Heavy Planet

by Hal Clement

  “Are you all right, and is the tracker still working?”

  “We’re uncomfortable but still alive. I haven’t looked at the machine since we stopped. I don?t suppose heat will hurt it, considering who made it. I?ll shade it so I can see the figures and get a reading.? “Whenever you can, please. There are people here who will have trouble breathing until they learn its condition, now that we know you’re all right. Its reading here hasn’t changed for some minutes now.” Jeanette was not actually a skilled liar, but had some natural diplomatic ability. It seemed unlikely that the captain, just now, would be able to sympathize very well with people worrying more about the instrument’s condition than his own. “That’s reasonable,” Barlennan concurred. “We’ve been stranded for some time now. Here’s what I read.” He pronounced the symbols carefully. “Good. That’s what we have here. If it should change its reading, please let me know.” Another thought struck the captain. “Can you tell us whether the fall is still going on, upstream? Dondragmer says it stopped just below his location.”

  “It did. We can see clearly with his communicator. I can’t answer your question. You’re practically at the pole, we’re over the equator. The only reason we can see your area at all from here is atmospheric refraction, which doesn’t help the image. Otherwise you’d be below our horizon. We’d have to send out another mapping rocket.”

  “Do your people think that’s worth doing? I’d be glad of any information I could get from that direction.”

  “I’ll ask.” The Flyer’s voice fell silent, and there seemed no more excuse for delay in testing the slush, if that’s what it was. Gingerly, his head and a few inches of his body over the basket’s gunwale, Barlennan reached a chela toward the nearly white stuff. The sun was low as always at this latitude and season. At the moment it was beyond cliff and fog, but there was plenty of light. He could feel some warmth from the surface of whatever-it-was, but it didn’t seem as bad as before. About like the inside of the balloon bag, which had been found to be bearable much earlier when control lines had tangled in flight. The stuff was soft, though it resisted a little when poked. Whether it would be firm enough to support his weight, and what would happen if it weren’t, were still open questions. There was only one way to get answers that the captain could see. At least, only one which could preserve his self-respect; he could order one of the others to climb over. He didn’t. The stuff did resemble the slush they had encountered near the equator, as the mate had said. It was uncomfortably but not dangerously warm. It did not support him until he had sunk perhaps a third of his body volume. His report, when he finally got back in the basket with the assistance of the others and a length of rope, paraphrased history for some of the human listeners. “Too soft to walk on, too hard to swim in. We’re here for a while, but we can stand the heat. Have you tried it, Dondragmer?”

  “Yes, Captain. You describe it well. We think we can see the ship, but whatever it is is almost entirely immersed in the slush, and we can’t be sure. If it is, it’s well to this side of the fallen rocks.”

