Diaspora

Yatima listened to the news from the gleisners, not quite believing it, staring past Inoshiro into the scape's empty sky. Oceans of quarks, invisible meson jets, plummeting neutron stars… it all sounded terribly quaint and arcane, like some elegant but over-specific theorem at the end of a cul-de-sac.

Inoshiro said bitterly, "The gleisners took forever to convince themselves that the effect was real. We've got less than twenty-four hours before the burst hits. A group in Carter-Zimmerman is trying to break into the fleshers' communications network, but the cable is sheathed with nanoware, it's defending itself too well. They're also working on reshaping the satellite foot prints, and sending drones straight into the enclaves, but so far—"

Yatima cut in. "I don't understand. How can the fleshers be in any kind of danger? They might not he as heavily shielded as we are, but they still have the whole atmosphere above them! What portion of the gamma rays will make it to ground level?"

"Almost none. But almost all of them will make it to the lower stratosphere." An atmospheric specialist in C-Z had modeled the effects in detail; Inoshiro offered an address tag, and Yatima skimmed the file.

The ozone layer over half the planet would be destroyed, immediately. Nitrogen and oxygen in the stratosphere, ionized by the gamma rays, would combine into two hundred billion tons of nitric oxides, thirty thousand times the current amount. This shroud of NOx would not only lower surface temperatures by several degrees, it would keep the ultraviolet window open for a century, catalyzing the destruction of ozone as fast as it reformed. Eventually, the nitric oxide molecules would drift into the lower atmosphere, where some would split apart into their harmless constituents. The rest—a few billion tons—would fall as acid rain.

Inoshiro continued grimly, "Those predictions all assume a certain total energy for the gamma-ray burst, but that could be as wrong as everything else people thought they knew about Lacerta G-1. At best, the fleshers will need to redesign their whole food supply. At worst, the biosphere could be crippled to the point where it can't support them at all."

"That's terrible." But Yatima felt verself retreating into a kind of weary resignation. Some fleshers would almost certainly die… but then, fleshers had always died. They'd had centuries to come into the polises if they'd wanted to leave the precarious hospitality of the physical world behind. Ve glanced down at vis glorious experiment; Inoshiro still hadn't even given ver a chance to mention it.

"We have to warn them. We have to go back."

"Go back?" Yatima stared at ver, baffled.

"You and I. We have to go back to Atlanta."

A tentative image appeared: two fleshers, one of them seated. A man and a woman? Yatima had a feeling ve'd seen them in some artwork of Inoshiro's, long ago. We have to go back to Atlanta? Was that a line from the same piece? Inoshiro's slogans all began to sound the same after a while: "We must all go and work in our gardens," "We have to go back to Atlanta"…

Yatima consciously invoked full retrieval of the fragment's context. As ve'd aged, ve'd opted for memory layering—rather than degradation or outright erasure—to keep vis thoughts from being swamped with a paralyzing excess of recollections. They'd taken two abandoned gleisners for a ride! Just the two of them, when Yatima was barely half a gigatau old. They'd been gone for something like eighty megatau-which must have seemed like an eternity at that age, though as it turned out even Inoshiro's parents had been unfazed by the whole juvenile stunt. The jungle. The city surrounded by fields. They'd been afraid of quicksand—but they'd found a guide.

For a moment, Yatima was too ashamed to speak. Then ve said numbly, "I'd buried them. Orlando, Liana… the bridgers. I'd buried them all." Over time, ve'd let the whole experience sink from layer to layer to make room for more current preoccupations—until it could no longer enter vis thoughts by chance at all, interact with other memories, sway vis attitudes and moods. Until fleshers were just fleshers again: anonymous and remote, exotic and dispensable. The apocalypse could have come and gone, and ve would have done nothing.

Inoshiro said, "There isn't much time. Are you with me, or not?"

Atlanta, Earth

24 046 380 407 629 CST

5 April 2996, 21:20:04.783 UT

The gleisners were exactly where they'd left them, twenty-one years before. Once they were awake, they each had the drone pass them a file of instructions for the robots' maintenance nanoware. Yatima watched nervously as the programmable sludge flowing in fine tubes throughout vis body began reconstructing the tip of vis right index finger into something alarmingly like a projectile weapon.

That was the easy part. When the delivery system was completed, the maintenance nanoware's small subpopulation of assemblers was instructed to begin manufacturing Introdus nanoware. Yatima had been worried that the gleisners' assemblers, never designed for such demanding work, might not be capable of meeting the necessary tolerances, but the Introdus system's self-testing procedure returned an encouraging report: less than one atom in ten-to-the-twentieth incorrectly bonded. Working on feedstock in the gleisner, the assemblers managed to build three hundred and ninety-six doses; if more were needed, the bridgers would probably be able to supply the necessary raw materials. There were well-stocked portals scattered across the planet where any flesher who wished to enter the Coalition could do so, but it had always been judged politically insensitive to place them too close to the enclaves. The nearest one to Atlanta was over a thousand kilometers away.

Inoshiro used vis own gleisner's nanoware to build a pair of relay drones to keep them in touch with Konishi: no one had yet been able to trick the satellites into reshaping their footprints to include the enclaves. Yatima watched the glistening insectile machines forming in a translucent cyst on Inoshiro's forearm, then burrow out and disappear into the canopy. They'd based the design on existing drones, but these bootleg versions were entirely unfettered by prior instructions and treaty obligations, and would shamelessly fool the satellites into accepting a signal re-routed from within the forbidden region.

They stepped across the border. To test their link to the Coalition, Yatima glanced at a C-Z scape based on a feed from TERAGO. Two dark spheres limned by gravitationally-lensed starlight moved through a faintly sketched spiral tube, the tight record of past orbits widening out into the uncertainty of extrapolation; the hypothetical meson jets were omitted altogether. The neutron stars broadcast gestalt tags with their current orbital parameters, while points on the spiral at regular intervals offered past and future versions.

The orbit had shrunk by a "mere" 20 percent so far—100,000 kilometers—but the process was highly non-linear, and the same distance would be crossed again in roughly seventeen hours, then five, then one, then under three minutes. These predictions were all subject to error, and the exact moment of the burst remained uncertain by at least an hour, but the most likely swath of possibilities all placed Lacerta well above the horizon at Atlanta. For a hemisphere stretching from the Amazon to the Yangtse, the ozone layer would be blasted away in an instant. In Atlanta, it would happen beneath the blazing afternoon sun.

The path Orlando had taken when escorting them out of the enclave was still stored in the gleisners' navigation systems. They pushed through the undergrowth as fast as they could, hoping to trigger alarms and attract attention.