Certain stars glowed more brightly than others... and planetary systems circled them, greatly enlarged for effect. Now all but two of these systems turned sullen red-turned enemy. These were the worlds that had turned against the State.

One of the red systems sparkled and faded into the background, its colony destroyed.

The two neutral systems went red.

Another system faded out.

The view closed on Sol system... on more of Sol system than Corbell had known, with three dark gas giants beyond Pluto, and countless swarming comets.

Fleets of s.p.a.cecraft moved out toward the renegade colonies. Other fleets invaded. Sometimes they came like a hornet's nest, many ships cl.u.s.tered around a Bussard ramjet core. Sometimes like a Portuguese man-of-war: thousands of ships as weights around the fringe of a great silver light-sail. Early fleets included hospital ships and return fuel; later there were ma.s.sive suicide attacks.

It went on for centuries. The State utopia became a subsistence civilization, turning all its surplus energy to war. The fleets moved at just less than lightspeed. News of success or failure or need for reinforcements moved barely faster. The State was Boys and Girls and dictators all united for the common good. Corbell hurt with the loss of that unity.

He watched a beam of light bathe Sol system: laser cannon firing from Farside colony. Farside launched warships by light-sail at terrific accelerations. The ships dropped their sails and decelerated most of the way to Sol, arriving just behind the beam itself, long before the State could prepare. Corbell squirmed in his chair; he wanted to cry warning. For the State beat the invaders back, but failed to stop their hidden treachery.

The war continued. Farside, economically ruined by its effort, fell before the counterattack. It took a man's lifetime... too much time, before Astronomy noticed what the Farside traitors had done in the dark outside their dazzling light beam, in the distraction provided by the invasion.

The State had looked for the light of fusion s.p.a.cecraft, not the dim watery light of a new planet. The trans-Plutonian planet called Persephone had had a peculiar orbit, tilted nearly vertical to the plane of the solar system. Its new path had already taken it deep into the system.

10 to the power 23 tons of hydrogen and hydrogen-compound ices were aimed to strike the sun at solar-escape velocity. Earth's oceans would boil...

The State did what it could. Tens of thousands of fusion bombs, Sol system's entire armory, were set off at the dawn side of Persephone, just above the atmosphere. A thick rind of the planet's atmosphere peeled away and streamed off like a comet's tail, its ma.s.s pulling at Persephone's dense core. A streamer of gas far more ma.s.sive than the Earth broke free, and rounded the sun, and sprayed back toward the cometary halo.

If the bombs could have been placed earlier, Persephone's core would have done the same. It was rock and iron, yellow-hot, and it glowed X-ray hot as it streaked into the solar photosphere and disappeared.

The sun grew bright.

Oceans shrank, crops withered, tens of millions died before the State could place a disk of reflecting tinsel between Earth and Sol. It was a temporary measure. The sun's new heat was permanent, at least on the human scale of time. Fusion would run faster in Sol's hotter interior. The buried heat would leak to the photosphere and out.

The State had one chance for survival. It could move the Earth by the method Farside had used to stop Persephone cold in its...o...b..t.

"Do you understand what you're seeing?"

Corbell made a shushing gesture. "Yeah."

"Good. We were afraid. The light show and the bottled memory are both very old. They date from the end of the rule of the Girls. They have been stored in zero-time for... perhaps a hundred thousand years, perhaps more. We feared they must have decayed," said Skatholtz.

"So you tried it on me." But his anger seemed impersonal, remote.

The State had had to abandon the Mercury mines: a serious industrial handicap. Nonetheless they were building something out there in the asteroid belt-something huge, like a starship big enough to carry the whole human race to safety. But no, that wasn't it. Corbell was fascinated. He knew it might be the memory RNA, but he was fascinated anyway. He hardly heard what Skatholtz was saying: "It was sensible, Corbell. The Girls who made the light show ruled the sky. You are familiar with such things. Do you know now who hurled a moon at us?"

"Not yet. Shut up and let me..."

They had finished the thing. Two tubes, concentric, each a hundred miles long; the inner tube a mile wide, with thick walls of complex construction; the outer tube thinner and twice as wide. At one end, a bell-shaped rocket nozzle. At the other... Corbell knew more than he was seeing. Reworked military laser cannon, and vents, and a flared skirt, and thick stubby fins, there at the bottom end. Now temporary liquid hydrogen tanks were attached. Now the structure moved under its own power... it was a tremendous fusion motor... moving outward, circled by tiny ships... yeah.

Corbell said, "How do you climb down off an elephant?"

