Diaspora

When Paolo woke and joined ver in the scape, Yatima said, “I’m trying to decide what we should tell them. When they ask why we came after them.”

Paolo laughed grimly. “Tell them about Lacerta.”

“They’ll know about Lacerta.”

“As a blip on a map. They won’t know what it did. They won’t know what it meant.”

“No.” Yatima gazed at Weyl, at the center of the blue shift. Ve didn’t want to antagonize Paolo with questions about Atlanta, but ve didn’t want to shut him out either. “You know Karpal, don’t you?”

“Yes.” Paolo accepted the present tense with a faint smile.

“And wasn’t he on the moon, running TERAGO ”

Paolo said coldly, “He did everything he could. It wasn’t his fault the whole planet was sleepwalking.”

“I agree. I don’t blame him for anything.” Yatima spread vis arms, conciliatory. “I just wondered if he’d ever talked about it. If he ever told you his side of things.”

Paolo nodded grudgingly. “He talked about it. Once.”

4. LIZARD HEART

Bullialdus observatory, Moon

24 046 104 526 757 CST

2 April 2996, 16:42:03.911 UT

Karpal lay on his back on the regolith for a full lunar month, staring up into the crystalline stillness of the universe and daring it to show him something new. He’d done this five times before, but nothing had ever changed within reach of his unaided vision. The planets moved along their predictable orbits, and sometimes a bright asteroid or comet was visible, but they were like spacecraft wandering by: obstacles in the foreground, not part of the view. Once you’d seen Jupiter close-up, firsthand, you began to think of it more as a source of light pollution and electromagnetic noise than as an object of serious astronomical interest. Karpal wanted a supernova to blossom out of the darkness unforeseen, a distant apocalypse to set the neutrino detectors screaming—not some placid conjunction of the solar system’s clockwork, as noteworthy and exciting as a supply shuttle arriving on time.

When the Earth was new again, a dim reddish disk beside the blazing sun, Karpal rose to his feet and swung his arms cautiously, checking that none of his actuators had been weakened by thermal stress. If they had, it wouldn’t take long for his nanoware to smooth away the microfractures, but each joint still needed to be tested by use in order to notice the problem and call for repairs.

He was fine. He walked slowly hack to the instrumentation shack at the edge of Bullialdus crater; the structure was open to the vacuum, but it sheltered the equipment to some degree from temperature extremes, hard radiation and micrometeorites. Looming behind it was the crater wall, seventy kilometers wide; Karpal could just make out the laser station on top of the wall, directly above the shack. The beams themselves were invisible from any vantage, since there was nothing to scatter the light, but Karpal couldn’t picture Bullialdus from above without mentally inscribing a blue L, a right-angle linking three points on the rim.

Bullialdus was a gravitational wave detector, part of a solar-system-wide observatory known as TERAGO. A single laser beam was split, sent along perpendicular journeys, then recombined; as the space around the crater was stretched and squeezed by as little as one part in ten-to-the-twenty-fourth, the crests and troughs of the two streams of light were shifted in and out of alignment, causing fluctuations in their combined intensity which tracked the subtle changes of geometry. One detector, alone, could no more pinpoint the source of the distortions it measured than a thermometer lying on the regolith could gauge the exact position of the sun, but by combining the timing of events at Bullialdus with data from the nineteen other TERAGO sites, it was possible to reconstruct each wavefront’s passage through the solar system, revealing its direction with enough precision, usually, to match it to a known object in the sky, or at least make an educated guess.

Karpal entered the shack, his home for the last nine years. Nothing had changed in his absence, and little had changed since his arrival; the racks of optical computers and signal processors lining the walls looked as gleamingly pristine as ever, and his emergency spares kit and macro repair tools had barely been moved from where he’d first placed them. He wasn’t quite alone on the moon—there were a dozen gleisners doing paleoselenology up at the north pole—but he was yet to receive a visitor.

Almost every other gleisner was in the asteroid belt, either working on the interstellar fleet, providing some kind of support service, or generally playing camp follower. He could have been there himself, in the thick of it—the TERAGO data was accessible anywhere, and being physically present at one site offered few advantages when overseeing repairs for all twenty—but he’d been tempted by the solitude here, and the chance to work without distractions, devoting himself to a single problem for a week, or a month, or a year. Lying on the regolith gazing up at the sky for a month at a time hadn’t been in his original plans, but he’d always expected to go slightly crazy, and this seemed like a mild enough eccentricity. At first, he’d been afraid of missing an important event: a supernova, or a distant galactic core’s black hole swallowing a globular cluster or two. Every speck of data was logged, of course, but even when the gravitational waves had taken millennia to arrive there was a certain thrill of immediacy about monitoring them in real time; to Karpal, now was a transect of space-time ten billion years deep, converging on his instruments and senses at the speed of light.

Later, the risk of being away from his post became part of the attraction. Part of the dare.

Karpal checked the main display screen, and laughed softly in pulse-coded infrared; the faint heat echoed back at him from the walls of the shack. He’d missed nothing. On the list of known sources, Lac G-1 was highlighted as showing an anomaly but it was always showing anomalies; this no longer qualified as news.

As well as recording any sudden catastrophes, TERAGO was constantly monitoring a few hundred periodic sources. It took an event of rare violence to produce a burst of gravitational radiation sufficiently intense to be picked up halfway across the universe, but even routine orbital motion created a weak but dependable stream of gravitational waves. If the objects involved were as massive as stars, orbited each other rapidly, and weren’t too remote, TERAGO could tune into their motion like a hydrophone eavesdropping on a churning propeller.

Lacerta G-1 was a pair of neutron stars, a mere hundred light years away. Though neutron stars were far too small to be observed directly—about twenty kilometers wide, at most—they packed the magnetic and gravitational fields of a full-sized star into that tiny volume, and the effects on any surrounding matter could be spectacular. Most were discovered as pulsars, their spinning magnetic fields creating a rotating beam of radio waves by dragging charged particles around in circles at close to lightspeed, or as X-ray sources, siphoning material from a gas cloud or a normal companion star and heating it millions of degrees by compression and shock waves on its way down their tight, steep gravity well. Lac G-1 was billions of years old, though; any local reservoir of gas or dust which might have been used to make X-rays was long gone, and any radio emissions had either grown too weak to detect, or were being beamed in unfavorable directions. So the system was quiet across the electromagnetic spectrum, and it was only the gravitational radiation from the dead stars’ slowly decaying orbit that betrayed their existence.

This tranquillity wouldn’t last forever. G-1a and G-1b were separated by just half a million kilometers, and over the next seven million years gravitational waves would carry away all the angular momentum that kept them apart. When they finally collided, most of their kinetic energy would be converted into an intense flash of neutrinos, faintly tinged with gamma rays, before they merged to form a black hole. At a distance, the neutrinos would be relatively harmless and the “tinge” would carry a far greater sting; even a hundred light years would he uncomfortably close, for organic life. Whether or not the fleshers were still around when it happened, Karpal liked to think that someone would take on the daunting engineering challenge of protecting the Earth’s biosphere, by placing a sufficiently large and opaque shield in the path of the gamma ray burst. Now there was a good use for Jupiter. It wouldn’t he an easy task, though; Lac G-1 was too far above the ecliptic to be masked by merely nudging either planet into a convenient point on its current orbit.

Lac G-1’s fate seemed unavoidable, and the signal reaching TERAGO certainly confirmed the orbit’s gradual decay. One small puzzle remained, though: from the first observations, G-la and G-1b had intermittently spiraled together slightly faster than they should have. The discrepancies had never exceeded one part in a thousand—the waves quickening by an extra nanosecond over a couple of days, every now and then—but when most binary pulsars had orbital decay curves perfect down to the limits of measurement, even nanosecond glitches couldn’t be written off as experimental error or meaningless noise.

Karpal had imagined that this mystery would be among the first to yield to his solitude and dedication, but a plausible explanation had eluded him, year after year. Any sufficiently massive third body, occasionally perturbing the orbit, should have added its own unmistakable signature to the gravitational radiation. Small gas clouds drifting into the system, giving the neutron stars something they could pump into energy-wasting jets, should have caused Lac G-1 to blaze with X-rays. His models had grown wilder and more daring, but all of them had come unstuck from a lack of corroborative evidence, or from sheer implausibility. Energy and momentum couldn’t just be disappearing into the vacuum, but by now he was almost ready to give up trying to balance the books from a hundred light years away.

Almost. With a martyr’s sigh, Karpal touched the highlighted name on the screen, and a plot of the waves from Lacerta for the preceding month appeared.

It was clear at a glance that something was wrong with TERAGO. The hundreds of waves on the screen should have been identical, their peaks at exactly the same height, the signal returning like clockwork to the same maximum strength at the same point on the orbit. Instead, there was a smooth increase in the height of the peaks over the second half of the month—which meant that TERAGO’s calibration must have started drifting. Karpal groaned, and flipped to another periodic source, a binary pulsar in Aquila. There were alternating weak and strong peaks here, since the orbit was highly elliptical, but each set of peaks remained perfectly level. He checked the data for five other sources. There was no sign of calibration drift for any of them.

Baffled, Karpal returned to the Lac G-1 data. He examined the summary above the plot, and sputtered with disbelief. In his absence, the summary claimed, the period of the waves had fallen by almost three minutes. That was ludicrous. Over 28 days, Lac G-1 should have shaved 14.498 microseconds off its hour-long orbit, give or take a few unexplained nanoseconds. There had to he an error in the analysis software; it must have become corrupted, radiation-damaged, a few random bits scrambled by cosmic rays somehow avoiding detection and repair.

He flipped to a plot showing the period of the waves, rather than the waves themselves. It began as it should have, virtually flat at 3627 seconds, then about 12 days into the data set it began to creep down from the horizontal, slowly at first, but at an ever-increasing rate. The last point on the curve was at 3456 seconds. The only way the neutron stars could have moved into a smaller, faster orbit was by losing some of the energy that kept them apart—and to be three minutes faster, instead of 14 microseconds, they would have needed to lose about as much energy in a month as they had in the past million years.

