Eventually, like a cancer, the holes would destroy Jupiter.

As the core was consumed the structure would implode, like a failing balloon; Poole guessed the planet would heat up and there would be pockets of disruption and instability — explosions that would blast away much of the substance of the atmosphere. Tidal effects would scatter the moons, or send them into elliptical orbits; obviously the human inhabitants of the region would have to evacuate. Maybe some of the moons would even be destroyed, by tidal stresses and gravitational waves.

"At last," Poole said, "there will be a single, massive singularity. There will be a wide accretion disk composed of what’s left of the Jovian atmosphere and bits of smashed satellites; and the rest of the moons will loop around the debris like lost birds."

Jaar’s silence was as bland as Xeelee construction material.

Poole frowned. "Of course a single singularity would be enough to collapse Jupiter, if that’s all you want to do. So why have you brought this great flock of the things?"

"No doubt you’ve figured that out too," Jaar said dryly.

"Indeed. I think you’re trying to control the size of the final singularity," Poole said. "Aren’t you? The multiple ‘seed’ singularities will cause the loss of a fraction of the mass of the planet… I think you’ve designed this implosion to result in a final hole of a certain size and mass."

"Why should we do that?"

"I’m still working on that," Poole said grimly. "But the time scales… This could take centuries. I understand a great deal, Jaar, but I don’t understand how you can think in those terms, without AS."

"A man may plan for events beyond his own lifetime," Jaar said, young and certain.

"Maybe. But what happens when you’ve shot off the last of your singularities? The earth-craft is going to break up. Even if the inner shell of construction material keeps its integrity, the exterior — the soil, the grass, the very air — is going to drift away as the source of your gravity field is shot away into space."

He imagined the menhirs lifting from the grass like the limbs of giants, sailing off into Jovian space; it would be a strange end for the ancient henge, far stranger than could have been imagined by those who had carved the stones.

"And what will become of you? You seem determined to refuse any help from us. You must die… perhaps within a few months from now. And certainly long before you see your Project come to fruition, with the collapse of Jupiter."

Jaar’s face was calm, smooth, characterless. "We will not be the first to sacrifice our lives for a greater good."

"And the repulse of the Qax is a greater good? Perhaps it is. But—" Poole stared into the Friend’s wide brown eyes. "But I don’t think a noble self-sacrifice is all that’s happening here. Is it, Jaar? You show no interest in our offers of AS technology. And you could be evacuated before the end. There isn’t really any need for your sacrifice, is there? But you don’t fear death at all. Death is simply… irrelevant."

Jaar did not reply.

Poole took a step back. "You people frighten me," he said frankly. "And you anger me. You rip Stonehenge out of the ground. Stonehenge, for Christ’s sake! Then you have the audacity to come back in time and start the destruction of a planet… the gravitational collapse of most of the System’s usable mass. Jaar, I’m not afraid to face the consequences of my own actions. After all I was the man who built the time machine that brought you here. But I don’t understand how you have the audacity to do this, Jaar — to use up, destroy, so much of humanity’s common heritage."

"Michael, you must not grow agitated over this. I’m sure Shira told you the same thing. In the end, none of this" — he indicated the cavern—"none of us — will matter. Everything will be made good. You know we’re not prepared to tell you any more than you’ve figured out already. But you must not be concerned, Michael. What we are doing is for the benefit of all mankind — to come, and in the past…"

Poole thrust his face into the young man’s. "How dare you make such claims, lay such plans?" he hissed. "Damn it, man, you can’t be more than twenty-five years old. The Qax are a terrible burden for mankind. I’ve seen and heard enough to be convinced of that. But I suspect your Project is more, is bigger, is vaster than any threat posed by a simple oppressor like the Qax. Jaar, I think you are trying to change history. But you are no God! I think you may be more dangerous than the Qax."

Jaar flinched briefly from Poole’s anger, but soon the bland assurance returned.

Poole kept the boy in the cavern for some time, arguing, demanding, threatening. But he learned nothing new.

At last he allowed Jaar to return him to the outer surface. On the way up Poole tried to work the elevator controls, as he’d watched the Friend do earlier. Jaar didn’t stop him. Of course, the controls did not respond.

When they returned to the grassy plain Poole stalked away to his ship, his head full of anger and fear.

"Michael." Harry Poole’s voice was soft but insistent. "Michael, wake up. It’s started."

Michael Poole emerged from sleep reluctantly. He pushed back his thin blanket, rolled on his back, and rubbed his eyes. Beside him, he saw, Berg was already awake and sitting up. Poole lifted himself onto his elbows, wincing at a stab in his lower spine: Shira’s little hut was quiet enough, and the air of the earth-craft was still and comfortably warm; but — despite Miriam’s assurances that the hard surfaces were doing him the world of good — he doubted if he would ever get used to sleeping on nothing more than an inch of coarsely stuffed pallet over a floor of Xeelee construction sheeting.

Miriam Berg was already pulling on her one-piece Friend’s jumpsuit. "What’s started, Harry?"

The Virtual construct of his father, coarsened by diffraction, hovered over Poole, fuzzy with pixels. "The high-energy particle flux from the Interface portal has increased. Something’s coming, Michael. An invasion from the future — we’ve got to get out of here."

Poole, still struggling into jumpsuit and shoes, stumbled to the teepee’s open doorway. He squinted in the Jovian light and turned his face to the sky. The Interface portal hung there, delicate and beautiful, apparently innocent of menace.

"Spline," Berg breathed. "They’ll send Spline through. The living ships the Friends described, the warships of the Qax, of the Occupation, come to destroy the earth-craft. Just as we’ve expected."

There was an edge in Berg’s voice Poole had never heard before, a fragility that induced in him an atavistic urge to take her in his arms, shield her from the sky.

Berg said, "Michael, those things will defeat the best humanity can throw at them — fifteen centuries from now. What can we do? We haven’t got a hope of even scratching their ugly hides."

"Well, we can have a damn good try," Poole murmured. "Come on, Berg. I need you to be strong. Harry, what’s happening in the rest of the System?"

The Virtual, sharp and clear out here outside the teepee, shrugged nervously. "I can’t send a message out, Michael. The Friends are still blocking me. But the ships in the area have detected the high-energy particle flux." He met Michael’s eyes, mournfully. "Nobody knows what the hell’s going on, Michael. They’re still keeping a respectful distance, waiting for us to report back. They don’t see any threat — after all the earth-craft has simply sat here in Jovian orbit for a year, enigmatic but harmless. What can happen now?" He looked vaguely into the sky. "They’re — curious, Michael. Looking forward to this. There are huge public Virtuals, images of the portal and the earth-craft hovering over every city on Earth… It’s like a carnival."