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:
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