  “Good. Find out for sure as quickly as possible.” The mate acknowledged the order which both knew to be superfluous. Half a day later, with the sun on their own side of the former cliff, nothing had been accomplished except testing the inertial tracker. This had been carried from one side of the basket to the other, and the change in readings on its surface and at the receivers on Toorey had remained in agreement. Barlennan was not surprised; from his point of view nothing at all violent had happened during the wrecking of Bree Three. The slush was still slush. This surprised the Flyers, who seemed to feel that if anything were going to settle at all it should do it pretty quickly on Mesklin; Barlennan had no basis for an opinion, though he certainly wished that something would happen. Fog was still rising from the slope a few hundred feet away. The Flyer prediction that the wind should cool the fallen rock fairly quickly seemed to have been another mistake. Barlennan didn’t raise the subject; he was quite sure that the beings would point out that they hadn’t actually specified a time numerically. This was quite true, and qualified as an excuse even by the captain’s standards. There had been, twice, sounds from inside the fog suggesting that rocks had moved, and the four people in the basket were alert for anything more of the sort. Dondragmer’s people had heard nothing like it, the mate reported; but they, too, were listening. Anything like that should happen upstream first, each told himself. This was not mentioned aloud. The fire had not been extinguished after the captain’s experiment, but was now dead for lack of fuel. There were plenty of Mesklin’s scraggy plants in sight in various directions on the shore beyond the slush, but there was no way to reach them; and there seemed not to be enough of them to get Bree Three into the air again in any case. Karondrasee had plenty of meat juice in his tank, but there seemed no way to use it. It was two whole days before anything noteworthy happened, and its development then was gradual. There were more of the falling-rock sounds. Nothing could be seen; the fog, if anything, was thicker, and the breeze toward the rubble slope somewhat faster. Then another quite familiar sound made itself heard. “Captain! A current! Flowing—” Hars uttered the words very softly for a Mesklinite, though Jeanette had no trouble hearing him. She heard the trickling of liquid, too, since the pilot had been doing his best not to drown it out with his own voice. “Which way? Can any of you tell?” she asked. Barlennan couldn’t decide himself; the sound had seemed to come first from the direction of the rocks, then from what had been upstream, then from many directions at once. The most convincing came from the fog. Flowing liquid? Methane? Was the ammonia, if that’s what it was, finally starting to settle? Methane, yes. Settling ammonia, apparently not. Motion caught the eyes of the four crewmen in several directions almost at once. Most of it was from cliffward and upstream, but Barlennan caught sight of a trickle which seemed to rise from almost under the basket, a rivulet which spread, and grew, and flowed downriver as he watched. Others appeared and behaved the same way, more and more, minute after minute; then quite suddenly, they vanished in a single spreading sheet of liquid which they now realized covered much of the landscape in the upstream direction. It was as though the river had resumed flowing, and was coming up through the slush, and making a new bed for itself beyond the tumbled rocks which had filled the old one. It was methane, as taste promptly proved — it was not a laboratory situation to the Mesklinites, who were by now pretty thirsty anyway. The river was being reborn. Yes, reborn. There was plenty of liquid coming from upstream, but there was nearly as much — perhaps more — welling up from under the slush and from the direction of the rocks. The basket began to move, as Jeanette promptly reported. “We know,” the captain replied tersely. “Will you float?” asked the Flyer. “We should. The basket’s made of wood — real wood, not that funny stuff from the ammonia flats. What we need to know is whether it’ll float level. We didn’t worry that much about weight distribution when we made it.”

  “How about the bag?”

  “That’s another question. We may have to cut it free. Depends whether it acts more like a sea anchor or a sail. Dondragmer, we must be heading your way. I can’t guess how long we’ll be getting there.”

  “We’re watching, Captain. If you have to free the bag, we’ll try to capture it, and you of course. The slush is still slush down here, but we’re watching for liquid, too. If the thing we think is the ship starts to move, I’ll take swimmers to do what we can.”

  “Good. We’re going to be busy here, but one of us will keep in touch. If you don’t hear from us for more than a few seconds, you’ll know something we didn’t expect has happened. In that case, send some people up this way to give any help they can. We’re going faster, I think. The bag is dragging behind us, whether it’s touching bottom or feeling wind I don’t know. Probably wind, I think; there’s an upstream component to that now, and the bag itself is pulling a little toward the fog. It’s pulling us that way too.”

  “Hadn’t you better cut loose, then,
Captain?”

