“Mmmm,” Badim said. “But it’s just island biogeography, right? The distance effect. And the farther the distance, the more the effect. In this case, twelve light-years. Must be the same as infinity.”

“So why didn’t they take that into account?”

“I think they tried to. We’re a heterogeneous immigration, as they would call it. A kind of archipelago of environments, all moving together. So they did what they could.”

“But didn’t they run the numbers? Didn’t they see it wouldn’t work?”

“Apparently not. I mean, they must have thought it would work, or they wouldn’t have done it.”

Devi heaved one of her big sighs. “I’d like to see their numbers. I can’t believe they didn’t put all that information here on board. It’s like they knew they were being fools, and didn’t want us to know. As if we wouldn’t find out!”

“The information is here on board,” Badim said. “It’s just that it doesn’t help us. We’re going to experience some allopatric speciation, that’s inevitable, and maybe even the point. There’ll be sympatric speciation within our eventual ecosystem, and we’ll all deviate together from Terran species.”

“But at different rates! That’s what they didn’t take into account. The bacteria are evolving faster than the big animals and plants, and it’s making the whole ship sick! I mean look at these figures, you can see it—”

“I know—”

“Shorter lifetimes, smaller bodies, longer disease durations. Even lower IQs, for God’s sake!”

“That’s just reversion to the mean.”

“You say that, but how could you tell? Besides, just how smart could the people who got into this ship have been? I mean, ask yourself—why did they do it? What were they thinking? What were they running away from?”

“I don’t know.”

“Look at this, Bee—if you run the data through the recursion algorithms, you see that it’s more than a simple reversion. And why wouldn’t it be? We don’t get enough stimulation in here, the light is wrong, the gravity was Coriolised and now it isn’t, and now we’ve got different bacterial loads in us than humans ever did before, diverging farther and farther from what our genomes were used to.”

“That’s probably true on Earth too.”

“Do you really think so? Why wouldn’t it be worse in here? Fifty thousand times smaller surface area? It isn’t an island, it’s a rat’s cage.”

“A hundred square kilometers, dear. It’s a good-sized island. In twenty-four semiautonomous biomes. An ark, a true world ship.”

No reply from Devi.

Finally Badim said, “Look, Devi. We’re going to make it. We’re almost there. We’re on track and on schedule, and almost every biome is extant and doing pretty well, or at least hanging in there. There’s been a little regression and a little diminution, but pretty soon we’ll be on E’s moon, and flourishing.”

“You don’t know that.”

“What do you mean? Why wouldn’t we?”

“Oh come on, Beebee. Any number of factors could impact us once we get there. The probes only had a couple of days each to collect data, so we don’t really know what we’re coming into.”

“We’re coming into a water world in the habitable zone.”

Again no reply from Devi.

“Come on, gal,” Badim said quietly. “You should get to bed. You need more sleep.”

“I know.” Devi’s voice was ragged. “I can’t sleep anymore.” She had lost 11 kilograms.

“Yes you can. Everyone can. You can’t not sleep.”

“You would think.”

“Just stop looking at these screens for a while. They’re waking you up, not just the content, but the light in your eyes. Close your eyes and listen to music. Number every worry, and let them go with their numbers. You’ll fall asleep well before you run out of numbers. Come on, let me get you into bed. Sometimes you have to let me help you.”

“I know.”

They began to move, and Freya slipped back toward her bedroom.

Before she got there she heard Devi say, “I feel so bad for them, Bee. There aren’t enough of them. Not everyone is born to be a scientist, but to survive they’re all going to have to do it, even the ones who aren’t good at it, who can’t. What are they supposed to do? On Earth they could find something else to do, but here they’ll just be failures.”

“They’ll have E’s moon,” Badim said quietly. “Don’t feel bad for them. Feel bad for us, if you like. But we’ll make it too. And meanwhile, we have each other.”

“Thank God for that,” Devi said. “Oh Beebee, I hope I make it! Just to see! But we keep slowing down.”

“As we have to.”

“Yes. But it’s like trying to live past the end of Zeno’s paradox.”

Tau Ceti’s debris disk successfully threaded, they came into its planetary zone. A close pass of Planet H pulled them into the local plane of the ecliptic.

The brief tug of H’s gravity, combined with a planned rocket deceleration, created enough delta v to slosh the water in the storage tanks, and thus cause some alarms in ship to go off, which then caused various systems to shut down; and some of these systems did not come back on line when they were instructed to.

The most important of the systems that did not come back was the cooling system for the ship’s nuclear reactor, which should not have gone off in the first place, unless an explosion in it was imminent. At the same time, the backup cooling system did not start up to replace its function.

More ship alarms immediately informed the operations staff of this problem, and quickly (sixty-seven seconds) identified the sources of the problem in both cooling systems. In the primary system, there had been a signal from the on-off switch directing it to turn off, caused either by computer malfunction or a surge in the power line to the switch; in the backup system, it was a stuck valve in a pipe joint near the outer wall of the reactor.

Devi and Freya joined the repair crew hurrying up to the spine, where the reactor was continuing to operate, but in a rapidly warming supply of coolant.

“Help me go fast,” Devi said to Freya.

So Freya held her by the arm and hurried by her side, lifting her outright and running with her when they had steps or bulkheads to get through. When they got to the spine they took an elevator, and Freya simply held Devi in her arms and then lifted her around when the elevator car stopped and g-forces pushed them across the car; after that she carried her mother like a dog or a small child, hauling her around the spine’s microgravity. Devi said nothing, did not curse as she did sometimes in their kitchen; but the look on her face was the same as in those moments. She looked as if she wanted to kill something.

But she kept her mouth clamped shut, and when they got to the power plant offices she grasped a wall cleat and a desk, and let Aram and Delwin do the talking with the team there while she scanned the screens. The backup cooling system was controlled from the room next door, and the monitors indicated the problem was inside the pipes that passed through the room beyond; it still looked like it was just a stuck valve, as far as the monitor in the joint could tell. But that was enough.

They went in the room containing that part of the pipes, and Aram applied the engineer’s solution, as they called it, tapping with a wrench the exposed curved jointed section that held the thermostat and valve regulator, which together seemed to be the source of the problem. Then he hit the joint itself with considerable force. With that a row of lights on the control panel turned from red to green, and the piping on both sides of the joint began to emit a soft flowing gurgle, like a flushed toilet.

“The valve must have closed and then stuck,” Aram said with an unhumorous smile. “The swing around Planet H must have torqued it.”

“Fuck,” Devi said, voice rich with disgust.