“If we empty out a tunnel on the sardside, won’t that shift the center of the Splinter garmwards?” Ruz protested. “If the Calm moves garmwards, the sardside will grow larger.”
“We can move the rubble anywhere we like,” Bard countered. “We won’t toss it out into the Incandescence. If we pack it into some small, empty tunnels that already lie sard of the excavation, the center of the Splinter will move sardwards, and it’s the garmside that will grow.”
Bard unfurled a scroll of skin. He had drawn up a plan, which showed two tunnels piercing the Splinter from rarb to sharq.
Roi said, “The mouths will be open directly to the Incandescence! How could anyone survive working there?”
“For the final few spans we’ll simply loosen the rock and then withdraw the workers,” Bard explained. “The wind itself will finish the job.”
“How wide will these tunnels be?” she asked.
Bard gave a noncommittal rasp. “As wide as possible. As wide as we can make them.”
“What’s that going to do to the sardside crops?”
“I expect it would reduce them,” Bard conceded. “The wind is what feeds us; if we let it pass by untapped, there has to be some cost. But would it be better to see the sardside torn from the garmside, and the broken halves left to fend for themselves?”
Roi had no reply. She was sure that had happened at least once before, but who could say how much suffering, how much death, it had cost?
Zak said, “This plan is ingenious, but recruiting a team big enough to carry it out, let alone gaining the understanding and consent of everyone affected, would take several lifetimes. I hate to admit it, but we might have to resign ourselves to enduring at least one more division. In the aftermath of a disaster people might be willing to do anything to avoid a recurrence, but I can’t see it happening while the majority still doubt that there’s anything at stake.”
His words brought Roi the same guilty sense of relief as she felt after each set of unchanged measurements. Let the danger and confrontation retreat into the future. Let some other generation deal with it.
“There could be a problem with that.”
Roi didn’t recognize the voice immediately. When she searched the chamber to see who had spoken, it was Neth, a young student of Tan’s. As far as Roi knew, Neth’s only other work since her hatchling’s education had been herding susk, but she had taken to template mathematics as if it were the most natural thing in the world.
Neth continued, a little shyly. “If the next division is like the last one, I’m sure many people would survive. The weights would be greater, but both new Splinters would be smaller, and the weights alone would not be enough to harm us. The wind would still blow, the crops would still spread, we would mourn our team-mates and then continue with our lives.
“But it might not be that way.”
She hesitated. Zak said encouragingly, “Go on. We all want to hear you.”
Neth said, “I’ve been studying the templates that describe the motion of the looping stones. When you toss a stone directly garm or sard from the Null Line, it follows a closed curve, an ellipse about three times as long as it is wide.
“This looping motion shows that an object that shares our orbit, then is slightly disturbed, won’t wander too far. Even if you toss the stone along the Null Line, giving it a sustained motion in that direction, it won’t go far garm or sard of us. Any small disturbance of the orbit we’re on leads to another orbit which stays more or less the same distance from the Hub.”
Zak said, “Agreed.”
“The problem,” Neth said, “is that it’s not the strength of the weights alone that has changed over time, but also the relationship between them. If we can believe the Map of Weights, then when it was drawn all the relative strengths were different. The total garm weight was three times the spin weight. At present, that ratio is more than three and a half. If we’d tossed a stone garmwards from the Null Line when the Map of Weights was drawn, the loop it followed would have been a different shape than the one we see now; it would have been just twice as long as it was wide.
“If the ratio between the garm weight and the spin weight keeps increasing the closer we get to the Hub, then the loop will keep growing longer and skinnier. But the shape changes faster than the ratio, and the ratio only has to reach a value of four in order for the loop to stop being a loop at all. If the ratio becomes four, then a stone tossed garmwards will never return to the Null Line. The swerve weight will still bend the stone’s path around, but the garm weight will be strong enough to tip the balance, and ensure that the stone never comes back.”
There was silence as people absorbed the implications of this. What Neth was describing for a stone tossed in the Null Chamber applied equally well to the Splinter itself. If the ratio of weights changed in the way she described, any slight disturbance that nudged the Splinter garmwards would no longer lead to a small variation in its path, a gentle meandering that never saw it stray far from the original orbit. Instead, it would immediately send it spiraling in toward the Hub.
Ruz said, “Might it not be that this ratio never actually reaches four? Might it not approach that value as we approach the Hub, without ever quite getting there?”
“That’s a possibility,” Neth replied. “As things stand, though, we have no way of knowing whether that’s true or not.”
The meeting’s attentive silence gave way to a cacophony, as most of the team began talking among themselves. Roi made her way over to Zak, whose body was hunched against the rock in a protective posture.
“Are you all right?”
“I’m fine,” he rasped. “Just a few pangs, nothing unusual.” After a moment he added, “I can still remember when we first calculated the period of the looping stones. The square of the inverse period was proportional to four times the spin weight minus the garm-sard weight. But I assumed that that quantity would always stay positive. I never considered the possibility that it might change sign, or what the consequences would be.”
“Let me get you out of here.” Roi started clearing a path for him.
Zak said, “Wait.” He forced his pain aside and looked up at her. “Let me speak to the meeting first.” Roi drummed a call for silence, and when it was finally heeded Zak addressed the team.
“Neth’s work changes everything,” he declared. “We are a long way from predicting the ratios of weights all the way down to the Hub, and even if we did find some beautiful templates that seemed to fit the handful of numbers we have, we would be foolish to trust them absolutely. We can’t rule out reaching a ratio of four, so we have to be prepared for that possibility.
“I believe that we have two priorities now, both of them equally urgent. The first is to continue the experiments, the calculations, and the philosophical speculations that have brought us this far. This is the work that led us to Neth’s insight. We must do our best to map the dangers that lie ahead, even if our foresight can never be perfect.
“Our other priority must be to strengthen our ability to act on whatever insights we can gain. We need to recruit, we need to educate, we need to start the whole Splinter talking about these dangers.
“A few heartbeats ago, I declared that Bard’s plan would take several lifetimes to achieve. That might or might not be true, but it’s no longer an excuse to delay taking it seriously. If we can devise an easier, less contentious way to move the Splinter out of danger, that would be the greatest achievement we could hope for. If we can’t, then we need to prepare ourselves to accept the reality: the lives of all our descendants might depend on whether we can recruit enough workers, and win enough support, to carve a tunnel from one side of the Splinter to the other.”