"Diaspora" - читать интересную книгу автора (Иган Грег)

14. Embedded

Carter-Zimmerman polis, Swift orbit

85 801 737 882 747 CST

18 March 4953, 23:17:59.901 UT

Yatima had arranged to meet Orlando in a scape of Lilliput Base, a twenty-meter dome full of scientific instruments located on an equatorial plateau, far from the temperate lowlands where the oases formed. The dome and everything in it had been built by conventional nanomachines, but the raw materials would have been impossible to obtain in situ without far more sophisticated technology. A former Star Puppy called Enif, who’d switched outlooks upon reaching 51 Pegasus and taken up nuclear physics with a vengeance, had succeeded in constructing the first femtomachines about a century before C-Z Voltaire’s arrival. Using the loosely-bound neutrons of halo nuclei in a manner analogous to the electron clouds of a normal atom, he’d managed to build "molecules" five orders of magnitude smaller than those with electron bonds, and then worked his way up to femtomachines able to ferry neutrons and protons to and from individual nuclei, holding the necessary increments of binding energy as deformations in their own structure. The invention had turned out to be priceless on Swift; not only were the normal, light isotopes of the five transmuted elements essential for some experiments, many other elements were rare on the planet’s surface in any form.

They’d had to wait two days for a bay to become free. Yatima entered the scape just as the previous apparatus, designed to search for traces of oxygen-16 in ancient mineral grains, was dissolving back into reservoirs of its constituent elements. Scaled at one centimeter to a delta, the meter-square hay looked big enough for any conceivable experiment, but in fact it was going to be a tight fit. Yatima had found plans for a neutron phase-shift analyzer in the library, designed by Michael Sinclair no less, a former student of Renata Kozuch. When Blanca’s proposed extensions to Kozuch Theory had reached Earth, most physicists had simply dismissed the new model as metaphysical nonsense, but Sinclair had scrutinized it carefully, hoping to devise an experimental test that would go beyond its success in explaining, after the fact, the length of the Forge’s traversable wormholes.

Orlando appeared. The scape software didn’t seem to know quite what to do with his exhalations; the Lilliput dome was maintained at high vacuum, and at first a faint cloud of ice crystals materialized and fell in front of him as his breath expanded and cooled, but after a moment some subsystem changed its mind and starred magicking the apparent contamination out of existence as soon as it left his mouth.

After raising a lattice of scaffolding, the bay’s nanomachines began work on the analyzer, drawing threads of barium, copper, and ytterbium from the reservoirs and spinning them into delicate gray coils of superconducting wire for the magnetic beam splitter—an odd name for the component, when the "beans" in this case would consist of a single neutron. Orlando regarded their handiwork dubiously. "You really think the Transmuters were relying on someone doing an experiment as subtle as this?"

Yatima shrugged. "What’s subtle? The shift between the spectrum of deuterium and hydrogen is a few parts in ten thousand, but we can’t imagine anyone missing it."

Orlando said dryly, "Deuterium at six thousand times the normal abundance isn’t subtle. Water vapor weighing twenty percent extra isn’t subtle. But particles that behave exactly like neutrons until you split them into two quantum states, rotate one by more than 720 degrees, then recombine them to check their relative phase? Somehow I think that might qualify."

"Maybe. But the Transmuters didn’t have much choice; you can’t make neutrons twenty percent heavier. All they could do was wrap them in other layers that would draw attention to them. What makes Swift special? The heavy isotopes in the atmosphere. What makes those isotopes special? The extra neutrons they contain. What makes those neutrons special? There’s only one thing you can change about a neutron, without turning it into something else entirely. The length of the wormhole."

Orlando seemed about to object, but then he raised his hands in a gesture of resignation. There was no point arguing; they’d soon have an answer, one way or the other.

In Blanca’s extension of Kozuch Theory, as in the traditional version, most elementary particle wormholes were as short as they were narrow; the two mouths, the two particles, shared the same microscopic 6-sphere. That was the most probable state for a wormhole created out of the vacuum, and unlike traversable wormholes they weren’t free to adjust their length once they were formed. But there was no theoretical reason why longer ones couldn’t exist: chains of short ones joined end-to-end, a string of linked microspheres looping out into the extra six macroscopic dimensions. Once created, they’d be stable; it was just a matter of knowing how to make them in the first place. Ordinary splicing methods—brute-force collisions—simply merged the two microspheres into one.

