Worldmakers

by Gardner Dozois

  The alarms were a little late.

  We both went outside to look. It was the right rear wheel that had failed; we found it a few dozen meters further on, where it had rolled up against a rock. The wheel itself was a titanium-alloy mesh, light enough to carry in one hand, for all that it was nearly two meters in diameter. The wheel bearing was steel. Or, it had originally been steel, when it had been there at all. There was little left of it.

  “Well,” Leah said.

  “Well,” I said. There was no way to replace a wheel; they weren’t supposed to come off. “I think maybe we can rebalance the rover. Shift the loading to the front left side. Five wheels ought to be enough. We might have to go a bit slower.”

  Leah nodded. “It’s a plan.”

  We piled rocks onto the rover, and strapped them down with bungees, to move the center of gravity forward, off of the missing wheel. Then we piled more rocks inside the rover, in the front left pilot’s seat. I didn’t mention that we would never get the Mars stink out of the rover; it was too late to worry about that, and we barely noticed it by then anyway. The autopilot refused to budge so much as a meter without an overhaul, so I piloted it on manual. This was good for less than a third the speed of the autopilot, but still, even that pace covered ground. Leah went back into the aft cabin to examine the samples she had scraped off of the wheel.

  It was only a hundred kilometers. We finished more than fifty of them before the second wheel fell off.

  We were going more slowly this time. There was no lurch, and no noise. The rover just slowly careened to the right, and kept on rolling until it slid to a stop on its side.

  Leah came out of the hatch after I did. She didn’t bother looking at the axle, or at the rover. No need; it was obviously not going anywhere, even if we had a crane to put it back right-side-up. The rocks we had piled onto the rover had cracked the bubble when it rolled. “Sulfur-reducing bacteria,” she said.

  “Say again?”

  “Sulfur-reducing bacteria,” she said, “convert iron to iron sulfide. There’s energy in free iron; in the presence of free sulfur, enough energy for a bacterium to exploit. The lack of iron at the site; I should have figured that ordinary weathering wasn’t enough to account for it.”

  “Oh,” I said.

  “Not that it matters now,” Leah said. “We don’t have time to waste. We’ve got to get to Tally and warn her.” With a matter-of-fact attitude, she hopped up onto a rock and stared across the horizon. “So how far do we have to walk?”

  I tried the radio one more time. Come on, Tally. What was she doing? I wondered. Did she even know that the antenna was down, or did she just think we were scrupulous in keeping radio silence? Was she standing at the door of the habitat with a gun? Hiding behind the rocks, waiting for enemies that would never come? If only she would answer, it would only take an instant to tell her about the dangerously low habitat pressure.

  Fix the antenna, Tally, I thought, just fix it, and listen to the radio. But she wouldn’t. Fixing the antenna would be too obvious a sign that the habitat was still occupied. I threw down the radio.

  The inside of the rover was a mess, but we managed to scrounge two spare sets of replacement packs for the rebreathers. I downloaded the bearing to the hab out of the rover’s computer, and set the inertial compass. Once we got close, we would be able to use the habitat’s come-hither beacon to hone in. I grabbed a set of portable radio transceivers and checked that they were working. I couldn’t think of anything more to carry. Before we left, Leah snipped two pieces of titanium sheeting away from internal partitions of the rover, and snapped them free.

  “Ready,” she said.

  We ran.

  The Mars gravity makes it easy to run, and the unwavering wind was, for a change, on our side. Still, after an hour of running I was winded, and the second hour was more trudging than running. Our cold-suits trapped sweat all too well, and it ran down my back and down my legs, like ants with clammy feet.

  Mars narrowed in on us. Ridges, followed by valleys; valleys followed by ridges. Another hour.

  “Bear further to the right here,” Leah said.

  “That’s not the most direct route.”

  “I know.”

  We were walking pretty slowly by now. Her route followed the contour, instead of cutting downhill, and was a bit easier, even if it was less direct. I was beginning to worry that we wouldn’t make it to the habitat by nightfall. It would be impossible to continue after darkness fell—Mars’s moons shed almost no useful light—and by the morning, we couldn’t even be certain that the habitat would still be there.

