Still River Read online

  Still River

  Hal Clement

  A riddle wrapped in a mystery inside an enigma ...

  Enigma 88, a tiny planet in the orbit of Arc, is a world with so little mass that it should have no atmosphere. But it does—and to find out why is the final study assignment that will earn five students, each the best of their species, their prestigious Respected Opinion degrees.

  But from the moment they arrive on Enigma, none of their careful calculations seem to fit; on the surface, the riddle seems insoluble. And when one of their wind robots disappears under the surface, closely followed by the Human, Molly, they find the mystery is indeed inside Enigma. For the vast subterranean network of caves and tunnels Molly tumbles into supports a rich profusion of life-life that can’t possibly exist ...

  Hal Clement

  Still River

  (1987)

  Personae

  The following students, all candidates for the Respected Opinion degree at the institution called by the Human name of Golden Fleece University (apparently from a rather remote association, through Human mythology and the constellation name Argus, with its location near the Leinster site at Eta Carinae), formed the voluntary associate team assigned to examine the standard laboratory object Enigma 88. This had been left untouched long enough to be sure that any casual memory of it would no longer be circulating in the School, and of course earlier laboratory reports had been sealed.

  The names of the nonhuman students are given as carried by Human interpreter equipment. All had met, both socially and in connection with course and laboratory work, and appeared to like and respect each other sufficiently to be able to form an effective work group. They are:

  1) Joe, Nethneen. Home planet Dinar, orbiting an MO main sequence sun, normal temperature range 220-260K, gravity 0.18 Earth standard, atmosphere inert at about 50 millibars. Body fluid ammonia based, nonbreathing. Spheroidal body, four equally spaced limbs of which two are adapted for handling and two for locomotion. Immobile head on top of body, four pairs of eyes covering full circle.

  2) Molly (Mary Warrender Chmenici), Human. Home planet technically Earth, circling a G2 main sequence sun, temperature range 260-310K, but, like most of her species, born, raised, and educated on other planets and on board spacecraft. Body fluid water based, oxygen breather. Age 27 Earth years, 165 centimeters tall, mass 57 kilograms. Married to another student, one six-year-old son.

  3) Charley, Kantrick. Home planet Merrvar, circling an M5 main sequence sun, temperature range 200-250K, gravity 0.87 Earth normal, atmosphere inert at about 850 millibars. Body fluid ammonia based, nonbreathing type. Physical shape roughly similar to Joe’s but considerably larger. His body is covered by an exoskeleton and therefore does not show Joe’s rubbery texture; he has four single eyes, covering, like Joe’s, the full circle. His prehensile organs are four-digited nippers rather than Joe’s delicate tendrils.

  4) Carol, Shervah. Home planet Krekka circles M2 main sequence flare star; temperature range 240-250K, gravity 0.83 Earth normal, normal atmospheric pressure 2700 millibars, partial pressure of NOC1 210-330 millibars. Body fluid ammonia based, NOC1 breather. Shape humanoid, but very small by human standards; height 137 centimeters, mass 32 kilograms. Face repulsive to human taste; no chin, mouth almost out of sight, large independently mobile eyes on opposite sides of head able to cover full circle. Covered with dense brown fur.

  5) Jenny, Rimmore. Planet Hrimm, sun an M2 main sequence star, temperature range 220-260K, gravity 1.85 Earth normal, atmospheric pressure 4300 millibars, oxygen partial pressure about 320 millibars, rest mostly nitrogen and carbon dioxide. Body fluids ammonia based, oxygen breather. Physical shape, two-meter-long centipede, front three of eighteen limb pairs modified for handling. Two large eyes on sides of head.

  Chapter One

  Datum One: Joe

  Joe, for the first time in weeks, felt really comfortable. True, the gravity was only half what it should be, but it was real gravity, and in a moment he would be outdoors. Not, of course, that he could feel any difference between acceleration and gravity—there wasn’t any—but having to compromise with beings who walked or slithered or crawled or even flew around weighing two or five or ten times what anything of their size should weigh was uncomfortable. It could even be dangerous, after a while.

  There was gas outside, too. More than enough, actually, but gas couldn’t do any real damage, even if the pressure was rather high. These people who had to breathe did tend to be quite choosy about their gas mixtures; it was a nuisance having to wear a sealed garment just for their comfort. Some day he would have to find out just what compounds his skin gave off that made the Human and Rimmore so uncomfortable. Once outside now, he might even shed the suit and feel really free.

  Waiting to calm Molly’s worries had been a nuisance, but probably worth doing, and Jenny had certainly been quick enough with her analysis. Of course there was nothing dangerous outside. No oxygen, no chlorine, none of Carol’s stinging nitrosyl chloride. Carbon dioxide, methane, and ammonia were all harmless. The ammonium carbamate and other dusts that the gases were constantly forming seemed inactive enough.

  He opened the inner lock door, speaking reassuringly as he went—the Human still looked anxious. As quickly as possible without actual rudeness he closed it behind him and keyed open the outer valve. The ship trembled slightly as he did so, and simultaneously the voices of the high-gravity women roared confusingly through his translator.