Sinclair had tested a few trillion electrons, protons, and neutrons, and found no long ones at all, but that didn’t prove that they were physically impossible, it merely confirmed that they were naturally rare. And if the Transmuters had wished to leave behind a single, enduring scientific legacy, Yatima could think of no better choice. Long neutrons had the potential to illuminate a fundamental question that might otherwise take an infant civilization millennia to resolve. Locked up in stable isotopes on a planet orbiting a slow-burning sun, they’d remain accessible for thirty or forty billion years. It was even possible that they’d shed some light on the diametrically opposite problem to their own creation: keeping traversable wormholes short, the secret to bridging the galaxy.

The nanomachines moved on from the beam splitter to a second set of coils, designed to rotate one quantum state of the neutron when it traveled simultaneously down two alternative paths. At first glance, there was no obvious way to tell a long particle from a short one; neither possessed a traversable wormhole, so you couldn’t send a signal through and time it. But Sinclair had realized that the usual classification of particles into fermions and bosons became slightly more complex when long particles were allowed. The classical properties of a fermion were having a spin of half a unit, obeying the Pauli exclusion principle (which kept all the electrons in an atom, and neutrons and protons in a nucleus, from falling together into the same, lowest-energy state), and responding to a 360-degree rotation by slipping 180 degrees out of phase with its unrotated version. A fermion needed two full rotations, 720 degrees, to come back into phase. Bosons needed only one rotation to end up exactly as they began.

Any long particle made up of an odd number of individual fermions would retain the first two fermionic properties, but if it also included any bosons, their presence would show up in the pattern of phase changes when the particle was rotated. A long particle with a wormhole sequence of "fermion-boson-fermion-fermion" would go out of phase and back like a simple fermion after one and two rotations, but a third rotation would bring it back into phase again immediately. Successive rotations could probe the wormhole’s structure at ever greater depths: for each individual fermion in the chain it would take two rotations to restore the particle’s phase, while for each boson it would take just one. As Orlando had put it—groping for a three-dimensional analogy when Yatima had started spouting group theory and topology—it was like sliding down into the particle’s wormhole on the banister of a spiral staircase. Sometimes after going full circle, a twist in the banister left you upside down, so you had to go round once more before the staircase appeared right—way up again. Other times, a single turn left everything looking normal.

As the nanomachines put the finishing touched the apparatus, wiring the neutron source and detectors to the bays data link, Yatima thought of contacting Blanca. But the one time they’d met, the Voltaire clone had shown no interest whatsoever in vis dead Fomalhaut-self’s ideas. Blanca had declined, everywhere, to rush the flesher equivalent—the de facto post-arrival standard adopted throughout the Diaspora—and as a consequence ve’d become rather isolated. Sinclair might have liked to witness the experiment, but he’d have to wait 82 years; he hadn’t taken part in the Diaspora at all.

Yatima gestured at a switch on the side of the neutron source; it was just a scape object grafted onto their view of the machine, but throwing it would transmit the signal down to Lilliput to cycle the first neutron through. "Do you want to do the honors?"

Orlando hesitated. "I’m still not sure what I’m hoping for. Exotic physics from the Transmuters… or the entertainment value of seeing you try to squirm out of this if you’re wrong."

Yatima smiled serenely. "The wonderful thing about hope is that it has absolutely no effect on anything. Just throw the switch."

Orlando stepped forward and did it. The display screen beside it—another scape object—was instantly filled with symbols scrolling past in an unreadable blur. Yatima had been expecting a short pattern, recurring after five or six rotations at most—or if the neutrons were sadly normal, just two. A few segments would have been enough to prove the point, but maybe the Transmuters had had no control over the total length.

Orlando said, "Is this equipment failure, or wild success?"

"Wild success, I hope."

Yatima sent the screen gestalt instructions to rewind. The start of the data showed the neutron slipping in and out of phase with repeated rotations:

-++-+--+-+-+-+-+-+++++…

Directly below was the interpretation: FbFFbbFFFbbbFFFFbbbb…

Orlando read aloud, "Fermion, boson, fermion, fermion, boson, boson…"

Yatima said, "It’s not a hoax, I swear."

"I believe you." The counting went up to 126, then the pattern stopped and something far less decipherable took over. Orlando looked almost fearful. "It’s a message. They’ve left us a message."

"We don’t know that."