  In another hour we had reached the edge of a long downhill. There, tiny in the distance was a glint of metal: our goal, the habitat.

  It was impossible to tell from the gleam whether it was still in one piece.

  Without a word, Leah handed me one of the two sheets of titanium. I looked at the downhill. It was a long, smooth grade, with the usual cover of Martian slime. I grinned, and Leah grinned back at me, her face in the rebreather mask like some painted mechanical demon, and then we both stood on our sleds, grasped the lanyards, and, at the same moment, pushed off.

  We would arrive in style.

  My sled skidded to a stop in a spray of slime a hundred meters or so from the habitat, and Leah stopped close behind me.

  The habitat was apparently empty. But at least it was still apparently in a single piece. I ran toward it, shouting for Tally. I reached the air lock, and was just reaching out for the handle when I felt the gun pushed gently between my shoulder blades.

  “Moving real slowly, friend, keep your hands in sight, and turn around. Slowly.”

  Tally was painted the same color as the Martian slime, bits of sand and rock sticking to her randomly. The projectile rifle was in her left hand, aimed steadily at my middle. I could see the crinkling at the edges of her eyes as she smiled behind the rebreather. “Tinkerman. Welcome home.”

  She lowered the gun, and turned to greet Leah. “Didn’t expect you to come back on foot. What brings y’all back so sudden?”

  “The air pressure,” Leah said. “It’s going to—”

  “Yeah,” Tally said. “I noticed something going on with the air. Could feel it in my bones, like a thunderstorm. ’Fact, I had to dial up the pressure in the hab three times in four days.”

  Leah stopped, thunderstruck. “You increased the hab pressure?”

  “Why, sure,” Tally said.

  We just looked at each other.

  “What?” Tally asked. “Something wrong with that? I figured that if the hab pressure wasn’t increased, there could be trouble.”

  Leah shook her head. “No, nothing wrong. Nothing at all.”

  It was our last night on Mars. We had filed a preliminary report with Spacewatch, and in the morning Langevin would bring the lander down to take us home.

  I was looking out the tiny window of the hab at the Martian landscape. In the evening twilight the browns had turned to purple. Tiny puddles of water caught the skylight and reflected it back at us. Even the slime looked fragile and ethereal. “It is beautiful,” I said, “in its way.”

  “Ask me, it still stinks,” Tally said.

  “It’s dying,” Leah said.

  “Dying?” I turned away from the window.

  Leah nodded slowly. “I’ve been finishing up the work from the data they had stored to optical before the accident. They got enough data to fully model the ecology. It’s dying.”

  “How?” I asked. “Why?”

  “Oxygen,” she said. “The oxygen level in the atmosphere is rising, slowly but inexorably. The photosynthetic forms simply outcompete the anaerobes, and the result is that oxygen is gradually accumulating in the atmosphere.”

  “But that’s good,” I said. “That’s what happened on Earth. The biosphere is evolving.”

  Leah shook her head. “But Mars isn’t Earth. The oxygen is starting to scavenge hydrocarbons out of the atmosphere, and after that, it will
begin to displace carbon dioxide. Just like on Earth, but for Mars that will be catastrophic. A few tens of millibars’ less carbon dioxide, and—” She clapped her hands. “Frozen solid. End of story.”

  “But the Gaia hypothesis—doesn’t the presence of life regulate the temperature?”

  She shook her head. “Bacteria are dumb. Gaia is a hypothesis; it’s never been a proven theory. In this case, it happens to be a wrong theory.”

  “You’re sure?”

  Leah nodded. We were silent for a moment, and then I asked, “How long?”

  “Hmmm? Well, couldn’t say precisely. Not enough data.”

  “Give or take.”

  “I’d give it few thousand years at the outside. Probably less than a thousand.” She saw me smiling, and added, shaking her head, “The time may be uncertain, but the fact still is, it will happen.”

  That put a little different spin on it. We would all be dead before the planet returned to bare rock. No need to mourn for Mars, not for quite a while yet.

