Charles Sheffield - Starfire

“Alpha C is a great example. Before 2026, every astrophysicist — including me — would have told you it couldn’t happen. Wrong type of binary system, no dwarf component, no supermassive star. But it happened. After that, no one predicted the gamma pulse would come along and wipe out all our microcircuits. It did. After the gamma pulse, we still didn’t learn. The fact that the burst was aimed directly at the solar system was dismissed as an ’accident of geometry.’ ”

“But you predicted the particle storm,” Celine objected. “Twenty-seven years ago, you told me it would happen.”

“I did. That was in the pre-supernova theories. And based on those theories we started to build the space shield. Then we were surprised again by an observational result, that the particles come grouped in trillion-component lumps instead of singly. The old shield was useless at stopping bundles. So we had to come up quick with a new shield idea. This one still assumed what everyone ’knew,’ that the strength of the particle storm would weaken over distance as it traveled farther away from the supernova. Now we find that the beam is converging as it approaches Sol. That means greater particle densities, and the new shield will be inadequate. I don’t know what Ben Mertok and the others are telling you, but if everybody’s track record — including mine — is anything to go by, whatever you are being told is going to prove wrong.”

“Marvelous. Wilmer, you can sit back and say you have no idea what will happen. I’m not allowed that luxury. I have to say something to the media this afternoon, whether I turn out to be right, wrong, or ridiculous. You sound as though you haven’t even been thinking about that.”

“I have. I’ll bet good money that we’ll see surprises this afternoon — only I can’t say what. Otherwise they wouldn’t be surprises. But I doubt they’ll be too awful. And today’s not what I’ve been thinking about most. Today might be messy, in ways I can’t begin to suggest, but I’m sure we’ll pull through. Our concern has to be with three weeks from now.”

“Three weeks?” Celine wasn’t sure she wanted to know. “Three weeks, when the main storm hits. You’re worried about more surprises?”

“I don’t need more surprises to make me worry. The things we already think we know are enough for that. Did you see the figures for peak energy input when the big storm arrives? That’s going to be the Fist of God.”

“The only summary I’ve seen is based on your and Star’s calculations. You said that the energy hitting us will be thirty times as much as we thought before. But the maximum impact will last only a few days, and thirty doesn’t sound too bad. I figure we can live through that.”

“You don’t mean figure. You mean you hope .” Wilmer turned to Star, seated next to him and so far silent. “You tell her.”

Star nodded amiably at Celine. She was holding a shiny metal canister about the size of a beer can. “See what he does? Puts me on ter give you the bad news. No worries, you think. But I got new data, and things don’t look good. D’yer know what cooperative phenomena are?”

“Assume I don’t. Tell me.”

“It’s when a lot of little things hook up together, ter produce effects yer wouldn’t expect from one of them. This here” — she held up the metal cylinder — “has a few thousand particle bundles in it. We collected ’em over the past day or two during the first slow rise in particle flux. Caught ’em in flight, slowed ’em down in a synchrotron, held ’em in using an electromagnetic field once they were down to thermal velocities. They’re fascinating little buggers. For starters, they’re stable as hell. We put individual bundles in the middle of a fusion plasma with an effective temperature of fifteen million degrees, and they hold together… When you get a lot of bundles, they exhibit a group attractive force — opposite ter what you’d expect, ’cause they’re all positively charged. That makes ’em converge as they travel through open space, an’ they’re doing it now. The only thing they can’t stand is neutral atoms — which is what they’ll find when they hit Earth. They lose their charge and fall apart. Trouble is, they don’t go quiet. A disintegrating bundle gives off loads of energy.”

“How much is a load?”

“About twenty times their free-space kinetic energy. I used ter say that each bundle hits as hard as a small bullet. Now I’d say it’s like an explosive bullet.”

“Not thirty times as much energy as we thought, but six hundred?”

“Yerss. An’ there’s an outside chance of worse news. D’you know what homeostasis is?”

“I used to, before I rotted my brain with politics.” Celine thought for a moment. “It’s a feedback effect, one that gives a system the tendency to return to its original state when it’s perturbed away from it.”

“Yer got it. An’ Earth’s one big homeostatic system. Dump in more energy, and when you stop doing that the temperatures and pressures and all the biosphere tend ter go back ter the original states. That’s how come the Sun could increase its energy output thirty percent over the past couple of billion years, like it did, but surface temperatures hardly shifted in all that time.

“But there’s limits. Hit Earth hard enough and quick enough, an’ homeostasis could fail. Yer might go to a steady state all right, but mebbe it’s not the one you started from. An’ that’s the way it looks to me sometimes, when I run the numbers for the big particle storm.”

“You mean Earth will be different forever after the main storm. Can you tell me how different?”

“Nah. I can’t tell, and nobody else can neither. We’re probably all right, but yer got some scary possibil’ties. One run I looked at has end-point oxygen at three percent — all right for plants, mebbe, but a bugger for animals. Another has global end-point temperature at forty-two Celsius. Blood heat for humans is thirty-seven Celsius. We’d all be goners.”

Celine looked at Wilmer. “That sounds like the end of the world to me. But you said it wouldn’t happen.”

“I said it wouldn’t happen today. We’ll come through today just fine. I’m talking weeks from now, and it’s all still speculation and theory. We might be wrong again. In fact, based on recent past experience, we will be. Victims of our theories, we are, like everybody else. Me and Star have some even newer ideas based on the bundles she caught, but it’s too soon to talk about them.”

“So what will happen today? What do I tell people?”

“If it were me, I’d follow what Ben Mertok said to do. You tell everybody that we’ll be all right. I think we will be, and there’s no point saying different. But I’d make damn sure there’s no planes in the air or space launches scheduled between three and four o’clock. And I’d freeze ground transportation. People talk about zero hour coming at three-fifteen as though that’s a single moment of time, but the blip has width. We’ll be at fifty percent particle flux seven minutes before we hit peak maximum.”

Celine nodded. She heard Wilmer, but already her mind was running ahead to another problem. What should the public know, and when? “About this possible change away from planetary homeostasis. I know science is an open field, and scientists hate any suggestion of secrecy. But could you avoid telling anyone else about Earth’s becoming uninhabitable?”

Wilmer and Star looked at each other. “It’s only a possibility,” Wilmer said weakly.

Scientific scruples. “ We don’t even want a possibility, Wilmer. Not until we can decide on policy.”