“Bollocks.”

Karpal checked for news from other observatories, but there’d been no activity detected in Lacerta: no X-rays, no UV, no neutrinos, nothing. Lac G-1 had supposedly just shed the energy equivalent of the moon annihilating its antimatter double; even a hundred light years away, that could hardly have passed unnoticed. The missing energy certainly hadn’t gone into gravitational radiation; the apparent power increase there was just 17 percent.

And the period had fallen about 5 percent. Karpal did some calculations in his head, then had the analysis software confirm them in detail. The increasing strength of the gravitational waves was exactly what their decreasing period required. Closer, faster orbits produced stronger gravitational radiation, and this impossible data agreed with the formula, every step of the way. Karpal could not imagine a software error or calibration failure that could mangle the data for one source only while magically preserving the correct physical relationship between the power and frequency of the waves.

The signal had to he genuine.

Which meant the energy loss was real.

What was happening out there? Or had happened, a century ago? Karpal looked down a column of figures showing the separation between the neutron stars, as deduced from their orbital period. They’d been moving together steadily at about 48 millimeters a day since observations began. In the preceding twenty-four hours, though, the distance between them had plummeted by over 7,000 kilometers.

Karpal suffered a moment of pure vertiginous panic, but then quickly laughed it off. Such a spectacularly alarming rate of descent couldn’t be sustained for long. Apart from gravitational radiation, there were only two ways to steal energy from a massive cosmic flywheel like this: frictional loss to gas or dust, giving rise to truly astronomical temperatures—ruled out by the absence of UV and X-rays—or the gravitational transfer of energy to another system: some kind of invisible interloper, like a small black hole passing by. But anything capable of absorbing more than a fraction of G-1’s angular momentum would have shown up on TERAGO by now, and anything less substantial would soon he swept away, like a pebble skipping off a grindstone, or blown apart like an exploding centrifuge.

Karpal had the software analyze the latest data from TERAGO’s six nearest detectors, instead of waiting an hour for the full set to arrive. There was still no evidence of any kind of interloper—just the classical signature of a two-body system—but the energy loss showed no sign of halting, or even leveling off.

It was still growing stronger.

How? Karpal suddenly recalled an old idea which he’d briefly considered as an explanation for the minor anomalies. Individual neutrons were always color neutral: they contained one red, one green and one blue quark, tightly bound. But if both cores had “melted” into pools of unconfined quarks able to move about at random, their color would not necessarily average out to neutrality everywhere. Kozuch Theory allowed the perfect symmetry between red, green, and blue quarks to be broken; this was normally an extremely fleeting occurrence, but it was possible that interactions between the neutron stars could stabilize it. Quarks of a certain color could become “locally heavier” in one core, causing them to sink slightly until the attraction of the other quarks buoyed them up; in the other core, quarks of the same color would be lighter, and would rise. Tidal and rotational forces would also come into play.

The separation of color would be minute, but the effects would be dramatic: the two orbiting, polarized cores would generate powerful jets of mesons, which would act to brake the neutron stars’ orbital motion a kind of nuclear analogue of gravitational radiation, but mediated by the strong force and hence much more energetic. The mesons would decay almost at once into other particles, but this secondary radiation would be very tightly focused, and since the view from the solar system was high above the plane of Lac G-1’s orbit the beams would never be seen head-on. No doubt they’d become spectacularly visible once they slammed into the interstellar medium, but after only 16 days they’d still he traveling through the region of relatively high vacuum that the neutron stars had swept clean over the last few billion years.

The whole system would be like a giant Catherine wheel in reverse, with the fireworks pointing backward, opposing their own spin. But as they bled away the angular momentum that kept them apart, gravity would draw them tighter and they’d whip around faster. The nanosecond glitches in the past might have involved small pools of mobile quarks forming briefly, then freezing back into distinct neutrons again, but once the cores melted completely it would be a runaway process: the closer the neutron stars came to each other, the greater their polarization, the stronger the jets, the more rapid their inward spiral.

Karpal knew that the calculations needed to test this idea would be horrendous. Dealing with interactions between the strong force and gravity could bring the most powerful computer to its knees, and any software model accurate enough to he trusted would run far slower than real time, making it useless for predictions. The only way to anticipate the fate of Lac G-1 was to try to see where the data itself was heading.

He had the analysis software fit a smooth curve through the neutron stars’ declining angular momentum, and extrapolate it into the future. The fall grew faster, gently at first, but it ended in a steep descent. Karpal felt a cool horror wash through him: if this was the ultimate fate of every binary neutron star, it helped make sense of an ancient puzzle. But it was not good news.

For centuries, astronomers had been observing powerful gamma-ray bursts from distant galaxies. If these bursts were due to colliding neutron stars, as suspected, then just before the collision—when the neutron stars were in their closest, fastest orbits—the gravitational waves produced should have been strong enough for TERAGO to pick up over a range of billions of light years. No such waves had ever been detected.

But now it looked as though Lac G-1’s meson jets would succeed in bringing the neutron stars’ orbital motion to a dead halt while they were still tens of thousands of kilometers apart. The Catherine wheel’s fireworks, having finally triumphed, would sputter out, and the end wouldn’t be a frenzied spiral after all, but a calm, graceful dive—generating only a fraction as much gravitational radiation.

Then the two mountain-sized star-heavy nuclei would slam straight together, as if there’d never been a hint of centrifugal force to keep them apart. They’d fall right out of each other’s sky—and the heat of the impact would be felt for a thousand light years. Karpal dismissed the image angrily. So far, he had nothing but a three-minute anomaly in an orbital period, and a lot of speculation. What was his judgment worth, after nine years of solitude and far too many cosmic rays? He had to get in touch with colleagues in the asteroid belt, show them the data, and talk through the possibilities calmly.

But if he was right? How long did the fleshers have before Lacerta lit up with gamma rays, six thousand times brighter than the sun?

Karpal checked and re-checked the calculations, fitted curves to different variables, tried every known method of extrapolation.

The answer was the same every time.

Four days.

5. BURSTER

Konishi polis, Earth

24 046 380 271 801 CST

5 April 2996,21:17:48.955 UT

Yatima floated in the sky above vis homescape, surveying the colossal network that sprawled across the hidden ground as far as ve could see. The structure was ten thousand delta wide and seven thousand high; winding around it was a single, elaborate curve, which looked a bit like one of the roller coaster rides ve’d seen in Carter-Zimmerman—and which ve’d ridden with Blanca and Gabriel, for the visual thrill alone. The “track” here was unsupported, just like the one in C-Z, but it weaved its way through what looked like a riot of scaffolding.

Yatima descended for a closer inspection. The network, the “scaffolding,” was a piece of vis mind, based on a series of snapshots ve’d taken a few megatau before. The space around it glowed softly in a multitude of colors, imbued with an abstract mathematical field, a rule for taking a vector at any point and calculating a number from it, generated by the billions of pulses traveling along the network’s pathways. The curve that wrapped the network encircled every pathway, and by summing the numbers that the field produced from the tangents to the curve along its entire length, Yatima was hoping to measure some subtle but robust properties of the way information flowed through the structure.

It was one more tiny step toward finding an invariant of consciousness: an objective measure of exactly what it was that stayed the same between successive mental states, allowing an ever-changing mind to feel like a single, cohesive entity. The general idea was old, and obvious: short-term memories had to make sense, accumulating smoothly from perceptions and thoughts, then either fading into oblivion or drifting into long-term storage. Formalizing this criterion was difficult, though. A random sequence of mental states wouldn’t feel like anything at all, but neither would many kinds of highly ordered, strongly correlated patterns. Information had to flow in just the right way, each perceptual input and internal feedback gently imprinting itself on the network’s previous state.

When Inoshiro called, Yatima didn’t hesitate to let ver into the scape; it had been far too long since they’d last met. But ve was bemused by the icon that appeared in the air beside ver: Inoshiro’s pewter surface was furrowed and pitted, discolored with corrosion and almost flaking away in places; if not for the signature, Yatima would barely have recognized ver. Ve found the affectation comical, but kept silent; Inoshiro usually viewed the fads to which ve subscribed with appropriate irony, but occasionally ve turned out to be painfully earnest. Yatima had been persona non grata for almost a gigatau after mocking the practice, briefly fashionable across the Coalition, of carrying around a framed portrait of one’s icon “aging” in fast-motion.

Inoshiro said, “What do you know about neutron stars?”

“Not a lot. Why?”

“Gamma-ray bursters?”

“Even less.” Inoshiro looked serious underneath all the rust, so Yatima struggled to remember the details from vis brief flirtation with astrophysics. “I know that gamma rays have been detected from millions of ordinary galaxies—one-off flashes, rarely from the same place twice. The statistics come down to something like one per galaxy per hundred thousand years… so if they weren’t bright enough to be seen a few billion light years away, we probably wouldn’t even know about them yet. I don’t think the mechanism’s been conclusively established, but I could check in the library—”

“There’s no point; it’s all out-of-date. Something’s happening, outside.”

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.

Yatima heard branches move suddenly, off to their left. Ve called out hopefully, “Orlando?” They stopped and listened, but there was no reply.

Inoshiro said, “It was probably just an animal.”

“Wait. I can see someone.”

“Where?”

Yatima pointed out the small brown hand holding a branch, some twenty meters away trying to release it slowly, instead of letting it spring back into place. “I think ve’s a child.”

Inoshiro spoke loudly but gently in Modern Roman. “We’re friends! We have news!”

Yatima adjusted the response curve of the gleisner’s visual system, optimizing it for the shadows behind the branch. A single dark eye stared back through a gap between the leaves. After a few seconds, the hidden face shifted cautiously, choosing another peephole; Yatima reconstructed the blur into a jagged strip of skin joining two lemur eyes.

Ve showed the partial image to the library, then passed the verdict to inoshiro. “Ve’s a dream ape.”

“Shoot ver.”

“What?”

“Shoot ver with the Introdus!” Inoshiro remained motionless and silent, speaking urgently in IR. “We can’t leave ver to die!”