  Later, alone with just Leah in the tiny sleeping cubbyhole, I made love to her slowly and deliberately. She closed her eyes and arched her back as I stroked her, in her own way sensuous as a cat, but still I couldn’t tell what sort of feelings she had for me.

  When it was over, and we were lying in the dark, I had to ask. “Do you feel anything for me? Anything at all?”

  Leah turned over. “Quit asking meaningless questions. I unask your question. Mu.”

  Much later, after I thought she had fallen asleep, she said softly, “It looks like I’m stuck with you. I suppose there are worse people I could get stuck with. Don’t get in the way.”

  It was all I could ask for. I will follow her as long as she will allow it, love her, ask nothing in return. Maybe someday I will mean something to her, maybe someday as much as a comfortable pair of slippers or a favorite chair.

  In the meantime, though … It was a large universe. There would be places to go, no end of places to follow her to. That was enough.

  In the morning, the lander would come, and I would follow her home.

  People Came from Earth

  STEPHEN BAXTER

  Like many of his colleagues here at the beginning of a new century—Greg Egan comes to mind, as do people like Paul J. McAuley, Michael Swanwick, lain Banks, Bruce Sterling, Pat Cadigan, Brian Stableford, Gregory Benford, Ian McDonald, Gwyneth Jones, Vernor Vinge, Greg Bear, David Marusek, Geoff Ryman, and a half-dozen others—British writer Stephen Baxter has been engaged for the last ten years or so with the task of revitalizing and reinventing the “hard science” story for a new generation of readers, producing work on the Cutting Edge of science which bristles with weird new ideas and often takes place against vistas of almost outrageously cosmic scope.

  Baxter made his first sale to Interzone in 1987, and since then has become one of that magazine’s most frequent contributors, as well as making sales to Asimov’s Science Fiction, Science Fiction Age, Zenith, New Worlds, and elsewhere. He’s one of the most prolific new writers in science fiction, and is rapidly becoming one of the most popular and acclaimed of them as well. Baxter’s first novel, Raft, was released in 1991 to wide and enthusiastic response, and was rapidly followed by other well-received novels such as Timelike Infinity, Anti-Ice, Flux, and the H. G. Wells pastiche—a sequel to The Time Machine—The Time Ships, which won both the John W. Campbell Memorial Award and the Philip K. Dick Award. His other books include the novels Voyage, Titan, and Moonseed, and the collections Vacuum Diagrams: Stories of the Xeelee Sequence and Traces. His most recent books are the novels Mammoth, Book One: Silverhair and Manifold: Time, and a novel written in collaboration with Arthur C. Clarke, The Light of Other Days.

  “People Came from Earth” takes us to a troubled future, to an embattled, desperate world dancing on the brink of extinction, a world where an ambitious terraforming project is not sticking very well in the long run, for the autumnal story of people struggling to hold on to what they have … and perhaps even regain something of what has been lost.

  At dawn I stepped out of my house. The air frosted white from my nose, and the deep Moon chill cut through papery flesh to my spindly bones. The silver-gray light came from Earth and Mirror in the sky: twin spheres, the one milky cloud, the other a hard image of the sun. But the sun itself was already shouldering above the horizon. Beads of light like trapped stars marked rim mountain summits, and a deep bloody crimson was working its way high into our tall sky. I imagined I could see the lid of that sky, the millennial leaking of our air into space.

  I walked down the path that leads to the circular sea. There was frost everywhere, of course, but the path’s lunar dirt, patiently raked in my youth, is friendly and gripped my sandals. The water at the sea’s rim was black and oily, lapping softly. I could see the gray sheen of ice farther out, and the hard glint of pack ice beyond that, though the close horizon hid the bulk of the sea from me. Fingers of sunlight stretched across the ice, and gray-gold smoke shimmered above open water.

  I listened to the ice for a while. There is a constant tumult of groans and cracks as the ice rises and falls on the sea’s mighty shoulders. The water never freezes at Tycho’s rim; conversely, it never thaws at the center, so that there is a fat torus of ice floating out there around the central mountains. It is as if the rim of this artificial ocean is striving to emulate the unfrozen seas of Earth which bore its makers, while its remote heart is straining to grow back the cold carapace it enjoyed when our water—and air—still orbited remote Jupiter.

