"All the stars of the core must have been just that much closer to going nova, ten thousand years ago.
"Then one star went nova. It let loose a lot of heat and a blast of ganuna rays. The few stars around it got that much hotter. I gather the gamma rays also make for increased stellar activity. So a couple of neighboring stars blew up.
"That made three. The combined heat set off a few more. It was a chain reaction. Pretty soon there was no stopping it. That white patch is all supernovae. If you like, you can get the math of it a little further along in the tape."
"No thanks," she said — predictably. "I gather it's an over by now?"
"Yeah. That's old light you're looking at, though it hasn't reached this part of the galaxy yet. The chain reaction must have ended ten thousand years ago."
"Then what is everyone excited about?"
"Radiation. Fast particles, all kinds." The masseur chair was beginning to relax him; he settled deeper into its formless bulk and let the standing wave patterns knead his muscles. "Look at it this way. Known space is a little bubble of stars thirty-three thousand light years out from the galactic axis. The novae began exploding more than ten thousand years ago. That means that the wave front from the combined explosion will get here in about twenty thousand years. Right?"
"Sure."
"And the subnuclear radiation from a million novae is traveling right behind the wave front."
"… Oh."
"In twenty thousand years we'll have to evacuate every world you ever heard of, and probably a lot more."
"That's a long time. If we started now, we could do it with the ships we've got. Easily."
"You're not thinking. At three days to the light year, it would take one of our ships about six hundred years to reach the Clouds of Magellan."
"They could stop off to get more food and air … every year or so."
Louis laughed. "Try talking anyone into that. You know what I think? When the light of the Core explosion starts shining through the dust clouds between here and the galactic axis, that's when everyone in human space is suddenly going to get terrified. Then they'll have a century to get out.
"The puppeteers had the right idea. They sent a man to the Core as a publicity stunt because they wanted financing for research. He sent back pictures like that one. Before he'd even landed, the puppeteers were gone; there wasn't a puppeteer on any human world. We won't do it that way. Well wait and we'll wait, and when we finally decide to move we'll have to ship trillions of sentient beings completely out of the galaxy. We'll need the biggest, fastest ships we can build, and we'll need as many as we can get. We need the puppeteer drive now, so that we can start improving it now. The -"
"Okay. I'm going with you."
Louis, interrupted in midlecture, said, "Huh?"
"I'm going with you," said Teela Brown.
"You're out of your mind."
"Well, you're going, aren't you?"
Louis clamped his teeth on the explosion. When he did speak, he spoke more calmly than the situation deserved. "Yes, I'm going. But I've got reasons you don't, and I'm better at staying alive than you are, because I've been at it longer."
"But I'm luckier."
Louis snorted.
"And my reasons for going may not be as good as yours, but they're good enough!" Her voice was high and thin with anger.
"The tanj they are."
Teela tapped the face of the reading screen. A bloated comma of nova light flared beneath her fingernail. "That's not a good reason?"
"We'll get the puppeteer drive whether you come or not. You heard Nessus. There are thousands like you."
"And I'm one of them!"
"All right, you're one of them," Louis flared.
"What are you so tanj protective about? Did I ask for your protection?"
"I apologize. I don't know why I tried to dictate to you. You're a free adult."
"Thank you. I intend to join your crew." Teela had gone icily formal.
The hell of it was, she was a free adult. Not only could she not be coerced; an attempt to order her about would be bad manners and (more to the point) wouldn't work.
But she could be persuaded …
"Then think about this," said Louis Wu. "Nessus has gone to great lengths to protect the secrecy of this trip. Why? What's he got to hide?"
"That's his business, isn't it? Maybe there's something worth stealing, wherever we're going."
"So what? Where we're going is two hundred light years from here. We're the only ones who can get there."
"The ship itself, then."
Whatever was unusual about Teela, she was no dummy. Louis himself hadn't thought of that. "Then think about our crew," he said. "Two humans, a puppeteer, and a kzin. None of us professional explorers."
"I see what you're doing, but honestly, Louis, I am going. I doubt you can stop me."
"Then you can at least know what you're getting into. Why the odd crew?"
"That's Nessus's problem."
"I'd say it's ours. Nessus gets his orders directly from those-who-lead — from the puppeteer headquarters. I think he figured out what those orders meant, just a few hours ago. Now he's terrified. Those … priests of survival have got four games going at once, not counting whatever it is we'll be exploring."
He saw that he had Teela's interest, and he pressed on. "First there's Nessus. If he's mad enough to land on an unknown world, can he possibly be sane enough to survive the experience? Those-who-lead have to know. After they reach the Clouds of Magellan they'll have to set up another commercial empire. The backbone of their commerce is the mad puppeteers.
"Then there's our furry friend. As ambassador to an alien race, he should be one of the most sophisticated kzinti around. Is he sophisticated enough to get along with the rest of us? Or will he kill us for elbow room and fresh meat?
"Third, there's you and your presumed luck, a blue-sky research project if I ever heard of one. Fourth is me, a presumably typical explorer type. Maybe I'm the control.
"You know what I think?" Louis was standing over the girl now, pounding his words home with an oratorical technique he'd mastered while losing an election for the UN in his middle seventies. He would honestly have denied trying to browbeat Teela Brown; but he wanted desperately to convince her. "The puppeteers couldn't care less about whatever planet we're being sent to. Why should they, when they're leaving the galaxy? They're test-ing our little team to destruction. Before we get ourselves killed, the puppeteers can find out a lot about how we interact."
"I don't think ifs a planet," said Teela.
Louis exploded. "Tanj! What has that got to do with it?"
"Well, after all, Louis. If we're going to get killed exploring it, we might as well know what it is. I think it's a spacecraft."
"You do."
"A big one, a ring-shaped one with a ramscoop field to pick up interstellar hydrogen. I think it's built to funnel the hydrogen into the axis for fusion. You'd get thrust that way, and a sun too. You'd spin the ring for centrifugal force, and you'd roof the inner side with glass."
"Yeah," said Louis, thinking of the odd picture in the holo he'd been given by the puppeteer. He'd spent too little time wondering about their destination. "Could be. Big and primitive and not very easy to steer. But why would those-who-lead be interested?"
"It could be a refugee ship. Core races would learn about stellar processes early, with the suns so close together. They might have predicted the explosion thousands of years ahead … when there were only two or three supernovas."