“The strength of rock is what holds the Splinter together,” Tan said. “But the Wanderer doesn’t seem to be made of rock. So why doesn’t it simply fall apart from the usual weights? Spinning in different ways from the Splinter won’t do the trick. Without strength of
“So what kind of strength can it have?” Kem asked.
“Geometry,” Tan replied. “The same thing that keeps us close to the Hub holds the Wanderer together. But now the Hub and the Wanderer’s geometry are fighting each other for the Wanderer’s wind and light.”
Roi allowed herself a moment of pure exhilaration. It was a beautiful, audacious proposition. Who ever said the Hub was the only object in the void that could be wrapped in curvature? It might be the strongest thing in sight, powerful enough to twist the Wanderer’s path around it, but that didn’t mean the Wanderer itself was a mere passive follower of geometry, as the Splinter seemed to be. Why couldn’t it carry its own curvature? The Hub had the glory of the entire Incandescence, but the Wanderer, at least for now, held on to its own portion of wind and light. The two were alike, one smaller, one greater.
Unfortunately, if this elegant solution to the mystery was true, it changed everything. If the Wanderer was wrapped in space-time shaped as it was around the Hub, then in turn the geometry around the Hub itself could not be described perfectly by the rotationally symmetrical solution that she and Tan had found. The presence of the Wanderer was like a dent hammered into a smoothly curved sheet of metal; it could be ignored from afar, but the closer you came to it, the more significant it would be.
Kem appeared dazed. “Two Hubs fighting? We need the geometry for two Hubs fighting?”
Tan said, “It’s just one possibility. It needs to be thought through in a lot more detail.”
“But how will we know?” Kem demanded. “
Roi said, “We need to observe something in motion close to the Wanderer. That’s the only way to understand its geometry.” If they waited for it to have a measurable effect on the Splinter’s own motion, all their questions would be answered too late.
“What is there close it?” Kem asked forlornly. “Just its wind and light erupting chaotically every now and then. How can we make sense of that?”
Roi fought against a sense of panic. It seemed almost fortunate now that their progress outward was less rapid than they’d hoped; if it had been faster, she might have had to call a halt until they were certain this problem could be solved.
“What moves close to the Wanderer?” Tan mused. “Nothing stays, but many things pass by.”
Roi said, “This is no time for riddles.”
Tan chirped amusement. “After her victory over me, I would have thought Kem might find the solution first.”
“Victory?” Roi had lost track of all the minor squabbles and disputes among the team; once things became clear, she had trouble remembering who had first thought of each idea.
“Light travels at Neth’s speed,” Tan replied, “or as close to it as makes no difference. As fast as that is, though, its natural paths still respond to geometry.”
Roi thought she knew what he was hinting at now, but it was Kem who put it into words.
“The Wanderer moves against the background of lights,” Kem said. “We need to observe and record the positions of a small, closely spaced group of lights very carefully. We do this once when the Wanderer is among them, then once again when it’s far away. If there’s a change in the angles between them, it will tell us that the geometry has changed. It will tell us that the Wanderer is like the Hub, wrapped in curvature of its own.”
As the Splinter spiraled slowly outward, Roi traveled with Kem and Nis toward the junub edge. This was too complex a matter to explain to Ruz through messages, whether sent in writing or by flashes of light. There was nothing to keep her at the control post; they would not be dodging and weaving around the Wanderer for many shifts yet.
The light-messengers remained at their posts, though, ready to get word swiftly to Tan and the others if anything suddenly changed. As Roi greeted each one along the way, it struck her that the whole Splinter was almost like a single work team, now. In a sense that had always been true: couriers had worked with depot organizers, susk herders had worked with cuticle-wrights, and even those teams that had not directly cooperated had shared a common goal: the welfare of the Splinter as a whole. There was no denying, though, that since the Jolt the old borders had melted, and the old system had been twisted into a new shape, far richer and more contorted than even the Hub’s strange geometry.
When the delegation of theorists reached Ruz, he called his best recruits together and they listened to Kem’s proposal.
“There’s one problem,” Ruz said. “We’ve already made the kind of measurements you’ve described, and to the limits of our ability we’ve found no changes.”
Kem said, “Can you check the data? If you weren’t expecting this effect, you might have dismissed it as just part of a background of observational error.”
“Perhaps.” Ruz sent someone to carry out that task.
Cho said, “There’s a way we might be able to improve the accuracy of our measurements. It involves curving the metal plates, bending and polishing them to systematically distort what we see.”
“Distort?” Roi was skeptical. “Isn’t that just going to make the errors greater?”
“If we didn’t know the shape of the plate well enough, then of course it would,” Cho conceded. “But if we can calibrate the shape with enough confidence, we might be able to exploit a system of such plates to magnify the angles we’re able to discern.”
Ruz seemed displeased; Roi wondered if Cho had proposed this system before, and Ruz had ruled it out as too complex and uncertain. She tried not to let her loyalty to Ruz sway her; she had to be ready to judge the ideas of every team member on their merits.
“Can you explain in more detail?” she said.
Cho believed he’d found a simple geometrical principle governing the paths that light took when it struck metal: the angle it made with a line perpendicular to the surface when it hit the metal was the same as the angle when it departed. For a flat plate, the consequences were straightforward, and they lay behind the contraption the void-watchers were now using to observe the lights from the safety of the tunnel below the crack.
For a curved surface, Cho’s principle had more complex ramifications. He had templates to show that if the shape followed a certain curve, light from distant objects could be brought together sharply on a certain plane; using the opposite side of the same shape, the light could be made to appear as if it was coming from a plane
By combining elements of these two kinds, Cho believed he could construct a system that, while bringing the light down from the surface, modified the geometry of its paths in such a way as to make it seem as if the observer was closer to the distant lights. With one of his designs, all the angles would become larger by a factor of twelve.
Roi looked to Ruz, to hear his objections.
“The principles appear sound,” he said. “But we can’t be sure that we can shape the metal to the necessary precision. And how can we test it, when our one passage to the surface is taken up completely with the system we need, and that we know is reliable? How can we disrupt all our observations to gamble on this?”
“I understand.”
Roi struggled to weigh up the risks. They desperately needed to understand the nature of the Wanderer. If Nis’s idea was right then the geometry that wrapped it would influence the Splinter’s path, and while as yet she had no idea how to combine the Hub and the Wanderer’s geometry into a single shape, the sooner they learned exactly what the geometry close to the Wanderer was, the better their chances of making sense of that complex interaction before it was too late.
At the same time, the present system was certainly running smoothly for the void-watchers. If they disassembled Cho’s first invention to make room for his second, they would have to resort to observers clambering back and forth from the surface every junub dark phase. They would lose observations, or even people, in the rush.
She could always ask Bard to close the tunnel, to buy them more time. The Wanderer had its own schedule,
