Worldmakers

by Gardner Dozois

  In a very small voice, I said, “I volunteer to share a bunk with Leah.”

  Tally looked up sharply. Leah gazed back at her, her expression unreadable. But she didn’t voice an objection.

  “Huh,” said Tally. I don’t think I’d ever seen Tally at a loss for words. “Well. Guess I get a cubby to myself.” She paused, and then added, almost to herself, “Lucky me.”

  Terraformed Mars had an atmosphere half as thick as Earth’s. That was enough pressure for a human to survive, but with no oxygen to breathe. With rebreathers to recirculate exhaust carbon dioxide back into breathable oxygen, we could survive outside comfortably without a vacuum suit. For that matter, you could survive outside stark naked, as long as you had your rebreather, and didn’t mind the cold.

  Outside again, this time with boots and coveralls to keep the worst of the stinking dirt out of our habitat, we walked in silence across the rock-littered landscape the hundred meters to the place the earlier habitat had been. Ragged edges of aluminum stuck out from the platform like ribs. Pieces of the habitat had been scattered across the plain by the wind, a fantail of shining metal and shards of composite sheeting visible against the brown all the way to the horizon.

  There were two bodies, one within the remains of the exploded habitat, one out on the plain. Not much was left of them. The bodies were barely more than piles of dirt with a ribcage and part of a pelvis protruding, even the bones covered with the purple-brown of the Martian microbiota. I was glad for the filtering effect of the rebreather. I made videos of the bodies in position while Leah knelt down to examine them and take samples: clothing, hair, skin, tissue. After she examined the one in the habitat, she rose without speaking and went to the one outside. Unlike the other one, the clothing on this one was partly eaten away by bacteria.

  Leah’s long black hair blew around her face as she worked, but the carbon-dioxide breeze wasn’t strong enough to move the pieces of aluminum framework. The wind must have been much stronger to have spread the wreckage so far.

  Tally stood, as always, a dozen paces away, eyes restlessly scanning the horizon for enemies.

  “We really should have had a doctor to do this analysis,” Leah said, standing up. “But a few things are obvious. For example, the man in the habitat had a fractured skull.”

  “What?”

  “But this one,” she nodded down at the body she was standing over, “shows no apparent sign of trauma. No rebreather, either, so I’ll hazard a guess that carbon-dioxide poisoning was what did it for him.” Leah put the tissue samples into her sample-pack and took a step toward the habitat. “I’ll have to let the computer analyze the samples to verify that, of course.” She looked around. “Who could have killed them? Why?” She looked up the plain, following the trail of debris. “I think we’ve seen enough. Tinkerman, you have enough pictures? Does your checklist have anything else?”

  I looked down at the list. “No, as far as forensics is concerned, we’re done.”

  “Then, unless you have any further suggestions, do you think maybe we could get them decently buried?”

  When there’s a fatal incident in space, of whatever kind, there needs to be an investigation. If it was an accident, the cause has to be found so that Spacewatch Authority can take appropriate measures to prevent its recurrence, and deliver a warning to anybody else with similar equipment.

  We were that incident-investigation team, Leah and I. Tally, a freelance survival specialist, was our protection. If somebody had killed the two researchers, deliberately blown up their habitat for some as-yet-undetermined motive, whoever it was that had killed them might come back.

  But nobody cared about Mars. The exciting horizons were light-years away, where relativistic probes lasercast back terabits of images, giving the excitement of vistas that anybody could access on optical disk without the danger and discomfort of leaving Earth, and with far stranger life-forms than any mere microbes. Mars was such an uninteresting location that it took over a year before Spacewatch Authority noticed that a scientific team that had gone there to study microbes hadn’t returned. They were the first researchers to bother with an on-site investigation of Mars in over a century.

  “It doesn’t make sense,” I told Leah, back in the habitat. “Why would anybody want to murder two researchers on a stinky planet too close to Earth to even be interesting?”

  She shrugged. “Kooks. Bacteria-worshipers. Or maybe one of ’em had an angry ex.”

  “It’s not as if the planet were exciting,” I said. “They tried to terraform it. They failed. End of story, go home.”

