Incandescence

15

Rakesh was dreaming that he was a child on Shab-e-Noor, diving into a river with a group of friends, when Parantham appeared among them. She stood on the riverbank, smiling. “We’ve found an Ark,” she said.

“Is this real, or am I dreaming?” he asked.

“Both,” she replied.

His friends seemed troubled by the news. “Don’t worry,” he told them, “I’ll be back as soon as I’m finished with this.” A sense of panic was rising in his chest. Why couldn’t he remember any of these children’s names?

“If we let you come back,” one said darkly.

Rakesh woke. He had not imagined the claim about the Ark; the telescope’s report had entered his skull and the discovery had seeped into the dream’s scenario.

He walked to the control room. Parantham said, “I was about to wake you.”

“The news did that itself.”

“What do you think?”

Rakesh scanned the data. The neutron star where the Ark had been found was twenty light years from the galactic center. Even with ninety per cent of the telescope’s mirror in place the image of the find was just a tiny dark blur against the glow of the accretion disk. The spectrum was unmistakable, though; the object in question was made from the same material as the failed Ark that had been left behind.

This Ark would be immersed in powerful winds from the differences in orbital velocity across its length. In spite of the turmoil of its surroundings it had apparently managed to remain in place for fifty million years, kept from spiraling inward by a passive asymmetry in its structure that allowed it to gain energy from the wind if it ever sank too close to the neutron star. It was in precisely the environment for which it had been built. If its makers survived anywhere, surely it was here.

“Is there anything to keep us here?” he wondered. They had already built a communications link that would allow the telescope to convey any further discoveries to Lahl’s Promise; before departing they could aim it at their destination, and if they moved again from there they could leave a relay behind.

“Nothing I can think of,” Parantham replied.

Rakesh felt a twinge of anxiety. “What if this one’s empty, too?”

“Then we wait for the telescope to find another one.” Even if this neutron star had captured all of the successful Arks initially, that didn’t mean it had held on to them all. If there had been enough of them to start with—or if the Arkmakers had flourished in their new environment and found a way to build more—then viable Arks might have ended up orbiting several different neutron stars.

“And if it doesn’t find another one?”

Parantham walked up to him and put a hand on his cheek, an almost maternal gesture of tenderness mixed with exasperation. “Then our time here will be over. We’ll move on.” She took her hand away. “But it hasn’t come to that yet, so can you please stop fretting? Whatever this Ark contains will be fifty million years removed from its makers, so I’m not offering any bets about the nature of its inhabitants. But even fifty million years of energy starvation didn’t finish off the other one completely. We’ve already faced the worst-case scenario. We’ve seen the desert; now we’re heading for an oasis.”

When their hosts rebuilt and woke them at their destination, the sky had turned from dazzling salt to luminous milk. Fifty times more crowded than before, it had lost every perceptible trace of black. The closer stars still outshone the bright backdrop formed by the crowd behind them, but the contrast was greatly diminished. Night had become day; it was almost as if they were back on Massa, where the stars of the bulge could be seen against the pale twilight sky long before darkness fell.

When the accretion disk came into view it outshone the sky around it, but it was not the kind of spectacle that it would have been against the black night of the disk. Then again, it could never really have existed out there. This was not a blazing X-ray binary, where a neutron star actively tore strips off a closely orbiting companion, but no star was truly isolated here, and the combined exhalations of thousands of neighbors kept the accretion disk aglow. The neutron star itself was almost lost in the bright center of the disk, where a narrow jet of plasma shot up from the plane. Its days as a conventional sun were long gone, but the chances were that it had never hosted life until it traded its own thermonuclear glow for this gravity-powered renaissance.

The Ark was far too small to see with the naked eye from their distant vantage point, so Parantham aimed the shipboard telescopes while launching surveyor probes. The gray ovoid was six hundred meters long, the same size as the one they’d left behind, but its surface appeared far smoother. That might have meant better repairs by better-fed fungus, or it might just have meant that it had avoided more of the debris from the destruction of the home world.