  I thought I heard a barking out on the pack ice. Perhaps it was a seal. A bell clanked: an early fishing boat leaving port, a fat, comforting sound that carried through the still dense air. I sought the boat’s lights, but my eyes, rheumy, stinging with cold, failed me.

  I paid attention to my creaking body: the aches in my too-thin, too-long, calcium-starved bones, the obscure spurts of pain in my urethral system, the strange itches that afflict my liver-spotted flesh. I was already growing too cold. Mirror returns enough heat to the Moon’s long Night to keep our seas and air from snowing out around us, but I would welcome a little more comfort.

  I turned and began to labor back up my regolith path to my house.

  And when I got there, Berge, my nephew, was waiting for me. I did not know then, of course, that he would not survive the new Day.

  He was eager to talk about Leonardo da Vinci.

  He had taken off his wings and stacked them up against the concrete wall of my house. I could see how the wings were thick with frost, so dense the paper feathers could surely have had little play.

  I scolded him even as I brought him into the warmth, and prepared hot soup and tea for him in my pressure kettles. “You’re a fool as your father was,” I said. “I was with him when he fell from the sky, leaving you orphaned. You know how dangerous it is in the pre-Dawn turbulence.”

  “Ah, but the power of those great thermals, Uncle,” he said, as he accepted the soup. “I can fly miles high without the slightest effort.”

  I would have berated him further, which is the prerogative of old age. But I didn’t have the heart. He stood before me, eager, heartbreakingly thin. Berge always was slender, even compared to the rest of us skinny lunar folk; but now he was clearly frail. Even these long minutes after landing, he was still panting, and his smooth fashionably-shaven scalp (so bare it showed the great bubble profile of his lunar-born skull) was dotted with beads of grimy sweat.

  And, most ominous of all, a waxy, golden sheen seemed to linger about his skin. I had no desire to raise that—not here, not now, not until I was sure what it meant, that it wasn’t some trickery of my own age-yellowed eyes.

  So I kept my counsel. We made our ritual obeisance—murmurs about dedicating our bones and flesh to the salvation of the world—and finished up our soup.

  And then, with his youthful eagerness, Berge launched into the seminar he was evidently itching to deliver on Leonardo da Vinci, long-dead citizen of a
long-dead planet. Brusquely displacing the empty soup bowls to the floor, he produced papers from his jacket and spread them out before me. The sheets, yellowed and stained with age, were covered in a crabby, indecipherable handwriting, broken with sketches of gadgets or flowing water or geometric figures. I picked out a luminously beautiful sketch of the crescent Earth—

  “No,” said Berge patiently. “Think about it. It must have been the crescent Moon.” Of course he was right. “You see, Leonardo understood the phenomenon he called the ashen Moon—like our ashen Earth, the old Earth visible in the arms of the new. He was a hundred years ahead of his time with that one … .”

  This document had been called many things in its long history, but most familiarly the Codex Leicester. Berge’s copy had been printed off in haste during the Failing, those frantic hours when our dying libraries had disgorged their great snowfalls of paper. It was a treatise centering on what Leonardo called the “body of the Earth,” but with diversions to consider such matters as water engineering, the geometry of Earth and Moon, and the origins of fossils.

  The issue of the fossils particularly excited Berge. Leonardo had been much agitated by the presence of the fossils of marine animals, fishes and oysters and corals, high in the mountains of Italy. Lacking any knowledge of tectonic processes, he had struggled to explain how the fossils might have been deposited by a series of great global floods.

  It made me remember how, when he was a boy, I once had to explain to Berge what a “fossil” was. There are no fossils on the Moon: no bones in the ground, of course, save those we put there. Now he was much more interested in the words of long-dead Leonardo than his uncle’s.

  “You have to think about the world Leonardo inhabited,” he said. “The ancient paradigms still persisted: the stationary Earth, a sky laden with spheres, crude Aristotelian proto-physics. But Leonardo’s instinct was to proceed from observation to theory—and he observed many things in the world which didn’t fit with the prevailing worldview—”