"How far could we take this? I’d anticipate the manufacture of singularities themselves, on the scale of a few tons up to, maybe, asteroid masses."

"What for?"

Poole spread his hands wide. "Compact power sources. If you had a black hole in your kitchen you could just throw in the waste and see it compressed to invisibility in a fraction of a second, releasing floods of usable short-wavelength radiation. And how about artificial gravity? Bury a black hole at the center of, say, Luna, and you could raise the surface gravity as high as you like."

Harry nodded. "Of course you’d have to find some way of keeping the singularity from eating the Moon."

"Yeah. Then there’s gravity waves, to be generated by colliding black holes. You could build tractor beams, for instance." Poole settled back into his couch and closed his eyes. "Of course, if they’ve taken this far enough, maybe they will have found some use for naked singularities."

"And what’s a naked singularity?"

"…Maybe we’re going to find out."

Now they were entering a region of space filled with ships; hundreds of drive sparks flitted over the patient ocean of Jupiter. The ships were too distant to afford any detail, but Poole knew that there must be ships from the navies of the inhabited Jovian moons, science craft from the inner Solar System, and goddamned tourists and rubbernecks from just about everywhere. A subdued chatter in the background of the lifedome told him that signals were starting to come in from that motley armada — since the receipt of Berg’s message a year earlier, Poole knew, Jovian space had been the center of attention of most of the human race, and his own arrival here had been the most eagerly anticipated event since the emergence of the future ship itself.

He ignored the messages, letting Virtual copies of himself handle them; if there was anything devastating they’d let him know.

Peering into the crowded space ahead, and after his decades of isolation in the bleak outer lands of the Solar System, Poole felt a pang of absurd claustrophobia. He was driven on by curiosity as well as by a residual concern for Miriam Berg and her crew; but now that his year-long journey in from the Oort Cloud was complete he found he really, really didn’t want to be here, back among the fetid worlds of humankind.

Harry was studying him, his youthful brow creased. "Relax, son," he said. "It was never going to be easy."

"Oh, for Christ’s sake shut up," Poole snapped. Even as he spoke he was aware of an odd feeling of relief at having someone, or something, reasonably tangible outside his own head to react to. "I should put you in an electronic bottle labeled ‘Dad,’ and take you out when I feel the need of another patronizing fatherly homily."

Harry Poole grinned, unmoved. "Just doing my job," he murmured circumspectly.

Now the Crab, drive still blazing ahead of her, was approaching the densest knot of ships in the sky. The cloud of vessels, as if sensing the approach of the Crab, began to part.

Inside that firefly mist Michael could make out the lines of something huge: an artifact, a splash of green against the murky pink of Jupiter.

"That’s it," Poole said, finding his voice hoarse. "The ship from the future. Time to go to work…" He snapped a command into the air.

The crowded universe outside the lifedome was clouded by a sudden hail of pixels that danced like dust motes around the Crab, slowly congealing into planes, orbs, and strands around the lifedome. Harry squirmed in his seat, mouth open, as he watched the huge Virtual take shape around the ship. At last they were looking out through eyes that were each at least a hundred yards wide, with eyelids that swept like rainstorms over the glistening spheres. A nose like a vast engineering project, with nostrils like rocket nozzles, obscured the Crab’s GUT-drive module; and huge sculpted ears sailed alongside the lifedome.

A mouth, whale size, opened moistly.

"My God," Harry breathed. "It’s you, isn’t it? We’re looking out through your face."

"I couldn’t think of any other way to be sure we were identified properly. Don’t worry: the Virtual is all show; it’s not even as sentient as you are. It repeats a five-second phrase of greeting, over and again."

"So how will they hear what it has to say?"

"Harry, the Virtual is two miles high," Poole said, irritated. "Let them lip-read!"

Harry swiveled his head, surveying the nostrils, the cablelike hairs above the cabin, skin pores the size of small asteroids. "What a disgusting experience," he said at last.

"Shut up and watch the show."

Now there were ships all around the camouflaged Crab. Poole recognized Jovian Navy ships that bristled with weapon ports, science platforms open and vulnerable, even one or two inter-moon skitters that should surely never have been allowed so close. Many of the larger craft followed the same basic design as the Crab, with drive unit and living quarters separated by a stem; from this distance the ships looked like lit matchsticks, scattered through space.

"How do you think the men from the future will react to us?" Harry asked with sudden nervousness.

Poole, glancing across, saw Harry chewing a nail, a habit he remembered from a distant childhood. "Maybe they’ll shoot us out of the sky," he said maliciously. "What do you care? You’re tucked up in bed on Earth, well away from any danger."

Harry looked at him reproachfully. "Michael, let’s not go over that again. I’m a Virtual, but I have my identity, my sense of being."

"You think you do."

"Isn’t that the same thing?"

"Anyway, I doubt if we’re in any danger," Poole said. "The future people haven’t made any attempt to use weapons so far; why should they now?"

Harry nodded grudgingly. "True." After the future ship had settled into its orbit around Jupiter there had been several attempts by Jovian ships to approach the craft. The future humans hadn’t responded, or fired on the Navy ships; they’d simply run away, faster than they could be tracked.

"Maybe they haven’t any weapons," Harry said.

Poole pursed his lips. "That’s possible, I guess. They do have their superdrive. though."

"I know there’s speculation that could be some kind of hyperspace drive," Harry said.

"Maybe. But if that’s true we’ve no idea how it works. It’s not possible to extrapolate from existing technologies, the way I speculated about singularity technologies; a hyperdrive would represent a quantum leap."

"Maybe it’s not a human invention. Maybe it’s alien."

"Anyway, I don’t think we’re in any danger of being fired on; and if they want us to come in they’ll not run away."

"How reassuring," the Virtual murmured.

Now the last few layers of craft peeled away before them, the GUT-drive fire-sparkles sliding aside like scared insects.

The future craft was revealed, like a fragment of landscape emerging through a layer of cloud. The Crab’s drive died at last, and Poole’s Virtual, mouthing its idiot words of greeting, loomed over a disk of green Earth a quarter mile wide. To Poole it was like looking down from an aircraft. He could clearly make out the ring of ancient stones at its center, like gray-brown scars against the greenery. A belt of anonymous-looking dwellings encircled the stones, and beyond the belt grass grew as in some surrealist’s vision, all the way to the edge of the world; the green of it clashed in his eyes with the purple-pink of Jupiter, so that it was as if the craft were encircled by a scar of indeterminate color.

Close to the rim Poole made out a splash of metal, a scarred crater in the grass. Could that be a boat from the Cauchy?

Sparks of light, like entrapped stars, were sprinkled over this floating fragment of Earth. And here and there Poole could see tiny, insectlike forms crawling across the landscape. People? He imagined faces upturned in wonder to his own vast, smiling mouth.