The Ark’s rotation was tidally locked: it spun around its axis in exactly the time it took to complete an orbit, fixing its orientation with respect to the neutron star. This froze the stretch and squeeze of tidal forces into a stationary pattern, allowing the material of the Ark to respond to those stresses once and for all rather than suffering endless cycles of flexing; no doubt this had not always been the case, but the process of flexure would have stolen energy from the rotation until the spin finally did fall into synch. The fixed stance the Ark had achieved did not aim its long axis directly at the neutron star, though; the torque from the orbital wind produced a perceptible slant on the telescope’s annotated image.

Rakesh wondered if this leaning tower had been crafted to take account of its inevitable inclination. The interior of the Ark they’d visited had been essentially weightless, but here the orbit, fifty thousand kilometers from the neutron star, was small enough for tidal forces to be felt. While they waited for the surveyor probes, he summoned up a map of that other Ark to see which directions its makers had expected to be “up” and “down”. It looked as if they’d hedged their bets: most chambers tended to be almost spherical, with no special orientation required to make particular surfaces work as floors. Similarly, the tunnels sloped in all directions. The makers had been prepared for some uncertainty, but they had clearly not expected the tidal gravity to grow strong enough to dictate the lives of the inhabitants. They had trusted the wind-based buoyancy to keep the Arks in comfortable orbits, and in this case they’d been proven right: the strongest that the tidal gravity would reach here, augmented by centrifugal force from its spin, would be about one sixth the surface gravity of the home world.

The surveyor probes reached their target. Rakesh watched anxiously as the neutrino tomograph slowly accumulated details, a solid labyrinth emerging from fog. The layout was not a tunnel-by-tunnel copy of the interior of the other Ark, but it was very similar, as were the density gradients in the walls. Here, those gradients could achieve their purpose: models showed the wind being scattered into the interior, spreading nutrients deep into the dead zone around the Ark’s center where the plasma orbited at the same velocity as the habitat itself. In fact, the main difference the scan showed from the Ark they’d left behind lay in the center; where the last one had been full of rubble and unrepaired cracks, this Ark was in pristine condition.

The probes added an analysis of the Ark’s thermal budget, which showed that a substantial fraction of the energy from the wind was being degraded into heat, in a manner that turbulence alone could not explain. On that basis, the biomass within appeared to be at least ten thousand times more than its barren sibling had contained.

Parantham said, “Let’s see if anyone wants to talk to us.” She broadcast a greeting from one of the probes, sweeping across the spectrum from the longest practical wavelengths down to far infrared. The plasma of the accretion disk stirred by the neutron star’s magnetic field would not make for ideal radio reception, but shorter wavelengths would have no chance of penetrating the walls, and there were no visible external antennas or detectors that they could target. The other Ark had contained stretches of conductive wire, but if they had been part of the original design here they must have been broken up and dispersed. Perhaps that was a sign of technological change rather than decay or disrepair, with the old infrastructure being cannibalized for other purposes.

Rakesh said, “I’m loath to barge in until we’ve given them a chance to respond. It’s hard to know how to warn them that we’re coming when they don’t seem to be looking outward at all, but we should at least try.”

“That sounds reasonable,” Parantham agreed.

Was it reasonable to enter this place at all? Rakesh tried to step back from his own agenda and ask the question objectively. Whether or not the Ark contained the descendants of a single cultural lineage stretching all the way back to the Steelmakers, these creatures or their ancestors had already suffered greatly from forces beyond their control. Weren’t they entitled to do their best to shut out the universe and make their own lives inside this cocoon? It was true that the Amalgam could offer them far greater security than the most stable orbit in this perilous neighborhood, but it would be naive to think that contact itself would be a neutral experience. Out in the disk, the Amalgam had usually waited for cultures to develop interstellar travel for themselves before making contact with them; the exceptions had often been messy.

He turned to Parantham. “Assuming there’s someone in there, why can’t the Aloof keep them safe? Do you think they could really have been unaware of this place until we came here?”

“We don’t know that they’re not looking after them,” she countered. “Maybe they’re tweaking all the local stellar orbits, even as we speak. Maybe they’ve wrapped their giant hands around this spark of life to shield it from harm, just as meticulously as they’ve shielded the bulge from intruders.”

“Then why are we here? What do they expect us to do?”

