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.