  “Failed? Tinkerman, you have it all wrong. You should go learn a little history before going on a trip.” I could hear her switching into lecture mode. “They didn’t try to terraform Mars. They never tried to terraform Mars. What they did was ecopoesis, and they succeeded spectacularly, more than anybody had a right to expect.”

  “Ecopoesis,” I said, “terraforming, same thing.”

  “Not at all.”

  The way Leah told it, it was part epic, part farce.

  It’s hard for us, now, to imagine what it was like in the age of confusion, before the fusion renaissance and the second reformation, but the people of the twenty-first century had a technology of chemical rockets and nuclear reactors that, although primitive, had its own crude power. By the middle of the twenty-first century, Mars had been explored, catalogued, and abandoned. It was too cold to harbor life, even of the most primitive sort; the atmosphere was closer to vacuum than to air, and there were far more accessible resources in the asteroids. Mars was uninteresting.

  It didn’t even make good video. The largest canyon in the solar system—so big that if you stand in the middle, the walls on both sides were out of sight over the horizon. The biggest mountain in the solar system—but the slope so gentle that it meant nothing on any human scale. Ancient fossil bacteria—but not even a hint of anything that hadn’t been dead and turned to rock a billion years before trilobites crawled the oceans. A hundred spots on Earth and across the solar system were more spectacular. Once somebody had climbed Olympus (and in the low gravity of Mars it wasn’t a hard climb) and placed flags at both poles of Mars, why go back?

  The ecopoesis of Mars was done by a band of malcontents from one of the very first space settlements, Freehold Toynbee. Habitats—they called them “space colonies” back then—were crowded, dangerous, undersupplied, constantly in need of repair, and smelly. They were haven to malcontents, ideologues, fanatics, and visionaries: the vanguard of humanity, the divine agents of the manifest destiny of mankind into the universe. More succinctly, the habitats were home to people who couldn’t get along with their fellow humans on Earth. Arguments were their way of life.

  It was an engineer named Joseph Smith Kirkpatrick who proposed that Toynbee could transform Mars. The people of Toynbee debated the question for a year, arguing every conceivable point of view with a riotous enthusiasm. At the beginning, the consensus of the colony seemed to be that since human destiny was in space, even to consider living on planetary surfaces could only be idiocy, or some deviant plot to subvert that destiny. But Kirkpatrick was more than just a maverick engineer with wild dreams, he was a man with a divine mission. A year later, the quibble about living on a planetary surface wasn’t even part of the argument. Toynbee decided that the right of Mars to remain unchanged was preempted by the imperative of life to spread into new niches. They had convinced themselves that they had not merely a right, but a divine duty to seed life on Mars.

  Mars, back then, was completely inhospitable to life. The atmosphere was less than one percent of the Earth’s, and the average temperature was far below freezing, even at the equator. But their analysis showed that the climate of Mars just might be unstable. The surface of Mars showed networks of canyons and run-off channels, dry lakes, and the seashores of ancient oceans. There had been water on Mars, once, a billion years or more ago, and plenty of it. All that water was still there, hidden away. The old sc
ientific expeditions had proven that—frozen in the polar ice-caps, locked into kilometer-thick hills of permafrost in the highlands. They convinced themselves that there was, in fact, far more water on Mars than previously suspected, frozen into enormous buried glaciers under featureless fields of sand. Enough to form whole oceans—if it could be melted. All that was needed was a trigger.

  It’s not easy to heat up a planet, even temporarily. They did it by setting off a volcano. There were a number of ancient volcanoes on Mars to choose from; after many geological soundings to determine magma depth, they picked a small one. Or rather, a volcano small by Mars standards, still a monster by the standards of any Earthly mountains. Hecates Tholus; the Witch’s Teat. To set it off, they determined, required that they drill five kilometers deep into the crust of Mars.

  Just because it was clearly impossible was no reason they wouldn’t do it. Mars has no magnetic field, and so the solar wind impacts directly on the planetary exosphere. A thousand miles above Mars, currents of a billion amperes course around the planet, driven by the solar wind-derived ionization. Joseph Smith Kirkpatrick and his team of planetary engineers short-circuited this current with a laser beam, ionizing a discharge channel through the atmosphere, creating the solar system’s largest lightning bolt. They discharged the ionosphere of Mars into the side of Hecate, instantly creating a meter-deep pool of molten rock. And then they did it again. And again, as soon as the ionospheric charge had a chance to renew. And again, a new lightning bolt every five minutes, day and night, for ten years.