Parantham shook her head. “I could spin some half-plausible theory about them hunting for companions for these lonely foundlings, but the truth is I really don’t know. It’s not our responsibility to read their minds, though; our responsibility is to whoever is inside that Ark.”

“To do what, exactly?” Rakesh hadn’t realized quite how tense he was until he heard it in his own voice. He didn’t want the fate of a civilization resting on his shoulders, but nor could he simply turn and walk away. Any people who’d survived their world being dragged from star to star and then torn apart deserved sanctuary. What he did not want to do, though, was blunder in and destroy their paradise, if they had already found it right here.

Parantham said, “Whether the Aloof are pulling our strings, or whether they really don’t give a damn what we do, in the end we only have our own judgment. All we can do is tread carefully. I say we wait a few weeks to see if anyone answers our message. If they don’t, we go in as unobtrusively as possible and take a look around.”

Standing on the surface of the Ark at the point closest to the neutron star, Rakesh could feel the plasma wind and the tidal gravity trying to peel him off and fling him away into the accretion disk. It was like hanging upside down in a stiff breeze, albeit in low gravity and very low pressure. The adhesive pads on his jelly-baby feet could easily resist his avatar’s minuscule weight, but the insistent tug was still disconcerting. It was no wonder that in all of their time watching the Ark they had seen no locals foolish enough to venture outside.

Parantham said, “Come on, it’s this way.” He followed her across the gray plain; the surface felt rough to his clinging feet, but it was flat to the eye and bore no visible cratering. The plasma around them was extremely hot, but also very thin; its temperature in Kelvin made it sound like it would fry anything instantly, but if you calculated its energy density it suddenly seemed a whole lot tamer. The inner edge of the disk and the plasma falling on to the surface of the neutron star were emitting hard radiation that would not have been too healthy for an organic body, but it was nothing to their avatars, and the Arkrock would block it once they were inside.

The crack they’d found was even narrower than the last one, and they’d had to shrink their avatars accordingly. Parantham entered first and Rakesh followed, reaching up by bending sharply at the waist to get a handhold before unsticking his footpads. They could have used their ion thrusters and let the autopilots navigate them through the crack without even touching the sides, but to Rakesh that would have ruined the whole sense of presence; he might as well have sent in a surveyor probe and merely watched the feed from its cameras. Whatever the Arkdwellers might think, he felt far more comfortable making an uninvited entrance in this form than he would have about sending in an autonomous spying device; this way seemed respectful, rather than sneaky. No doubt that reflected his own cultural bias, but until he had something better to go on it was as good a basis for choosing his actions as any.

As soon as they reached a point sheltered from the direct force of the wind, fungus began appearing on the Arkrock. Rakesh took some samples and sequenced them; they were recognizable cousins of the species on the other Ark, though there were significant genetic differences relating to the different environments. As they clambered up the walls, the winding of the crack soon blocked out the starlight, but this time as well as the thermal radiation of the walls themselves they had another kind of light to see by: the Arkrock was translucent to a band of terahertz radiation being produced by electrons spiraling around the magnetic field lines of the plasma. This window appeared to have been tuned to the predominant frequency in the plasma surrounding the Ark’s natural orbit, so it was almost certainly a deliberate part of the design. The Arkmakers had not built a dark world of subterranean tunnels and caverns; they had made a world of glass and set it swimming in a sea of light.

Combining the visual processing techniques they’d used in the previous Ark with sensitivity to this new illumination was remarkably effective; although the kind of information they were receiving was very different from that yielded by the usual scattering of light from surfaces, making use of the right cues still generated a rich, detailed sensorium. Rakesh found that he could distinguish most of the species of fungus by sight, and even spot one kind buried beneath another. It was a shock at first to realize that almost nothing was completely opaque across this new spectrum, but once you accepted that fact the potential confusion abated. It was still possible to determine which of two things in your line of sight was the closest; it was just a matter of abandoning the old expectation that the nearer would obscure the farther as a matter of course.

They passed through a point where the fungus was exuding tendrils that criss-crossed the width of the break in the wall. As Rakesh understood the organism’s behavior from genome-based simulations, this structure would develop into a net that would trap drifting material—both the “sand” of eroded Arkrock and the mineral-rich corpses of micro-organisms—and use it to reconstruct the wall. Perhaps within a century or two the fissure would be completely sealed.