Isolated by the frame of leaves, the dream ape’s eye appeared eerily expressionless. “But we can’t force ver—“

“What do you want to do? Give ver a lecture in neutron star physics? Even the bridgers can’t get through to dream apes! No one’s going to explain the choices to ver—not now, not ever!”

Yatima insisted stubbornly, “We don’t have the right to do it by force. Ve’d have no friends inside, no family—”

Inoshiro made a sound of disgust and disbelief. “We can clone ver some friends! Give ver a scape just like this, and ve’d barely know the difference.”

“We’re not here to kidnap people. Imagine how you’d feel, if some alien creature reached into the polis and dragged you away from everything you knew—”

Inoshiro almost screamed with frustration. “No, you imagine how this flesher will feel, when vis skin’s burnt so badly that the fluid beneath starts seeping out!”

Yatima felt a wave of doubt sweep through ver. Ve could picture the whole, hidden dream ape child, standing there waiting fearfully for the strangers to pass and though ve could barely comprehend the idea of physical pain, images of bodily integrity resonated deeply. The biosphere was a disordered world, full of potential toxins and pathogens, ruled by nothing but the chance collisions of molecules. A ruptured skin would be like a wildly malfunctioning exoself that let data flood across its borders at random, overwriting and corrupting the citizen within.

Ve said hopefully, “Maybe vis family will find a cave to shelter in, once they notice the effects of the UV. That’s not impossible; the canopy will protect them for a while. They could live on fungi—”

“I’ll do it.” Inoshiro grabbed Yatima’s right arm, and swung it toward the child. “Give me control of the delivery system, and I’ll do it myself.”

Yatima tried to pull free. Inoshiro resisted. The struggle confused their separate copies of the interface, which was too stupid to realize it was fighting itself; they both overbalanced. As ve toppled into the undergrowth, Yatima almost felt it: the descent, the inevitable impact. Helplessness. Ve could hear the child running away.

Neither of them moved. After a while, Yatima said, “The bridgers will find a way to protect them. They’ll engineer some kind of shield for their skin. They could release the genes in a virus—”

“And they’ll do all this in a day? Before or after they work out how to feed fifteen thousand people when their crops are wilting, the ground is frozen, and the rain’s about to turn into nitric acid?”

Yatima had no reply. Inoshiro rose to vis feet, then pulled ver up. They walked on in silence.

Halfway to the edge of the jungle, they were met by three bridgers, two females and a male. All were fully grown, but young-looking, and wary. Communication proved difficult.

Inoshiro repeated patiently, “We are Yatima and Inoshiro. We came here once before, twenty-one years ago. We’re friends.”

The man said, “All your robot friends are on the moon; none of them are here now. Leave us in peace.” The bridgers remained several meters away; they’d retreated in alarm when Yatima had approached them with an outstretched hand.

Inoshiro complained in IR, “Even if they’re too young to remember… our last visit should he legendary.”

“Apparently not.”

Inoshiro persisted. “We’re not gleisners! We’re from Konishi polis; we’re just riding these machines. We’re friends of Orlando Venetti and Liana Zabini.” The bridgers showed no sign of recognizing either name; Yatima wondered soberly if it was possible that they were both dead. “We have important news.”

One of the women asked angrily, “What news? Tell us, then leave!”

Inoshiro shook vis head firmly. “We can only give our news to Orlando or Liana.” Yatima agreed with this stand; a garbled account, half-understood, would do untold damage.

Inoshiro asked in IR, “What do you think they’d do if we just marched into the city?”

“They’d stop us.”

“How?”

“They must have weapons of some kind. It’s too risky; we’ve both used up most of our maintenance nanoware—and anyway, they’re never going to trust us if we barge in uninvited.”

Yatima tried addressing the bridgers verself. “We are friends, but we’re not getting through to you. Can you find a translator?” The second woman was almost apologetic. “We have no robot translators.”

“I know. But you must have translators for statics. Think of us as statics.”

The bridgers exchanged bemused glances, then went into a huddle, whispering.

The second woman said, “I’ll bring someone. Wait.”

She left. The other two stood guard over them, refusing to be drawn into further conversation. Yatima and Inoshiro sat on the ground, facing each other rather than the fleshers, hoping to put them at ease.

By the time the translator arrived it was late afternoon. She approached and shook their hands, but regarded them with undisguised suspicion.

“I’m Francesca Canetti. You claim to be Yatima and Inoshiro, but anyone could he inhabiting these machines. Can you tell me what you saw here? What you did?”

Inoshiro recounted the details of their visit. Yatima suspected that their frosty reception was partly due to Carter-Zimmerman’s well-intentioned “assault” on the fleshers’ communications network, and ve felt a renewed pang of shame. Ve and Inoshiro had had twenty-one years in which to re-establish a secure gateway between the networks; even with the problems of subjective time differences, that might have led to some kind of trust by now. But they’d done nothing.

Francesca said, “So what’s the news you’ve brought us?”

Inoshiro asked her, “Do you know what a neutron star is?”

“Of course.” Francesca laughed, clearly offended. “That’s a rich question, coming from a couple of lotus-eaters.” Inoshiro remained silent, and after a moment Francesca elaborated, in a tone of controlled resentment. “It’s a supernova remnant. The dense core left behind when a star is too massive to form a white dwarf, but not massive enough to forms a black hole. Should I go on, or is that enough to satisfy you that you’re not dealing with a hunch of agrarian throwbacks who’ve regressed to pre-Copernican cosmology?”

Inoshiro and Yatima conferred in IR, and decided to risk it. Francesca seemed to understand them as well as Orlando and Liana; stubbornly holding out for their old friends would cause too much hostility, and waste too much time.

Inoshiro explained the situation very clearly—and Yatima resisted interjecting with provisos and technicalities—but ve could see Francesca growing ever more suspicious. It was a long, long chain of inferences from the faint waves picked up by TERAGO to the vision of a frozen, UV-blasted Earth. With an asteroid or comet, the fleshers could have used their own optical telescopes to reach their own conclusions, but they lead no gravitational wave detectors. Everything had to be taken on trust, third hand.

Finally, Francesca admitted, “I don’t understand this well enough to question you properly. Will you come into the city and address a convocation?”

Inoshiro said, “Of course.”

Yatima asked, “You mean we’ll talk to representatives of all the bridgers, through translators.”

“No. A convocation means all the fleshers we can contact. Not just talking to Atlanta. Talking to the world.”

As they made their way through the jungle, Francesca explained that she knew Liana and Orlando well, but Liana was sick, so no one had yet troubled them with the news that the Konishi emissaries had returned.

When Atlanta came into view ahead, surrounded by its vast green and golden fields, it was as if the scale of the problems the bridgers would soon be facing had been laid out for inspection in hectares of soil, megaliters of water, tons of grain. In principle, there was absolutely no reason why suitably adapted organic life couldn’t flourish in the new environment Lacerta would create. Crops could employ robust pigments that made use of UV photons, their roots secreting glycols to melt the hardest tundra, their biochemistry adapted to the acidic, nitrogenous water and soil. Other species essential to the medium-term chemical stability of the biosphere could be given protective modifications, and the fleshers themselves could engineer a new integument to shield them from cell death and genetic damage even in direct sunlight.

In practice, though, any such transition would be a race against time, constrained at every step by the realities of mass and distance, entropy and inertia. The physical world couldn’t simply be commanded to change; it could only be manipulated, painstakingly, step by step—more like a mathematical proof than a scape.

There were low, dark clouds rolling over the city as they approached. On the main avenue, people stopped to watch the robots arriving with their escort, but the crowds seemed strangely lethargic in the shadowless light. Yatima could see that their clothes were damp, their faces shiny with perspiration. The gleisner’s skin told ver the ambient temperature and humidity: 40 degrees Celsius, 93 percent. Ve checked with the library; this was not generally considered pleasant, and there could be metabolic and behavioral consequences, depending on each exuberant’s particular adaptations.

A few people greeted them, and one woman went s far as to ask why they’d returned. Yatima hesitated, and Francesca intervened. “The emissaries will address a convocation soon. Everyone will hear their news, then.”

They were taken to a large, squat, cylindrical building near the center of the city, and led through the foyer and down a corridor to a room dominated by a long wooden table. Francesca left them with the three guards—it was impossible to think of them as anything else—saying she’d return in an hour or two. Yatima almost protested, but then ve recalled Orlando saying that it would take days to gather all the bridgers together. Arranging a planet-wide convocation in an hour—to discuss claims by two self-declared but possibly fraudulent Konishi citizens of an imminent threat to all life on Earth—would be a major feat of diplomacy.

They sat on one side of the long table. Their guards remained standing, and the silence seemed tense. These people had heard the whole conversation about Lacerta, but Yatima wasn’t sure what they’d made of it.

After a while, the man asked nervously, “You talked about radiation from space. Is this the start of a war?”

Inoshiro said firmly, “No. It’s a natural process. It’s probably happened to the Earth before, hundreds of millions of years ago. Maybe many times.” Yatima refrained from adding: Only never this close, never this strong.

“But the stars are falling together faster than they should be. So how do you know they’re not being used as a weapon?”

“They’re falling together faster than astronomers thought they would. So the astronomers were wrong, they misunderstood some of the physics. That’s all.”

The man seemed unconvinced. Yatima tried to imagine an alien species with the retarded morality required for warfare and the technological prowess to manipulate neutron stars. It was a deeply unpleasant notion, but about as likely as the influenza virus inventing the H-bomb. The three bridgers spoke together quietly, but the man remained visibly agitated. Yatima said reassuringly, “Whatever happens, you’re always welcome in Konishi. Whoever wants to come.”

The man laughed, as if he doubted it.

Yatima raised vis right hand, displaying his index finger. “No, it’s true. We’ve brought enough Introdus nanoware—”

Inoshiro was sending warning tags even before the expression on the man’s face changed. He leant forward and grabbed Yatima’s hand by the wrist, then slammed it down on the table. He screamed, “Someone get a torch! Get a cutting tool!” One of the guards left the room; the other approached warily.