"It could be the equivalent of their whole polis library. Tied on a single neutron wormhole, like knots on a string." He was beaming unsteadily now; Yatima wondered if his embodiment software would let him pass out from shock.

"Or it might just be proof of artificiality. An improbable sequence, so no one mistakes this for a natural phenomenon and screws up their physics trying to explain it that way. Don’t jump to conclusions."

Orlando nodded, and wiped his forehead with his palm. He gestured at the screen to scroll forward to the latest data; the torrent continued, but it was visibly slower. Each test for a different number of rotations had to he performed several times to get reliable statistics and after a billion rotations and an interference measurement, you couldn’t just rotate the neutron one more time for test one-billion-and-one, you had to start again from scratch.

They waited for the pattern to recur. After twenty-two minutes, the neutron decayed without repeating itself. In theory, the resulting proton should have retained the same hidden structure, but Yatima hadn’t made any provision to capture it, and the whole machine would have had to he rebuilt to handle a charged particle.

Ve instructed the analyzer to shift to a much higher rotation frequency. The second neutron rapidly yielded exactly the same sequence as the first, and survived long enough to start repeating, after six times ten-to-the-eighteenth segments. Six exabytes of data wasn’t exactly a polis library, but it left room for a lot more than a maker’s imprint or some idle subatomic graffiti.

The screen translated the sequence into Orlando’s stylized spiral staircase, a twisted ribbon reminiscent of DNA, but far longer than any genome or mind seed. Until this moment, Yatima had never really felt the hand of an alien civilization here; the isotope signature was unambiguous, but too amorphous to convey anything more than its own artificiality. They’d found no ruins, no monuments, no shards—and it was impossible to say whether the oasis life had been the Transmuters' biological cousins, their artificial pets, or just an accident with no connection to them at all. But now the planet was revealed to be dense with artifacts older than any skyscraper or pyramid, richer than any papyrus or optical disk. And every picogram of atmospheric carbon dioxide held three hundred billion of them.

Ve turned to Orlando. "Do we spread the news now, or try for an interpretation first?" The library was bursting with pattern analysis software, three millennia’s worth of attempts to he prepared for this moment. People had already run most of it on various Swift genomes, looking for hidden messages without success.

Orlando managed a conspiratorial grin. "It’s not like breaking into a tomb. We can’t damage this just by looking at it."

Yatima jumped to the xenolinguistics indexscape, a room full of display cases holding mock Rosetta stones, fragile scrolls and manuscripts, and quaint electromechanical code-breaking machines. Ve built a pipeline from the store of neutron data to a string of these analysis programs. Orlando had followed ver, and they stood in the carpeted room watching silently as a swarm of blue-white fireflies, representing the data, moved from icon to icon.

The twelfth icon in the chain was an ancient cathode ray tube display, representing an absurdly naive program that Yatima had only included because it would take so little time to run. The instant the fireflies alighted on its bakelite case, the screen burst into life.

The image began with a single, short vertical line, then zoomed out slowly to reveal dozens, then hundreds, of similar lines. Yatima didn’t recognize the pattern, but the software had: the bottom end points of the lines marked the positions of stars—Voltaire and its backdrop from a certain angle, about fifty million years ago. Oddly enough, it wasn’t a perspective view but an orthogonal projection. Did that say something about the Transmuters' perceptual system? Yatima caught verself; maps of the Earth had been made looking like everything from flattened orange peel to a reflection of the planet in a giant distorting mirror. None of them revealed a thing about fleshers' ordinary vision.

Orlando exhaled heavily. "Pixel arrays? It’s that simple?" He sounded almost disappointed, but then he laughed, elated. "Good old two-dimensional images, changing with time! How’s that for an antidote to abstractionism?" After a moment he added, "Even if it is just a fragment of the data." Yatima was receiving gestalt tags broadcast by the cathode-ray tube icon, packed with supplementary information, but Orlando was tortuously reading the same things in linear text from a translation window pasted into the scape by his exoself.

From the motion of the stars, the time between each frame was determined to he about 200 years; the software displayed 50 frames, 10,000 years, per tau. The whole view was heavily stylized, and the image was binary: not even a gray scale, just black and white. But the software had concluded that the vertical lines attached to each star were a kind of luminosity scale, giving the distance at which the energy density of the star’s radiation fell to 61 femtojoules per cubic meter, coincidentally or not, the same as the cosmic microwave background. For Voltaire, this distance was about one eighteenth of a light year; for the sun, about one seventh. The orthogonal projection enabled the "luminosity lines" for a few hundred stars to be visible simultaneously, all at the same scale; a realistic perspective from anywhere in the galaxy would have shown all but a few diminished by distance to the point of invisibility, making the intended meaning much more obscure. As the view continued to expand, though, all the stars' lines were soon reduced to identical, single-pixel specks anyway. Yatima was puzzled, but reserved judgment.

