“Do you understand what these numbers mean, Kapur? I know you’ve hardly been off Earth before this assignment.” Mace wasn’t bothering to conceal his relaxed, malice-free contempt. In fact this was Kapur’s second such mission. The first had been a requisition to the failed Assimilation of the Khorte Colony.

He said, “Why iron?”

“Because iron is the most stable element. The Snowmen — the builders — wanted this to last a long time, Kapur.”

Kapur nodded. “Then was this a planet, once, before being spun out like a… fairy tale castle?”

“Maybe. Maybe not. When this was built, only a billion years after the Bang, there were scarcely any heavy elements to form planets. The Galaxy itself would have been no more than a disc of smoke, illuminated here and there by hot-spot protostars.” The gun-metal Eyes rotated to Kapur. “Kapur, you also need to understand that it’s not just the physical structure that’s important here. There are many levels beyond the material; even now that thing is an iron-wisp web of data, a cacophony of bits endlessly dancing against the depredations of entropy.”

Kapur smiled. “You use words well, Mace,” he said.

Mace seemed uninterested. He went on, “The Snowmen loaded everything they knew into this artifact. Eventually, they… went away.” He grinned at Kapur. “Maybe. Or maybe they’re still here.”

Kapur shivered; he grasped his own bony elbows. “And why, my friend? What do you think? Why did they build this marvelous sculpture of iron and data, slowly cooling?”

Mace still grinned. “It’s your job to find out, isn’t it?”

Kapur stared into the cold, waiting heart of the Snowflake.

He was not expected to succeed here.

Kapur had failed before.

He had watched the Khorte Colony, an ancient, hivelike accretion of crystalline carbon — diamond — fold in on itself, burn, die; perhaps one percent of the Colony’s stored knowledge had been saved amid the devastating beams.

Kapur’s mission was Assimilation. Humans would not let the Xeelee take anything they could not Assimilate.

Kapur wondered if this bright young Navy man had ever heard of the Khorte Colony.

The yacht tacked into the laser breeze, slowed, halted before one tetrahedral plane. Two men pushed through an air-curtain into space, bulbous and clumsy in cold-suits.

The faintest spurt of low-velocity helium pushed at Kapur’s back, propeling him towards the Snowflake. The fat, padded suit was snug and warm around him, like a blanket; he felt oddly safe, remote from the immensities around him. At the center of his visor Mace sailed ahead, arms and legs protruding comically from the bulk of his cold-suit.

They stopped a few thousand miles from the iron plane. The face swept to infinity all around Kapur like a vast geometrical diagram; the horizon was razor-sharp against the intergalactic darkness, the three vertices too distant to perceive as corners. His Eyes, set to human wavelengths, made out some detail in the ’Flake; it was like a gigantic engraving, glowing dully in the smoky light of the Galaxy.

Kapur felt small and helpless. He had four days left.

Mace’s commentary came to him along a laser path, helmet to helmet. “All right,” Mace said. “Here we are in our patent cold-suits; inside, as snug as bugs; outside, radiating heat at barely a fraction more than the background three K.”

As Kapur stared the Snowflake seemed to open out like a flower; he saw layer on layer of recursive detail, sketches of nested tetrahedra dwindling into the soft brown heart of the artifact. “It’s wonderful, Mace.”

“Yeah. And as delicate as wishes. Hey, Kapur. Give me your Eyes. I’ll show you the data.”

Kapur hesitated, gathering his resolve.

He hated using the implants. Each time he Opened his Eyes he felt a little more of his humanity leach away.

Now he breathed deeply. The air inside the cold-suit was warm and scented, oddly, of cut grass. With an odd, semi-hypnotic relinquishing of will, he deferred to Mace.

His Eyes Opened wide.

The Snowflake changed, kaleidoscopically.

“You’re seeing a construct from our passive probes,” Mace whispered. “False-color graphics of the data streams.”

Terabits of ancient wisdom hissed on whiskers of iron, sparking like neurons in some splayed-out brain. It was beautiful, Kapur thought; beautiful and monstrous, like the mind of the antique gods of mankind.

His soul recoiled. He sought refuge in detail, the comparatively mundane.

Kapur knew that the mission profile had been designed with caution in mind. The Spline ship had parked over an AU away; he and Mace had approached in a yacht riding a tight laser beam, eschewing chemical flame. “Mace, what would happen if we let stray heat get at the ’Flake? Would we disrupt the structure?”

“You mean the physical structure? Maybe, but that’s not the point, Kapur. It’s the data that’s the treasure here.”

“And would a little heat be so harmful?”

“It’s to do with thermodynamics. There’s a lower bound on how much energy it takes to store a bit. The limit is set by the three K background temperature of the Universe.”

“So the lower that global temperature is, the less energy a bit would take.”

“Right. And so if we raised the ’Flake’s temperature, even locally, we would risk wiping out terabits. Also, it follows from the thermodynamic limit that there’s an upper bound on how much data you can store with a given amount of energy — or, equivalently, mass. The upper limit for the Snowflake’s mass is around ten to power sixty-four bits. Kapur, we estimate that the ’Flake actually holds around ten to power sixty.”

Kapur stared into the flowerlike heart of the Snowflake. “I should be impressed?”

“Damn right,” Mace growled, “For a start, the whole of human civilization would be characterized by only ten to power twenty bits. Even after hundreds of Assimilations. And, just in technological terms, to get within four orders of magnitude of the theoretical limit… it’s almost unimaginable.

“Now. Look.” Mace, silhouetted like a cartoon grotesque, pointed at a knot of color and activity. Kapur perceived something like a sunflower, a fist of spirals and tessellations surrounded by “petals,” great sheets of information which faded into the background chatter. Pellets of data streaked into and out of the core — a little like insects, Kapur thought at first; but then he saw how the pellets embedded themselves in the sunflower, endlessly enriching and renewing it.

“What is it?”

“It seems to be the dominant data configuration,” Mace called. “The analogue of the tetrahedral motif on the physical level. It represents a theorem. See, the heart of the structure is the core statement, the petals corollaries, endlessly thrown off and lost…”

“What theorem?”

“Gödel’s Incompleteness. We think. We’re guessing, extrapolating on hints of structure we’ve picked up elsewhere… But it’s not really a theorem, here. It’s merely a statement of the result. Like an axiom; a given.”

“I don’t understand.”

Mace laughed, briefly and scornfully. Wriggling before the landscape of information he pointed again. Amid a meadow of data structures, Kapur picked out another sunflower, the characteristic Gödel shape. Mace jabbed both arms against the vast data diorama, again and again. “There, and there! What do you see, Kapur?”

Gödel, Kapur saw, repeated over and over; there was a fractal spiral of Gödel sunflowers here, embedded in this chill web of data.

“There’s more, of course,” Mace said. “We’ve recognized a lot of physical understanding in here, particularly representations of cosmic events. See that starburst?” A firework of red and yellow, endlessly dynamic, scattered a hundredfold through the ’Flake. “That’s Mach’s principle: that the inertia of an object is induced by the net gravitational attraction of the rest of the Universe—”