Dexter faced her. “Why would I want to do that?”
“Because he’s your half-brother.”
His expression was blank. “Grandfather said you were like this. Manipulating.” He looked down at Eddie, who for his own unfathomable reason smiled. “But I guess it’s not his fault. Come on, kid. We’ll have to make sure the other little ones don’t play too rough, I think you’re probably a bit more easily broken than they are.”
“I’ll come too,” Masayo said.
Eddie took Dexter’s hand. “My name’s Eddie. What’s your name?”
“Dexter. I’m Dexter.” They walked off together, with Masayo following.
“Families,” Mike Wetherbee said, sneering.
Mel asked, “Are you ready?”
He let Kelly take his arm and walked her down the corridor. Mike, Thandie and Lisa followed. Mel kept his pace slow, as if they were very elderly, very frail, but distinguished visitors.
They climbed a metal stair, and followed a corridor that stretched around the circumference of one of the big spheres that comprised this habitat-spheres which, Mel said, the inhabitants called “tanks.” The light cast by fluorescents was bright and harsh. Doors off the corridor were labeled with the names of facilities like air management, water filtration, biomass processing, medical isolation, geothermal power. Evidently this particular tank housed core technical functions.
They walked past a robust decompression chamber which, Mel said, also served as an emergency inner refuge in case of a pressure breach. “Which we call storm shelters, which is wrong every which way, but it’s a bit of space program terminology we picked up from Gordo. The other tanks are more open than this. We have big communal spaces, an eating hall, an amphitheater. And factories, a big hydroponics plant-although we mostly rely on produce from the sea-and major laboratory facilities, particularly biological. Our power comes from geothermal heat, the energy of the Earth itself.”
Mike asked, “How many are you?”
“Around a hundred, including thirty kids under eighteen or so. We’re about the same size of community as Ark One, with about the same habitable volume per head as you guys had. Although in free fall I guess you could make more of your space. We’re a human colony in the abyss.”
The outer wall, subtly curved, was punctured by thick windows set in tapered frames that, Kelly surmised, offered protection against blow-ins. They paused by one window and looked out. The external lights’ glow spread only a little way into the dark. Kelly saw gleaming arcs, the walls of more tanks. More of those crab-like creatures scrabbled in the ooze, and a fish swam by, bony and angular. Kelly reminded herself she was twelve kilometers down, as deep as any oceanic trench on Earth before the flooding began. Something else moved across the ooze. It was a robot, low, like a table, with articulated legs and a camera cluster and a manipulator arm like a cut-down version of Ark One’s. It crawled out of her view, intent on its own unknown business.
“The waters are still rising,” she said. “These hulls must have a maximum crush depth.”
Thandie said, “Even at the current depth they’re withstanding a ton per square centimeter. But they’re overdesigned. Should be able to tolerate an ocean depth of a hundred kilometers, the maximum theoretically possible. In fact it looks as if the flood will top out at around eighteen kilometers above the old mean, well below that upper bound. And as this area was around two kilometers high before the flood, there won’t be a problem.”
Mike asked, “Why is a hundred kilometers the maximum?”
“Above that limit the pressure is such that water solidifies into a form of ice. No world with similar gravity to Earth’s could have an ocean deeper than that, although the precise freeze depth depends on surface temperature and thermal mixing…”
Mel said, “When we came down here the topping out at eighteen klicks wasn’t yet apparent. We thought we might finish up entombed in exotic ices.”
Kelly gazed out into the dark. “This place was a couple of kilometers high, before the flood. Where are we?”
“Wyoming,” Mel said.
Thandie said, “Yellowstone Park, to be precise. Did you ever come here, Kelly? Geysers and mud spots and steam vents, and car parks and pine trees, and tourists at the railings around Old Faithful. You were born after such things as tourists existed in the world, but you might have been brought here for a training expedition. No?”
Mel stood with Kelly and peered out. “Edward Kenzie and Gordo Alonzo brought me here in ’44, right after we had to abandon Alma. I didn’t even know this place existed, even though Ed had devoted years of his life to it.”
“Nor did I,” Kelly said with feeling.
“Ark Two was also intended as a last refuge for the President of the United States and his administration. President Peery never made it. I believe it’s a long time since we had formal communication with any government. I don’t even know who the President is, now. We kind of like being left to run things ourselves, I guess.”
Thandie said, “I do know a LaRei consortium began the construction of this place back in the 2020s, when they also started serious work on Ark One, long before the flood waters got here. They used the grounds of the old Yellowstone Volcano Observatory. They built these tanks right out in the open, and waited for the waters to close over them. Built the submarine ferries over in Jackson, and let them float off too.”
“The floods came in ’43,” Mel said. “By then the eye-dees had found this place and were besieging it. That didn’t stop even when the waters came; the eye-dees just took to rafts and carried on. When I was brought here in ’44, in the evacuation from Alma, the big domes were already just about covered by the water. We were lowered down from the choppers to hatches in the roofs. The first weeks were scary, Kelly. Even when the waters rose up above us, the eye-dees could still dive down to get at us. They used limpet mines, and managed to wreck one of the domes. That was the incident where Gordo Alonzo got himself killed. But the water was rising three hundred meters a year by then. That’s a meter a day. We watched those eye-dees being lifted on the breast of the sea up and out of sight, until they were too far above our heads to bother us. Then it got darker and darker, until after about three months the sun was shut out altogether. Incredible times.”
Kelly tried to stay composed. “And what about Don Meisel?”
He looked at her, surprised. “He stayed at Alma to the end. Protecting Mission Control. That’s the last place I saw him; I made it out, he didn’t. You didn’t know?”
“Nobody told me.” Mike Wetherbee was watching her, waiting for her to crack. She forced a smile. “So why Yellowstone, Thandie? What’s here?”
Thandie said, “This park contains half the word’s geothermal features. Two-thirds of the world’s geysers, in fact. I think your father and his advisers dreamed of surviving down here, and living off geothermal heat and the produce of black smokers. And I, and others, argued for a major seismic monitoring facility.”
Mike frowned. “What’s a black smoker?”
“A drowned geyser,” Thandie said. “Heated water escaping from the depths, eventually building up chimneys like smokestacks. You found them in the deepest oceans, in the trenches. And each of them attracts life, extremophile bacteria-that is, lovers of heat and salinity and extreme pressure-off which feed the crabs and the fish and the worms. A whole food chain fed by the Earth’s inner heat, and entirely independent of sunlight, which, you’ll notice, they don’t get much of here. And, Ed Kenzie’s idea is, maybe people could live off that. Also you’d have access to the seabed and related resources which wouldn’t be available from a raft on the ocean surface. You could mine for metals and oil and such.”
Kelly said, “And the seismology?”
Yellowstone was such a geologically active area because it sat directly over a mantle plume, a hot spot, a fountain of rock flowing like liquid up from the Earth’s deeper core.
“There’s actually a supervolcano here,” Thandie said. “It’s erupted several times in the past-the last more than six hundred thousand years ago. Some of us theorize that the shifting weight of water over the land might trigger a new eruption, which is actually overdue. Which is why we wanted a station here. Even before the waters came there was evidence of uplift, for instance Old Faithful turned off in 2039.
“They’ve also been running seismic tomography surveys, studying rock flows in the deep mantle. We’re still working on theories of why all the subterranean water should have been released just now. It may have something to do with human activity or it may not. Perhaps it’s because of the configuration of the continents. They