When the whole Milky Way was visible, not quite edge-on, the zoom-out stopped. Then a short vertical line appeared suddenly: twelve hundred light years long, pointing up from the plane of the galactic disk, vanishing after just one frame. Yatima had been wondering how the map would portray sources of radiation that shone for less than 200 years; the simplest method would be to match their total energy to an ordinary star’s output over two centuries. On that basis, a twelve-hundred-lightyear luminosity line corresponded to a burst of radiation comparable to the output of the sun over fourteen billion years. The kind of burst produced by two colliding neutron stars.

Neutrons to warn of neutron stars? Was that another level of the isotopes' multilayered meaning?

Every two or three hundred thousand years, another burst appeared somewhere in the galaxy. Smaller lines flashed up more frequently, most of them probably supernovae; a few corresponded to known remnants. Orlando asked soberly, "So is this history, or prediction?"

"Well, from the pattern of heavy isotopes in the crust, it looks like the Transmuters processed the atmosphere at least a billion years ago." So if their predictions of these events in their far future were accurate, it would prove that they’d understood the dynamics of neutron star binaries far better than C-Z or gleisner astronomers. It was impossible to judge their record on these ancient bursts, predating even flesher gamma-ray astronomy, but if it turned out that they’d correctly anticipated the time of Lac G-1’s collision, they’d have shown themselves to be extraordinarily trustworthy forecasters.

Yatima glanced at Orlando, his eyes locked on the screen. The Transmuters could promise him a flesher’s eternity without another Lacerta. They could guarantee a safe return to Earth, and everything he’d once valued.

Around 100,000 years before the present, the scale began to change again. Yatima watched uneasily as the Andromeda galaxy, the whole Local Group, and then ever more distant galactic clusters came into view. Then at 26,000 BP a line appeared, almost two billion light years long, skewering the tiny Milky Way.

The image zoomed back in rapidly, just in time to show a gamma-ray burst at 2000 BP: Lac G-1. The Transmuters had correctly predicted the time of the burst to the nearest 200-year frame, and its position and energy to the nearest pixel.

Orlando remained silent as the map ran on for another twenty million years. In all that time, it showed no more gamma-ray bursts near enough to Earth to harm the biosphere.

But if the map’s predictions were all equally reliable, then 26,000 years ago there’d been an event in the galactic core that rendered every ordinary burst irrelevant. In a thousand more years, the consequences would finally sweep through the region—and even if the Diaspora, the gleisners, and the Earth-based polises began to flee at once, when the pulse of radiation finally washed over them it would be thirty million times more intense than Lacerta.

Paolo said firmly, "It’s not possible. You’d need six or seven billion solar masses undergoing gravitational collapse to release that much energy."

Yatima had asked to meet him to talk about Orlando, not to debate the meaning of the neutron data for the thousandth time. But Paolo seemed determined to dispose of the core burst itself before he’d listen to a word on any other subject, and maybe that was fair enough. Belief or disbelief in the event formed the ground beneath everything else, now.

"The galactic core contains more than enough mass, depending on where you draw the boundary."

"Yes, but those stars are all in orbit. They’re not about to fall together into a giant black hole."

Yatima laughed humorlessly. "Lac G-1’s neutron stars were in orbit, too. They weren’t supposed to fall together for another seven million years. So I wouldn’t stake my life on conservation of angular momentum until I found out where it all went with Lacerta."

Paolo shrugged dismissively. The burden of proof wasn’t his. Even if it was being read correctly, the Transmuters' message wasn’t necessarily honest; even if it was honestly intended, that didn’t mean it was infallibly true. And the failure to explain Lacerta hardly meant that conservation laws could be discarded at will. If it had been a purely theoretical argument, Yatima would have happily conceded every point.

