Wheelers

by Ian Stewart

  Nagarjuna copied the data summary to his suitnode. When he got back to the monastery, he would have two things to report: a rare-earth-rich asteroid, and an inbound dinokiller— probable prognosis Jupiter-bound. The first, he knew, would win him a commendation. His superior's reaction to the second would depend on whether, in fact, today was an uposatha day. He could check on the 'node, of course—as well be hung for a sheep as for a lamb. But he didn't dare. If it was an uposatha day, the news would be just too depressing.

  Bailey leaned over the mezzanine balcony and surveyed the pandemonium in the hotel lobby, while Jonas took a few shots. "This should please the manager. It'll really put this place on the map."

  Cashew always felt uneasy in crowds. "Maybe he's worried it'll wipe it off the map altogether."

  "Rioting and mayhem are the lifeblood of journalism, Cash. This is our party: let's enjoy it." They took the rear elevator down to the gathering.

  While the press filmed the expedition, Jonas filmed the press, infraredding the choicer images to the room's giant screen. Every wristnode had a tiny built-in screen, but this was useless for anything beyond a brief message or for displaying operational icons. There was also a holographic facility that projected an illusion of a flat screen in front of the user's face, about where you would hold an antique book. However, the screen resolution was barely acceptable and the picture tended to fade in bright light, so the usual way to display wristnode information was on flatfilm screens, slaved by infrared signals. Flatfilm technology was cheap, and public screens were stuck up everywhere—literally, for they came in huge rolls of flexible plastic with self-adhesive backing. You could cut them to shape with scissors and put them up anywhere, powered by ambient lighting. Enthusiasts often carried rolled-up screens disguised as umbrellas or walking-sticks, or stuck stretchable ones onto their travel bags, their clothes, their companions' clothes . . . or sometimes just onto their companions. A broad back made a highly effective display, and a stomach or a thigh wasn't so bad, either. Most users, however, were happy to select a temporary personal window on a public screen. The method lacked privacy, but what with the hackers and the snoops it was crazy to imagine nobody else was reading your Xmail. Anyway, if you really wanted to access a private message, you did so in private.

  The questions came thick and fast. The reporter from Wicked predictably focused on the wisdom of two men and one woman being confined together on a small boat for two weeks. With malice aforethought, Jonas pointed out that there would also be an all-male crew of six, because someone had to be able to sail the boat. The Wicked reporter nodded knowingly and spoke rapidly into her 'node. "No problem," said Cashew. "I'm sure the boys will be capable of protecting themselves."

  "Jemima Reynolds, Xclaim," said a tall blonde in the front row. "Is it really true that you're not using navsats?" Next to her what looked like a bodybuilder in a khaki T-shirt hoisted a huge wide-angle W camera on his shoulders and zoomed in for a close-up. Bailey paused until he judged that his face would fill the frame.

  "Yes. That's the whole point of the expedition. We intend to validate a pretech navigational technique, so we are deliberately cutting ourselves off from the navsats." A shudder of excitement went around the room. "And there'll be no cheating. To prove the navigational concept, we will lock ourselves off from most of the Xnet, leaving only a mathematical processing facility. The lockout will be independently verified and enforced by Xop." Several people in the audience nodded. "And to anticipate the next question: no, we are not carrying any insurance, we are taking responsibility ourselves." That really got to them.

  It didn't all go as smoothly. An overweight reporter from XBC was clearly having problems with the heat, and he sounded irritable. "Bailey, why did you have to start out on a godforsaken lump of rock like this?"

  "To make life difficult for you guys." There were a few wry laughs. The ferry from Dakar had been unable to cope, and local fishermen had quickly spotted the chance for a profit. Only problem was, their boats were inches deep in water and the smell of fish took days to wear off. Bailey chuckled. "Just kidding. No, Varin and des Hayes began their voyage at Goree Island, and therefore so shall we."

