Arthur Clarke - Sunstorm

Mikhail and Toby, this motley crew, was her last gamble. But she wasn’t about to tell them that. She said briskly, “Let’s get on with it.”

Mikhail glanced at notes off camera. “I have Eugene’s latest predictions.”

Graphics glowed in the smart top of the table before Siobhan and Toby, showing energy flux plotted against wavelength, particle mass, and other parameters. “Nothing substantial has changed, I’m afraid. We are looking at a major influx of solar energy on April 20, 2042. It will last most of twenty-four hours, so that almost every point on Earth’s surface will be turned directly into the fire. We won’t even have the shelter of night. As we will be close to the spring equinox, even the poles won’t be spared. At this stage do you need the details of what will become of the atmosphere, the oceans? No. Suffice to say the Earth will be sterilized to a depth of tens of meters beneath the ground.

“But,” Mikhail went on, “we now have a much more precise handle on how the energy will be delivered. We are looking at flaws in the radiative and convective zones, where a great deal of energy is in normal times stored …” He tapped the hidden surface before him, and one tabletop chart was highlighted.

“Ah,” Siobhan said. “The intensity will peak in the visible spectrum.”

“As the spectrum of sunlight does normally,” Mikhail said. “In green light, as it happens. Which is where our eyes are most sensitive, and where chlorophyll works best—which is why, no doubt, chlorophyll was selected by evolution to serve as the photosynthetic chemical that fuels all aerobic plant life.”

“Then that’s what we face: a storm of green light from the sun,” Siobhan said firmly. “Let’s talk about options to deal with it.”

Toby grinned. “The fun part!”

Mikhail offered, “Shall I begin?” He tapped at his softscreen, and on the displays before Siobhan a number of schematics, tables, and images came up.

“As it happens,” Mikhail said, “even before our present crisis a number of thinkers have considered ways to reduce the solar insolation—the proportion of the sun’s energy flux that reaches the planet. Of course this was mostly in the context of blocking sunlight to mitigate global warming.” He brought up images of clouds of dust injected into the high atmosphere. “One proposal is to use space launchers to fire sub-micrometer dust up into the stratosphere. That way you would mimic the effects of a volcanic eruption; after a big bang like Krakatoa you often get a global temperature drop of a degree or two for a few years. Or you could inject sulfur particles up there, which would burn in the atmosphere’s oxygen to give you a layer of sulfuric acid. That might be rather lighter and so easier to deliver.”

Siobhan said, “But how much of the storm would this screen out?”

Mikhail and Toby displayed their figures. It turned out to be only a few percent.

“Enough to mitigate global warming, perhaps,” Mikhail said sadly. “But far from adequate for the problem we face now. We are going to have to take out almost all of the incoming radiation—letting even one percent through may be far too much.”

“Then we’ll have to think bigger,” Siobhan said firmly.

Toby said slyly, “Bigger it is. If you want to inject dust into the air, rather than trying to mimic a volcano—why not just set one off?”

Mikhail and Siobhan glanced at each other, startled. Then they went to work.

Coming up with such ideas was precisely why Siobhan had invited Toby to these sessions.

He had been unsure. “Siobhan, why me? I’m an events manager, for heaven’s sake! My contribution should have ended at making sure there were enough biscuits to go around.”

She had studied him with fond exasperation. He was a big, somewhat overweight, shambling man, with raggedly cut brown hair and a weak chin. He wasn’t even a scientist; he had majored in languages. He was a peculiarly English type who would always be valued by stuffy British institutions like the Royal Society, not only for his intelligence and obvious competence, but also for his comforting air of upper-middle-class safeness. But he had one typically English characteristic that she, born in Northern Ireland and so something of an outsider, didn’t value so highly, and that was an excess of self-deprecation.

“Toby, you’re not here for biscuits, appreciated though they are, but for your other career.”

He looked briefly baffled. “My books?”

“Precisely.” Toby had published a whole series of lyrically written popular histories of forgotten corners of science and technology. And that was what had prompted her to turn to him. “Toby, we’re faced by a megaproblem. But since Tsiolkovski people have been dreaming up a whole suite of more or less wacky mega-engineering possibilities. And that’s what I think we’re going to need to draw on now.”

There had been one group in London she was thinking of particularly, called the British Interplanetary Society. “I gave them a chapter in one of my books,” Toby had told her when she mentioned them. “The Society has been absorbed into a pan-European grouping now, and doesn’t seem to be half so much fun. But in its heyday it was a place to play for a lot of respectable scientists and engineers. They dreamed up lots of ways to bother the universe …” This sort of fringe thinking was what they needed to draw on now, she believed.

He grinned. “So I’m an ambassador from the lunatic fringe? Thanks very much.”

But Mikhail had said, “We must consider ways to protect the whole Earth. Nobody has faced such responsibility before. I think in the circumstances a little lunacy might be just what we need!”

With some hard work on their softscreens, and frequent calls to Aristotle, they hurriedly fleshed out Toby’s volcano option. Perhaps it could be done—but it would have to be a big volcanic bang, far bigger than any in recorded history and possibly bigger than anything in the geological record. As nobody had tried such a thing before, its effects would be quite unpredictable, and possibly a remedy even worse than the problem. Siobhan stored the discussion in a file in Aristotle’s capacious memory that she labeled “last resorts.”

They quickly rattled through some more research on so-called “intrinsic” methods of protection, things you could do within the Earth’s atmosphere, or maybe from low orbit. But they all provided inadequate screening. There was no reason why some of these methods shouldn’t be put in place. They would provide an extra few percent of cover—and would at least give the impression to the public that something was being done, a not inconsiderable political factor. But if they couldn’t dig up a way to knock out almost all of the sun’s ferocious glare, such projects would be nothing but sops, which wouldn’t make any difference to the final outcome.

“So we move on,” Siobhan said. “What next?”

Toby said, “If we can’t protect the Earth, perhaps we have to flee.”

Mikhail growled, “Where? The storm will be so intense that even Mars is not safe.”

“The outer planets, then. An ice moon of Jupiter—”

“Even at five times Earth’s distance, the reduction in intensity of the storm would not be sufficient to save us.”

“Saturn, then,” Toby pressed. “We could hide on Titan. Or a moon of Uranus, or Neptune. Or we could flee the solar system altogether.”

Siobhan said quietly, “The stars? Can we build a starship, Toby?”

“Make it a generation starship. That’s the most primitive sort: an ark, big enough to hold a few hundred people. It might take a thousand years to reach Alpha Centauri, say. But if the emigrants’ children, living and dying on the ship, could continue the mission—and then their children would do the same—eventually humans, or at least descendants of humans, would reach the stars.”