Inoshiro said calmly, “We would never have used it on anyone without permission. We just wanted to be prepared to offer you migration, if things went badly.”

The man raised his free hand toward ver in a fist. “You keep back!” Sweat was dripping from his face; Yatima was doing nothing to resist, but the gleisner’s skin reported that the man was straining hard against it, as if he was wrestling with some monstrous opponent.

He spoke to Yatima, without taking his eyes off Inoshiro. “What’s really going to happen? Tell me! Will the gleisners set off their bombs in space, so you can herd the last of us into your machines?”

“The gleisners have no bombs. And they respect you much more highly than they respect us; the last thing they’d want to do is force fleshers into the polises.” They’d faced some strange misconceptions before, but nothing like this level of paranoia.

The woman returned, carrying a small machine with a metal rod shaped into a semi-circle protruding from one end. She touched a control and an arc of blue plasma appeared, joining the tips of the rod. Yatima instructed the Introdus nanoware to begin crawling up the repair system ducts in vis arm, back toward his torso. The man leaned down harder than ever, then the woman approached and began slicing through the limb, high above the elbow.

Yatima didn’t waste the nanoware’s energy by pestering it with a stream of queries; ve just waited for the strange experience to be over. The interface didn’t know what to make of the damage reports from the gleisner’s hardware—and it declined to reach into Yatima’s self-symbol and perform matching surgery. When the plasma arc broke through to the other side and the man pulled the robot’s severed arm away, the corresponding part of Yatima’s icon was left mentally protruding from the stump-a kind of phantom presence, only half-free of the feedback loop of embodiment.

When ve dared to check, fifteen doses of the Introdus nanoware had made it to safety. The rest were lost, or heat-damaged beyond repair.

Yatima met the man’s eyes and said angrily, “We came here in peace; we would never have violated your autonomy. But now you’ve limited the choices for others.” Without a word, the man placed the plasma saw on the edge of the table and began feeding the gleisner’s hand back and forth through the arc, reducing the delicate machinery to slag and smoke. When Francesca returned, she seemed equally outraged by the guards’ revelation that nanoware had been brought into the enclave, and the less-than-diplomatic ad hoc remedy they’d employed to deal with it.

Under the Treaty of 2190, Yatima and Inoshiro should have been expelled from Atlanta immediately, but Francesca was prepared to bend the rules to allow them to address the convocation—and to Yatima’s surprise, the guards agreed. Apparently they believed that a public interrogation by the assembled fleshers would be the best way to expose the gleisner-Konishi conspiracy.

As they walked down the corridor toward the Convocation Hall, Inoshiro said in IR, “They can’t all be like this. Remember Orlando and Liana.”

“I remember Orlando ranting about the evil gleisners and their wicked plans.”

“And I remember Liana setting him straight.”

The Convocation Hall was a large cylindrical space, roughly the same shape as the building itself. Concentric rows of seats converged on a circular stage—and there were about a thousand bridgers filling them. Behind and above the seats, on the cylinder’s wall, giant screens displayed the images of representatives from other enclaves. Yatima could easily distinguish the avian and amphibian exuberants, but ve had no doubt that the unmodified appearance of the others hid a greater range of variation.

The dream apes were not represented.

The guards stayed behind as Francesca led them up onto the stage. It was divided into three tiers; nine bridgers stood on the outermost tier, facing the audience, and three stood on the second.

“These are your translators,” Francesca explained. “Pause after every sentence, and wait for all of them to finish.” She pointed out a slight indentation on the stage, at the very center. “Stand here to be heard; anywhere else, you’ll be inaudible.” Yatima had already noticed the unusual acoustics—they’d walked through excesses and absences of background noise, and the intensity of Francesca’s voice had fluctuated strangely. There were complex acoustic mirrors and baffles hanging from the ceiling, and the gleisner’s skin had reported sudden air pressure gradients which were probably due to some form of barrier or lens.

Francesca took center stage and addressed the convocation. “I am Francesca Canetti of Atlanta. I believe I am presenting to you Yatima and Inoshiro of Konishi polis. They claim to bring serious news, and if it’s true it concerns us all. I ask you to listen to them carefully, and question them closely.”

She stepped aside. Inoshiro muttered in IR, “Nice of her to inspire such confidence in us.”

Inoshiro repeated the account of Lacerta G-1 that ve’d given to Francesca in the jungle, pausing for the translators and clarifying some terms in response to their queries. The inner tier of three translators spoke first, then the outer nine offered their versions; even with the acoustics arranged to allow some of them to speak simultaneously, it was painfully slow. Yatima could understand that automating the process would have gone against the bridgers’ whole culture, but they still should have had some more streamlined way to communicate in an emergency. Or maybe they did, but only for a predetermined set of natural disasters.

As Inoshiro began describing the predicted effects on the Earth, Yatima tried to judge the mood of the audience. Flesher gestalt, limited by anatomy, was much more subdued than the polis versions, but ve thought ve could detect a growing number of faces expressing consternation. There was no dramatic change sweeping through the hall, but ve decided to interpret this optimistically: anything was better than panic.

Francesca moderated the responses. The first came from the representative of an enclave of statics; he spoke a dialect of English, so the interface slipped the language into Yatima’s mind.

“You are shameless. We expect no honor from the simulacra of the shadows of departed cowards, but will you never give up trying to wipe the last trace of vitality from the face of the Earth?” The static laughed humorlessly. “Did you honestly believe that you could frighten us with this risible fairy-tale of 'quarks’ and 'gamma rays’ raining from the sky, and then we’d all file meekly into your insipid virtual paradise? Did you imagine that a few cheap, shocking words would send us fleeing from the real world of pain and ecstasy into your nightmare of perfectibility?” He gazed down at them with a kind of fascinated loathing. “Why can’t you stay inside your citadels of infinite blandness, and leave us in peace? We humans are fallen creatures; we’ll never come crawling on our bellies into your ersatz Garden of Eden. I tell you this: there will always be flesh, there will always be sin, there will always be dreams and madness, war and famine, torture and slavery.”

Even with the language graft, Yatima could make little sense of this, and the translation into Modern Roman was equally opaque. Ve dredged the library for clarification; half the speech seemed to consist of references to a virulent family of Palestinian theistic replicitors.

Ve whispered to Francesca, dismayed, “I thought religion was long gone, even among the statics.”

“God is dead, but the platitudes linger.” Yatima couldn’t bring verself to ask whether torture and slavery also lingered, but Francesca seemed to read vis face, and added, “Including a lot of confused rhetoric about free will. Most statics aren’t violent, but they view the possibility of atrocities as essential for virtue—what philosophers call `the Clockwork Orange fallacy.’ So in their eyes, autonomy makes the polises a kind of amoral Hell, masquerading as Eden.”

Inoshiro was struggling to respond, in English. “We don’t ask you to come into the polises if you don’t wish to. And we aren’t lying in order to frighten you; we only want you to be prepared.”

The static smiled serenely. “We are always prepared. This is our world, not yours; we understand its perils.”

Inoshiro began to speak earnestly about shelter, fresh water, and the options for a viable food supply. The static interrupted ver, laughing loudly. “The final insult was choosing the millennium. A superstition for addled children.”

Inoshiro was bewildered. “But that’s gigatau away!”

“Close enough to make your contempt transparent.” The static bowed mockingly, and his image vanished.

Yatima gazed at the blank screen, unwilling to accept what it seemed to imply. Ve asked Francesca, “Will others in his enclave have heard Inoshiro speak?”

“A few, almost certainly.”

“And they could choose to go on listening?”

“Of course. No one censors the net.”

There was still hope, then. The statics weren’t entirely beyond reach, like the dream apes.

The next response came from an unmodified-looking exuberant woman, speaking a language unfamiliar to the library. When the translation came, she turned out to be asking for more details of the process that was assumed to be robbing the neutron stars of their angular momentum.

Inoshiro had grafted extensive knowledge of Kozuch Theory into vis mind, and ve had no trouble answering; Yatima, wanting to stay fresh for the Mines, understood slightly less. But ve did know that the computations linking Kozuch’s Equation to the neutron stars’ dynamics were intractably difficult, and it was mainly just a process of elimination that had left polarization as the most plausible theory.

The exuberant listened calmly; Yatima couldn’t tell if this was mere courtesy, or a sign that someone was taking them seriously at last. When the outer-tier translator was finished, the exuberant made a further comment.

“With such low tidal forces it would take many times longer than the lifetime of the universe for the runaway polarization state to tunnel through the energy barrier and dominate the confinement state. Polarization cannot he the cause.” Yatima was astonished. Was this confident assertion misplaced—or a mistranslation—or did the exuberant have a solid mathematical reason for it? “However, I accept that the observations are unambiguous. The neutron stars will collide, the gamma-ray flash will occur. We will make preparations.”

Yatima wished she could have said more, but with twelve translators involved a prolonged discussion on the subject would have taken days. And they’d finally had one small victory, so ve savored it; a post mortem of the neutron stars’ physics could wait.

As Francesca chose the next speaker, several people in the audience stood and began making their way out. Yatima decided to treat this as a good sign: even if they weren’t entirely convinced, they could set in motion precautionary steps that would save hundreds or thousands of lives.

With extensive mind grafts, and the library at vis disposal, Inoshiro fielded technical questions easily. When the amphibious exuberant asked about UV damage to plankton and pH changes in the surface waters of the oceans, there was a Carter-Zimmerman model to quote. When a bridger in the audience questioned TERAGO’s reliability, Inoshiro explained why cross-talk from some other source couldn’t be the cause of the neutron stars’ ever quickening waves. From the subtleties of photochemistry in the stratosphere to the impossibility of Lacerta’s soon-to-be-born black hole forming fast enough to swallow all the gamma rays and spare the Earth, Inoshiro countered almost every objection that might have made the case for action less compelling.

