Incandescence

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 behind the metal.

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.