  “Not until we can see whether moving in toward the rock is good or bad. We’re standing by to cut if we have to. There doesn’t seem to be anything yet for us to hit.” Barlennan kept a running comment going, as he had promised, while basket and bag headed downstream. The nearest motionless objects were now either too distant — features on the land away from the cliff — or too vague, like the fog, to allow a trustworthy estimate of speed. It was one of the Flyers who pointed out that the tracker was moving downstream surprisingly fast. He didn’t seem really sure that it was surprising; all earlier estimates of the river current had come from direction measurements of the communicator outputs, which were not very reliable with the line of sight to the moon practically horizontal. This was not the tracker’s first trip to the lower ground, but was its first ride on what had become a surface vehicle. One of the watchers remarked audibly that he was surprised the vehicle wasn’t in white water; another, not bothering to correct the name of the liquid, suggested that the first speaker think gravity. Just what would “white” imply about the current’s speed on Mesklin? The twelve-plus kilometers an hour was several times any earlier estimate, however unreliable that might have been. It implied a source of liquid unrelated to what had been seen of the upstream areas from earlier balloon flights. This was not merely methane which had found its way, after some delay, around the recent rockfall. The people on the basket finally observed this, too. The drag toward the rocks had been maintained as wind kept its grip on the now rapidly flattening bag. The sharp rocks were suddenly passing uncomfortably close to a structure which had been designed for lightness. Contact could be awkward even if the pieces continued to float, as they no doubt would. Barlennan heard himself commenting on this as part of his running report, and interrupted the monologue with a sudden, sharp order. “All of you! Cut it free!” Simultaneously the bag caught on a sharp, solid rock corner, jerking the basket to a halt; anywhere near the equator the crew would have been hurled overboard. Karondrasee, in fact, did get jerked over the side. For just a moment the cook could be seen borne away from the suddenly anchored car; then, as the others finished cutting the dozen cords which had held basket and bag together, the former resumed its downstream rush even more rapidly than before. It was now relatively motionless with respect to the swimmer, and he had no trouble wriggling back to what might or might not be safety. He needed no help getting aboard through one of the gunwale crenellations, and the fact that he brought a good deal of methane with him made no real difference. In spite of the total absence of spray, the footing on board was already extremely wet. During the brief halt, the river had spilled over the upstream gunwale and nearly washed several more objects into the river. The communicator was high enough above the deck to stay clear, but the inertial tracker was not. Neither were the three remaining natives. It was Hars, perhaps more concerned with all things connected with flying, who curled his long body about the sphere, gripping it with every leg which could be brought to the task. Sailor and instrument washed rapidly across the deck in the direction from which Karondrasee was swimming, but they did not go overboard. Hars’ own display of personal strength surprised no one, but his fellows and the watching Flyers were all rather startled that the gunwale seized by one of his chelae did not tear loose from the rest of the basket. He uncoiled partly, still retaining his grip on the tracker, and spread the load on the gunwale with more pincers; by the time the cook was safely aboard, the sloshing of liquid across the deck had ceased and the tension had eased. “It would have been easy enough to find,” Barlennan remarked. “I know it would have sunk, but the river’s pretty clear.”

  “Is the bottom solid?” a Flyer voice — again, not Jeanette’s — asked pointedly. “I don’t know, but it looks—” the captain paused, then went on, “Just a moment.” He vanished over the rail. His crew watched with interest but no great concern; the aliens were highly concerned but couldn’t watch. The long body reappeared and moved in front of the lens. “It might have been serious at that. It’s the same slushy stuff, and it’s travelling — not as fast as the river, but if the tracker had sunk we’d never have found it. Good work, Hars.” The exhaled breaths were audible through the communicator, but carried no meaning to the natives. Dondragmer could not see anything nor hear everything, but had been able to infer what was happening. “Is anyone watching ahead, Captain? You must be travelling pretty fast. We’re getting ourselves and the radio back from the river; it seems from what you said it’s a lot wider and faster where you are now, and that it became so very suddenly. All of us are staying with the radio as we move it; I’m sure the Flyers know that faster-moving methane carries things more easily.”

  “Sixth-power law,” a barely audible alien voice muttered. The words were not in Stennish, but the mate understood both them and their mathematical implications. Barlennan got the former only, but no order was needed to drive the mate to greater haste. The captain had heard the question about looking ahead, and without acknowledging the words was doing so. Actually, looking aside was more worrisome; the basket was still closer than he liked to the edge of the rockfall. Worse—much worse — it could be seen that much of the finer waste from the cliff was being washed away by the current, leaving widening spaces between the larger fragments. Well, the Flyers weren’t always wrong, of course. He could not see what was happening to the loosened stuff. The surface was too turbulent to offer a clear view below it. He remembered his earlier promise and began describing the new phenomenon to Dondragmer. Sherrer, his flexible body partly overside, rotated the basket to let the communicator eye look ahead. His chelae were poorly shaped for the work, but his paddling did have results. “You seem to be approaching a bend to the right, in both fog and river,” Jeanette remarked. “I’d guess it’s that kink — that point — in what used to be the cliff, a couple of miles or so upstream from where Don is.” Barlennan saw no reason to disagree, and the possibilities which a quick change in flow might offer were enough to focus his attention. “Dondragmer, is your part of the river widening at all rapidly? It should be if the Flyer’s right. How well are you moving the radio? Can you keep it moving and also let it look upstream?”

  “We are moving. I’m not sure about change in width, since we’re away from the river itself now. We’re keeping the lens pointed more or less upstream, but I’m afraid they’re not getting a very steady view.”

  “Don’t worry about that, Don. We can take pix when it’s steady and look at them. You’re right about keeping the viewer as safe as possible.”