Yatima was filled with uneasy admiration. Inoshiro had pragmatically become exactly what the crisis required ver to become, grafting in all this second-hand understanding without regard for the effects on vis own personality. Ve would probably choose to have most of it removed afterward; to Yatima this sounded like dismemberment, but Inoshiro seemed to view the whole prospect as less traumatic than the business of taking on and shrugging off their gleisner bodies.

More enclave representatives began signing off; some clearly persuaded, some obviously not, some giving no signals that Yatima could decipher. And more bridgers left the hall, but others came in to take their place, and some Atlanta residents asked questions from their homes.

The three guards had sat in the audience and let the debate run its course, but now the woman who’d sliced off Yatima’s arm finally lost patience and sprang to her feet. “They brought Introdus nanoware into the city! We had to cut the weapon from vis body, or they would have used it by now!” She pointed at Yatima. “Do you deny it?”

The bridgers responded to this accusation the way Yatima had expected them to greet the news of the burst: with an audible outcry, agitated body movements, and some people rising to their feet and yelling abuse at the stage.

Yatima took Inoshiro’s place at the acoustic focus. “It’s true that I brought in the nanoware, but I would only have used it if asked. The nearest portal is a thousand kilometers away; we only wanted to offer you the choice of migration without the risks of that long journey.”

There was no coherent response, just more shouting. Yatima looked around at the hundreds of angry fleshers, and struggled to understand their hostility; they couldn’t all be as paranoid as the guards. Lacerta itself was a crushing blow, a promise of decades of hardship, at best… but maybe talk of “the choice of migration” was worse. Lacerta could only drive them into the polises if it could hammer them into the ground; maybe the prospect of following the Introdus seemed less like a welcome escape hatch, a means of cheating death, than a humiliating means of allowing the fleshers to witness their own annihilation.

Yatima raised vis voice to ensure that the translators could hear ver. “We were wrong to bring in the nanoware—but we’re strangers, and we acted out of ignorance, not malice. We respect your courage and tenacity, we admire your skills—and all we ask is to be allowed to stand beside you and help you fight to go on living the way you’ve chosen to live: in the flesh.”

This seemed to split the audience; some responded with jeers of derision, some with renewed calm and even enthusiasm. Yatima felt like ve was playing a game ve barely understood, for stakes ve hardly dared contemplate. They had never been fit for this task, either of them. In Konishi, the grossest acts of foolishness could barely wound a fellow citizen’s pride; here and now, a few poorly judged words could cost thousands of lives.

One bridger called out words that were translated as, “Do you swear that you have no more Introdus nanoware—and will make no more?”

This question silenced the hall. Trust the bridgers in their diversity to have someone who knew the workings of a gleisner body. The guards glared up at Yatima, as if ve’d misled them merely by failing to confess the existence of these possibilities.

“I have no more, and I will make no more.” Ve spread his arms, as if to show them the innocent phantom protruding from the stump, incapable of touching their world.

The convocation stretched on through the night. People came and went, some splitting off into groups to coordinate preparations for the burst, some returning with new questions. In the early hours of the morning, the three guards called on the meeting to expel Yatima and Inoshiro from Atlanta immediately; upon losing the vote they walked out.

By dawn, most of the bridgers and the representatives of many of the enclaves seemed to have been won over, if only to the point where they accepted that the balance of probabilities made it well worth the risk of wasting effort on unnecessary precautions. At seven o'clock, Francesca told the second shift of translators to get some sleep; the hall wasn’t quite empty, but the few people remaining were absorbed in their own urgent discussions, and the wallscreens were blank.

One of the bridgers had suggested that they find a way to get the TERAGO data onto the fleshers’ communications network. Francesca took them to Atlanta’s communications hub—a large room in the same building—and they worked with the engineer on duty to establish a link to the Coalition via the drones. Translating the gestalt tags into suitable audiovisual equivalents looked like it would be the hardest part, but there turned out to be a centuries-old tool in the library for doing just that.

When everything was working the engineer summoned a plot of the Lacerta gravity waves and an annotated image of the neutron stars’ orbit onto two large screens above her console: stripped-down versions of the rich polis scapes playing as flat, framed pictures. Compared to the historical baseline, the waves had doubled in frequency and their power had risen more than tenfold. G-1a and G-1b were still a little more than 300,000 kilometers apart, but the higher-derivative trends continued to imply a sudden, sharp fall around 20:00 UT—two p.m. local tune—and any flesher on the planet with minimal computing resources could now take the raw data and confirm that. Of course, the data itself could have been fabricated, but Yatima suspected it would still be more convincing than vis word, or Inoshiro’s, alone.

“I’m going to need a few hours’ rest.” Francesca had developed a fixed gaze and monotone speech; her skepticism about the burst had clearly faded long ago, but she’d shown no sign of emotion, and she’d kept the convocation running to the end. Yatima wished ve could offer her some kind of comfort, but the only thing within vis gift was poisonous, unmentionable “I don’t know what your plans are now.”

Neither did Yatima, but Inoshiro said, “Can you take us to Liana and Orlando’s house?”

Outside, people were constructing covered walkways between buildings, wheeling sacks and barrels of food into repositories, digging trenches and laying pipes, spreading tarpaulins to make new corridors of shade. Yatima hoped the message had got through that even reflected UV would soon have the power to burn or blind; some of the bridgers working in the heat had bare limbs or torsos, and every square centimeter of skin seemed to radiate vulnerability. The sky was darker than ever, but even the heaviest clouds would make a weak and inconstant shield. The crops in the fields were as good as dead; medium-term survival would come down to the ability to design, create, plant, and harvest viable new species before existing food supplies ran out. There was also the question of energy; Atlanta was largely powered by photovoltaic plants tailored to the atmosphere’s current spectral windows. Carter-Zimmerman’s botanists had already offered some tentative suggestions; Inoshiro had sketched the details at the convocation, and now they were available in full, on-line. No doubt the fleshers would regard them as the work of model-bound dilettante theoreticians, but as starting points for experimentation they had to be better than nothing.

They reached the house. Orlando looked tired and distracted, but he greeted them warmly. Francesca left, and the three of them sat in the front room.

Orlando said, “Liana’s sleeping. It’s a kidney infection, a viral thing.” He stared at the space between them. “RNA never sleeps. She’s going to be all right, though. I told her you’d returned. She was pleased.”

“Maybe Liana will design your new skin and corneas,” Yatima suggested. Orlando made a polite sound of agreement.

Inoshiro said, “You should both come with us.”

“Sorry?” Orlando rubbed his bloodshot eyes.

“Back into Konishi.” Yatima turned to ver, appalled; ve’d told ver about the surviving nanoware, but after the reactions they’d had so far, this was madness.

Inoshiro continued calmly, “You don’t have to go through any of this. The fear, the uncertainty. What if things go badly, and Liana’s still sick? What if you can’t travel to the portal? You owe it to her to think about that now.” Orlando didn’t look at ver, and didn’t reply. After a moment, Yatima noticed tears running into his beard, barely visible against the sheen of sweat. He cradled his head in his hands, then said, “We’ll manage.”

Inoshiro stood. “I think you should ask Liana.”

Orlando raised his head slowly; he looked more astonished than angry. “She’s asleep!”

“Don’t you think this is important enough to wake her? Don’t you think she has a right to choose?”

“She’s sick, and she’s asleep, and I’m not going to put her through that. All right? Can you understand that?” Orlando searched Inoshiro’s face; Inoshiro gazed back at him steadily. Yatima suddenly felt more disoriented than at any time since they’d woken in the jungle.

Orlando said, “And she doesn’t fucking know yet.” His voice changed sharply on the last word. He bunched his fists and said angrily, “What do you want? Why are you doing this?”

He stared at Inoshiro’s bland gray features, then suddenly burst out laughing. He sat there grimacing and laughing angrily, wiping his eyes on the back of his hand, trying to compose himself. Inoshiro said nothing.

Orlando rose from the chair. “Okay. Come on up. We’ll ask Liana, we’ll give her the choice.” He started up the stairs. “Are you coining?”

Inoshiro followed him. Yatima stayed where ve was. Ve could make out three voices, but no words.

There was no shouting, but there were several long silences. After fifteen minutes, Inoshiro came down the stairs and walked straight out onto the street. Yatima waited for Orlando to appear. Ve said, “I’m sorry.” Orlando raised his hands, let them drop, dismissing it all. He looked steadier, more resolved than before.

“I should go and find Inoshiro.”

“Yeah.” Orlando stepped forward suddenly, and Yatima recoiled, expecting violence. When had ve learned to do that? But Orlando just touched vis shoulder and said, “Wish us luck.”

Yatima nodded and backed away. “I do.”

Yatima caught sight of Inoshiro near the edge of the city.

“Slow down!”

Inoshiro turned to took at ver, but kept walking. “We’ve done what we came for. I’m going home.”

Ve could have returned to Konishi from anywhere; there was no need to leave the enclave. Yatima willed vis viewpoint forward faster, and the interface switched the body’s gait into a different mode. Ve caught up with Inoshiro on the road between the fields.

“What are you afraid of? Getting stranded?” When the burst hit, part of the upper atmosphere would turn to plasma, so satellite communication would be disrupted for a while. “We’ll have enough warning from TERAGO to send back snapshots.” And then? The more hostile bridgers might go as far as killing the messengers, once post-Lacerta realities began to strike home, but if it came to that they could always just erase their local selves before things became too unpleasant.

Inoshiro scowled. “I’m not afraid. But we’ve delivered the warning. We’ve spoken to everyone who was capable of listening. Hanging around any longer is just voyeuristic.”

Yatima gave this serious thought. “That’s not true. We’re too clumsy to help much as laborers, but after the burst we’d be the only people here guaranteed immune to UV. Okay, they can cover themselves, protect their eyes, nothing’s impossible if they do it carefully. But two robots built for unfiltered sunlight might still be useful.”

Inoshiro didn’t reply. Soft-edged shadows were racing across the fields from black filaments of cloud streaming low overhead. Yatima glanced back at the city; the clouds were piling up into structures like dark fists. Heavy rain might be good; cool the place down, keep people indoors, blunt the first shafts of UV. So long as it didn’t hide so much that it left the bridgers complacent.

