“I had no idea. Everything seemed perfectly normal.”

“Except for that first minute.”

“I thought that was more me than you. People are different. There’s always an adjustment to get the geometry right.”

“The geometry feels just fine.” Jan relaxed against his body. The sleeping bag provided warm intimacy. He had more chest hair than she expected, and she liked the soft tickle of it against her breasts. He also smelled different, a sexual odor which came as an unexpected pleasure. She closed her eyes in contented silence. Maybe she was all set to fall asleep herself, for certainly when he spoke his voice seemed to come from far away.

“I don’t want to spoil the mood, because this is really pleasant. But I did have something else that I wanted to talk to you about. It may sound pretty ridiculous.”

Jan said lazily, “You said, ask me anything. So I’ll say, tell me anything.”

“It’s about Sebastian.”

It was Jan’s turn to stiffen. “What about him?”

“I know that you’ve looked after him almost all his life, and you care for him very much.”

“Like a brother. There has never been one shred of sexual feeling between us.”

“Once I had time to see you interact, I never thought there had been. You don’t look at each other that way. And I understand that Dr. Bloom may be the person who has the most contact with him from now on. But because you’ve been so close for so long, you ought to hear this.”

“Has Sebastian done something?”

“He has done nothing wrong. He spends lots of time wandering around the ship, staring at things and not saying anything.”

“That’s harmless enough.”

“I think so, too. But it has made a few people uneasy, and they are reacting. There’s been a rumor going around that he’s a Jonah. Do you know what a Jonah is for ships in space?”

“I imagine that it’s the same as it is for ships on the seas of Earth. Someone who brings bad luck.”

“That’s what they’re saying. Sebastian Birch will bring bad luck to the Achilles.”

“I never heard such nonsense. Sebastian wouldn’t harm anyone or anything.”

“I believe you, Jan. But I want you to know the wild talk that’s been going around some of the crew and passengers, so you won’t get a nasty surprise. It’s nothing more than dumb superstition, but they say that with Sebastian Birch on board this ship will never make it to Ganymede. Somewhere along the way, no one knows how or where, the presence of Sebastian will lead the Achilles to disaster.”

16

The model… a worrying new insight, burning to be tested.

A meeting with Prosper and Lena Ligon… top priority, they insist it can’t be put off even for a day.

Kate Lonaker… cold as Charon, unsympathetic to any attempt at reconciliation, refusing to talk.

Travel notification… a trip to the Saturn system, with no explanation.

Alex was going mad. He had never felt himself under such multiple pressures. Somehow he had to impose logic and a set of priorities.

Prosper Ligon and his mother first. Alex composed the shortest message he could imagine: Meet four o’clock at Ligon HQ, Notify if not acceptable.

Next he checked the travel authorization. As soon as he saw the origin: Ligon Industries, he put the worry to the back of his mind. He would find out what it was about soon enough.

Now for the tough one. He called Kate.

She answered at once, as though she had been sitting waiting by her communications terminal.

“Yes?”

“I’m going to run the model again. I have a new idea, and to test it I’m going to DP Central. I would very much appreciate your assistance and insights.”

“Very well. I will meet you there.”

Still cold, still aloof. What was wrong with the woman? Would he make a big deal of it, if Kate had gone off and screwed somebody and she didn’t even remember who?

Alex decided. Yes, he would mind. He would be totally pissed. He owed Kate a big apology, if only she would endure his company long enough to listen.

He hurried along to DP Central, where they would enjoy access to the highest computational priority and the best displays, courtesy of Magrit Knudsen. Somehow, Kate was there ahead of him.

“Kate, I just want to say—”

“I’m ready for work when you are. You tell me you have a new idea. What is it?”

So much for apologies. Hell hath no fury like a woman scorned. He hadn’t exactly scorned her, but that logic wouldn’t get him far. To work.

“I’ve reviewed the old results over and over. I’m still convinced that the model is basically correct.”

“So you mean, a hundred years from now there will be no humans left, anywhere. Right. That’s very reassuring.”

“I don’t believe that result. I think that the problem lies in the Seine.”

“Two weeks ago you told me that the Seine would solve all our problems.”

“All our computational problems. We have ample computing capacity for the first time ever, but the Seine is much more than simple computer power.”

“Like what?”

“Like a huge number of external databases, online for the first time. We were careful not to introduce what we thought of as inappropriate exogenous variables into the model, but the Seine doesn’t have that constraint. Anything that is not specifically ruled out is open for consideration. The trouble is, the Seine is so complex that we don’t know what it includes and what it excludes. I believe that we have to do something radically different. We have to introduce our own exogenous variables, things that we believe are possible logical components of the future. We have to see how this affects the computed results.”

Kate, for a change, didn’t act like an ice princess. The lines of her face softened, and she stared directly at Alex. “But there could be a million things in the possible future. How are we supposed to know what to choose?”

“We assess possible events on the basis of our own estimates of their likelihood. We change the model to reflect it, and see what difference it makes to the results.”

“I wouldn’t know where to begin.”

“Well, I think I do. The Seine doesn’t try to predict the future, or make random assumptions. It uses only facts that are present somewhere in the System right now. If the computed future suggests the extinction of humanity, that’s because those factors are already present today.”

“Such as what?”

This was one that Alex wished he could avoid. “Such as the Commensals. They are basically human, but a thousand other life forms have been spliced into them. It occurred to me that the way we have been running the model, neither the computer nor the Seine data banks makes any distinction between a human and Commensal. We don’t know if future population figures refer to humans, or Commensals, or both. If everyone in the System eventually elects to become a Commensal, then the model that we have may be predicting that the future holds no true humans. On the other hand” — Alex had to face an intolerable possibility — “maybe Commensals become the human norm, but they have a built-in flaw that causes them to die out.”

A built-in flaw like guaranteed sterility, so that no one is reproducing anymore.

Kate began to nod agreement, then stared wide-eyed at Alex. “But if that’s the case, then your mother—”

“I’ve already thought of that.”

“Oh, Alex.” She reached out as though to take his hand, then withdrew. “I’m really sorry. I hope that’s not true.”

“So do I.” Alex saw his chance, and jumped in. “And I’m really sorry, too. I don’t mean for my mother and the other Commensals, I mean for what I did. I know I screwed Lucy Mobarak, or Deirdre de Soto, or somebody. Maybe I screwed all of them. But they sabotaged me, I’m sure of it now, down in the Holy Rollers. The drinks were spiked. I had no idea what I was doing — I don’t even remember it. That doesn’t excuse what I did, but maybe it explains it. I want to say again, I’m sorry.”