Green Mars. Kim Stanley Robinson

too much time outdoors, after all, taking on far too much radiation; but it was Simon who had died. And she was the one who had fallen asleep at the wheel; but it was Frank who had died. It was simply a matter of chance, of accidental survival or erasure.

      It was hard to believe natural selection had made any way in such a universe. There under her feet, in the troughs between the dunes, Archae bacteria were growing on sand grains; but the atmosphere was gaining oxygen fast, and all the Archae bacteria would die out except those that were by accident underground, away from the oxygen they themselves had respired, the oxygen that was poisonous to them. Natural selection or accident? You stood, breathing gases, while death rushed toward you—and were covered by boulders, and died—or covered by dust, and lived. And nothing you did mattered in that great either/or. Nothing you did mattered. One afternoon, reading randomly in the AI to distract herself between her return to the car and her dinner hour, she learned that the Czarist police had taken Dostoevsky out to be executed, and only brought him back in after several hours of waiting for his turn. Ann finished reading about this incident and sat in the driver’s seat of her car, feet on the dash, staring at the screen blindly. Another garish sunset poured through the window over her, the sun weirdly large and bright in the thickening atmosphere. Dostoevsky had been changed for life, the writer declared in the easy omniscience of biography. An epileptic, prone to violence, prone to despair. He hadn’t been able to integrate the experience. Perpetually angry. Fearful. Possessed.

      Ann shook her head and laughed, angry at the idiot writer, who simply didn’t understand. Of course you didn’t integrate the experience. It was meaninglessness. The experience that couldn’t be integrated.

      The next day a tower poked over the horizon. She stopped the car, stared at it through the car’s telescope. There was a lot of ground mist behind it. The tremblors registering on her seismograph were very strong now, and appeared to be coming from a bit to the north. She even felt one of them herself, which, given the car’s shock absorbers, meant they were strong indeed. It seemed likely there was a connection with the tower.

      She got out of her car. It was almost sunset, the sky a great arch of violent colours, the sun low in the hazy west. The light would be behind her. She wound between dunes, then carefully made her way to the crest of one, and crawled the final metres of the way, and looked over the crest at the tower, now only a kilometre to the east. When she saw how close its base was she kept her chin right on the ground, among ejecta the size of her helmet.

      It was some kind of mobile drilling operation, a big one. The massive base was flanked by giant caterpillar tracks, like those used to move the largest rockets around a spaceport. The drill tower rose out of this behemoth more than sixty metres, and the base and lower part of the tower clearly contained the technicians’ housing and equipment and supplies.

      Beyond this thing, a short distance down a gentle slope to the north, was a sea of ice. Immediately north of the drill, the crests of the great barchan dunes still stuck out of the ice—first as a bumpy beach, then as hundreds of crescent islands. But a couple of kilometres out the dune crests disappeared, and it was ice only.

      The ice was pure, clean—translucent purple under the sunset sky—clearer than any ice she had ever seen on the Martian surface, and smooth, not broken like all the glaciers. It was steaming faintly, the frost steam whipping east on the wind. And out on it, looking like ants, people in walkers and helmets were ice-skating.

      It had come clear the moment she saw the ice. Long ago she herself had confirmed the big impact hypothesis, which accounted for the dichotomy between the hemispheres; the low smooth northern hemisphere was simply a superhuge impact basin, the result of a scarcely imaginable collision in the Noachian, between Mars and a planetesimal nearly as big as it. The rock of the impact body that had not vaporised had become part of Mars itself, and there were arguments in the literature that the irregular movements in the mantle which had caused the Tharsis bulge were late developments resulting from perturbations originating with the impact. To Ann that wasn’t likely, but what was clear was that the great crash had happened, wiping out the surface of the entire northern hemisphere, and lowering it by an average of four kilometres relative to the south. An astonishing hit, but that was the Noachian. An impact of similar magnitude had in all probability caused the birth of Luna out of Earth. In fact there were some anti-impact holdouts arguing that if Mars had been hit as hard, it should have had a moon as big.

      But now, lying flat looking at the giant drilling rig, the point was that the northern hemisphere was even lower than it first appeared, for its bedrock was amazingly deep, as much as five kilometres beneath the dunes. The impact had blown that deep, and then the depression had mostly refilled, with a mixture of ejecta from the big impact, windblown sand and fines, later impact material, erosional material sliding down the slope of the Great Escarpment, and water. Yes, water, finding the lowest point as it always did; the water in the annual frost hood, and the ancient aquifer outbreaks, and the outgassing from the blistered bedrock, and the lensing from the polar cap, had all eventually migrated to this deep zone, and combined to form a truly enormous underground reservoir, an ice and liquid pool that extended in a band all the way around the planet, underlying almost everything north of 60°north latitude, except, ironically, for a bedrock island on which the polar cap itself stood.

      Ann had discovered this underground sea many years before, and by her estimates between sixty and seventy percent of all the water on Mars was down there. It was, in fact, the Oceanus Borealis that some terraformers talked about—but buried, deeply buried, and mostly frozen, and mixed with regolith and dense fines; a permafrost ocean, with some liquid down on the deepest bedrock. All locked down there for good, or so she had thought, because no matter how much heat the terraformers applied to the planet’s surface, the permafrost ocean would not thaw any faster than a metre per millennium—and even when it did melt it would remain underground, simply as a matter of gravity.

      Thus the drilling rig before her. They were mining the water. Mining the liquid aquifers direct, and also melting the permafrost with explosives, probably nuclear explosives, and then collecting the melt and pumping it onto the surface. The weight of the overlying regolith would help push the water up through pipes. The weight of water on the surface would help push up more. If there were very many drilling rigs like this one, they could put a tremendous amount on the surface. Eventually they would have a shallow sea. An ice sea to start with, but between atmospheric warming, sunlight, bacterial action, increased winds—it would melt eventually. And then there would be an Oceanus Borealis. And the old Vastitas Borealis, with its world-wrapping garnet barchan dunes, would be sea bottom. Drowned.

      She walked back to her car in the twilight, moving clumsily. It was difficult to operate the locks, to get her helmet off. Inside she sat before the microwave without moving for more than an hour, images flitting through her mind. Ants burning under a magnifying glass, an anthill drowned behind a mud dam … She had thought that nothing could reach her any more in this preposthumous existence she was living—but her hands trembled, and she could not face the rice and salmon cooling in the microwave. Her stomach was a small stone in her body. In the random flux of universal contingency, nothing mattered; and yet, and yet …

      She drove away. She couldn’t think of anything else to do. She returned south, driving up the low slopes, past Chryse and its little ice sea. It would be a bay of the larger ocean, eventually. She focused on her work, or tried. She fought to see nothing but rock, to think like a stone.

      One day she drove over a plain of small black boulders. The plain was smoother than usual, the horizon its usual five kilometres away, familiar from Underhill and all the rest of the lowlands. A little world, and completely filled with small black boulders, like fossil balls from various sports, only all black, and all faceted to one extent or another. They were ventifacts.

      She got out of the car to walk around and look. The rocks drew her on. She walked a long way west.

      A front of low clouds rolled over the horizon, and she could feel the wind pushing at her in gusts. In the premature dark of the suddenly stormy afternoon, the boulder field took on a weird beauty; she stood in a slab of dim air, rushing between two planes of lumpy blackness.

      The boulders were basalt rocks, which had been scoured by the winds on one exposed