“I thought Liana would understand.” Inoshiro laughed bitterly. “Maybe she did.”

“Understand what?”

Inoshiro shook vis head. It was strange to see ver in this robot body again, which looked more like Yatima’s enduring mental image of ver than vis current icon back in Konishi.

“Stay and help, Inoshiro. Please. You’re the one who remembered the bridgers. You’re the one who shamed me into coming here.”

Inoshiro regarded ver obliquely. “Do you know why I gave you the Introdus nanoware? We could have swapped jobs, you could have made the drones.”

Yatima shrugged. “Why?”

“Because I would have used it all by now. I would have shot every bridger I could. I would have gathered them all up and carried them away, whether they wanted it or not.”

Inoshiro walked on down the smooth dirt road. Yatima stood and watched ver for a while, then headed back into the city.

Yatima wandered Atlanta’s streets and parks, offering information wherever ve dared, approaching anyone who wasn’t working unless they looked openly hostile. Even without official translators ve often found ve could communicate with small groups of people, with everyone pitching in to cover the gaps.

An incomprehensible “What are the boundaries of purity?” became: “Can the sky be trusted this far?”—with the speaker glancing at the clouds—which became: “If it rains today, will it burn us?”

“No. The acidity won’t rise for months; the nitric oxides will take that long to diffuse down from the stratosphere.”

The translated answers sometimes sounded like they’d traversed a Mobius strip and returned inverted, but Yatima clung to the hope that all sense wasn’t evaporating along the way, that “up” wasn’t really turning to “down.”

By midday the city looked abandoned. Or besieged, with everyone in hiding. Then ve spotted some people working on a link between two buildings, and even in the forty-degree heat they were wearing long-sleeved clothing, and gloves, and welding masks. Yatima was encouraged by their caution, but ve could almost sense the dispiriting, claustrophobic weight of the protective gear. The bridgers clearly retained an evolved acceptance of the constraints of embodiment, but it seemed that half the pleasure of being flesh came from pushing the limits of biology, and the rest from minimizing all other encumbrances. Maybe the maddest of the masochistic statics would relish every obstacle and discomfort Lacerta could impose on them, waxing lyrical about “the real world of pain and ecstasy” while the ultraviolet flayed them, but for most fleshers it would do nothing but erode the kind of freedom that made the choice of flesh worthwhile.

There was a seat suspended by ropes from a frame in one of the parks; Yatima recalled seeing people sitting on it and swinging back and forth, an eternity ago. Ve managed to sit without falling, holding tight to one rope with vis remaining hand, but when ve willed the interface to set the pendulum in motion, nothing happened. The software didn’t know how.

By one o'clock, the Lacerta waves had strengthened to a hundred times their old power level. There was no point any more in waiting for data to arrive from two or three of TERAGO’s scattered detectors in order to eliminate interference from other sources; the feed now came straight from Bullialdus in real time, and Lac G-1’s racing pulse was loud enough to drown out everything else in the sky. The waves were visibly “chirping,” each one clearly narrower than its predecessor; the latest two peaks were just 15 minutes apart, which meant the neutron stars had crossed the 200,000 kilometer mark. In an hour that separation would be halved, then in a few more minutes it would vanish. Yatima had been clinging to a faint hope of a shift in the dynamics, but the gleisners’ ever-steeper extrapolation had kept on proving itself right.

The seat wobbled. A half-naked child was tugging on the side, trying to get vis attention. Yatima stared at ver, speechless, wanting to wrap vis invulnerable polymer body around the child’s exposed skin. Ve looked about the deserted playground for an adult; there was no one in sight.

Yatima stood. The child abruptly started crying and screaming. Ve sat, stood, tried to sweep the child up in vis single arm, failed. The child banged its fist on the vacated seat. Yatima obeyed.

The child clambered onto vis lap. Yatima glanced nervously at the TERAGO scape. The child stretched vis arms out and held the ropes, then leaned back slightly. Yatima imitated the motion, and the seat responded. The child leaned forward, Yatima followed.

They swung together, ever higher, the child screaming with delight, Yatima torn between terror and joy. A few sparse drops of rain descended, and then the clouds around the sun thinned, and parted.

The sudden clarity of the light was shocking. Looking across the sunlit playground—with a viewpoint gliding smoothly through this world, at last—Yatima felt an overpowering sense of hope. It was as if the Konishi mind seed still encoded the instinctive knowledge that, in time, the darkest stormclouds would always clear, the longest night would always yield to dawn, the harshest winter would always be tempered by spring. Every hardship the Earth forced upon its inhabitants was bounded, cyclic, survivable. Every creature born in the flesh carried the genes of an ancestor who had lived through the most savage punishment this world could inflict.

No longer. Sunlight breaking through the clouds was a lie, now. Every instinct that proclaimed that the future could be no worse than the worst of the past was obsolete. And Yatima had long understood that, outside the polises, the universe was capricious and unjust. But it had never mattered, before. It had never touched ver.

Ve didn’t trust verself to halt the swing safely, so ve froze and let the motion die away, ignoring the child’s complaints. Then ve carried ver shrieking to the nearest building, where someone seemed to know where ve belonged, and snatched ver away angrily.

The stormclouds had closed in again. Yatima returned to the playground and stood motionless, watching the sky, waiting to learn the new limits of darkness.

The neutron stars made their last full orbit in under five minutes, 100,000 kilometers apart and spiraling in steeply. Yatima knew ve was witnessing the final moments of a process that had taken five billion years, but on a cosmic scale was about as rare and significant as the death of a mayfly. Gamma-ray observatories picked up the signature of identical events in other galaxies, five times a day.

Still, Lac G-1’s great age meant that the two supernovae which had left the neutron stars behind predated the solar system. Supernovae sent shockwaves rippling through surrounding clouds of gas and dust, triggering star formation. So it was not inconceivable that G-1a or G-1b had created the sun, and the Earth, and the planets. Yatima wished ve’d thought of this when Inoshiro was talking to the statics; renaming the neutron stars “Brahma” and “Shiva” might have carried the right kind of mythic resonance to penetrate their mythic stupor. The vacuous metaphor might have saved a few lives. Other than that, whether Lacerta giver-of-life was about to show the hand that takes, or whether it was preparing to rain gamma rays on the accidental children of another dead star altogether, the scars inflicted would be equally painful, and equally meaningless.

The signal from Bullialdus climbed, peaked at ten thousand times the old level, then dived. In the orbit scape, the two arms of the inward spiral twisted into perfect radial alignment, and the narrow cones of uncertainty flaring out from each branch of the orbit shrank and merged into a single translucent tunnel. Each neutron star made a microscopic target for the other, so a succession of near misses granting five or ten minutes’ reprieve would not have been unthinkable, but the verdict was that all sideways motion had vanished to the limits of measurement. The neutron stars would merge at the first approach.

In twenty-one seconds.

Yatima heard a voice wailing with anguish. Ve looked away from the scapes and swept vis robot gaze across the playground, for a moment convinced that the flesher child had escaped vis parents and returned, that search parties were out beneath the threatening sky. But the voice was distant and muffled, and there was no one in sight.

Ten seconds.

Five.

Let all the models be wrong: let an event horizon swallow the blast. Let the gleisners be lying, faking the data: let the most paranoid flesher be right.

An auroral glow filled the sky, an elaborate dazzling curtain of pink and blue electrical discharges. For a moment Yatima wondered if the clouds had been seared away, but as vis eyes desaturated and adjusted their response ve could see that the light was shining right through. The clouds made a faint grubby overlay, like smudges of dirt on a window pane, while ethereal patterns edged in luminous white and green swirled behind them, delicate wisps and vortices of ionized gas tracing the flows of billion-ampere currents.

The sky dimmed then began to flicker, strobing at about a kilohertz. Yatima instinctively reached for the polis library, but the connection had been severed; the ionized stratosphere was radio-opaque. Why the oscillation? Was there a shell of neutrons outside the black hole, ringing like a bell as it slipped into oblivion, Doppler-shifting the last of the gamma rays back and forth?

The flicker persisted, far too long for the burst itself to be the cause. If the remnants of Lac G-1 weren’t vibrating, what was? The gamma rays had deposited all their energy high above the ground, blasting nitrogen and oxygen molecules apart into a super-heated plasma, and the electrons and positive ions in this plasma had a billion terajoules to dispose of before they could recombine. Most of this energy would be going into chemical changes, and some was clearly reaching the ground as light, but powerful currents surging through the plasma would also be generating low frequency radio waves, which would bounce back and forth between the Earth and the now-ionized stratosphere. That was the source of the flicker. Yatima recalled the C-Z analysis stating that these waves could do real damage under certain conditions, though any effects would he highly localized, and insignificant compared to the problems of UV and global cooling.

As the auroral light behind the clouds faded, a blue white spike flashed across the sky. Yatima had barely registered this when a second discharge forked between the Earth and the clouds. The thunder was too loud to be heard; the gleisner’s acoustic sensors shut down in self-defense.

The sky darkened suddenly, as if the hidden sun had been eclipsed; the plasma must have cooled enough to start forming nitric oxides. Yatima checked the tags from vis skin; the temperature had just dropped from 41 to 39, and it was still falling. Lightning struck again, close by, and in the flash ve saw a layer of dark, wind-streaked cloud moving overhead.

Ripples appeared in the grass, at first just flattening the blades, but then Yatima saw dust rising up between them. The air came in powerful gusts, and when the pressure rose so did the temperature. Yatima raised vis hand into the hot wind, and tried to feel it flowing past vis fingers, tried to grasp what it would mean to be touched by this strange storm.

Lightning hit a building on the far side of the playground; it exploded, showering glowing embers. Yatima hesitated, then moved quickly toward the burst shell. Patches of grass were burning nearby. Ve could see no one moving inside, but between the lightning flashes it was like a starless night, and as the embers and the grass fires sputtered out there was a moment when everything seemed blanketed, smothered by darkness. Yatima stretched the gleisner’s vision into infrared; there were patches of body-temperature thermal radiation among the wreckage, but the shapes were ambiguous.