  "Why did they start from here?" asked another, whom Bailey recognized as the anchorperson for Xworld.

  "It's all on the X, Vladimir—you can pull it up anytime."

  "There's too goddamned much on the X, Bailey And too many media trying to access too few feeds. The information parking lot. Let's have it in your own words. Gimme a quote I can use, willya?"

  "Mmm, okay, but I'll keep it short; most of these guys don't have your attention span. Netbite: we will remake history. In-depth, or what counts for that nowadays: Varin and des Hayes were carrying out a commission from King Louis XIV of France. Goree Island is on the extreme western edge of Africa, and the French had just established a colony here, so it was a logical choice."

  "It was a science jaunt, right?"

  "Yes. They took lots of astronomical instruments, including two telescopes. We've got copies of them both."

  "We haven't seen your boat yet. Why not?"

  "Ship. It's being readied in Dakar harbor. The crew will sail it over here tomorrow for a prevoyage shakedown."

  "What sort of boat is it?"

  "The ship is a reconstruction of a late second millennium seagoing sailing vessel, which has generously been supplied by the Senegalese Nautical History Association, at their own expense." The strangely named Tanzrouft was from a period about two hundred years too late, but an old boat was an old boat, right? "It is required by law to have an engine, for emergencies, but we intend to make the entire journey using only sail. There are six crew members, all volunteers from the association's membership." There had been more than two hundred volunteers, and to avoid arguments the crew had been chosen by ballot.

  "Where do you plan to make landfall?"

  "Guadeloupe," said Bailey, putting up a map of the eastern Caribbean.

  Jonas set his wristnode for local information exchange. "To be precise: right there, where the red arrow is."

  "How confident are you that you can navigate by the moons of Jupiter?"

  "Jonas," said Cashew sweetly, "tell everyone about the bet."

  The press's collective antennae pricked up. Here was a human interest angle; even the dumbest viewer would understand what a bet was. Jonas was reluctant, but he didn't have much choice.

  "A week's pay if my navigation is out by more than a hundred yards," he confirmed, admiring the way he had been maneuvered into a public admission. He wouldn't be able to back down now.

  Cashew glanced up at the screen. "You all heard him. Jonas, I've got independent witnesses." She flourished her wristnode. "I'll just take a copy of those coordinates, so that there won't be any argument when I come to collect my winnings."

  4

  Secondhome, 1936th Continuity

  The cities were feeding.

  Deep beneath Secondhome's multicolored canopy they cruised, sucking up aeroplankton by the billions.

  Other creatures grazed on the aeroplankton, and those attracted predators.

  In the skies above, a terrified blimp larva was metamorphosing, spilling precious lift gas into the thin air, sinking toward the cloud layer. Though it had not yet achieved full intelligence, the adolescent's instincts were smart enough to keep it scanning the gaps in the clouds, frantically searching for a city—for only a city could save it from the gathering predators in the lower cloud layers . . . There!

  Miles below. Serene Balladeer of the Humid Luster picked up the public announcement from the babywatchers and instantly scratched his plan to spend the morning parading the lending malls. Suddenly in an upbeat mood, he grabbed his second-best knapsack and headed downflow Merry crowds thronged the city's cushioned floatways, all with the same objective, and he joined the impromptu street party, chanting an ancient and mildly racy life-poem in an overconfident baritone.

  He hoped he wouldn't be late, for such an opportunity
was quite uncommon.

  Toward every city's prow, off-center either to port or starboard, was the birthing arena—an amphitheater in the shape of an inverted truncated cone—and there the crowds were now assembling. The flat central court was ringed by hundreds of concentric circles of tethering rails, and Balladeer secured himself to one by a few of his secondary (that is, nonmanipulative) trunks. There he could float in serene comfort while enjoying a clear view of the court—and, especially, the trimming pond.

