Lindgren said from nightmare, staring at a bulkhead as if she could see through: “When the last of us dies— We must put in an automatic cutoff. The ship must not keep on after our deaths. Let the radiation do what it will, let cosmic friction break her to bits and let the bits drift off yonder.”

“Why?” asked Reymont.

“Isn’t it obvious? If we throw ourselves into a circular path… consuming hydrogen, always traveling faster, running tau down and down as the thousands of years pass… we get more massive. We could end by devouring the galaxy.”

“No, not that,” said Telander. He retreated into pedantry. “I have seen calculations. Somebody did worry once about a Bussard craft getting out of control. But as Mr. Pereira remarked, any human work is insignificant out here. Tau would have to become something like, shall we say, ten to the minus twentieth power before the ship’s mass was equal to that of a minor star. And the odds are always literally astronomical against her colliding with anything more important than a nebula. Besides, we know the universe is finite in time as well as space. It would stop expanding and collapse before our tau got that low. We are going to die. But the cosmos is safe from us.”

“How long can we live?” Lindgren wondered. She cut Pereira off. “I don’t mean potentially. If you say half a century, I believe you. But I think in a year or two we will stop eating, or cut our throats, or agree to turn the accelerators off.”

“Not if I can help it,” Reymont snapped.

She gave him a dreary look. “Do you mean you would continue— not just barred from man, from living Earth, but from the whole of creation?”

He regarded her steadily in return. His right hand rested on his gun butt. “Don’t you have that much guts?” he replied.

“Fifty years inside this flying coffin!” she almost screamed. “How many will that be outside?”

“Easy,” Fedoroff warned, and took her around the waist. She clung to him and snatched after air.

Boudreau said, as carefully dry as Telander: “The time relationship appears to be somewhat academic to us, n’est-ce pas? It depends on what course we take. If we let ourselves continue straight outwards, naturally we will encounter a thinner medium. The rate of decrease of tau will grow proportionately smaller as we enter intergalactic space. Contrariwise, if we try for a cyclical path taking us through the densest hydrogen concentrations, we could get a very large inverse tau. We might see billions of years go by. That could be quite wonderful.” His smile was forced, a flash in the spade beard. “We have each other too. A goodly company. I am with Charles. There are better ways to live but also worse ones.”

Lindgren hid against Fedoroff’s breast. He held her, patted her with a clumsy hand. After a while (an hour or so in the history of the stars) she raised her face again.