Sianna nodded agreement, though she understood that explanation a lot more poorly than she let on. She stood there and watched as Wally worked his controls, diverting resources toward a new construction site in the farther reaches of what had once been the Solar System. He started time moving at a minute-a-year and then sat back to watch the show. Constructor teams fabricated huge new Ring-and-Hole systems and sent them on their ways, out beyond the limits of the Solar System. Once the Rovers were on their way, the new construction site set to work manufacturing Sphere shell material.
“Okay,” Wally said. “I think we’re on course here now.” He lifted his hands from the controls, folded his arms, and watched the Sphere sections grow, huge bowl-shaped forms taking shape just inside Earth’s old orbit. Then the linkups began. First the equatorial regions were joined into one. The arc-shaped form of the hole spinner was pulled back from its interior orbit to form a large fraction of the circumference.
From there, huge arcs of Sphere shell began to reach for the poles. But the polar arcs didn’t hold. They began to buck and sway.
“Hell!” Wally said, reaching out to freeze the program. “Dynamic loads are too high.”
“How so?”
“Simple. The equatorial areas are orbiting the Sun with just about Earth’s old orbital speed, but as you get away from the equator, the surface moves more and more slowly. Basic rule of a rotating sphere. If the entire surface rotates as a rigid unit, speed of rotation goes from zero at the pole to maximum at the equator.”
“Then why not cut the rotation and get rid of the stress?” Sianna asked.
“Hmmm. The real Sphere here in the Multisystem rotates at about a normal orbital velocity, but I suppose the Charonians could have spun the Sphere back up after it was complete. Once the whole Sphere is built, it’s more rigid and a lot stronger. We’ll do it that way, and be more conservative in our assembly strategy.” Wally ran the simulation backwards, with bits of Sphere shell vanishing, melting away.
He stopped at the moment just before the final equatorial section was dropped into position. He ran it forward from there, making the final linkup and then pausing further construction for a full year while he attached gravitic thrusters to the equatorial ring and used them to slow to a halt. “Of course, now every part of the equatorial ring is going to want to fall in toward the Sun, but all the inward stresses will cancel each other out—unless some outside perturbation throws it out of whack. If you view it as a static system, it’s stable, but without a spin, it’s an unstable dynamic system. Doesn’t matter, though, because we can use the gravitic thrusters to keep it in trim.”
The sections of Sphere shell material started to go again, but this time in a different pattern. This time, instead of building great arcs up toward the poles, the shell sections were added evenly all around the edge of the equatorial ring, adding equally to its northern and southern edges, working to make sure the whole system stayed in trim and balance. Sianna blinked and rubbed her eyes. There was something quite dizzying about the way Wally was running things.
The simulation seemed so intensely real when it was running at a steady clip and seen from one viewpoint. The degree of detail, the sharpness, the clarity of the images all gave the simulation a tremendous degree of verisimilitude. It was easy to imagine a real Dyson Sphere abuilding out there, and that she, Sianna, was watching it from the observation port of a nearby spacecraft. It took an act of will to remember that the images she saw were wholly imaginary. It was all brighter, more solid, more logical, more authentic than reality ever was.
But then Wally would slow time, speed it up, freeze it, run it backwards, pan and shift and zoom and flip the viewing angles, project this diagnostic screen or that status display over part of the sim, and the whole thing would be shown up for the dream, the hallucination it was.
God help them all if it was real, if this was what was happening to the Solar System in real life, instead of in a simulator nightmare.
Sianna took a deep breath and forced herself to concentrate on the matter at hand. She had already missed some key details. Did that mean her central idea was wrong as well? One way to find out. Watch the sim and see what happens.
Once Wally had the assembly-pattern problem worked out, things proceeded smoothly for a while, the Sphere growing steadily from the equator toward the two poles.
Quite abruptly, two fiery-bright points of light appeared in the outer edge of the system, spaced well away from each other. “Alpha Centauri A and B,” Wally said. “The first Captive Suns for the new system. Going to be tough to stabilize them this early on. Take some doing.” Sianna glanced at the display that showed elapsed time for the simulation. She was startled to see that more than a hundred years had already gone by since the initial Charonian attack, five years in her own past. She was seeing a century into a future that might have been.
But then something started to go wrong. The Moon, the last natural object of any size in the simulated Solar System, started to wobble in its orbit. “Hold it a second,” Wally said. “The Moon’s orbit is going unstable. Gravity from the Captive Suns is throwing it off.”
Another knot tied itself in Sianna’s stomach. She hadn’t foreseen this, either. It might be enough to blow off her whole theory, but if it did ruin things, then her theory was too flimsy for the real world anyway. She was tempted to nudge Wally toward her idea, but no. She was trying to get him to think like a Charonian. If anything, she should encourage him away from her idea. “So who cares about the Moon’s orbit, or the Moon, for that matter?” she asked in a level voice. “Why not just get rid of it altogether?”
“No, no I can’t,” Wally said. “Hold it a second.” His hands flew over the controls. “Stabilize it,” he muttered to himself. “Maybe a six-sided rosette pattern. That give us a dynamic load balance? Yeah, that ought to do it.” Five Ring-and-Hole sets moved out from the various construction sites and positioned themselves at equidistant points along the Moon’s orbit, so that the five anchor rings and the Moon were sixty degrees apart from each other in orbit.
“That seems like a lot of trouble just to hold the Moon in place,” Sianna said again, quite perversely pushing in the direction opposite to the one she wanted Wally to go. “Why not just get rid of it?” Sianna asked.
“Can’t,” Wally said. “It is a lot of trouble, I agree, but I’m stuck with the Moon. Remember the Lunar Wheel, inside the Moon, started this whole thing off by grabbing the Earth. The Wheel was the central conduit for power for the first twenty years or so, receiving gravity energy transmitted through the wormhole link by our Sphere. Once the Solar System started being a net gravitic energy producer, most of that power still had to move through the Lunar Wheel. In fact, the Lunar Wheel’s power transmission capacity had to go way up—and the Wheel had to handle a lot of new processing power.”