Seated, he was taller than she was standing up. In his brown eyes was a curious expression. Celine felt that at any moment he might call for his imperial guards — or whatever their equivalent was in New Rio — to come and drag Astarte Vjansander away to the dungeons.

“Star,” she said. “Keep quiet for a minute. And you, Wilmer, I’m sick of hearing what the particle flux isn’t; that kind of talk could go on forever. In two sentences, what’s your new theory?”

Celine was aware of passing time — Lopez had promised an hour, and that was long past — but with Wilmer she should have known better. He didn’t speak often, but when he did it took him two minutes to tell you the time. Now he scowled and frowned and rubbed the top of his head, and finally muttered, “Do you know what Einstein said? An explanation should be as simple as possible, but no simpler. I can’t describe a new theory in two sentences. Nobody could.”

“Two for the President, then, and two for me,” Nick Lopez said mildly. His telcom was beeping. Once again he ignored it. “Go ahead, Dr. Oldfield. I’m supposed to be somewhere else, but when we’re talking about the way the world ends I’ll find an extra ten minutes.”

Wilmer nodded. “That should be enough. Star already pointed out the important fact: The particles rushing toward the solar system are bare nuclei and they’re electrically charged. More than that, they’re all positively charged — nuclei are just protons and neutrons, no electrons. That means they repel each other, and certainly they have no tendency to travel in groups. But that is precisely what the Sniffer data says they do.

“Now, that gives us a few possibilities. The thing you think of first is that the groups of nuclei might contain equal amounts of matter and antimatter. Antimatter might be created in a supernova explosion. The antiproton has a negative charge equal to the charge of the electron, so a nucleus made up of antiprotons and anti-neutrons will be attracted to a nucleus of ordinary matter. We looked at that idea, me and Star, and chucked it out in two minutes. For one thing, it’s hard to make stable matter-antimatter constellations. Worse still, any antimatter would annihilate itself when it met the Sniffer — and it wouldn’t do the Sniffer much good, either. So forget that idea, and what’s left?

“Well, we looked at other possibilities — a fifth force, which has been speculated on lots of times. Associated toroidal EM fields, binding clusters together. Phase change condensations. You can do calculations for all of them, and nothing comes close to reasonable answers. But we finally found something that works. Suppose that the strong force — that’s the glue that holds nuclei together, in spite of the electrical repulsion of the protons inside them — has been modified. Sounds wild, because we’re used to thinking of the strong force as something in nature that can’t be touched. Like people thought about magnetism three hundred years ago. But Gottlieb, before he went off his head, had an alternative form of unification theory, and if he was right, there are ways of locally modifying the strong force so that it’s longer-range and nonmonotonic — it will permit regions of attraction and repulsion at different distances. Of course, we have no idea how to make that happen.”

Celine had listened long enough. She began to stand up, and for a change Wilmer noticed it. “I’m nearly there,” he said, “don’t get steamed. We did the calculations. A local modification of the strong force can allow stable assemblies of nuclei, just like the Sniffers are finding. Extremely stable, as a matter of fact, with trillions of nuclei in each group. Matter clumps. That’s what I’m getting at.”

“Wilmer, you blithering ditz, so what?” Celine was amazed at Nick Lopez’s patience. He was still listening, and still smiling. “A particle storm is going to reach the solar system years earlier than anyone planned. It will smash Earth back to the dark ages because the shield’s not finished. We’re in trouble, and you’re wasting our time telling us about some new half-assed theory?”

“Yer still don’t get it, do yer?” Astarte stepped in front of Wilmer. “We got good news, not bad news. It’s like Wilmer says, we don’t know how to modify the strong force. But we don’t need to. Thing is, if the particle flux is coming at us in big, stable particle groups, you want a different shield design. You’ve been buildin’ an umbrella net with a mesh close enough to keep off a fine rain of single nuclei, but that won’t do you a bit of good.

What’s going to hit isn’t a drizzle, it’s matter clumps. Bloody great hailstones, trillions of nuclei at a go. Sounds at first as though you’re a lot worse off, but you’re not. ’Cause with big clusters you can detect, catch, and divert ’em one at a time. Only you can’t do that with your present shield design. You hafta make big changes, and you hafta go at it arse-over-teakettle to finish in time. But we think it can be done.”

She turned to Nick Lopez. “Get it? We brought you good news.”

“I get it, Star. Dumb as I am, I really get it.” He stood, and the top of Astarte’s head reached only to the middle of his chest. “Now, you and Wilmer will have to excuse us.”

“Yer can’t leave. I don’t care what your other bleeding meeting is, this is more important than anything.”

“I agree. It is.” Nick met Celine’s eye.

She nodded. “As Senator Lopez said, you must excuse us. He and I have to discuss this in private.”

“Hmph.” Astarte reluctantly allowed Wilmer to usher her to the door. On the threshold she turned. “Yer all right, Senator. Not full of shit, like I expected.”

“Don’t mind her ways,” Celine said as soon as the door was firmly closed. “She was raised in the North Australian wilderness.”

“And I was raised in an eighties LA ghetto.” Lopez sat down. “Until I was fifteen I thought that fucking was a necessary adjective in every sentence. I don’t mind the way Star speaks. I think she’s terrific. She paid me the most sincere compliment I ever had.”

“I heard it. ’Yer all right, Senator.’ ” Celine imitated Astarte’s broad accent and delivery. “So what do you think?”

She was not referring to Astarte’s comment. Lopez sat motionless, his brown eyes staring far beyond the walls of the room. At last he spoke.

“It’s easy to be distracted by the wrong thing. In this case, the wrong thing is Wilmer’s insistence that the supernova was somehow arranged. Because if it was or if it wasn’t, that’s not our current problem. The supernova happened. A lethal particle flux is on the way, and it will get here a lot sooner than we expected. The shield we’re building won’t be ready in time. That’s what’s important. Do you believe it?”

“I’ve known Wilmer Oldfield for thirty years. I believe him without reservations.”

“So, oddly enough, do I. So we’re in deep trouble with the present shield. It won’t be ready in time, nor will I.”

Celine did not ask for an explanation of that last sentence. Nick Lopez had already indicated that he would be taking precautions to ensure his own survival.

She said, “The other important thing is that the particles arrive in big clumps, rather than solo and uncorrelated. We’re building the wrong shield. Do you believe they are right about that, too?”

“I don’t think it makes much difference. Look at where we stand.” Lopez began to tick off points on his long, carefully manicured fingers. “Fact: The particle flux will be arriving sooner than expected. Fact: The shield can’t be ready in time with its present design. Conclusion: Even if Wilmer and Star are wrong, we’re screwed with the shield the way it is. Therefore: Our best shot is to assume that they are right, and modify the shield so it can deal one at a time with large clusters of particles. That leaves only one question: Can we make the changes fast enough?”