Incandescence

two hundred light years wide a billion stars sped along a complex tangle of orbits, and the deeper into this swarm you dived the more crowded and violent it became. To Rakesh, it brought to mind the image of a nest of furious ants caught in a steep subsidence, kept from falling into the depths only by the sheer energy of their motion.

At the bottom of the pit lay Goudal-e-Markaz: a black hole with the mass of three million suns, the one place from which you could fall no further. It wasn’t easy to reach this nadir: the hole’s zone of capture was barely fifty million kilometers wide, and it was rare for a star to lose so much of its angular momentum that it could execute a head-on dive into oblivion.

However, a bull’s-eye hit was not the only route to destruction. Once every hundred millennia or so a star would come close enough to Goudal-e-Markaz for tidal forces to disrupt it catastrophically. As it dived toward the hole, the star would be stretched along its orbit at the same time as it was squeezed in the orthogonal directions, a distended streak of nuclear fire growing ever hotter and more compressed. In some encounters the star would merely be torn apart and the debris sprayed across a range of orbits, but if the tidal compression was strong enough to trigger a burst of new fusion reactions, as the star swung away from the hole and the pressure was released it could explode with the force of a hundred supernovas. The remnants of these explosions could still be seen thousands of years later, tenuous but energetic shells of gas spreading out into the galactic nucleus.

Ordinary supernovas were even more common, of course, and the central cluster was littered with their remnants: white dwarfs, stellar mass black holes, and neutron stars. The Aloof’s map showed no less than fifteen million neutron stars. That was a daunting census, and the chaotic dynamics of the region made it impossible to rule out more than a few per cent as potential culprits in the death of the Arkmakers’ world.

Standing in the control room of Lahl’s Promise, looking out into the blaze of stars that hid their quarry, Rakesh asked Parantham, “Would you be willing to visit fifteen million neutron stars, one by one, until we found a living Ark?”

She replied without hesitation, “Absolutely.”

For a moment Rakesh considered calling her bluff, but he was sure his own will would crack long before hers. When the creators of de novos chose their traits, they were prone to excesses that rarely appeared in even the most technologically augmented versions of inheritance. No gene for keenness could ever compete with Parantham’s fiat-driven personality.

He said, “I think it’s time we built a decent telescope.”

She nodded assent, without betraying the slightest hint of relief that he hadn’t been serious about inspecting each candidate in person. “Where?”

“Here would be as good a place as any,” Rakesh suggested. “At least there’s plenty of raw material.” They could try to select an observation point even closer to the galactic center, but their chances of finding a closer star that still clung on to a substantial asteroid belt weren’t good.

“That’s fitting,” Parantham said. “To use a little of the Arkmakers’ world, in order to find their new home. I don’t think they’d begrudge us that.”

Rakesh felt his now habitual twinge of discomfort, at the thought that they might be risking an act of desecration. But there seemed to be nobody around to be offended, apart from the Aloof, who he was sure were looking over their shoulders constantly, ready to veto any unacceptable behavior.

From this distance, a six-hundred-meter Ark somewhere in the central cluster would in principle be resolvable with an optical telescope four million kilometers wide, but to obtain a clear spectrum that would unambiguously identify the wall material it would be prudent to aim a bit higher.

“Ten million kilometers?” he suggested.

“That sounds about right.”

Rakesh plucked some standard designs from the library and tweaked them for their specific goals and the local conditions. They could mine the rubble of the Arkmakers’ world for the raw materials, then stream the refined feedstock into an orbit clear of dust and micrometeors, where the mirror segments would be constructed. With sunlight and the stellar winds as their main energy sources the project would proceed at a leisurely pace, taking more than a year to complete. Still, that was nothing to the time they’d already spent in transit within the bulge, let alone the time it would have taken to hop from neutron star to neutron star.

Rakesh initiated the process, sending twelve delivery modules into the asteroid belt to sow the rocks with engineering spores.

“No veto from the Aloof,” he noted. “They won’t allow spores in from the outside, but they don’t mind us spreading these ones around.”

“Which either means that they trust us,” Parantham replied—making it clear from her tone what she thought of that proposition—“or they’re watching us so closely that they know exactly what these spores will and won’t do.”

Rakesh mused, “What if we tried to build a node here? Conforming to the Amalgam’s standards? We’d have our very own short cut through the bulge.”

Parantham responded cautiously, “I’d say we’re too far from the edge to establish a reliable link with the Amalgam’s network.”

“Perhaps,” Rakesh conceded. “That’s not the point, though. What if we tried it?”

Parantham said, “I think the moment we so much as formed a serious intention to contravene the rules they’ve spent the last million years enforcing, our hosts would turn our bodies into dust and feed it to Goudal-e- Markaz. We’re here on their sufferance. We shouldn’t even think about pushing our luck.” She smiled. “Do you dream, Rakesh?”

“Yes.”

“Then draw up a list of topics for your dream censor. We wouldn’t want the Aloof getting the wrong idea.”

Rakesh followed one of the mirror spiders, hovering beside it as it drank from the feedstock streaming down from the asteroid belt. Though the milky flow resembled a liquid, it was actually composed of tiny granules, each one consisting of a core of volatiles wrapped in a distinctive mineral shell that both protected it and labeled its contents. The spider’s acute vision and nimble mouthparts allowed it to extract exactly what it needed, leaving the rest for other users further downstream.

Once the sac of its belly was full, the spider launched itself back toward its web with a barely visible burst of ions. It had already constructed a rigid, skeletal frame for the mirror segment it was building. Each segment was a kilometer wide, but even when the planned ten billion segments were completed they would only fill one ten- thousandth of the eighty trillion square kilometers spanned by the telescope’s total width. Seen as a whole, the mirror would be mostly empty space, but the individual segments lost none of their light-gathering power by being spread out like this, and it increased the resolution of the instrument by a factor of a hundred.

The spider started at the rim of the frame and began secreting a glistening polymer film, more like a metallic-looking tape than a silken thread. Mobile electrons in the polymer made it as reflective as silver, but it was lighter and stronger than any metal. The precise molecular structure of the polymer was being constantly tweaked as it was synthesized, tailoring the natural curvature of the film to fit the parabolic shape of the mirror to within a fraction of a wavelength.

The frame was rotating, so the spider only had to inch its way slowly toward the center, depositing the film in a tightly wound spiral while the growing mirror turned beneath it. Rakesh watched patiently as the annular strip finally reached a sufficient size for him to glimpse the blaze of the central cluster reflected back at him, a view so sharp that it looked more like some kind of rift in space than a mere reflection.

When this segment was completed and moved into position, an array of precision accelerometers measuring the phase difference between counter-rotating superconducting currents would track its orientation, and a faint breath of ions from its attitude thrusters would keep it perfectly aligned. The insect-eyed instrument package that sat at the telescope’s focus was already complete, and undergoing testing and calibration. Once a million or so of the ten billion segments were in place, some worthwhile data collection could take place, albeit far more slowly than it would when the full light-collecting area was brought into play. At that point, the telescope would be imaging the accretion disks of thousands of neutron stars simultaneously, hunting for the telltale spectrum of an Ark’s synthetic walls.

Probes had scoured the rubble-strewn center of the sole Ark that remained in this system, but had found neither artefacts nor the mummified remains of its original inhabitants. Though the higher tiers of the wind-fed ecosystem had probably collapsed quite quickly, there was a sufficient population of microbes even now to make