Donald Moffitt - Genesis 02

you’re the only one who can make the decision, and I agree.”
    With a sinking feeling, Bram said, “Go ahead.”
    “We’ve got to get in and out of the galactic core fast. There’s no way we can simply back up, the laws of physics being what they are. We’ve got to use the mass at the center to bend our path in a hyperbola and swing around and out. Now our patron mass turns out to be two masses, very close together—right?—but for the purposes of our hyperbolic orbit, we’re treating it as a single mass.”
    “Yes,” Bram said, wondering what Jao was driving at.
    “Even if there were some magical new law of physics that would let us dump all our inertia at once and come to a dead stop without rattling the glassware, it wouldn’t do us a bit of good. Because we’d have to back out from a standing start and build up all our lovely gamma factor all over again, and that would take us fifty thousand years longer than whipping around the focus of the hyperbola. So we’re committed.”
    “Yes, certainly. Everyone understands that.”
    Jao tried to wave a leaden hand, gave up the effort. “We also have to add a vector to angle the outward path somewhat above the plane of the galaxy if we want to aim at the Milky Way. That makes it even more tricky, but I won’t go into that now.”
    “Yes, yes,” Bram said, wishing Jao would get to the point.
    “So, as you said, we decided to pile on all the acceleration that Yggdrasil will bear in the hope of beating the merger of the two black holes and the final explosion by the widest margin possible. But the extra speed means we need an even tighter hyperbola—we’ve got to brush that doomsday engine ever closer, and that has its own dangers.”
    “We all decided to take the risk.”
    “Otherwise,” Jao said, ignoring the interruption, “we’d escape the galaxy, all right, and save our own skins. But we’d sail on out into intergalactic space and miss our target.” He looked around and lowered his voice. “Of course, there may be some who are frightened enough of the core maneuver to want to do that on purpose.”
    “If you’re asking—”
    “Bram, there’s a way we can pick up some extra velocity without adding more g’s and taking the risk of cracking Yggdrasil’s branches—to say nothing of our own sacroiliacs.”
    “Go on.”
    Jao hitched himself closer on his elbows. He took another look around the bridge to make sure that he would not be overheard.
    “We use the satellite hole as a gravity machine.”
    “What?”
    “We’re already going to pick up the rotational energy of the primary hole. It’s got a rotation parameter of point nine nine eight, and it’s doing weird things to the space around it, and the field lines from the accretion disk are going to reach out with magnetic fingers and fling us along by our own magnetic field. Now, what I’m saying is that we can refine our orbit and loop around the satellite hole, and pick up its orbital energy. It’s whizzing around its primary at a ferocious rate at this point. We could pick up fifty thousand g’s of acceleration without it costing us a thing. We wouldn’t even feel it!”
    “We’d have to fly between the two holes to make that loop.”
    “Uh huh.”
    “Jun Davd says they’re only a few diameters apart at this stage. And they’re spiraling closer. The final dive could happen at any moment.”
    “He thinks we have enough time to squeak through.” Bram’s heart was pounding. “He said that at the present high rate of spin, the static limit is well above the edge of the accretion disk. The region between them must be very weird. We could get sucked into the hole with no warning. Into either one of the holes.”
    “Yah. That’s why he says it’s your decision.” Bram was going to ask for an estimate of their chances. But that would be begging the question—asking Jao and Jun Davd to make the decision. “Do it,” he said.
    Jao nodded and crawled off on his elbows and knees to confer with Smeth.
     
    The ghost of a star drifted by, a ball of red so dull as to be at the limits of visibility. The universe outside the long observation wall was no longer blind; it was filled with a meaningless red fog that showed a suggestion of vast billows, specks, twisting sheets. The phantom star cleared a tunnel ahead of it, but that was an illusion; actually, the star was going the other way, and the tunnel, of course, was its wake.
    “Can you see it?” Jun Davd’s voice