Michel shouted his insistence that they press forward, and get through the Gate on the bench. “If we hurry we can make it! We must try!” And when Maya continued to protest, he added forcefully, “The head of South Coprates is steep! The car would never get up it, it’s a cliff like these! And we don’t have the supplies to add so many extra days to our trip! We can’t go back!”
The insane roar of the flood was his only answer. They sat in the car, in their separate thoughts, separated by the roar as if by many kilometers of space. Ann found herself wishing the bench would slide from under them, or a piece of the south wall fall onto them, and put an end to their indecision, and to the awful, maddening noise.
They drove on. Frank and Maya and Simon and Nadia stood behind Michel and Kasei, watching them drive. Sax sat at his screen, stretching like a cat, staring myopically at the little picture of the deluge. The surface calmed for a moment, and froze over, and the explosive noise reduced to a violent low rumble. “It’s like the Grand Canyon on a kind of super-Himalayan scale,” Sax said, apparently to himself, although only Ann would be able to hear him. “The Kala Gandaki Gorge is about three kilometers deep, isn’t it? And Dhaulagiri and Annapurna only forty or fifty kilometers apart, I think. Fill that with a flood like . . .” He failed to recall any comparable flood. “I wonder what all that water was doing so high on the Tharsis Bulge.”
Cracks like gunshots announced another surge. The white surface of the flood blew apart and tumbled downstream. White noise suddenly enveloped them, battening everything they said or thought, as if the universe were vibrating. A bass tuning fork . . .
“Outgassing,” Ann said. “Outgassing.” Her mouth was stiff, she could feel in her face how long it had been since she had last spoken. “Tharsis rests on an upwelling of magma. Rock alone couldn’t sustain the weight; the bulge would have subsided if it weren’t being supported by an upwelling current in the mantle.”
“I thought there was no mantle.” She could just hear him through the noise.
“No no.” She didn’t care if he could hear her or not. “It’s just slowed down. But currents are still there. And since the last great floods, they have refilled the high aquifers on Tharsis. And kept aquifers like Compton warm enough to stay liquid. Eventually the hydrostatic pressures were extreme. But with less vulcanism, and fewer big meteor strikes, nothing set it off. It might have been full for a billion years.”
“Do you think Phobos broke it open?”
“Maybe. More likely a reactor meltdown.”
“Did you know Compton was this big?” Sax asked.
“Yes.”
“I never heard of it.”
“No.”
Ann stared at him. Had he heard her say that?
He had. Concealing data— he was shocked, she could tell. He couldn’t imagine any reason good enough to conceal data. Perhaps this was the root of their inability to understand each other. Value systems based on entirely different assumptions. Completely different kinds of science.
He cleared his throat. “Did you know it was liquid?”
“I thought so. But now we know.”
Sax twitched, and called up on his screen the image from the left side camera. Black fizzing water, gray debris, shattered ice, boulders like great tumbling dice; standing waves freezing in place, collapsing and sweeping away in clouds of frost steam. . . the noise had risen back to its crackling jet howl.
“I wouldn’t have done it this way!” Sax exclaimed.
Ann stared at him. He steadfastly regarded the TV.
“I know,” she said. And then she was tired of talk again, tired of its uselessness. It had never been any more than it was now: whispers against the great roar of the world, half-heard and less understood.
• • •
They drove as quickly as they could through the Dover Gate, following the Calais Ramp as Michel called their bench. Progress was nerve-rackingly slow, it was a bitter struggle to get the rover over the rockfall covering this narrow terrace; boulders were scattered everywhere, and the flood ate away at the land to their left, narrowing the bench at a perceptible rate. Landslides from the cliff walls fell ahead and behind them, and more than once individual rocks crashed into the car’s roof, making them all jump. It was perfectly possible that a bigger rock would hit them and smash them like bugs, without a single bit of warning. That possibility subdued them all, which was fine by Ann. Even Simon left her alone, throwing himself into the navigational effort and going out on scouting trips with Nadia or Frank or Kasei, happy, she thought, to have some excuse to get away from her. And why not?