They emerged from the crack and clambered up on to the floor of a small tunnel; though it dwarfed their tiny avatars, it was less than a centimeter wide. Dozens of varieties of fungus were growing on the walls, inflecting the Arkrock’s crystalline translucence with a rich spectrum of colors. If this place turned out to be empty of higher lifeforms, it would not be for want of food. Rakesh could feel the plasma wind even now, flowing right through the walls.

Parantham said, “We don’t seem to have sprung any alarms yet, but I suspect they don’t have a big problem with intruders.”

“No.”

“So what now?”

“We take it slowly,” Rakesh suggested. “Give them a chance to react. Wait here a couple of hours, to avoid appearing hostile or impatient. If there’s no response, we go a little deeper and do the same again.”

They waited. Rakesh was sure that certain kinds of fifty-million-year-old civilizations could not have avoided noticing their presence the instant their feet touched the Ark, but then, they were also the kind most likely to have left this place behind completely. The various possibilities were not mutually exclusive, though: even a technologically advanced culture with the power to travel far from the Ark need not have deserted it, and the fact that he and Parantham were not yet facing a welcoming party was no proof that the Arkdwellers had died out or migrated elsewhere.

After two hours with no sign that they’d been noticed, they started walking along the tunnel.

As they approached an intersection the sensors in Rakesh’s avatar began to pick up a faint, complicated set of vibrations coming through the rock. It didn’t match the footfall of the twelve-legged creatures they’d found in the other Ark; if it was being caused by any kind of animal, it was a large group of a different species altogether.

At the intersection they turned into a wider tunnel, following the vibrations. Their own footsteps didn’t seem to be attracting attention, but then even if they were audible in principle this crowd’s own noise might have been drowning them out.

The tunnel veered sharply, then opened up into a large chamber. At first all Rakesh could see was the far wall, thickly layered with fungus, but as they drew closer to the entrance the view took in the chamber’s floor. Dozens, perhaps a hundred, creatures were moving through the fungus. They were each about a centimeter wide—ten times the size of the curious arthropod that had greeted them in the first Ark. Some had six legs, some had eight. The trunks of their bodies were flattened ovoids, encased in smooth, bilaterally segmented exoskeletons. Within, Rakesh could see small, pulsing organs pumping fluid through a series of cavities surrounding the other viscera, whose functions were less immediately apparent.

They stood at the mouth of the tunnel and observed the creatures in silence. Their motion seemed purposeful, systematic. After a while Parantham said, “They’re not feeding on this stuff, but I think they’re tending it.”

Rakesh agreed. They were crushing some of the rarer plants with their claws, and doing the same to some much smaller animals living among the fungus, but they did not seem to be ingesting anything. They were favoring a handful of species, which were visibly flourishing under this attention, while killing what amounted to weeds and pests.

That didn’t prove that they were sentient; agriculture was a fairly common form of innate symbiosis. Would such skilled genetic engineers as the Arkmakers have sentenced their descendants to toiling in the fields? Surely they could have devised maintenance-free crops. Was this proof that the genetic infrastructure had fallen into disrepair? Or perhaps the whole idea that this was a failure was cultural bias; perhaps for them this was enjoyable toil, as exhilarating as running could be for Rakesh’s own phenotype.

Parantham said, “You see how they’re drumming their legs against their torsos?”

“Yes.”

“The vibrations are making it through the rock, so it could be a form of communication. I’ve been searching for correlations with their surroundings and behavior, but nothing’s emerged so far.”

“So either it’s not communication at all,” Rakesh concluded, “or it’s playing a more sophisticated role than coordinating this task.”

“It looks that way,” Parantham agreed. “I was thinking that these might be domestic animals, engineered to tend the crops, but if they’re talking to each other about matters far from the here and now, I would hope that means they’re the farmers.”

“What else could it mean?”

“They could be sentient, but enslaved in some fashion.”

Rakesh was dismayed. “Where do you get these charming hypotheses?”

“It’s been known to happen,” Parantham replied dryly.