  Even if he could have untangled the messages, they would have been too late. There was no word for wind in Joe’s vocabulary or that of his communication device. His home world wasn’t quite airless—there was pressure enough to keep body fluids liquid—but no one had ever been blown away.

  Until now. It was surprising that gas could transfer so much momentum, he thought rather blurrily as the landing boat spun out of sight.

  Of course, his species had not used rockets for a long, long time.

  Chapter Two

  Datum Two: Carol

  The little Shervah dashed through the near-darkness at the top of her speed. With so little gravity, this meant an awkward series of leaps rather than a graceful run, but she could see ahead well enough in the beam of her hand light to be willing to risk that. There was no time to waste; there was life, however unlikely that might be, and, if her own eyes could be believed, all competing explanations for Enigma’s retention of atmosphere had to take second place. Biology just did too many improbable things.

  She had no idea at the moment what that life might be doing, or what sort of ecological pattern would have to be worked out before the little planet made sense. Life, however, could do things like make oxygen and ammonia coexist in large quantities on Hrimm, or oxygen and cellulose on so many other worlds. This was even odder than having the oxygen, one of the most savagely active elements in the universe, existing free, as it did—thanks to life—in so many environments.

  She had to see more. Finding Molly was also desirable, of course, taking reasonable care of her own safety should be given some sort of weight, but a possibility like this simply had to be checked out.

  There was that sparkling, metallic stuff, too; now that she remembered, that could be living. She knew perfectly well there were races made of high-conducting hydrocarbons. Molly had collected some of this, of course, but Carol wanted to see for herself. Hurrying, even under near-zero gravity, was safe enough as long as one could see well ahead ...

  And as long as one looked underfoot.

  Her mind did not work as fast as Joe’s. He would probably have thought about hydrogen bonds being characteristic of life even while he was spinning through the air; he would have reasoned that that might be what made the sticky stuff that Molly had reported so sticky; he would have exp
ected it to produce slippery material, too.

  Carol didn’t. She was very annoyed with herself as she spun, but none of the explanations got to her consciousness until somewhat later. Instead, her memory flashed back to an incident months before on Pearl, the inner planet of Smoke, where most of the Humans lived because of the gravity. She had only recently met Molly, and the high-temperature family was engaged in teaching Carol’s group the sport of skating—ammonia, which does not expand when it freezes, is consequently not slippery. The rink had shop facilities, and skates had been quickly provided for the Shervah family, with interesting and challenging consequences.

  Carol and one of her Others had seriously considered mastering the art of figure skating ...

  Contact with the cavern floor brought her mind back to the present.

  Even then, she didn’t discuss either hydrogen bonds or ice with the others; speed was not the only way in which her mind differed from Joe’s.

  Chapter Three

  Of Course I Said That

  Joe felt a very slight, unfamiliar sensation. He knew that it was about time for reality interface, and wanted to believe that this was merely the effect of a strange drive system, but he somehow couldn’t feel completely sure.

  There was an odd touch of disorientation, as though his walking flaps and handling tendrils might not be exactly where they seemed; and he felt oddly reluctant to move so as to find out.

  It was encouraging that there had been no change in the display before him; even the most minor error as a carrier penetrates the interface between real and unreal space-time usually kills sensing apparatus completely. As it was, the terrifying image on the screen had not even flickered. Perhaps it had all been his own state of mind; a star like Arc could unsettle anyone.

  Or almost anyone. He had forgotten for an instant the giant seated at her own instruments beside him. For a moment he hesitated to look at her; his standards of courtesy would have made it an intrusion, since she was presumably busy. Then he remembered—this always took a moment—that the human being would not even be aware of his glance; her only eyes were inside the hood surrounding her vision screen. Reminding himself firmly that he really wasn’t doing anything improper, he let his right-side pair of optics center on her hands.

  The fingers, which the Nethneen simultaneously envied for their strength and pitied for their clumsiness, rested motionless at the key bank. If she had been bothered by the jolt, the worry was not being translated into action so far. Whether that meant she hadn’t felt it or was too familiar with what she had felt to be bothered by it was impossible to tell; asking would be intrusion even by Human standards as long as she appeared to be working. He could, of course, get her readings onto his own screen without disturbing the giant, but there were two objections to this. The first was that it probably wouldn’t answer his question, and the second that it could easily be dangerous. If she were looking at Arc in anything like its natural color ...

  Joe shivered. There were usually five or six hundred species at any one time at the Eta Carinae establishment, and these tended to be fairly sophisticated about alien life forms; but the recent arrival of human beings had startled most of them badly. It had been casually accepted by the community that life could not be expected near suns hotter than about K8. One of the reasons for the face-fitting mask around the Human student’s screen was protection of her classmates from the short-wave radiation she used for vision.

  Joe gave up useless speculation for the moment and went back to particle counting. It was less unnerving than examining an O-type star would be. He could ask Molly if she had felt the whatever-it-was later on.