  In a society in which each individual possessed extreme longevity, the arrival of a potential new citizen was a comparatively rare event and a highly significant occasion. So as soon as the babywatchers who scanned the overhead cloud layers became aware of an impending arrival, a general alert went out for wakeful citizens to throng to the birthing arena. It was this that had attracted Balladeer and his fellows. Along with thousands of other citizens he bobbed gently in the local swirl of air, as the city coasted along at the mean speed of its incident winds. Like them, he did his best to sway away from the vertical, in the hope of catching the first glimpse of the approaching larva.

  Miles above, in the thin air of the troposphere, the larval blimp whirled aimlessly along in an interzonal jet stream, a spongy mass of gas-sacs that resembled a cross between a bunch of grapes and bladderwrack seaweed. The larva was nearing the end of its third-instar stage, and its rudimentary consciousness had awakened to a crisis. Billions of tiny pores in its lift-sacs had spontaneously opened in response to an age-old imperative, triggered by subtle changes in the weather, bleeding away precious hydrogen. Slowly but relentlessly the adolescent was sinking back into the depths where its life had first come into being ...

  The life cycle of a blimp was complex and poorly understood, even by the blimps themselves after a billion years of speculation and research. The main reason for their ignorance was that several early stages of development took place two thousand miles down in the high-pressure abyss of Second-home's oceans, at the upper phase boundary where a gaseous mixture of hydrogen and helium gave way to liquid hydrogen and the pressure was unbelievable. Here neither blimp nor symbiaut artifact could penetrate. So what little they knew about these stages of their own life cycle was inferred from larval and adult genetics and physiology—and they were well aware of the limitations of such inferences.

  Reproductively, blimps were r-strategists—they produced huge numbers of potential offspring and totally ignored them until a drastically reduced subset neared adolescence. Although blimps had approximate analogues of sexes, these denoted cultural roles rather than reproductive ones; there was no separation of genetic material into sperm and ovum. Instead, when a blimp came into season—typically an interval of six days in every eight hundred, except when collectively excited—it produced trillions of submicroscopic nanogametes, tiny packages of genetic material, each containing perhaps one-tenth of a complete blimp genome. Oddly enough, each such fragment contained about twice as much "information" as was actually expressed in the phenotype of an adult blimp—but blimp development proceeded along lines very different from most terrestrial lineages, and even in principle no single nanogamete could ever give rise to a complete adult.

  Every city trailed behind it a cloud of nanogametes, small enough to blow away on the local winds like spores of earthly fungus or orchid, dense enough to sink once they had been left behind in the city's wake, and compressible enough to continue sinking until—if they survived—they finally regained neutral buoyancy at the upper phase boundary. As the nanogametes made their perilous descent toward Union, they were winnowed by innumerable species of aeroplankton—along with countless numbers of nanogametes of other species—those indigenous to Secondhome and the many imports from Firsthome.

  Every organisms new generation began its existence as food for everyone else's larvae.

  At the phase boundary, the miracle of Union was enacted. Drawn together by Van der Waals forces, fitting snugly into place through molecular geometry, nanogametes linked themselves into Fibonacci chains—first in twos; then in threes as single nanogametes attached themselves to a pair; then fives, as pairs and triples conjoined; then chains of eight, thirteen, twenty-one, thirty-four, and finally the Sacred Number of the Lifesoul Cherisher, fifty-five. Temporary molecular markers, stripped off later by specialist enzymes, tagged each chain to ensure that the sequence of Fibonacci lengths was maintained . . . but in the seething sea of organics at the phase boundary, many mistakes were made. None of these were viable, but they provided nourishment for the perfect fifty-five-link chains.

  Each completed chain of nanogametes closed into a ring, an act of fertilization that created a cyclozygote, newly capable of growth and development under the orchestration of its fifty-five-fold genome. Across the nanogametic ring there grew two thin, soft membranes, and in the space between there was room to trap molecules of both nonviable and viable but incomplete chains of nanogametes, sucked in like spaghetti through osmotic pores. Once inside, they were stripped back to simpler components and rebuilt into the growing body of the cyclozygote. These strange molecular machines, little bigger than an earthly virus, constituted the first instar of a blimp's metamorphic existence. Each cyclozygote incorporated parts of the genetic codes of fifty-five separate adults.