  “Thank you, Flyer Jeanette.” It was indeed a turn to the right, the captain saw as they approached it. The current was visibly swifter; they were still close enough to the shattered, pulverized, and steaming rocks for this to be very obvious. He suddenly realized that everything at the foot of the pile was much larger now; the fragments resembled the gigantic — to him — slabs and prisms which had earlier shown only on the higher and steeper part of the fall. It was hard to tell from this close, but the general slope seemed to be steeper, too, as though the whole fallen mass were still gently sinking. Maybe it was. The fine stuff below was certainly vanishing. There was a fan of standing ripples angling out across their course ahead; the mate would almost certainly have been curious about this, but Barlennan was just uneasy. The river was still liquid. He felt it again to make sure. He did not, however, wonder what made these little ridges in it — only what would happen to the basket and its passengers when they reached them. Which they would do in seconds. Would they be hitting liquid, or something solid enough to support those humps which lay a little above the general river level, or something slippery which would bend the raft’s structure into its own shape? It was liquid, both its high and its low parts, they found. Motionless waves were something new to Barlennan, and he reported as well as he could to his mate and the aliens. The basket was still intact, though everyone aboard had felt the deck under his feet follow the up-and-down displacement of the surface as they passed the still
ripples. The Flyers seemed unsurprised, but Barlennan was not asking for explanations just yet. The foursome ceased thinking about the ripples at once. The next event was prompt, less unfamiliar, and more frightening. There was an eddy on the downstream side of the point, where the liquid swept around, They had all seen such things before, but never in gravity this high. If there had been time to think, they might have foreseen this one, though not in full detail. They had never, after all, felt one in gravity this high either. Barlennan tried to keep reporting. “We’re around the corner. We can’t see you, though—”

  “I haven’t seen you, either.”

  “Not surprising. There’s a hollow in the methane, we’re quite a bit below the river level, and can’t see much but the rocks — when we’re looking that way.”