People were shouting frantically, somewhere, but it didn’t seem to be coming from the building. The wind masked and distorted the sound, scrambling all cues for distance and direction, and with the streets deserted it was like being in a scape with a soundtrack of disembodied voices.

As Yatima approached the building, buffeted by the wind, ve saw that it was empty; the body-temperature regions were just charred wood. Then vis hearing cut out again and the interface lost balance. Ve hit the ground face down, an image lingering on vis retinas: vis shadow stretched out across the grass, black and sharp against a sea of blue light. When ve scrambled to vis feet and turned around, there were three more buildings charred and smoking, walls split open, ceilings collapsed. Ve ran back across the playground.

There were people stumbling out of the ruins, ragged and bleeding. Others were searching frantically through the debris. Yatima spotted a man half-buried in rubble, eyes open but expressionless, a black splintered length of wood lying across his body from thigh to shoulder. Ve reached down and grabbed one end of the beam, and managed to lift it and swing it away.

As ve squatted beside the man, someone started punching and slapping the back of vis head and shoulders. Ve turned to see what was happening, and the flesher began yelling incoherently and striking vis face. Still squatting, ve backed off from the injured man awkwardly, as someone else tried to pull vis assailant away. Yatima stood and retreated. The flesher screamed after ver, “Vulture! Leave us in peace!”

Confused and disheartened, Yatima fled.

As the storm intensified, the bridgers’ hasty modifications were falling apart; crumpled tarpaulins were blowing down the street, and the ceilings of some of the walkways had come loose and crashed to the ground. Yatima looked up at the dark sky and switched to UV. Ve could just make out the disk of the sun, penetrating the stratospheric NOx easily at these wavelengths, but still veiled by the heavy clouds.

Inoshiro had been right, there was nothing ve could do; the bridgers would bury their dead, treat the injured, repair their damaged city. Even in a world where the darkness at noon could blind them, they’d find their own ways to survive. Ve had nothing to offer them.

The link to Konishi was still down, but ve wasn’t prepared to wait any longer. Yatima stood motionless in the street, listening to the cries of pain and mourning, preparing verself for extinction. To forget this would be nothing but a sweet relief; vis Konishi self would be free to remember the bridgers in happier times.

Then the sky roared, and the lightning descended like rain.

The street became a sequence of dazzling staccato images bathed in blue and white, shadows jumping wildly with each new jagged arc of light. Buildings began exploding one after another, a relentless cascade of sudden orange flashes spraying sparks and fist-sized lumps of burning wood. People appeared, ducking and screaming, panicked out of their vulnerable shelters. Yatima watched, helpless but transfixed. The dying stratospheric plasma had found a way to reach down to Earth, its radio frequency pulses pumping vast quantities of ions through the lower atmosphere, inducing a massive voltage difference between the stormclouds and the ground. But now the voltage had crossed the breakdown threshold of the dust-filled air below, and the whole system was short-circuiting, rapidly and violently. Atlanta just happened to be in the way. Local damage, insignificant on a global scale.

Yatima moved slowly through the actinic blaze, half hoping for a lightning strike and the mercy of amnesia, but unable to abandon the bridgers now by choice. Driven from their homes, people were cowering beneath the onslaught, many of them burnt, torn, bloodied. A woman strode past with her arms stretched wide and her face to the sky, shouting defiantly: “So what? So what?”

A child, a half-grown girl, sat in the middle of the street, the side of her face and one exposed arm a raw pink, weeping lymphatic fluid. Yatima approached her. She was shivering.

“You can leave all this behind. Come into the polises. Is that what you want?” She stared back, uncomprehending. One of her ears was bleeding; the thunder might have deafened her. Yatima delved into the instructions for the gleisner’s maintenance nanoware, and had it rebuild the lost delivery system in vis left forefinger. Then ve commanded the surviving Introdus doses to move into place.

Ve raised vis arm and aimed the delivery system at the girl, shouting “Introdus? Is that what you want?” She cried out and covered her face. Did that mean no, or was she just bracing herself for the shock?

The child began sobbing. Yatima backed away, defeated. Ve could save fifteen lives, ve could drag fifteen people out of this senseless inferno, but who could ve be sure even understood what ve was offering?

Francesca. Orlando. Liana.

Orlando and Liana’s house wasn’t far. Yatima steeled verself and pushed on through the chaos, past the shattered buildings and the terrified fleshers. The lightning was finally dying away—and the fireproof buildings had only burnt when directly hit—but the city had been transformed into a scene from the age of barbarism, when bombs had rained from the sky.

The house was partly standing, but unrecognizable; Yatima only knew ve’d found the right place because of the gleisner’s navigation system. The top story was gutted, and there were holes in the ceiling and walls of the ground floor.

Someone was kneeling in the shadows, picking away debris at the edge of a vast heap where the ashes of most of the top story seemed to have landed. “Liana?” Yatima broke into a run. The figure turned toward ver.

It was Inoshiro.

Inoshiro had half-exposed a corpse, all black dessicated flesh and white bone. Yatima looked down at it, then recoiled, disoriented. This charred skull was not a symbol in some jaded work of polis art; it was proof of the involuntary erasure of a living mind. The physical world could do that. The death of a cosmic mayfly could do that.

Inoshiro said, “It’s Liana.”

Yatima tried to absorb this, but ve felt nothing, the idea meant nothing.

“Have you found-?”

“Not yet.” Inoshiro’s voice was expressionless.

Yatima left ver, and began scanning the rubble in IR, wondering how long a corpse would remain warmer than its surroundings. Then ve heard a faint sound from the front of the house.

Orlando was buried beneath pieces of the ruptured ceiling. Yatima called Inoshiro, and they quickly uncovered him. He was badly injured; both his legs and one arm had been crushed, and a gash in his thigh was spurting blood. Yatima checked the link to Konishi—ve couldn’t even guess how to treat such wounds—but either the stratosphere was still ionized, or one of the drones had been lost in the storm.

Orlando stared up at them, ashen but conscious, eyes pleading for something. Inoshiro said flatly, “She’s dead.” Orlando’s face contorted silently.

Yatima looked away and spoke to Inoshiro in IR. “What do we do? Carry him to a place where they can treat him? Fetch someone? I don’t know how this works.”

“There are thousands of injured people. No one’s going to treat him; he’s not going to live that long.”

Yatima was outraged. “They can’t leave him to die!”

Inoshiro shrugged. “You want to try finding a communications link and calling for a doctor?” Ve peered out through the broken wall. “Or do you want to try carrying him to the hospital, and see if he survives the trip?”

Yatima knelt beside Orlando. “What do we do? There are a lot of people hurt, I don’t know how long it will take to get help.”

Orlando bellowed with pain. A weak shaft of sunlight had appeared, coming through a hole in the ceiling and illuminating the skin of his broken right arm. Yatima glanced up; the storm was over, the clouds were beginning to thin and drift away.

Ve moved to block the light, while Inoshiro crouched behind Orlando, half-lifted him under the arms, and dragged him over the rubble into the shade. The wound in his thigh left a thick trail of blood.

Yatima knelt beside him again. “I still have the Introdus nanoware. I can use it, if that’s what you want.”

Orlando said clearly, “I want to talk to Liana. Take me to Liana.”

“Liana’s dead.”

“I don’t believe you. Take me to her.” He was struggling for breath, but he forced the words out defiantly.

Yatima stepped back beneath the hole in the ceiling. In ordinary light the sun appeared as a meek orange disk through the stratosphere’s brown haze, but in UV it shone fiercely amidst a blaze of scattered radiation.

Ve left the room, and returned carrying Liana’s body one-handed by the collarbone. Orlando covered his face with his unbroken arm and wept loudly.

Inoshiro took the corpse away. Yatima knelt by Orlando a third time, and put vis hand on his shoulder clumsily. “I’m sorry she’s dead. I’m sorry that hurt you.” Ve could feel Orlando’s body shaking with each sob. “What do you want? Do you want to die?”

Inoshiro spoke in IR. “You should have left when you had the chance.”

“Yeah? So why did you come hack?”

Inoshiro didn’t reply. Yatima swung around to face ver. “You knew about the storm, didn’t you? You knew how bad it would be!”

“Yes.” Inoshiro made a gesture of helplessness. “But if I’d said anything when we arrived, we might not have had a chance to speak to the other fleshers. And after the convocation, it was too late. It would have just caused panic.”

The front wall creaked and lurched forward, breaking loose from the ceiling in a shower of black dust. Yatima sprang to vis feet and backed away, then fired the Introdus into Orlando.

Ve froze. The wall had struck an obstacle; it was tilted precariously, but holding. Waves of nanoware were sweeping through Orlando’s body, shutting down nerves and sealing off blood vessels to minimize the shock of invasion, leaving a moist pink residue on the rubble as flesh was read and then cannibalized for energy. Within seconds, all the waves converged to form a gray mask over his face, which bored down to the skull and then ate through it. The shrinking core of nanoware spat fluid and steam, reading and encoding crucial synaptic properties, compressing the brain into an ever-tighter description of itself, discarding redundancies as waste.

Inoshiro stooped down and picked up the end product: a crystalline sphere, a molecular memory containing a snapshot of everything Orlando had been.

“What now? How many do you have left?”

Yatima stared at the snapshot, dazed. Ve had violated Orlando’s autonomy. Like a lightning bolt, like a blast of ultraviolet, ve had ruptured someone else’s skin.

“How many?”

Yatima replied, “Fourteen.”

“Then we’d better go use them while we can.”

Inoshiro led ver out of the ruins. Yatima shot everyone they came across who looked close to death, and had no one to care for them—reading the snapshots immediately, piping the data in IR into vis gleisner’s memory. They’d taken twelve more bridgers when a mob led by the border guards found them.

They started cutting up Yatima first. Ve passed the snapshot data to Inoshiro, then followed.

Before they’d finished destroying vis old body, the link to Konishi returned. The drones had survived the storm.

