rung with his hands, he vaulted into the abyss himself. It was a feathery feeling floating down at less than half the speed one would have on Earth, but there it ended. His actual weight was not far below Earth normal, considering the two oxygen cylinders he carried, each the largest size available at the farm.
His head projected above surface. Bigman was staring at him, wide-eyed. David said, "Now get away and take the car with you. Return the films and viewers to the Council and leave the scooter."
"Right," said Bigman. All cars carried emergency four-wheeled platforms that could travel fifty miles under their own power. They were uncomfortable and no protection at all against cold or, worse still, against dust storms. Still, when a sand-car broke down miles from home, scooters were better than waiting to be found.
David Starr looked downward. It was too dark to see the end of the ladder, the sheen of which glimmered into grayness. Allowing his legs to dangle free, he scrambled down the face of the cliff rung by rung, counting as he did so. At the eightieth rung he reached for the free end of the ladder and reeled it in after hooking an arm about and through a rung, leaving both hands free.
When the lower bulb was in his hand, he reached to the right and thrust it at the face of the cliff. It remained there. He yanked hard at it, and it held. Quickly he swung himself from his previous position to the branch of the rope ladder now dangling from the new anchor. One hand remained on the portion of the ladder he had left, waiting for it to give. When it did so, he swung it outward, so that the bulb from above would swing wide of himself as it fell.
He felt a slight pendulum effect upon himself as the bulb, which had been at the lip of the fissure thirty seconds before, now lashed back and forth some one hundred and eighty feet below the surface of Mars. He looked up. There was a broad swath of purple sky to be seen, but he knew it would get narrower with each rung he descended.
Down he went, and at every eighty rungs he set himself a new anchor, first to the right of the old one and then to the left, maintaining in general a straight passage downward.
Six hours had passed, and once again David paused for a bite of concentrated ration and a swig of water from his canteen. Catching his feet in rungs and relaxing the pressure on his arms was all he could do in the way of resting. Nowhere in all the descent had there been a horizontal ledge large enough for him to catch his breath upon. At least nowhere within the reach of Ms flashlight.
That was bad in other ways. It meant that the trip upward, supposing that there ever was to be a trip upward, would have to be made by the slow method of jabbing each bulb, in turn, at a spot as high as one could reach. It could be done and had been-on the Moon. On Mars the gravity was more than twice what it was on the Moon, and progress would be horribly slow, far slower than the journey down was. And that, David realized grimly, was slow enough. He could not be much more than a mile below surface.
Downward there was only black. Above, the now narrow streak of sky had brightened. David decided to wait. It was past eleven by his Earth-time watch, and that had fair significance on Mars, where the period of rotation was only half an hour longer than on Earth. The sun would soon be overhead.
He thought soberly that the maps of the Martian caverns were at best only rough approximations from the action of vi
bration waves under the planet's surface. With very slight errors existing he could be miles away from the true entrance into the caverns.
And then, too, there might be no entrances at all. The caverns might be purely natural phenomena, like the Carlsbad Caverns on Earth. Except, of course, that these Martian caverns were hundreds of miles across.
He waited, almost drowsily, hanging loosely over nothing, in darkness and silence. He flexed his numbed fingers. Even under the gloves, the Martian cold nipped. When he was descending, the activity kept him warm; when he waited, the cold burrowed in.
He had almost decided to renew his climbing to keep from freezing when he caught the first -approach of dim light. He looked up and saw the slowly descending dim yellow of sunlight. Over the lip of the fissure, into the small streak of sky that remained to his vision, the sun came. It took ten minutes for the light to increase to maximum, when the entire burning globe had become visible. Small though it was to an Earthman's eyes, its width was one quarter that of the fissure opening. David knew the light would last half an hour or less and that the darkness would return for twenty-four hours thereafter.
He looked about rapidly, swinging as he did so. The wall of the fissure was by no means straight. It was jagged, but it was everywhere vertical. It was as though a cut had been made into the Martian soil with a badly crimped knife, but one which cut straight down. The opposite wall was considerably closer than it had been at the surface, but David estimated that there would be at least another mile or two of descent before it would be close enough to touch.
Still, it all amounted to nothing. Nothing!
And then he saw the patch of blackness. David's breath whistled sharply. There was considerable blackness elsewhere. Wherever an outcropping of rock cast a shadow, there was blackness. It was just that this particular patch was rectangular. It had perfect, or what seemed to be perfect, right angles. It had to be artificial. It was like a door of some sort set into the rock.
