In the next car Maya and Frank passed the hours by calling over and asking Michel questions about the hidden colony, or discussing with Sax the physical changes occurring, or speculating about the war. Hashing it all over endlessly, trying to make sense of it, to figure out what had happened. Talking talking talking. On Judgment Day, Ann thought, as all the quick and the dead staggered around together, Maya and Frank would still be talking, trying to figure out what had happened. Where they had gone wrong.
Their third night out, the two cars ran down the lower end of Ius, and came to a long lemniscate fin dividing the canyon. They followed the official Marineris Highway down the south fork. In the last hour before dawn, they caught sight of some clouds overhead, and the dawn was much lighter than those of the previous days. It was enough to send them to cover, and they stopped in a fall of boulders stacked against the foot of the canyon’s south wall, and gathered in the lead car to wait out the day.
Here they had a view out over the broad expanse of Melas Chasma, the biggest canyon of them all. Ius’s rock was rough and blackish in comparison to the smooth red floor of Melas; it seemed to Ann possible that the two canyons were made of rock from ancient tectonic plates, once moving past each other, now juxtaposed forever.
They sat through a long day, talked out, tense, exhausted, their hair oily and uncombed, their faces grimy with the ubiquitous red fines of a dust storm. Sometimes there were clouds, sometimes haze, sometimes sudden pockets of clarity.
In mid-afternoon, without any warning at all, the rover rocked on its shock absorbers. Startled to attention, they jerked up to look at the TVs. The rover’s rear camera was pointed back up Ius, and suddenly Sax tapped the screen displaying its view. “Frost,” he said. “I wonder . . .”
The camera showed the frost steam thickening, moving down-canyon toward them. The highway was up on a bench above the main floor of Ius’s south fork; and this was lucky, because with a roar that shook the rover, that main floor disappeared, overwhelmed by a low wall of black water and dirty white mush. It was a juggernaut of ice chunks, tumbling rocks, foam, mud and water, a slurry throwing itself down the middle of the canyon. The roar was like thunder. Even inside the car it was too loud to talk, and the car trembled under them.
Below their bench, the canyon floor proper was perhaps fifteen kilometers across. The flood filled this whole expanse in a matter of minutes, and promptly began to rise against a long talus slope that ran out from the cliff down-canyon from them. The surface of the flood settled as it pooled against this dam, and froze solid as they watched: a lumpy discolored chaos of ice, strangely stilled. Now they could hear themselves shout over the cracks and booms and omnipresent roaring, but there was nothing to say. They only stared out the low windows or at the TVs, stunned. The frost steam coming off the flood’s surface lessened to a light fog. But no more than fifteen minutes later the ice lake burst at its lower end, rupturing in a surge of black steaming water that tore the talus dam away, with an explosive roar of avalanching rock. The flood poured down-canyon again, its leading edge beyond their view, down the great slope from Ius into Melas Chasma.
• • •
Now there was a river running down Valles Marineris, a broad, steaming, ice-choked deluge. Ann had seen videotape of the outbreaks in the north, but she hadn’t been able to get to one to see it in person. Here in the flesh, she found it almost impossible to grasp. The landscape itself was now speaking a kind of glossolalia. The inchoate roar smashed at the air, and quivered their stomachs like some bass tearing of the world’s fabric. And it was visual chaos as well, a meaningless jumble that she couldn’t seem to focus on, to distinguish near from far, or vertical from horizontal, or moving from still, or light from dark. She was losing the ability to read meaning from her senses. Only with great difficulty could she understand her companions in the car. She wasn’t sure if it was her hearing or not. She couldn’t stand to look at Sax, but then Sax she at least understood. He was trying to hide it from her, but it was clear he was excited by what was happening. That calm dead exterior had always masked a passionate nature, and she had always known it. Now he was high-colored as if he had a fever, and he never met her eye; he knew that she knew what he felt. She despised his shirking inability to confront her, even if it did arise from some kind of consideration for her. And the way he stayed always busy at his screen— he never actually looked out the low floor windows of the rover, to see the flood with his own eyes. The cameras have a better view, he would say mildly when Michel urged him to have a look. And after only a half hour of watching the first arrival of the flood on the TVs, he had gone to his AI screen to work out what it might mean to his project. Water rushing down Ius, freezing, breaking up and rushing down again; certainly into Melas; whether there would be enough water to make it into Corprates, and then down into Capri and Eos, and then down into the Aureum Chaos . . . it seemed unlikely on the face of it, but the Compton Aquifer had been big, one of the biggest ever found. Marineris very likely owed its existence to outbreaks from earlier incarnations of the same aquifer, and the Tharsis Bulge had never stopped outgassing . . . She found she was lying on the floor of the rover, watching the flood, trying to comprehend it. She tried to calculate its flow in her head, just as a way to focus better on what she saw, to bring it back out of the meaninglessness that threatened to overwhelm her. Despite herself she felt the fascination of the calculation, and of the view, and even of the flood itself; this had happened on Mars before, billions of years ago, and probably just like this. There were signs of catastrophic floods all over, beach terraces, lemniscate islands, channel beds, scablands . . . And the old broken aquifers had refilled, from the Tharsis upwelling and all the heat and outgassing that that engendered. It would have been slow, but give it two billion years. . . .