"It's possible that Jupiter has several biospheres," Jasmine said. "They might mix a little, like Lilo's suggestion that her critter might be born at a lower level and rise to the top. But it's going to be tough to study it, especially down at the lowest levels where the Jovians probably are."

"Why do you think they're down there?"

"Well, I... you're right. They might live in the upper layers. But it's unlikely, I think, if only on straight probability. There are so many strata they could occupy. The probes I've sent in have identified thirty-seven distinct environments, like layers of an onion. Some of them mix in different weather conditions, which makes even more possibilities. But it's hard to imagine anything that could live in all of them. Down there at the bottom, just before my probes stop sending, is a core of hot metallic hydrogen. I don't know if anything could live in that, but I wouldn't take any bets that it's impossible to live in the layer just above."

"And what's in that layer?"

"It's a layer of liquid hydrogen, but it's hot. About twelve thousand degrees. Three million atmospheres pressure. And don't ask me what kind of life might be there. It wouldn't be like anything Lilo's ever studied. But if the Invaders and Jovians live in that stuff, all bets are off. We may never touch them."

The conversation was disturbing Lilo. She was new to the concept of weapons research; it was not something she had ever thought of before. It was not pleasant to think that your research is aimed at only one result: to kill anything you could discover.

After finishing her work in the lab and spending some time in the farm, Lilo would often go exploring with Cathay and Cass and Jasmine, or sometimes just with one of them. After about a month, however, Jasmine gradually lost interest. At one hundred and fifty, she was the oldest of the group. Jasmine had borne her child over a century ago, found that she wasn't really interested in children, and had not had another on Poseidon.

The situation with the three of them grew awkward. Lilo had moved in with them and things had gone well for a while. But it gradually became clear that Jasmine was more drawn to Lilo than to Cathay. Cathay was unhappy about it, and a little resentful of Lilo. Jasmine was talking about having a sex change, which further alienated Cathay since he was a confirmed male with no interest in other men. Lilo, on the other hand, liked them both. She was a female-stable personality—though not to the degree that Cathay was male-stable—and had spent only three of her fifty-seven years as a male. Jasmine was a member of the no-preference majority.

The months went by. Jasmine got her sex change from Mari. For a short while it seemed that it might work with the three of them, but eventually Jasmine drifted out of their lives. Lilo and Cathay got along well, in all but one area.

"You're crazy. We'll never get out of here until Tweed is ready to let us go."

"Which will be never." She didn't want to get into an argument with him about it, but could not help feeling aggravated at his acceptance of imprisonment. She looked at him and saw herself after ten years.

"You're right," he said. "Never. That is, unless you think there's a chance we'll find a way to defeat the Invaders—"

"And I do not, not for a—"

"—in which case we'll be welcomed all over the system as heroes. Otherwise, one of these days he's going to run out of money or get tired of the project."

"And we'll all be eliminated."

"Exactly. Surely you don't think I like that idea? But what the hell can we do about it?"

"We can devote all our energy to trying to do something!"

"Fine, fine. I'm all for that. What did you have in mind?"

Lilo swallowed her anger and tried to discuss it calmly with him. This is what it always came to: Give me a concrete proposal, tell me your plan. And every time she mentioned one, half-formed and highly tentative, someone would pick a million holes in it.

"I don't have anything specific," she admitted, again.

"Okay. Why don't you think about it some more and—"

"But I'll never get one without some help! Can't you see that giving up is the surest way to stay here forever? I know all my plans have been bad ones. So far! But I keep meeting with this fatalistic attitude. And from you! That continues to amaze me." She stopped, and calmed herself again. She had not meant to yell at him, and now he seemed hurt. She put her arms around him. He was unresponsive for a time, but gradually softened.

It was good with Cathay. He was a considerate lover, a good man, and a person she could trust.

"There are some who are working on getting away," he said. "But they're pretty much stuck, too, the last I heard. You might want to talk to them. There was one plan to move the whole damn moon. But it's crazy."

"Who? That's all I want to do; talk to people who want to get away."

"You're talking to me. We all want out. But the only ones who are still working on it that I know of are Vejay and Niobe."

Vejay hovered near the ceiling of his room, hanging by one foot, rummaging in a box of papers. The room was cluttered, all six walls holding furniture and boxes stuffed with paper.

"It's a simple principle, really," he said. "It's even been done a couple of times, in the asteroid belt. But it's not economical." He found what he was looking for—a ragged sheet of blue paper, much folded—and began to spread it in the air. Lilo twisted and came up beside him. She wrinkled her nose as she got close to him. Vejay was not very popular; on a civilized planet he would always be in trouble with the law for forgetting to bathe.

Vejay often forgot to eat, and never exercised at all. He neglected taking his booster pills to the point that he was all skin and bones, with just enough muscle to move him around in a weightless state. Mari had told Lilo he was healthy enough, as long as he never had to cope with gravity. Vejay believed in operating at an optimum state, and on Poseidon, that meant massing thirty kilos soaking wet.

There could not have been a greater contrast between Vejay and the third occupant of the room. Niobe the Dancer was a flawless physical specimen. Every muscle in her body was perfectly defined, standing out in a graceful pattern of swells and hollows all over her arms, legs, belly, and back.

"It's a good space drive," Vejay was saying. "But it only works well for something massive. The hole itself would outweigh any ship I ever heard of. The hole is on the other side, directly opposite us. Have you been over there to see it?"

"No. I've been meaning to, but I didn't think it was really important. I think I will now, though."

"You should. It's rather remarkable, being on the surface of the moon. You put one down on Luna and if something goes wrong it would just sink right through the surface and start orbiting underground. Pretty soon, no Luna."

Lilo shivered. No one really liked black holes.

It would have been easy to dismiss them as just another scientific abstraction if they had stayed decently distant from human affairs. When black holes were first postulated, it was thought that only a huge star which had burned itself out could ever form one. When the nuclear fires in the core of a star could no longer support the star's mass, gravity would take over; it would begin to collapse. Eventually it would reach a size and density that meant its escape velocity exceeded the speed of light.

But it was determined that at the creation of the universe, during the Big Bang, there were forces powerful enough to form tiny black holes, some of them being smaller than an atomic nucleus. Shortly afterward, that theory was modified. Though the holes might have been formed, they would have quickly evaporated, and would no longer be around to give human scientists headaches.