  One million lightning discharges, all on exactly the same spot. They melted a channel through to the magma chamber below, and a volcano that had been sleeping for almost half a billion years awakened in a cataclysmic explosion. The eruption put carbon dioxide and sulfur dioxide into the atmosphere; more importantly, it shot a hundred billion tons of ash directly into the stratosphere. Over the course of several months, the ash settled down, blackening the surface.

  The new, darker surface absorbed sunlight, warming the planet and releasing adsorbed carbon dioxide from the soil. The released carbon dioxide thickened the atmosphere, and the greenhouse effect of the thicker atmosphere warmed the planet yet more. The resulting heat evaporated water from the polar ice-caps into the atmosphere. Water in the atmosphere is an effective greenhouse gas, even more effective than carbon dioxide, and so the temperature rose a little more. Finally ice trapped underground for eons melted. A whole hemisphere of Mars was flooded, eventually to form the vast Boreal Ocean, as well as innumerable crater seas and ponds. But that was much later. In the beginning, in Joseph Smith Kirkpatrick’s lifetime, only on a band around the equator was water actually liquid all year round. But that was enough for what they wanted to do. Slowly, the eons-frozen permafrost of Mars was melting.

  The atmosphere was still thin, and still almost entirely carbon dioxide, But Mars is a sulfur-rich planet. Sulfur dioxide frozen into the soil was also released, and rose into the atmosphere. Ultraviolet light from the sun photolyzed the sulfur dioxide into free radicals, which recombined to form sulfuric acid, which instantly dissolved into the new equatorial oceans. The new acid oceans attacked the ancient rocks of Mars, etching away calcium carbonate and magnesium carbonate, releasing carbon dioxide. In a few years, the acid oceans had been once more neutralized—and the atmosphere was thick, fully half a bar of carbon dioxide, enough for a greenhouse effect warm enough to keep the new oceans liquid year-round.

  Mars had been triggered.

  But how to keep this new atmosphere, to keep the planet warm? Not even Joseph Smith Kirkpatrick could keep a volcano erupting forever, and already the Witch’s Tit was settling down from an untamed explosion of ash to a sedate mound of slowly oozing lava.

  Joseph Smith Kirkpatrick’s answer was bacteria. Anaerobic bacteria, to live in the oxygen-free atmosphere of Mars.

  “Sewer bacteria,” I said.

  “You got it, Tinkerman. Anaerobic bacteria—modified sewer organisms. Yeasts, slime-molds, cyanobacteria, methanogens, and halophiles as well; but all in all, bacteria closer to gangrene than to higher life.”

  “No wonder it stinks.” I shuddered. “They were crazy.”

  “Not so. They were, in fact, very clever. They engineered a whole anaerobic ecology. The bacterial ecology darkened the surface, taking over the job of the volcanic ash. It burrowed into the rocks and broke them apart into soil, releasing adsorbed carbon dioxide in the process. The methanogens added methane, a vitally important greenhouse gas, to that atmosphere, and raised the temperature another few degrees. They didn’t dare establish too many photosynthetic forms, of course, because if the carbon dioxide in the atmosphere were to be converted into oxygen, the greenhouse effect that kept the planet warm would vanish, and the planet would return to its lifeless, frozen state.

  “But terraforming Mars hadn’t been their goal in the first place; in fact, terraforming was the very antithesis of what they intended. Their goal was ecopoesis, the establishment of an ecology. They were Darwinists, and diversity was their creed. They looked down in contempt on unimaginative humans who believed that humans were the pinnacle of creation; they saw humanity as only agents of life, spore-pods by which life could jump from one world to another. They believed that once life, however primitive, could establish a toehold on Mars, it would adapt to its environment, and flourish, and someday evolve. Not to make a copy of Earth, but into something new, something indigenously Martian.”

  “So they wanted to be gods.”