  “Captain! What’s happening? The eye and the tracker both say you’re — you’re moving in a tight circle. How can? — ” It was often nice to have the Flyers tell him what was going on and advise him what to do about it. It was sometimes nice to have them unable to tell him what was going on, thus providing a little salting to the flavor of omniscience they claimed not to want. It was not nice when he didn’t know what to do about it himself. He described what was happening in as much detail as he could observe, and as he did so realized what was probably going to happen next. The broad swirl of liquid cut in toward the edge of the rock slope and divided there, some swerving back upstream and some resuming its original journey down. At the point where the division occurred, the biggest rocks were visibly settling still. Not fast, but visibly. The finer stuff had washed out from between and among them, and the higher and larger items were crowding vertically closer to each other as the material originally separating them vanished. The pieces were big. They were very big, and as the seconds brought the basket closer the face of the slope began to change. It grew still steeper, and the spaces between the huge boulders seemed to open like mouths, leading into the face of the bank — with throats leading under it. All four sailors were familiar with the hazard of striking rocks. They had even, occasionally, been swept between rocks. But they were Mesklinites, and if any of their colleagues had ever been carried under rocks no one had ever heard about it. The four paddled frantically but without much result, even after the captain got them all paddling in the same direction. The basket flung itself toward the bank, swerving only at the last moment, with some of the huge fragments close enough for even the Mesklinites to touch. The swerve was upstream, back toward the point, which meant that they would be going through it all again. And perhaps again, and again? The rocks were still quite hot, though the wind toward the rocky bank made things a little better. Methane striking the fragments didn’t actually splash, though it did rise a short distance above its regular level before boiling into invisibility and reappearing as fog. Spray was extremely rare this far from the equator. They reached the upstream side of the eddy, swept out into the main current once more, but were not yet free. It was going to be again. But only once. They were carried back toward the fallen cliff somewhat farther downstream this time. The settling was still going on, but less rapidly; could one hope it was actually stopping? that the mud was nearly all gone, and the big fragments resting directly on each other? Well, yes, one could hope. There were no sounds of falling and grinding, after all. The lowest part of the rock pile was now definitely much steeper and formed of really huge fragments, with open spaces between sometimes wide enough for one of the old Bree’s rafts; and the current was not dividing at the very edge any more. Methane was flowing into the interstices, flowing almost as rapidly as in the farther-out parts of the eddy. There was no way to paddle the basket fast enough and far enough either up- or downstream to get it carried in either direction. It was going to travel into the wreckage of the cliff. Not even the Flyers could find words. They could see it coming; their lens at the moment was pointing in the basket’s direction of motion. None of them ever admitted whether the fate of the natives or the loss of the communicator and tracker concerned them more. There were other communicators, of course, and Dondragmer might prove to be a better agent than his captain; but there was only the one tracker, and great things had been planned for it once it had been found to be still functional. If it could be carried over land and sea all the way back to the equator, while being followed from above by communicator waves so that gravity and inertial effects could be distinguished, what couldn’t be learned of Mesklin’s interior? No one had yet discussed this project with Barlennan, and in any case it would not have been the captain’s primary concern just now. He and his men were being washed underground, on what amounted to a patch of driftwood. It was much, much later before any of them realized how lucky it was that the sun was ahead of them, on the high side of the cliff, just then. It grew relatively dark the moment they had rock nearly surrounding them, with only a modest illumination from the sunlit ground across the river. Their heads and eyes turned back toward the light, and stayed there as the view narrowed; and before they really saw and could respond to the unimaginable tonnage of material suddenly above them, the darkness was complete except for the faint glow of the tracker’s numbers. The Flyers, Barlennan thought after a moment, should have commented on the darkness or the fact that the tracker was still indicating motion or something, but the communicator was silent. It remained so after several hopeful calls by the captain. It had never occurred to him that whatever carried the messages to and from Toorey might be blocked by intervening rock. The concept of a completely surrounding bed of intervening anything had never crossed his mind. For a moment he managed to concentrate on all he could see. The digits on the tracker screen agreed with his own sensations; they were speeding up, slowing down, jerking from side to side — the basket was in fact still being carried by a current, which was weaving its way around things. He should have been able to tell which way and how far, from the tracker readings; should, indeed, have been able to retrace their path if he had had any control of their motion. The general direction was indeed obvious; they were heading deeper under the former cliff. How far under was another matter; he didn’t remember the position reading when they had gone into the dark, and the succession of numbers which had followed that moment had been too complex to memorize. It was never clear to any of them later how they were able to keep thinking — why the four of them didn’t succumb at once to total panic. The Flyers commented later how fortunate it was that all four had had balloon experience, but it was not clear to Barlennan why that should help them with the concept of heavy material overhead. He tended to credit his own retention of sanity to his profession. He was a captain, he was responsible, he was used to doing whatever he could that was called for at the moment, and leaving what he couldn’t control to luck. This may have corresponded to an almost human personal arrogance. Even so, every little while — he had no way of telling how often — the thought of what he was under threatened to crowd his attention away from everything else. Anything to take that awareness away from him would have helped. He would even have welcomed a theoretical argument from the Flyers. Why all this open space under the cliff, or where the cliff had been? How much mud had there been to wash away, and how had it vanished this quickly so far from the actual river? Or had it? How far did the open space extend? Up and down, probably not very; they were still floating, and it was hard to imagine how the methane surface could have gotten either above the river outside or very far below it. That inspiration caused him to focus on the vertical readings of the tracker for a while; he found that their height was indeed almost constant. But liquid flows downhill, and this was flowing, so there must be at least a small drop. There might be a big one farther ahead; this didn’t seem very good to think of either. How deep was it? What were their chances of grounding — and staying there in the dark with too much of the world overhead? He thought of trying to find out by swimming, but could imagine no way for a swimmer to find the basket again. He realized later what his failure to think of safety ropes must have implied about his sta
te of mind. They could call to each other, of course; he tried that. Multiple echoes responded to his hoots and made sound direction meaningless. In a way this was comforting; Mesklin’s stratosphere started only a few hundred meters above the general surface at this latitude. The air, after cooling for a very short distance upward, began to rise in temperature with increasing altitude, so that sounds originating at one spot refracted downward again before going too far. Complex echo patterns from sounds of distant origin were standard, and these gave a slight — very slight — suggestion of clear air above. They actually fooled Karondrasee, who asked, “Captain! It’s got to be open above after all! Why is it so dark?” The captain was quick enough to reply that he didn’t know, and almost as quickly inspired to ask, “See if you can think of an answer before the Flyers tell us.” That should provide something to distract all the others. Hars, though, seemed somehow able to think coherently, at least for the moment. “Captain, shouldn’t we do something to secure the instruments? We could run aground any time, though we do seem to be getting carried around things so far, and we don’t know how hard we’d strike. The radio isn’t any good to us right now, but the tracker might make a lot of difference. If it went overboard I don’t see how we’d ever get back out.”