  Mary Warrender Chmenici felt the jolt, but paid no real attention to it; it was less noticeable than the interface transitions she was used to, and she interpreted it as merely another of these.

  She was not even as conscious as she should have been of the display on her screen, though this was not of very great importance. In principle, students were supposed to be observing while on watch; in practice, even the stuffiest of the Faculty would not expect much useful material to be picked up before the traveling classroom got a lot closer to Enigma. If anyone had known that Molly had already formed a working hypothesis and used it to plan her operations for the next few weeks, there would have been criticism; most of the red-sun races, if the individuals she had met so far were typical, were conservative in their ideas of where reasonable organization ended and wild speculation began. Even these, however, might have made allowance for her youth.

  If asked, she could have claimed she was searching for Enigma at the moment. Presumably the body would be emitting the long waves characteristic of planetary temperatures, combined with reflected light from Arc; she had set her equipment to respond to such a combination and to center her screen on the source and shift to maximum resolution if it were found. Her mind, however, was elsewhere—though her eyes, like Joe’s side and rear ones, would put in a call for attention if their input pattern changed significantly. She was taking for granted, from the barely detectable sensation that had bothered her little Nethneen friend so greatly, that they were back on the real side of interface, but that left a couple of her days of ordinary flight before the laboratory site could be examined in any detail. Arc and its almost equally huge companion formed too massive a system to permit interface transfer at planetary distances; real space-time was too badly warped in their vicinity.

  Enigma. Did the Faculty member of centuries past who had named the little planet have a sense of humor? Most intelligent beings did, of course. Actually, it was Enigma 88 in decimal notation—which, she reminded herself, was not used at the School. One of the things that had made her feel more at home, during her first weeks at Eta Carinae, had been the story of a major administrative upheaval, during the establishment of the place, over the question of octal or duodecimal time units.

  The Faculty had a file of Enigmas for student investigation, she knew, within reasonably short distances from the Leinster site. Molly thought she could guess why this one had been given to a team containing a Human student. The guess assumed that the Faculty had already learned a good deal about her species, but this was likely enough. Any red-sun native would have been curious about the combination of a high-energy star and a fairly habitable—from their point of view—world like Titan, and even more so about a place like Earth. In asking the Human students about these, they could hardly have failed to learn a lot about the beings they were questioning.

  But that was really letting her mind wander. The assigned exercise was to produce an explanation for the basically surprising fact that Enigma, with far less mass than Earth’s moon, had a very substantial atmosphere. The team was to present observational support for its solution with an absolute minimum of items taken for granted; and here was the trouble. Ten months at Eta Carinae, and a really close friendship with Joe, had certainly not supplied her with a complete list of what even one red-star type took for granted. This was bad enough. Worse, twenty-seven Earth years of life and a good education still left her unsure of which of her own everyday assumptions would need supporting evidence to nonhuman minds. Science was science, physical evidence was evidence, but there are spaces between the points on any graph. To her, the explanation demanded by the exercise seemed obvious to the point of being trivial: the planet was too young to have lost its initial atmosphere. She was sure, however, that supporting evidence was going to have to be very carefully handled indeed. She was not normally inclined to worry, but dealing with minds of such different background still made her uneasy. They certainly weren’t all like Joe.

  The hull trembled again, much more noticeably this time, snapping her attention back to her instruments. Back into false-space? Why? It didn’t feel like that, though she knew there were scores of different faster-than-light techniques and she was not really used to the one employed by Classroom. No, she was seeing directly, not by relay. Solid matter—meteoroid? It was hard to believe that any spacecraft could no
t handle such an incident without attracting the attention of the passengers, though in a system as young as Arc’s must be there were no doubt lots of unaccreted particles. Her fingers played over her console, shifting from simple visual imaging to build a tridimensional model of the space around the craft for a kilometer radius.

  There was matter, of course—the Eta Carinae region is rich in nebulosity; but material at a density measured in atoms, or even billions of atoms, per liter does not jolt several million tons of spacecraft. The matter was unusually rich in heavy atoms, since it had cycled through more generations of star formation than even Molly’s part of space; but this seemed irrelevant, too.

  There was energy. Arc was still hundreds of astronomical units away, and its companion even farther, but both radiated fiercely in their appropriate spectral ranges. None of Molly’s fellow students would have dreamed of exposing themselves to the flux outside the hull—she herself would have been uneasy about the X-ray component. Still, there seemed nothing to account for the ship’s behavior.

  She frowned in thought for a moment, then flicked off her screen and removed her face from the viewing mask. Beside her, Joe made a gesture indicating that he was aware of her motion and willing to converse, though he kept his front eyes at his monitor.

  “Joe, did you recognize that last bump? We went real two or three minutes ago and still are; it couldn’t have been interface.”

  “Not sure. I wasn’t sure about the earlier one—it didn’t feel like faces I’ve been through, but if that’s what it seemed like to you, you’re probably right. This was some sort of real acceleration, then. Have you checked our surroundings? I’ve been concentrating on ion counts, and nothing has changed much there.”