Incandescence

Roi said, "We were pushed." The pattern was unmistakable; she'd tossed enough stones in the Null Chamber to know how to set things cycling back and forth. "That's what threw us off the ground. It wasn't the fact that we entered the void that did it: the push came first, the disturbance came first. Whatever struck us changed our orbit slightly, enough to knock us into the void."

"Why is the void half as big as our orbit, though?" Gul protested.

The darkness thickened, the wind fell away. Roi pictured the orbit of the Splinter, and the motion of the stones in the Null Chamber. What happened twice in every shomal-junub cycle? The "falling" stone passed by the "fixed" one. First it passed it on its way shomal, then it did so again on its way junub. Twice in each cycle, the stones were close together. And twice, they were far apart.

"The void's not half as big as our orbit," she said. "It's far bigger than that. And it hasn't wandered up to us by chance; it hasn't moved at all. It's been right beside us all along."

Gul was silent for a while, contemplating her cryptic remarks. Then he said, "If the Incandescence isn't everywhere, but we never left it before, then maybe it's confined to a thin layer around the plane of our old orbit. Now something's disturbed the Splinter, and we're moving shomal and junub — above and below that plane — for the first time."

"Exactly!" Roi said. "Out of the Incandescence, then back. Twice every shomal-junub cycle. The whole Splinter has become the falling stone."

She waited, picturing the stones in her mind's eye. As one imaginary stone ascended from its low point and approached the other, the walls began to brighten.

Gul said soberly, "We're lucky we survived this. And lucky we can understand it." Then he let out an ecstatic chirp that woke half the hatchlings. "We're not going to die!" He scooped up two bewildered children and tossed them on to his back, then started running around in a circle. "Darkness, light, it doesn't matter! We're safe, we're fine. Everything is perfect!"

Roi watched him, dizzy with relief herself, if not so exuberant. This was not the end of the Splinter, not the plunge into the Hub that Neth had foretold. The crops would suffer, though. There would be food shortages, and everyone would struggle to complete their work as the darkness came and went.

The strange event had shown them something new about the Incandescence, even as it had confirmed Zak's picture of the Splinter orbiting the Hub. It might even persuade some people to accept his ideas and agree to the tunnel. The loss of crops was a hard price to pay, but in the end it might change things for the better.

The one thing that worried Roi most was that she still had no idea what dazzling thing had flown past and knocked them out of their orbit. Where had it gone? To the Hub? Into the void? Could it cross their path again?

And if it did return, which way would it push them next?

Zak stretched his legs out across the wall of his chamber, trying to ease the pain in the joints. "I have a plan," he said. "But I'm going to need your help."

"Whatever you want from me, just ask." Roi had left the hatchlings in Gul's care to travel to the Null Line and check on Zak's condition. He had survived the Splinter's Jolt and the aftermath, with members of the theorists' team still bringing him food regularly, in spite of their own problems and distractions. His health had been fading for a long time before the event, though, and Roi suspected that his death was close now.

Zak said, "When I was working in the library, I heard about a crack in the wall at the junub edge. Some people had climbed right through it and reached the Incandescence."

Roi was skeptical. "Are you sure that's not just a story?"

"I have a map."

"You always have a map. Did anyone come back?"

"Of course not. The Incandescence killed them; nobody has ever walked into it and survived. It's not just the strength of the unfiltered wind: even at the Calm, there's something fatal, something that the rock protects us from."

Roi could see where this was heading. "You think it might be possible to survive there, now? In the times when our orbit takes us right out of the Incandescence?"

"It's worth trying," Zak said. "We don't know how long the new orbit will last. This might be our only chance to look into the void."

There had already been measurable changes in the orbit. Although the period of the complete light/dark cycle remained the same, with Ruz's clock it had been possible to detect a small reduction in the time the Splinter spent in darkness. This suggested that the total distance they were traveling away from the old orbital plane had diminished slightly.