Incandescence

As Haf set to work, Roi stared pensively at the stones of the blank frame. Sometimes the problem really did appear to be impossible to solve, but the geometry that twisted around the Hub had once seemed almost as intractable, and now the Splinter was spiraling out along a path that was confirming that solution, shift after shift. The weights, the cycles, the view of the void, all fitted together exactly as the templates decreed. Ruz had been up to the surface a few times, and he'd told her that the strange quarter-circle was expanding: the angle of the arc, its radius and its thickness had all grown visibly larger. Part of this change was due to the Splinter traveling more slowly around its larger orbit, and part to the gentler space-time curvature as they moved away from the Hub bending the incoming light less severely.

"I have a friend called Tio," Haf said, without looking up from his frame. "He told me that the best way to think about curved geometry is to imagine it as lots of little flat pieces stuck together. I mean, a cube is just six flat pieces, but it's not that far from the shape of a sphere. And if you use more pieces, you can get closer."

"That's true," Roi said. "You can shift all the curvature into the corners between the pieces. But I'm not sure where that gets you. Who did Tio study with? Kem? Nis?"

"I don't think it was either of them. He spoke to a lot of different people. Picked things up here and there."

Roi kept staring at the frame, but her mind was blank. Having exhausted all the elegant tricks she knew, she had finally attacked the problem directly, with no subtlety but all the diligence she could muster, hoping that somewhere along the way an opportunity to simplify the mess would appear before her eyes. It hadn't happened yet. There must be something simple, Zak had declared. But he'd found that once already, in the principle of the weights. In a void full of Jolts and Wanderers, and countless distant lights that for all Roi knew could be wrapped in curvature of their own, how much more simplicity could they expect?

Sen, one of Neth's students, appeared at the entrance to the chamber. "We're opening the tunnel now," she said.

Roi put down her frame. Haf made ready to heft the light machine on to his back, but Roi said, "I don't think we'll need that." The dark phase was almost over, and Sen knew the area so well that she'd come to them without any light of her own. Roi was getting better at following people by the sound of their footsteps, even when she was in an unfamiliar place, a skill that seemed to come naturally to Haf and the others hatched since the Jolt.

They followed Sen down a narrow, sloping tunnel toward the rarb-sard edge.

By the time they reached their destination, there was enough light to see Neth, Bard, and a few dozen others gathered in the plug chamber adjoining the new tunnel. The outer wall where the tunnel approached the surface had been thinned and weakened to the point where it had almost certainly broken apart during the last light phase. From this chamber, the first of the sets of stone plugs that were keeping the tunnel sealed would be pulled aside, at the same time as eleven others further downwind were withdrawn. If everything went as planned, the wind would flow freely across the width of the Splinter and strike the sharq end of the tunnel with enough force to break through the thin crust that had been left by the workers there, opening up a third unimpeded channel from Incandescence to Incandescence.

Roi approached Neth. "Surely your work's done here now," she joked. "We'll be waiting for you to join us at the Null Chamber." In fact the Null Chamber was empty of theorists and Roi had no reason to visit it any more, but no other place had the same ring to its name.

"When the tunnels have steered us past the Wanderer, I might take you up on that," Neth replied, in all seriousness. "I want to work with someone who's interested in a deep understanding of the changes we've seen in the density of the Incandescence as we've moved away from the Hub. There are many mysteries there. We understand weight and motion pretty well for rocks like the Splinter, I think, but when it comes to anything else we're still just gathering data, and guessing."

Bard consulted a clock, and called out to the plug operators. There was no need to send a light-message to the operators in the other chambers; they'd be following prearranged instructions and clocks of their own.

The plug operators, lined up in rows, began hauling on their ropes, which ran through a system of pulleys to the huge stone sitting at the far end of the chamber. Although this single stone was probably close to the limit of what could be moved with a wheeled cart and metal tracks, it was only about a sixth of the size of the tunnel's aperture; six separate plugs inserted from their own separate chambers came together to block the tunnel at this point alone.