6. DIVERGENCE

Konishi polis, Earth

24 667 272 518 451 CST

10 December 3015, 3:21:55.605 UT

Yatima looked down on the Earth through the window of the observation bay. The surface wasn’t entirely obscured by NOx, but most of it appeared in barely distinguishable shades of muted, rust-tinged gray. Only the clouds and the ice caps stood out, back-lighting the stratosphere impartially to reveal it as a vivid reddish-brown. Spread over the clouds, spread over the snow, it looked like decaying blood mixed with acid and excrement: tainted, corrosive, rotten. The wound left by Lacerta’s one swift, violent incision had festered for almost twenty years.

Ve and Inoshiro had constructed this scape together, an orbital way station where refugees could wake to a view of the world they’d left behind as surely as if they’d physically ascended beyond its acid snow and its blinding sky; in reality, they were a hundred meters underground in the middle of a wasteland, but there was no point confronting them with that claustrophobic and irrelevant fact. Now the station was deserted; the last refugees had moved on, and there’d be no more. Famine had taken the last surviving enclaves, but even if they’d hung on for a few more years, plankton and land vegetation were dying so rapidly that the planet would soon be fatally starved of oxygen. The age of flesh was over.

There’d been talk of returning, designing a robust new biosphere from the safety of the polises and then synthesizing it, molecule by molecule, species by species. Maybe that would happen, though support for the idea was already waning. It was one thing to endure hardship in order to go on living in a familiar form, another to he reincarnated in an alien body in an alien world, for the sake of nothing but the philosophy of embodiment. The easiest way by far for the refugees to re-create the lives they’d once led was to remain in the polises and simulate their lost world, and Yatima suspected that in the end most would discover that they valued familiarity far more than any abstract distinction between real and virtual flesh.

Inoshiro arrived, looking calmer than ever. The final trips they’d made together had been grueling; Yatima could still see the emaciated fleshers they’d found in one underground shelter, covered in sores and parasites, delirious with hunger. They’d kissed their robot benefactors’ hands and feet, then vomited up the nutrient drink which should have healed their ulcerated stomach linings and passed straight into their bloodstreams. Inoshiro had taken that kind of thing badly, but in the last weeks of the evacuation ve’d become almost placid, perhaps because ve’d realized that the horror was coming to an end.

Yatima said, “Gabriel tells me there are plans in Carter-Zimmerman to follow the gleisners.” The gleisners had launched their first inhabited fleet of interstellar craft fifteen years before, sixty-three ships heading out to twenty-one different star systems.

Inoshiro looked bewildered. “Follow them? Why? What’s the point of making the same journey twice?”

Yatima wasn’t sure if this was a joke, or a genuine misunderstanding. “They’re not going to visit the same stars. They’ll launch a second wave of exploration, with different targets. And they’re not going to mess about with fusion drives like the gleisners. They’re going in style. They plan to build wormholes.”

Inoshiro’s face formed the gestalt for “impressed” with such uncharacteristic purity and emphasis that any inflection hinting at sarcasm would have been redundant.

“The technology might take several centuries to develop,” Yatima admitted. “But it will give them the edge in speed, in the long run. Quite apart from being a thousand times more elegant.”

Inoshiro shrugged, as if it was all of no consequence, and turned to contemplate the view.

Yatima was confused; ve’d expected Inoshiro to embrace the plan so enthusiastically that vis own cautious approval would seem positively apathetic. But if ve had to argue the case, so be it. “Something like Lac G-1 might not happen so close to Earth again for billions of years, but until we know why it happened, we’re only guessing. We can’t even be sure that other neutron star binaries will behave in the same way; we can’t assume that every other pair will fall together once they cross the same threshold. Lac G-1 might have been some kind of freakish accident that will never be repeated—or it might have been the best possible case, and every other binary might fall much sooner. We just don’t know.” The old meson jet hypothesis had proved short-lived; no sign of the jets blasting their way through the interstellar medium had ever shown up, and detailed simulations had finally established that color-polarized cores, although strictly possible, were extremely unlikely.

Inoshiro regarded the dying Earth calmly. “What harm could another Lacerta do, now? And what could anyone do to prevent it?”

“Then forget Lacerta, forget gamma-ray bursts! Twenty years ago, we thought the greatest risk to the Earth was an asteroid strike! We can’t be complacent just because we survived this, and the fleshers didn’t; Lacerta proves that we don’t know how the universe works—and it’s the things we don’t know that will kill us. Or do you think we’re safe in the polises forever?”

Inoshiro laughed softly. “No! In a few billion years, the sun will swell up and swallow the Earth. And no doubt we’ll flee to another star first… but there’ll always be a new threat hanging over us, known or unknown. The Big Crunch in the end, if nothing else.” Ve turned to Yatima, smiling. “So what priceless knowledge can Carter-Zimmerman bring back from the stars? The secret to surviving a hundred billion years, instead of ten billion?”

Yatima sent a tag to the scape; the window spun away from the Earth, then the motion-blurred star trails froze abruptly into a view of the constellation Lacerta. The black hole was undetectable at any wavelength, as quiescent in the region’s high vacuum as the neutron stars had been, but Yatima imagined a speck of distorted darkness midway between Hough 187 and 10 Lacertae. “How can you not want to understand this? It’s just reached across a hundred light years and left half a million people dead.”

“The gleisners already have a probe en route to the Lac G-1 remnant.”

“Which might tell us nothing. Black holes swallow their own history; we can’t count on finding anything there. We have to look further afield. Maybe there’s another, older species out there, who’ll know what triggered the collision. Or maybe we’ve just discovered the reason why there are no aliens crisscrossing the galaxy: gamma-ray bursts cut them all down before they have a hope of protecting themselves. If Lacerta had happened a thousand years ago, no one on Earth would have survived. But if we really are the only civilization capable of space travel, then we should be out there warning the others, protecting the others, not cowering beneath the surface—”

Yatima trailed off. Inoshiro was listening politely, but with a slight smile that left no doubt that ve was highly amused. Ve said, “We can’t save anyone, Yatima. We can’t help anyone.”

“No? What have you been doing for the last twenty years, then? Wasting your time?”

Inoshiro shook vis head, as if the question was absurd.

Yatima was bewildered. “You’re the one who kept dragging me out of the Mines, out into the world! And now Carter-Zimmerman are going out into the world to try to keep what happened to the fleshers from happening to us. If you don’t care about hypothetical alien civilizations, you must still care about the Coalition!”

Inoshiro said, “I feel great compassion for all conscious beings. But there’s nothing to be done. There will always be suffering. There will always be death.”

“Oh, will you listen to yourself? Always! Always! You sound like that phosphoric acid replicator you fried outside Atlanta!” Yatima turned away, trying to calm down. Ve knew that Inoshiro had felt the death of the fleshers more deeply than ve had. Maybe ve should have waited before raising the subject; maybe it seemed disrespectful to the dead to talk so soon about leaving the Earth behind.

It was too late now, though. Ve had to finish saying what ve’d come here to say.

“I’m migrating to Carter-Zimmerman. What they’re doing makes sense, and I want to be part of it.”

Inoshiro nodded blithely. “Then I wish you well.”

“That’s it? Good luck and bon voyage?” Yatima tried to read vis face, but Inoshiro just gazed back with a psychoblast’s innocence. “What’s happened to you? What have you done to yourself?”

Inoshiro smiled beatifically and held out vis hands. A white lotus flower blossomed from the center of each palm, both emitting identical reference tags. Yatima hesitated, then followed their scent.

It was an old outlook, buried in the Ashton-Laval library, copied nine centuries before from one of the ancient memetic replicators that had infested the fleshers. It imposed a hermetically sealed package of beliefs about the nature of the self, and the futility of striving… including explicit renunciations of every mode of reasoning able to illuminate the core beliefs’ failings.

Analysis with a standard tool confirmed that the outlook was universally self-affirming. Once you ran it. you could not change your mind. Once you ran it, you could not be talked out of it. Yatima said numbly, “You were smarter than that. Stronger than that.” But when Inoshiro was wounded by Lacerta, what hadn’t ve done that might have made a difference? That might have spared ver the need for the kind of anesthetic that dissolved everything ve’d once been?

Inoshiro laughed. “So what am I now? Wise enough to be weak? Or strong enough to be foolish?”

“What you are now—“ Ve couldn’t say it.

What you are now is not Inoshiro.

Yatima stood motionless beside ver, sick with grief, angry and helpless. Ve was not in the fleshers’ world anymore; there was no nanoware bullet ve could fire into this imaginary body. Inoshiro had made vis choice, destroying vis old self and creating a new one to follow the ancient meme’s dictates, and no one else had the right to question this, let alone the power to reverse it.

Yatima reached out to the scape and crumpled the satellite into a twisted ball of metal floating between them, leaving nothing but the Earth and the stars. Then ve reached out again and grabbed the sky, inverting it and compressing it into a luminous sphere sitting in vis hand.

“You can still leave Konishi.” Yatima made the sphere emit the address of the portal to Carter-Zimmerman, and held it out to Inoshiro. “Whatever you’ve done, you still have that choice.”

Inoshiro said gently, “It’s not for me, Orphan. I wish you well, but I’ve seen enough.”

Ve vanished.

Yatima floated in the darkness for a long time, mourning Lacerta’s last victim.

Then ve sent the handful of stars speeding away across the emptiness of space, and followed them.

The conceptory observed the orphan moving through the portal, leaving Konishi polis behind. With access to public data, it knew of the orphan’s recent experiences; it also knew that another Konishi citizen had shared them, and had not made the same choice. The conceptory wasn’t interested in scattering Konishi shapers far and wide, like replicating genes; its goal was the efficient use of polis resources for the enrichment of the polis itself.

There was no way to prove causality, no way to he certain that any of the orphan’s mutant shapers really were to blame. But the conceptory was programmed to err on the side of caution. It marked the old, unmutated values for the orphan’s altered fields as the only valid codes, discarding all alternatives as dangerous and wasteful, never to be tried again.