Ve glanced around the Heart, trying to gauge the mood. People were talking quietly in small groups, edgy and subdued, but far from despairing. Since the neutron data had been released, Yatima had seen as wide a spectrum of responses in Voltaire C-Z as ve’d witnessed among the fleshers when they’d heard about Lacerta. Many citizens had simply refused to accept that the core burst was a real possibility—and a few had succumbed to paranoid fantasies to rival any flesher’s, declaring that the Transmuters' message had been planted in order to induce a state of panic and decay among "rival" civilizations. Others were searching for ways to survive the event. Arranging to be in the shadow of a planet could shield the polises from gamma rays, but the neutrino flux would be unavoidable, and intense enough to damage even the most robust molecular structures. The most plausible scheme Yatima had heard so far involved encoding every polis’s data as a pattern of deep trenches on a planetary surface, and then building a vast army of non-sentient robots on a variety of scales, from nanoware up, so numerous that there was a chance that the relatively few survivors would he capable of reconstructing the polis.

"Suppose this burst really is on its way, and the message is a warning." Paolo settled back in his chair, and regarded Yatima amiably. "Then having gone to the trouble of creating a whole planet’s worth of coded neutrons out of the goodness of their hearts, why didn’t the Transmuters leave us something more than the unpalatable facts? A few survival tips might have come in handy."

"Don’t give up on the rest of the data yet; it might contain all kinds of things. Preferably instructions for shortening traversable wormholes. Failing that, a reliable technique for sealing and reopening their mouths; then we could hide inside one as a stream of nanomachines until the burst is over."

Contemplating that scenario gave Yatima severe claustrophobia, but Gabriel had gone even further and suggested that the undeciphered bulk of the neutron data might be the Transmuters themselves: digital snapshots entombed in the particles in the hope that post core-burst life, once such a thing evolved, would stumble upon them and obligingly restore them to active existence. If that was the case, they’d left no obvious clues for anyone aspiring to join them in their sanctuary—and if they’d known about the burst a billion years ago, it seemed far more likely that they’d set off for another galaxy, whether by wormhole or by more conventional means.

Paolo said, "So you think they used a straightforward pixel array for the warning, but then switched to some diabolical encryption technique for all the helpful advice? Why? A little winnowing of the species, maybe?"

Yatima shook vis head and answered plainly, ignoring the sarcasm. "Everything they’ve done has seemed bizarre or ambiguous at first—and then obvious and transparent once we’ve made sense of it. I don’t believe any of it’s been willfully obscure. And I don’t believe their minds were so different from ours that we’re in danger of wildly misinterpreting anything that looks like a simple message. So far, the worst mistake we could have made would have been to give up too soon on trying to interpret the isotopes.

"But they couldn’t have avoided making a few assumptions about the way we’d think, and the kind of technology we’d be using—and some of those assumptions are bound to be wrong. I can easily imagine a space-faring civilization that wouldn’t have tried the neutron phase experiment in a million years. So maybe the meaning of the rest of the data will be inaccessible to us… but if it is, that won’t be out of malice, and it won’t be because their whole conceptual framework was beyond our comprehension. It will just be sheer bad luck."

Paulo gave up his smirk of tolerant amusement, as if reluctantly conceding that this was an appealing vision of the Transmuters, however naive. Yatima seized the moment.

"And whatever you think about the map yourself, just remember that Orlando can’t dismiss it the way you can. Everything about this drags him back to Lacerta."

"I know that." He regarded Yatima irritably. "But the fact that it brings back painful memories doesn’t make him right."

"No." Yatima steeled verself, and pressed on. "All I’m saying is, if he asks you to take steps to make yourself safe—"

"I’m not going to humor him." Paolo laughed indignantly. "And I don’t need some ex-Konishi solipsist to tell me about the traumas of carnevale."

"No?" Yatima scrutinized his face. "Maybe your mental architecture’s closer to his, but you act like you have no idea what he’s been through."

Paolo averted his eyes. "I know about Liana. But what could he have done? Forced her to use the Introdus? They both made the same decision. It wasn’t his fault." He looked up defiantly. "And saving me from the core burst won’t bring her back."

"No. It might not hurt Orlando, though."

After a while, Paolo said sullenly, "I could live with wasting a thousand years coding myself into some planet’s topography, while being ridiculed by every sane person in the Diaspora. But if I start giving in to him, where does it end? If he thinks I’m migrating back to the flesh with him afterward—"

Yatima laughed. "Don’t worry, he doesn’t. And once he has lots of little flesher children, he’ll probably disown you altogether. Write you off as an unfortunate mistake. You’ll never hear from him again."

Paolo looked uncertain, then openly wounded.

