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.
16
Zak called out, “Just a few more spans, and I’m there!”
He sounded exhausted, but utterly determined to complete the arduous climb. Roi circled anxiously around the edge of the crack. When she’d helped him up to the entrance, he’d struggled to maintain his hold on the steep, jagged surface, and she had doubted that he would make it all the way through the outer wall. She had underestimated his reserves of strength. He hadn’t taxed himself needlessly on the journey; he hadn’t even forced himself to stay awake to make polite conversation with his bearers when he’d felt like resting instead. He had been saving everything for this moment, and now it seemed that his strategy was about to prove its worth.
The light machine stopped chugging but it was out of reach, so Roi left the darkness undisturbed. On Zak’s instructions she and Ruz were clinging to the ceiling, the idea being that if whatever had killed those who’d ventured out before was present in the void as well as the Incandescence, they would be less exposed to it here than anywhere on the floor nearby. In fact, as Roi had helped Zak into the entrance, she had seen by the glow of the light machine that the crack was twisted in a way that allowed no direct line of sight. Still, during the shomal dark phase some light from the Incandescence had nonetheless made its way right down to the floor, so she couldn’t fault Zak’s logic.
Zak exclaimed suddenly, “I’m outside!” A moment later he added, “There’s an arc of light. I don’t understand this.”
“An arc?” What did he mean? “Zak?”
There was a long silence, then he replied in a labored voice, “I need to take some measurements. I’ll explain everything when I get back down.”
“All right.” Roi was desperate to hear exactly what he’d witnessed, but she knew it was unfair to expect a running commentary. Zak didn’t have much time, and he needed to concentrate on setting up the instruments and collecting the crucial data.
Whatever else there might be to discover in the void, the one possibility in which they had invested the most hope—and planning—was that Zak would be able to locate a distant object that he could track for a while, in order to obtain an independent measurement of the Splinter’s motion. From inside the Splinter, there were really only two distinct numbers that could be measured: the ratio of the garm-sard and shomal-junub weights, and the ratio between the periods of the shomal-junub cycle and the turning of the plane of the Rotator’s spinning bar. Those numbers were in agreement with Zak’s principle, but beyond that they revealed nothing about the geometry through which the Splinter was moving. If the simple geometry that the team had found in their calculations was the right one, then the time it took the Splinter to orbit the Hub would be identical to the period of the shomal-junub cycle. If all orbits at a given distance from the Hub were the same, regardless of their angle of inclination—the assumption of symmetry on which the simple geometry was based—then a stone moving shomal and junub of the Null Line would take the same time to complete its orbit as the Splinter itself, and so it would return to its greatest distance shomal of the Null Line after exactly one orbit for both.
How could you mark a fixed point on an orbit, though, in order to measure the time it took to return to it? The idea that two orbits at an angle to each other always intersected at the same two points was the very assumption they were trying to test, so it could not provide the signposts. The only method anyone on the team had been able to come up with was to rely on a different assumption—that objects far from the Hub moved on slower orbits—and then to hope that, with the Incandescence out of the way, it would be possible to observe something in the void so distant that it was as good as fixed. The apparent motion of that distant beacon would then be due—in the most part—to the Splinter’s motion around the Hub.