  The cyclozygote's double membrane also constituted the first step toward a lift-sac. Molecular machinery sucked liquid hydrogen from the surrounding ocean into the gap between these tough, thin membranes. Exothermic chemical reactions in the cyclozygote's digestive system could heat the hydrogen, causing it to expand, and in this manner the cyclozygote could make itself rise through Secondhome's dense atmospheric ocean. By releasing excess hydrogen through its valvelike feeding pores, the cyclozygote could—if necessary—sink.

  Mostly, it rose. There was a long way to go.

  The beauty of the system was this: it worked in any medium. The adult blimps in the upper atmosphere could float on hydrogen-filled gas bags, because there hydrogen was gaseous, and because at that height the air had twice the density of hydrogen (one-sixth of it being helium). Cyclozygotes, immersed in hydrogen, could find no lighter medium to create buoyancy, so they turned themselves into hot-air balloons rising through colder, hence denser, air. Except that the "air" at the phase boundary was a hydrogen sea. Evolution's physics were simple and elegant: as the tiny organism floated up into less dense layers, exactly the same buoyancy system still worked.

  How had such complex genetics evolved in the first place? Blimp scientists believed that back in the lost histories of Deep Time the process had been far simpler, with diminutive molecular machines competing for resources and driving each other into more sophisticated strategies. The evolution of the nanoga-metic ring, and much later its attendant double membrane, had sparked an explosion of diversity as the molecular gadgetry acquired the ability to explore the upper reaches of their planet's atmosphere. In a new environment, evolution played a new game. A game that had enormous implications for the old environment. A game that could change its own rules . . .

  Whatever the reason, the bizarre chemistry of blimp genetics was undeniable, even though it could not be observed directly. It left numerous traces that could be observed.

  From the almost crystalline numerology of the cyclozygote, blimp development headed toward its second instar, in which entire colonies of cyclozygotes merged together and grew into an endless variety of bizarre aeroplanktonic forms. There were no species here—creatures of the same species took on many distinct forms, while those from different species often converged on the same weird strategies for survival. Gone was the neat mathematical symmetry of Fibonacci chains, for now blimp molecular structure was deep in the domain of emergent complexity, where every process, functional or not, appeared to be entirely random unless contemplated in its totality. Intricately patterned clusters of tiny lift-sacs fought incomprehensible battles in the crushing dark, sensing each other through the chemistry of pheromones and excreta. Only a few of any species, howe
ver, had enough usable heredity to build their predator bodies. Those that didn't were food. A few became ephemeral parasites. Only a tiny fraction "worked." In the interplay of the laws of physics and the lawlessness of chance, the fundamental body plans of the organisms of Secondhome were cryptically laid down.

  The aeroplankton formed a rich soup of competing/computing molecules, and it sustained endless higher forms of Secondhome life. Indeed, the largest organisms on the planet—the cities—kept themselves vibrantly alive by grazing the aeroplankton. The blimps thus inhabited the converted bodies of countless trillions of their own dead children—a fact that they suspected, but did not know, and were completely unmoved by in any case. This is the way of the r-strategist, which has evolved not to care for its offspring ... for there are too many.

  Out of a million nanogametes spawned by a mature adult, perhaps ten would survive to reach the phase boundary. Out of a million cyclozygotes, perhaps one would make it into the aeroplankton. Out of a billion blimp aeroplanktonic instars, an average of just two might reach the next stage—a huge, high-floating preadolescent larva, a colony of fully developed gas-sacs. For every five preadolescents, only one would survive to begin the transformation into fourth-instar adulthood ... at which point its real trials would begin.