Yatima said, "That was a joke."

Blanca floated in a tranquil ocean made up of distinct layers of pastel-colored fluids, each about a quarter of a delta deep, separated by sheets of opaque blue colloid. The only light seemed to come from a diffuse and all-pervasive bioluminescence. As Yatima swam across the scape toward ver, ve wondered whether ve should ask politely about this strange world’s physics before pressing ver to explain the cryptic invitation.

"Hello Orphan." As Yatima’s viewpoint moved from layer to layer, the intersections of the colloid sheets with Blanca’s solid black absence looked like a diagram for a method of portraying a surface’s critical points as a sequence of curves. One rough ellipse through vis shoulders spawned two ovals on either side on the plane below; each of these split into five smaller ovals, which vanished just before the trunk’s ellipse fissioned. Unable to see the whole icon at once, Yatima found Blanca’s gestalt almost unreadable. "It’s been a while."

"More for you than me. How are you?" This clone had become estranged from Gabriel soon after arrival, and as far as Yatima knew, no one else had spoken to ver since vis own last visit.

Blanca ignored the question, or took it as rhetorical. "That was interesting data you sent me."

"I’m glad you had a look at it. Everyone else is stumped." Yatima had mailed ver a tag pointing to the neutron sequence, despite vis apparent lack of interest in Swift and the Transmuters; it seemed only right to let every clone of ver know that the Fomalhaut Blanca had been vindicated.

"It reminded me of Earth biochemistry."

"Really? In what way?" People had tried interpreting the data beyond the pixel array as a Swiftian genome, but Yatima doubted that even the quirkiest old SETI software would have attempted anything as absurd as a reading based on the DNA code.

"Just some rough analogies with protein folding. Both turned out to be specific examples of a much more general problem in N dimensions… but I won’t bore you with that." Blanca made a series of holes in the colloid sheets in front of ver, creating a transparent void, a sphere about two delta wide. Ve thrust vis hands into this arena, and a tangled structure appeared between them, like an intricately warped chain of heads. The structure was complex, but somehow not quite organic-looking. More like a nanomachine that someone had been forced to design from a single, linear molecule, shaped by nothing but the angles of the bonds between consecutive atoms.

Blanca said, "There was nothing to decipher, nothing to decode. You’ve read all the messages that were there to be read. The rest of the neutron sequence isn’t data at all; it’s there to control the shape of the wormhole."

"The shape? What difference does the shape make?"

"It enables it to act as a kind of catalyst."

Yatima was dazed, but part of ver was thinking: How stupid of me. Of course. The neutrons served as an attention grabbing beacon from a distance, then a warning message close-up; ve should have guessed that there was an entirely separate third function buried in the remaining structure. "What does it do? Make other long neutrons? They built just one, and it replicated itself all over the planet?"

Blanca spun the wormhole, but not in any visible dimension; it flexed oddly as the view rotated into other hyperplanes. "No. Think about it, Yatima. It can’t catalyze anything here. It has no shape in this universe, it’s just another neutron to us."

Ve extended the wormhole into a Kozuch diagram and began demonstrating some interactions with ordinary, short particles. "If you hit it with a neutrino, an antineutrino, an electron, or a positron, the effect propagates all the way along its length." Yatima watched, mesmerized; with each collision, even though the wormholes didn’t splice, the structure deformed in a distinctive way, like a protein switching between metastable conformations.

"Okay. We can change its shape. But what does that achieve?"

"It makes certain vacuum wormholes real. It creates a stream of particles."

"Creates them where?" The long neutron threaded its way through billions of adjacent universes, but since the wormhole didn’t open up into any of them, its presence barely registered. If it couldn’t catalyze anything here, it had even less chance of doing so in any universe it merely passed through.

Blanca sent gestalt instructions to the diagram, and suddenly the catalyst was threaded with dozens of tangled, translucent membranes. As each electron or neutrino struck, and the catalyst changed shape, one of these faintly sketched vacuum wormholes became two real wormhole mouths racing apart through the space in which the catalyst was embedded.

That space was the macrosphere. The long neutrons were machines for creating particles in the macrosphere.

Yatima performed an elated backflip through the layered ocean, and found verself upside down. "Let me kiss your feet. You’re a genius."

Blanca laughed, a remote sound from a hidden part of vis body. "It was a trivial problem. If you weren’t rushing like a flesher, you would have solved it yourself long ago.

