I’m not badly informed for a layman, she thought. I remember Professor Artur remarking how much remains unknown to any of the spacefaring races. He felt that in the nature of the case it would always be unknown too, because there is no possible way for information to reach us through the event horizon. But if a pair of them crash together—
“That must be rare indeed,” Orichalc said low.
“Unless at galactic center?” Valen mused.
“Conjecture,” Esker snorted. “Yes, perhaps lesser black holes are among the stars that the Monster engulfs. That might help account for some of the things we have glimpsed there, such as short-lived trails of radiation. They may be from matter that it somehow accelerates almost to light speed, soon slowed down again by interaction with the interstellar medium. We don’t know. I tell you, in spite of all proud pretensions to having a final theory, we don’t know.”
The Monster, Lissa remembered. The truly gigantic black hole at the galactic heart, hidden from sight behind the dust clouds gathered around there, barred from exploration by unloosed energies that would almost instantly kill any organic being and wreck the circuits of any robot.
How did the conventional scientists dare imagine that no fundamental mysteries remained in the universe?
Esker’s voice lifted as if in triumph. “Here such an event is out where we can watch it.”
Again the academic tone took over. “Also, this is not a simple linear collision, such as we believe we have some theoretical understanding of. That would be vanishingly improbable, two singularities aimed straight at each other. This will be a grazing encounter, the convergence of two eccentric galactic orbits.
[113] “From our observation of orbits and accelerations, we’ve obtained the masses of the bodies with considerable accuracy. They are approximately nine and ten Sols. That means the event horizons are about sixty kilometers in diameter. Calculation of closest approach—that involves some frank guesswork. We have good figures for the orbital elements. If these were Newtonian point masses, they’d swing by on hyperbolic paths at a distance of about thirty kilometers and a speed of about one-third light’s. But they aren’t, and it’d be a waste of breath to give you exact figures, when all I’m sure of is that the event horizons will intersect. The ship has programs taking relativistic and quantum effects into account. I’ve used them. However, certain key answers come out as essentially nonsense. The matrices blow up in a mess of infinities. We simply don’t know enough. We shall have to observe.
“Observe,” he whispered. “See.”
“Can we get that near, and live?” Valen asked.
“As near as the Susaians, I daresay.” Now Esker sounded boyishly bold and careless.
“How near is that, do you suppose?”
“Probably closer than humans would venture, if this were their project from the beginning. We’d send in sophisticated robotic vessels. The Susaians will do their best with probes, but that best isn’t very good. No nonhuman race’s is. They all keep trying to copy from us, and never get it right.”
“Every species has its special talents,” Lissa interjected for shame’s sake. She wondered if Orichalc cared, either way.
“Give me a figure, will you?” Valen snapped.
“An estimate,” Esker replied. “To start with, the collision will produce a stupendous gamma burst, detectable across the width of the universe. Nobody and nothing could survive anywhere near that. However, it’s known from theory and remote observation that this doesn’t happen at once. It results from the recollapse of matter hurled outward by the electromagnetic and other forces released in the encounter. The recollapse to critical density takes [114] two or three days. Meanwhile, yes, radiation background and gas temperatures will be high and increasing.
“However, our advanced protective systems can fend off more than most ships. The Susaians must have some that are equally shieldable. Integrating the expected radiation over time around the event, and throwing in a reasonable safety factor, I’d undertake to keep on station at a distance of two hundred million kilometers, for two hundred and fifty hours before the impact and maybe as much as thirty hours after it, depending on what the actual intensities turn out to be. That’s far too deep in the gravity well for a hyperjump escape, of course, but I’d call the odds acceptable.”