Saxtorph realized he had been holding his breath. He let it out in a gust. His ribs ached, his sweat stank. Why had he undertaken the flit, anyway?
Well, it was irresistible. Nobody felt able to leave without exploring just a little bit more. And after all, you never knew; a search could turn up a clue to Peter Nordbo's fate.
Saxtorph made for a surrealistic jumble of pipes, reticulations, and clustered globules. Dust, millimeters thick, scuffed up in ghost-wisps wherever his boots struck. After several leaps, he halted. “Okay, Carita, come join the fun. Don't land, remember. Stay a few meters above and behind me, on the alert.”
“You're afraid maybe I'll take a nap?” the crewman gibed. Edged with their luminance, her spacesuit arrowed across the stars.
I suppose we shouldn't crack jokes in the presence of something ancient and inscrutable, Saxtorph thought. We should be duly awed, reverent, and exalted. To hell with that. We've got a job to do. I hope Tyra will understand, when she writes this up.
Of course she will. She's our own sort. If her whole life didn't prove it already, the past couple of weeks sure did.
Saxtorph neared the complex. At hover, Carita directed a search beam as he desired, supplementing his flash. Undiffused, the brightness flowed like water over a substance that was not rock nor metal nor anything the humans knew. They both operated cameras as well as instruments, while their suits transmitted to the ship. Saxtorph's eyes strained.
“I think the microcraters everywhere were formed in the last hundred million years, plus or minus x,” he said. “Otherwise we'd see much more overlap.”
“You're supposing the construction is older than that, then,” Carita deduced.
“It certainly is,” Dorcas told them from the ship. “The computer just finished evaluating our data on the dust. Isotope ratios prove it's been collecting for a minimum of two billion years, likely more.” After a moment: “Incidentally, that suggests cosmic radiation isn't what weakened the shell to the point where impacts started leaving pockmarks and at last a big one broke through. The radiation inside must be mainly responsible. But if it hasn't done more damage, well, the thing was built to last.”
“Besides,” Saxtorph said, “if I've got any feeling for machinery, this bears every earmark of tnuctipun work.”
“How can you tell?” Carita asked. Her words sounded thin. Ordinarily she would have kept silence, except for business and an occasional wisecrack, but the weirdness had shaken her a bit, roused a need to talk. Saxtorph sympathized. “What do we know about the Slaver era? What little the bandersnatchi remember, or believe they do, and what got learned from the thrint that came out of stasis for a short while, before they got it bottled again.”
“That includes a smidgen of technical information, and a lot of thinking has been done about it ever since,” he reminded her. “I've studied the subject some. It interests me. Come on.”
He bounded ahead to the next aggregation and examined it as best he cursorily could.
And the next and the next and the next. Time ceased to exist. He drank from his water tube, stuffed rations through his chowlock, excreted into his disposer, without noticing. He had become pure search. Sturdily, Carita followed. She made no attempt to call halt, nor did anyone aboard ship. The quest had seized them all.
Monkey curiosity, Saxtorph thought once, fleetingly. The kzinti would sneer. But they'd examine this too, in detail, till they used up every possibility of discovery that was in their equipment and their brains. Because to them it'd spell power.
The knowledge was chilclass="underline" It is a terrible weapon.
“I suspect it's one of a kind,” he said. “Humans and their acquaintances haven't found any mini-black holes yet, and that hasn't been for lack of looking. They're bound to be uncommon.”
“Yes,” Dorcas agreed. “The tnuctipun doubtless came on this one by chance. I'd guess that was after they'd rebelled. They saw how to use it against the Slavers. Otherwise, if they'd built the machine around it earlier, the Slavers would have been in possession, and might have quelled the uprising early on. They might be alive today.”
Carita shuddered audibly. “A black hole—”
It could only be that. Mass, dimensions, radiation spectrum, everything fitted astrophysical theory. Peter Nordbo had recorded the idea in his notes, but he couldn't reconcile it with the sudden apparition in the heavens. The tumbling shell and the meteoroid gap accounted for that. Perhaps while they were here the kzinti, under his guidance, had found indirect ways to study the interior, the eerie effects of so mighty a gravitation on space-time. But Rover's crew already had ample data to be confident of what it was they confronted.
Burnt out, a giant star collapses into a form so dense, infinitely dense at the core singularity, that light itself can no longer escape its grip. The minimum mass required is about three Sols. Today. In the first furious instants of creation, immediately after the Big Bang, immeasurably great forces were at play. Where they chanced to concentrate, they had the power to compress any amount of mass, however small, into the black hole state. It must have happened, over and over. Countless billions must have formed, a few large, most diminutive.
In the universe of later epochs, they are not stable. Quantum tunneling causes them to give off particles, matter and antimatter, which mutually annihilate. For a body of stellar size, the rate of evaporation is negligible. But it increases as the body shrinks. Ever faster and more fiercely does the radiation go, until in a final supernal eruption the remnant vanishes altogether. Nearly every black hole made in the beginning has thus, long since, departed.
This one had been just big enough to survive to the present day. Applying what theory the ship's database contained, Dorcas had made some estimates. Three or four billion years ago it was radiating with about half its current intensity. Its mass, equal to a minor asteroid's, was now packed inside an event horizon with a diameter less than that of an atomic nucleus. Another 50,000 years or so remained until the end.
Carita rallied. “A weapon?” she asked. “How could that be?”
“Your mind isn't as nasty as mine,” Saxtorph replied absently. His attention was on high lattices, surrounding a paraboloid (?), which grew out of the shell where he stood. Their half-familiarity chewed at him. Almost, almost, he knew them.
“What else could it be?” Dorcas said. “A power source for peaceful use? Awkward and unnecessary when you have fusion, let alone total conversion. As a weapon, though, the thing is hideous. Invulnerable. Open a port, and a beam shoots out that no screen can protect against. At a minimum, electronics are scrambled and personnel get a lethal dose. No missile can penetrate that defense; if it manages to approach, it will be vaporized before it strikes. Sail through an enemy fleet, with death in your wake. Pass near any fort and leave corpses manning armament in ruins. Cruise low around a planet and sterilize it at your leisure.”
“Then why didn't the tnuctipun win?”
“We'll never know. But they can only have had this one. That was scarcely decisive. And… the war exterminated both races. Perhaps the crew here heard they were last of their kind, and went elsewhere to die.”
Saxtorph caught Tyra's whisper: “While the black hole, the machine, drifted through space for billions of years—” The Wunderlander raised her voice: “I am sorry. I should not interrupt. But do you not overlook something?”
“What?” Dorcas sounded edgy. As well she might be after these many hours, Saxtorph told himself.
“How could the tnuctipun bring the weapon to bear?” Tyra asked. “The black hole was orbiting free in interstellar space, surely, light-years from anywhere. The mass is huge to accelerate.”