By the end of the day Hunt’s mind was in a whirl. New information was coming in faster than he could digest it. The questions in his head were multiplying at a rate a thousand times faster than they could ever be answered. The riddle of the Ganymean spaceship grew more intriguing with every new revelation, but at the back of it there was still the Lunarian problem unresolved. He needed time to stand back and think, to put his mental house in order and sort the jumble into related thoughts that would slot into labeled boxes in his mind. Then he would be able to see better which question depended on what, and which needed to be tackled first. But the jumble was piling up faster than he could pick up the pieces.

The banter and laughter in the mess after the evening meal soon became intolerable. Alone in his room, he found the walls claustrophobic. For a while he walked the deserted corridors between the domes and buildings. They were oppressive; he had lived in metal cans for too long. Eventually he found himself in the control tower dome, staring out into the incandescent gray wall that was produced by the floodlights around the base soaking through the methane-ammonia fog of the Ganymedean night. After a while even the presence of the duty controller, his face etched out against the darkness by the glow from his console, became an intrusion. Hunt stopped by the console on his way to the stairwell.

"Check me out for surface access."

The duty controller looked across at him. "You’re going outside?"

"I need some air."

The controller brought one of his screens to life. "You are who, please?"

"Hunt. Dr. V. Hunt."

"ID?"

"730289 C/EX4."

The controller logged the details, then checked the time and keyed it in.

"Report in by radio in one hour’s time if you’re not back. Keep a receiver channel open permanently on 24.328 megahertz."

"Will do," Hunt acknowledged. "Good night."

"Night."

The controller watched Hunt disappear toward the floor below, shrugged to himself, and automatically scanned the displays in front of him. It was going to be a quiet night.

In the surface access anteroom on the ground level, Hunt selected a suit from the row of lockers along the right hand wall. A few minutes later, suited up and with his helmet secured, he walked to the airlock, keyed his name and ID code into the terminal by the gate, and waited a couple of seconds for the inner door to slide open.

He emerged into the swirling silver mist and turned right to follow the line of the looming black metal cliff of the control building. The crunch of his boots in the powder ice sounded faint and far away, through the thin vapors. Where the wall ended he continued walking slowly in a straight line, out into the open area and toward the edge of the base. Phantom shapes of steel emerged and disappeared in the silent shadows around him. The gloom ahead grew darker as islands of diffuse light passed by on either side. The ice began sloping upward. Irregular patches of naked, upthrusting rock became more frequent. He walked on as if in a trance.

Pictures from the past rolled by before his mind’s eye: a boy, reading books, shut away in the upstairs bedroom of a London slum… a youth, pedaling a bicycle each morning through the narrow streets of Cambridge. The people he had been were no more real than the people he would become. All through his life he had been moving on, never standing still, always in the process of changing from something he had been to something he would be. And beyond every new world, another beckoned. And always the faces around him were unfamiliar ones-they drifted into his life like the transient shadows of the rocks that now moved toward him from the mists ahead. Like the rocks, for a while the people seemed to exist and take on form and substance, before slipping by to dissolve into the shrouds of the past behind him, as if they had never been. Forsyth-Scott, Felix Borlan, and Rob Gray had already ceased to exist. Would Caldwell, Danchekker, and the rest soon fade away to join them? And what new figures would materialize out of the unknown worlds lying hidden behind the veils of time ahead?

He realized with some surprise that the mists around him were getting brighter again; also, he could suddenly see farther. He was climbing upward across an immense ice field, now smooth and devoid of rocks. The light was an eerie glow, permeating evenly through mists on every side as if the fog itself were luminous. He climbed higher. With every step the horizon of his vision broadened further, and the luminosity drained from the surrounding mist to concentrate itself in a single patch that second by second grew brighter above his head. And then he was looking out over the top of the fog bank. It was just a pocket, trapped in the depression of the vast basin in which the base had been built; it had no doubt been sited there to shorten the length of the shaft needed to reach the Ganymean ship. The slope above him finished in a long, rounded ridge not fifty feet beyond where he stood. He changed direction slightly to take the steeper incline that led directly to the summit of the ridge. The last tenuous wisps of whiteness fell away.

At the top, the night was clear as crystal. He was standing on a beach of ice that shelved down from his feet into a lake of cotton wool. On the opposite shore of the lake rose the summits of the rock buttresses and ice cliffs that stood beyond the base. For miles around, ghostly white bergs of Ganymedean ice floated on an ocean of cloud, shining against the blackness of the night.

But there was no Sun.

He raised his eyes, and gasped involuntarily. Above him, five times larger than the Moon seen from Earth, was the full disk of Jupiter. No photograph he had ever seen, or any image reproduced on a display screen, could compare with the grandeur of that sight. It filled the sky with its radiance. All the colors of the rainbow were woven into its iridescent bands of light, stacked layer upon layer outwards from its equator. They faded as they approached its edge and merged into a hazy circle of pink that encircled the planet. The pink turned to violet and finally to purple, ending in a clear, sharp outline that traced an enormous circle against the sky. Immutable, immovable, eternal… mightiest of the gods-and tiny, puny, ephemeral man had crawled on a pilgrimage of five hundred million miles to pay homage.

Maybe only seconds passed, maybe hours. Hunt could not tell. For a fraction of eternity he stood unmoving, a speck lost among the silent towers of rock and ice. Charlie too had stood upon the surface of a barren waste and gazed up at a world wreathed in light and color-but the colors had been those of death.

At that moment, the scenes that Charlie had seen came to Hunt more vividly than at any time before. He saw cities consumed by fireballs ten miles high; he saw gaping chasms, seared and blackened ash that had once held oceans, and lakes of fire where mountains had stood. He saw continents buckle and break asunder, and drown beneath a fury of white heat that came exploding outward from below. As clearly as if it were really happening, he saw the huge globe above him swelling and bursting, grotesque with the deceptive slowness of mighty events seen from great distances. Day by day it would rush outward into space, consuming its moons one after the other in an insatiable orgy of gluttony until its force was spent. And then…

Hunt snapped back to reality with a jolt.

Suddenly the answer he had been seeking was there. It had come out of nowhere. He tried to trace its root by backtracking through his thoughts-but there was nothing. The pathways up from the deeper levels of his mind had opened for a second, but now were closed. The illusion was exposed. The paradox had gone. Of course nobody had seen it before. Who would think to question a truth that was self-evident, and older than the human race itself?