Yatima shook vis head. "I doubt it." Ve hesitated. "So do you think the Transmuters could have—?"

"Migrated? Upward! Why not? It’s a closer escape route than heading for Andromeda."

Yatima tried to imagine it: a Diaspora into the macrosphere. "Wait. If our whole universe, our whole space-time, is the standard fiber for macrosphere physics, then our entire history only corresponds to an instant of macrosphere time. Their equivalent of a Planck moment. So how could the Transmuters create a sequence of particles, spread out in time?"

Blanca gestured at a portion of the catalyst. "Look more closely at this domain. Macrosphere space-time is woven out of vacuum wormholes, just like ours. It’s the same kind of Kozuch-Penrose network, only five-plus-one dimensions instead of three-plus-one." Yatima righted verself for a better view, and peered at the multi-lobed knot Blanca was pointing to; it seemed to hook into the ghostly structures of the vacuum like a grapple. "They’ve pinned our time to macrosphere time. What would have been a fleeting Planck moment endures as a kind of singularity. And that singularity can emit and absorb particles in macrosphere time."

Yatima’s mind was reeling. The Transmuters hadn’t indulged in any of the spectacular acts of astrophysical monument-building that a bored and powerful civilization might have gone in for: no planet-sculpting, no Dyson spheres, no black-hole juggling. But by tailoring a few neutrons on this obscure planet, they’d hitched the entire universe into synch with the time stream of an unimaginably larger structure.

"Wait. You said emit… and absorb? What happens if the singularity absorbs a macrosphere particle?"

"A small proportion of the catalysts change state. Which causes a small proportion of the long neutrons here to undergo beta decay, even if they’re in supposedly stable nuclei. If you monitored a ton of Swift’s atmosphere, you could detect absorption events with an efficiency of about one in ten billion." Yatima had positioned vis viewpoint in the same layer as Blanca’s head, and ve caught a characteristic tilt of amusement. "So it might be worth trying. The Transmuters' macrosphere clones could be blasting messages at the singularity even as we speak."

"After a billion years? I doubt it. But they might still be nearby; the originals would have fled the galaxy, but the clones would have had no special reason to travel far from the singularity. So if we went into the macrosphere ourselves, we might still have a good chance of finding them."

If they could make contact with the Transmuters, they’d have a chance to learn the reasons for both Lacerta and the core burst, helping to convince the skeptics to protect themselves. And if there was no other choice, anyone who was willing could hide in the macrosphere to escape the burst.

Yatima was beginning to feel a kind of vertigo. The Fomalhaut Blanca’s remote, hypothetical, six-dimensional universe of universes had suddenly become as real as the space of the Diaspora itself. As real, and perhaps accessible. For a space-faring civilization to step into the macrosphere was like a bacterium in a rain drop finding a way to stride across continents—and there was a vestigial ancestral temptation to respond to the scale and strangeness of this revelation with paralytic awe. Yatima struggled to concentrate on the practicalities.

"If we could work out macrosphere physics in enough detail, do you think we could cause the singularity to emit a stream of particles that coalesced into a functioning C-Z clone? Or maybe we could start with a cloud of raw materials, then create nanomachines to fabricate the polis?"

Blanca said, "You’re going to need something more like femtomachines, I think. Femtomachines larger than the universe. Do you want the laws of macrosphere physics?" Ve moved down through the scape a few layers, then reached into the blue colloid. As Yatima approached, Blanca opened vis dark palm to expose a single blue speck, which was radiating a gestalt tag.

"What is this?"

"Five spatial dimensions, one time. A 4-sphere as the standard fiber. Physics, chemistry, cosmology, the bulk properties of matter, interactions with radiation, some possible biologies… everything."

"When did you do this?"

"I’ve had a lot of time, Orphan. I’ve explored a lot of worlds." Ve spread vis arms to encompass the whole scape. "Every point you see is a different set of rules." Ve ran a hand below the blue sheer from which ve’d plucked the macrosphere rules, "These are six-dimensional space-times. Below is five. Notice how its thinner. But seven is thinner too. Even numbers of dimensions have richer possibilities."

The speck had escaped from Blanca’s hand and was drifting hack toward its place in the indexscape, but Yatima had memorized the tag.

"Will you come with me, Blanca? Into the macrosphere?"

Blanca laughed, swimming in worlds, drowning in possibilities.

"I don’t think so, Orphan. What would be the use? I’ve already seen it."