If the “farmers” had noticed their presence, there was no sign of it. Their avatars were a hundred times smaller than these creatures, and though they were culling pests barely larger than that out of the tangles of fungus, that was at close range. Rakesh couldn’t help feeling that if he and Parantham wandered down into the cavern, their most likely reception would involve a similar treatment. In any case, trying to introduce themselves at this point would be premature; they needed to learn the creatures’ language, if they had one, and determine exactly what could be expressed with it. Translating “we come in peace from another star” might be tricky if nobody in the Ark had braved the hard radiation of the exterior for several million years. It would be unwise to prejudge the matter, though; for all he knew these farmers could be passing their time debating cosmology and wondering whether life could exist outside the perfect conditions of the galactic bulge.

The two travelers continued to observe, patiently. Just as Rakesh was beginning to suspect that nothing was going to change however long they watched—there was no diurnal cycle here, after all—the farmers broke off traversing the crops and began milling toward the chamber’s exits. None approached the tunnel where he and Parantham were standing; they were all heading in the opposite direction, deeper into the Ark.

Rakesh exchanged glances with Parantham; even with their unexpressive jelly-baby faces they didn’t need to speak to confirm the decision. They switched on their thrusters and flew across the chamber. As they approached the far side the unspoken consensus continued; they flew together into one of the tunnels, then hovered in the middle to observe the exodus. The farmers jostled beneath them, crowding the small corridor, sometimes climbing the walls and ceiling to get past each other; with their claws splayed against the rock they seemed to have little trouble supporting their weight, but it could not have been entirely effortless as they weren’t disregarding gravity completely. In the near vacuum and with no contact with the walls, Rakesh could no longer detect the vibrations of their putative language directly, but everyone in the torrent of bodies surging around him was visibly engaged in the drumming gesture, even more so than when they’d been among the crops. The creatures still showed no interest in the avatars; with the faint glow of the ion thrusters far outside the frequency range of the ambient light, they probably looked like nothing more than specks of dust thrown up by the stampede, and it would have taken an unlikely second or third glance for anyone to wonder why they weren’t settling to the floor.

When the last of the farmers had surged past them, Rakesh and Parantham pursued the tail end of the crowd. When the tunnel forked, they split up. It was impossible to follow everyone, so Rakesh chose a group of five among his quarry who seemed to be sticking close together. One by one, though, in side tunnels and small chambers, each of the farmers dropped out of the group. They wedged their bodies into crevices in the rock, and simply stood there, dormant.

When Rakesh had no one left to follow he backtracked along the tunnels, not waiting for his avatar to meet up with Parantham’s before filling her in on what he’d seen.

“The same here,” she replied. “Perhaps the Arkmakers were constrained by a need for activity cycles in the ancestral biology, so they put in some internal, or social, cue to take the place of the diurnal triggers that would have been present on the home world.”

“Sleep, glorious sleep,” Rakesh rhapsodised. “These truly are my cousins.”

Their avatars returned to the fork where they’d parted. “So is everyone dormant now,” Rakesh wondered, “or is this night someone’s day?” He was about to suggest that they go hunting for signs of activity when he saw two creatures, identical to the farmers, approaching along the tunnel where Parantham had just been.

They were moving quite briskly, but pausing now and then to scrutinize the tunnel wall. Looking for pests, like the farmers in the chamber? Or hunting for some particular food?

The pair stopped completely, and Rakesh flew closer to see what they were doing. One was scraping fungus from the wall with its claws, while the other opened up the side of its body and removed a small, detached sac or bladder full of dark fluid. The contents were not literally opaque, but came as close to it as anything Rakesh had seen so far.

When the first creature had finished cleaning the wall, the other one punched a hole in the bladder with the tip of one claw, and began squeezing the fluid on to the wall in a slow, painstaking fashion. As Rakesh manoeuvred himself into a better vantage point, he saw that a complex pattern of intersecting lines was already present, marked on the wall with a thinner, paler version of the bladder’s dark contents. Line by line, this Arkdweller was repainting a faded sign.

Parantham caught up with him, then hovered beside him, watching in silence. When the signwriters had finished the two travelers remained, gazing at the strange symbols.