Manella leaned forward again. “So you’ve traced its orbit back? To the fools who let it go?”

Teresa sat up, feeling chilled. A strange light seemed to shine in Alex Lustig’s eyes.

“It’s not easy,” he began. “Even a tiny, weighty object like Beta must have suffered deflections. Besides magnetic fields, there were inhomogeneities in the crust and mantle—”

Manella would have none of it. “Lustig, I know that look on your face. You’ve got something. Tell us! Where and when did it fall? How close can you pinpoint it?”

The British physicist shrugged. “Within approximately two thousand kilometers in point of entry—”

Manella moaned, disappointed.

“ — and within nine years, plus or minus, for date of initial impact.”

“Years!” Pedro stood up. He slapped the tabletop. “Nine years ago, nobody on Earth was capable of building singularities! Cavitronics was still a harmless theory. Lustig, your results are worse than useless. You’re saying that while we’re still likely to be destroyed, there’s no way to track and punish the guilty ones!”

For the first time, Teresa saw Alex smile openly, a look both empathic and feral, as if he had actually been looking forward to this. “You’re right on one count, but wrong on two,” he told Manella. “Can’t blame you, really. I made the same faulty assumptions myself.

“You see I, too, figured Beta had to have entered the Earth sometime since cavitronics became a practical science. Only after tracing Beta’s rate of growth and correcting for some hairy internal topologies did I realize it just has to be a lot older than we’d thought. In fact, those error bars I mentioned are pretty damn good.

“The date of entry was probably 1908. The region, Siberia.”

Teresa brought a hand to her breast. “Tunguska!”

George Hutton looked at her. “Do you mean… ?” he prompted. But Teresa had to swallow before finding her voice again. “It was the greatest airburst explosion in recorded history — even including that electromagnetic pulse thing the Helvetians set off. Barometers picked up pressure waves all the way round the world.”

Everyone watched her. Teresa spread her hands. “Trees were flattened for hundreds of kilometers. But nobody ever found a crater, so it wasn’t a regular meteorite. Theorists have suggested a fluffy comet, exploding in the atmosphere, or a bit of intergalactic antimatter, or…”

“Or a micro black hole.” Alex nodded. “Only now we know it wasn’t simply a black hole, but a far more complex construct. A singularity so complex and elegant, it couldn’t be an accident of nature.” He turned to face the others. “You see our problem. Our models say the thing has to come from a time before mankind possessed the ability to build such things… if we could do so even now.”

This time both Teresa and Pedro were speechless, staring. George Hutton asked, “Are you absolutely certain no natural process could have made it?”

“Ninety-nine percent, George. But even if nature did stumble onto just the right topology, it’s absurd to imagine such an object just happening to arrive when it did.”

“What do you mean?”

Alex closed his eyes briefly. “Look. Why would something so rare and terrible just happen to strike the planet at the very time we’re around to notice? Earth has been here four and one half billion years, but humans only a quarter million or so. And for less than two centuries have we been capable of noticing anything at all but the bitter end. That coincidence stretches all credulity! As my grandmother might say — it’s ridiculous to claim an impartial universe is performing a drama solely for our benefit.”

He paused.

“The answer, of course, is that the universe isn’t impartial at all. The singularity arrived when we’re here because we’re here.”

Silence stretched. Alex shook his head. “I don’t blame you for missing the point. I, too, was trapped by my modern, Western-masochistic conceit. I assumed only humans were clever or vicious enough to destroy on such a scale. It took a reminder from the past to show me what a stupid presumption that is, after all.

“Oh, I can give you the date and point of entry now. I can even tell you something about the thing’s makers. But don’t ask me how to take vengeance on them, Pedro. I suspect that’s far beyond our capabilities at present.”

Some of the others looked at each other in confusion. But Teresa felt queasy. She fought the effects, breathing deeply. No physical crisis could affect her as this series of abstract revelations had.

“Somebody wants to destroy us,” she surmised. “It’s… a weapon.”

“Oh yes,” Alex said, turning to meet her eyes. “It is that, Captain Tikhana. A slow but omnipotent weapon. And the coincidence of timing is easily enough explained. The thing arrived only a decade or two after the first human experiments with radio.

“Actually, the idea’s rather old in science fiction, a horror tale of paranoia that’s chillingly logical when you work it out. Somebody out there got into space ahead of us and doesn’t want company. So it — or they — fashioned an efficient way to eliminate the threat.”

“Threat?” Manella shook his head. “What threat? Hertz and Marconi make a few dots and dashes, and that’s a threat to beings who can make a thing like this?” He pointed to one of the flat screens, where Alex’s latest depiction of the cosmic knot writhed and wriggled in malefic, intricate splendor.

“Oh yes, certainly those dots and dashes represented a threat. Given that some lot out there doesn’t want competition, it would make sense to eliminate potential rivals like us as early and simply as possible, before we develop into something harder to deal with.”

He gestured upward, as if the rocky ceiling were invisible and the sky were all around them. “Consider the constraints such paranoid creatures have to work under, poor things. It may have taken years for our first signals to propagate to their nearest listening post. At that point they must fabricate a smart bomb to seek and destroy the source.

“But recall how difficult it is to send anything through interstellar space. If you want to dispatch it anywhere near the speed of light, it had better be small! My guess is they sent a miniature cavitron generator, one just barely adequate to make the smallest, lightest singularity that could do the job.

“Of course, if you start with a small singularity it’ll require quite some time absorbing mass inside the target planet before it can really take off. In this case, about a hundred and thirty years. But that should be adequate, usually.”

“It almost wasn’t, in our case,” Teresa said, bitterly. “If we’d invested more in space, we’d have had colonists on Mars by now. Maybe the beginnings of cities on asteroids or the moon. We could have evacuated some of the life arks…”

“Oh, you’re right,” Alex agreed. “My guess is we’re unusually bright, as neophyte races go. Probably most others experience longer intervals between discovering radio and inventing spaceflight. After all, the Chinese almost did something with electricity a couple of times, Babylon and the Romans.”

Pedro Manella looked down at his hands. “Smart, but not smart enough. So even if we eliminate this horrible thing the nightmare may not be over?”

Alex shrugged. “I suppose not. We and our descendants, should we live to have any, are at best in for a rough time ahead. As a Yank might put it—” and his voice dropped to a drawl ” — the galaxy we’re livin’ in appears t’be a mighty tough neighborhood.”

Manella’s face reddened. “You’re taking this awfully well to be joking about it, Lustig. Has the news driven you over the edge? Or are you saving up for yet another surprise? Maybe another deus ex machina to pull out of your hat, like last time?”

Teresa suddenly realized that was, indeed, what she was holding her breath for! He’s done it before… turned despair around with fresh hope. Maybe this time, too?