  Leah shook her head. “They wanted to be men.”

  “So they’re responsible for this place. Great.”

  “The ecopoesis was a wonder in its day, Tinkerman. It spawned debate across the Earth and cis-lunar space: Was this the greatest feat of engineering in history, or was it a crime against nature? The year of arguing at Freehold Toynbee was nothing compared to the cyclonic fervor that was released when Joseph Smith Kirkpatrick proudly announced to the Earth what they had done.

  “Kirkpatrick was kidnapped from Toynbee and put on trial in Geneva as an ecocriminal. The question the High Court argued was, ‘Do Rocks Have Rights?’ Can it be a crime to destroy an ecosystem that contains no life? The trial took three years, and ended in a hung jury. Kirkpatrick was eventually acquitted of all charges, but he was never allowed to leave the Earth again, and died an angry, bitter man.

  “Freehold Toynbee claimed ownership of Mars, and passed a law making it illegal for any human to land on it for the next billion years—but nobody paid any attention to their claim. For decades, Mars was the subject of intense scientific scrutiny. In a few more years Toynbee went bankrupt, for ecopoesis paid no bills. Technologically obsolete, the colony itself was ripped apart for scrap; the colonists scattering to a hundred colonies and asteroid settlements. And then, after a few decades of fame, Mars was ignored. Bacteria or no bacteria, there were far more abundant resources elsewhere in the solar system.”

  “And if two researchers hadn’t decided to die here, it would still be uninteresting today.”

  “Not uninteresting, no. Ignored, maybe. But not uninteresting.”

  “To you.”

  Leah smiled. “To me.”

  Langevin took the lander back upstairs, flying the utility platform in formation with him, leaving us alone on the planet. We were in the tiny kitchen area of the habitat, sitting around the only table large enough to serve as a conference area. Leah spoke first. “Tally, did you learn anything?”

  “After almost two years,” Tally said, “did you really seriously believe any footprints of the perpers would be left preserved? Well, surprise.” She grinned. “Yeah, I found some bootprints. Took me some looking, let me tell you, but I found ’em.”

  “So tell,” Leah said. “What did you get?”

  “A few places in the lee of the rocks didn’t get washed away by rain or blurred by wind.” Tally shook her head. “But I checked them all; every damn print matches the size and patterns of one of the boots in the ha
b. Either whoever did it used the same boots as our late friends, or, more likely, whoever did it didn’t leave any bootprints. That’s all I’ve got. You?”

  Leah spoke slowly. “The one in the hab died from being hit in the head. The other one died outside. No rebreather in evidence, and he wasn’t dressed for outside. Just a thin robe. Carbon-dioxide poisoning, as I expected.”

  “Hmm,” said Tally. “Two guys sleeping in the same cubby. Ask me, I’d call it as a lovers’ quarrel gone violent. The one guy bashes the other in a fit of rage, probably didn’t mean to hit quite so hard. Then, realizing what he did, he blows up the habitat and walks outside to die.”

  “Could be,” Leah said. “It’s a hypothesis, anyway. Can’t prove it one way or another with the evidence we have so far. One odd thing—the man who died outside had charred clothing.”

  That explained the ragged appearance of the clothing of the man who had been outside. His clothes hadn’t been eaten by bacteria; they had been charred.

  “Maybe caught alight when he blew the habitat?” Tally suggested.

  Leah shook her head. “Carbon dioxide—and—methane atmosphere. Nothing burns, outside.”

  “Um,” Tally said. “Guess I don’t have an explanation for that one.”

  “Tinkerman?” Leah said. “You get anything?”

  I shook my head. “I collected as much of their records as I could find, but so far I can’t read them. A lot of their opticals were damaged by fire, and on the ones that weren’t, the surfaces are pretty corroded by exposure. I’ve started cleaning them off, and I may be able to get at some of their records, but even if I can do it, reading it will be pretty much a bit-by-bit process. They weren’t very conscientious at making backups and putting them in a secure location, I’m afraid.”

  “Pity. If we could read their diaries, it would help, let us see if anything was going wrong before the blowup. Oh, well. Do what you can, and we’ll get together again tomorrow and check progress.”