"Should I know that?"

"You don't climb down off an elephant. You climb down off a duck."

"Why?"

"It's so much safer. How do you move the Earth?"

Small wonder if the light show meant little to Skatholtz. Watching the construction of the motor-in the naked sunlight and sharp-edged, totally black shadows of s.p.a.ce-was bewildering. The diagrams made sense to an architect, but they were only rotating lines to Skatholtz. But without bottled memory and without Corbell's career in s.p.a.ce, Skatholtz was still bright enough to make some some sense of what he was seeing. sense of what he was seeing.

"You move something else," Skatholtz said. "The damage done by the rocket's thrust and by mistakes you might make will not kill anyone if n.o.body lives on the working body. Then the working body can be moved until the world falls toward it as a rock falls to the ground. What was the working body? Ganymede?"

"Ura.n.u.s. Can you stop the light show at that picture?"

The lecture froze on an "artist's conception": a blurred, curved arc of Ura.n.u.s's upper atmosphere. The motor looked tiny floating there. Corbell said, "You see? It's a double-walled tube, very strong under expansion shock. It floats vertical in the upper air. Vents at the bottom let in the air, which is hydrogen and methane and ammonia, hydrogen compounds, like the air that the sun burns. You fire laser cannon up along the axis of the motor, using a... color hydrogen won't let through. You get a fusion explosion along the axis."

"I don't understand all your words. Fusion?"

"Fusion is the way a star burns. You probably used fusion bombs against the Girls."

"Okay. The hydrogen fusions in the middle of the motor-"

"-and the explosion goes out and up. It's hottest along the axis, cooler when it reaches the walls of the motor. The whole ma.s.s blasts out the top, through the flared end. It has to have an exhaust velocity way higher than Ura.n.u.s's escape velocity. The motor goes smashing down into deeper air. You see there's a kind of flared skirt at the bottom. The deep air builds up there at terrific pressure, stops the tube and blasts it back up. You fire it again."

"Elegant," said Skatholtz.

"Yeah. n.o.body's there to get killed. Control systems in orbit. The atmosphere is fuel and shock absorber both-and the planet is mostly atmosphere. Even when it's off the motor floats high for awhile, because it's full of hot hydrogen compounds. If you let it cool off it sinks, of course, but you can bring it back up to high atmosphere by heating the tube with the laser, firing it almost almost to fusion. Start the light show again, will you?" to fusion. Start the light show again, will you?"

Skatholtz barked something at Krayhayft. Corbell watched: Earth held out, barely. Heat-superconducting cables had to be run to the north polar cap to borrow its cold. The cap melted. Millions died anyway. No children were born; there wasn't shelter for them. It took over a century to drop Ura.n.u.s into place, six million miles ahead of the Earth in Earth's...o...b..t. The planet accelerated slowly, drawing Earth after it... and then sped up, to leave Earth behind, in a wider orbit. They lost the Moon.

The sun expanded via its own internal heat. Light was reddened, but the greater surface lost more heat to s.p.a.ce... to Earth. By now the Girls had charge of Ura.n.u.s and the floating fusion motor. They moved the Earth again.

Five times the Earth had to be moved. At one time it was circling precisely opposite Mars. Later, further out. Internally Sol's fusion furnace had stabilized; but the photosphere was still growing. And the Earth must be moved a sixth time.

With RNA-augmented intuition Corbell said, "Here's where they have their trouble."

The Earth was too warm. There is a region around any stable sun, a rather narrow band in which an Earthlike world can have Earthlike temperatures. But Sol's ideal temperature band had moved too close to Jupiter. The giant world would have pulled Earth out of orbit- perhaps into a collision course.

Put Earth in orbit around Jupiter itself? But the sun's heat output was leveling off. The Earth would suffer a permanent ice age-unless Jupiter could be made to shine hotter.

"I can't figure that last part," said Corbel. "Run it again."

Krayhayft ran it again. Two nearly identical astronomical scenes divided by a wall across s.p.a.ce. Corbell watched Ura.n.u.s pull away from Earth, drop behind Ganymede and coast outward. Ganymede fell... twice. In one scene it grazed Jupiter, flaring as it pa.s.sed through the atmosphere a dozen times, and finally decaying in a prolonged burst of h.e.l.lfire. In the second scene the fleck of light dropped straight in: one flare, and gone.

"Yeah. They tried to be clever," said Corbell. "They thought they were good enough to do a two-shot. They used Ura.n.u.s to pull the Earth past Jupiter, slowed it to put the Earth in Jupiter orbit, then dropped Ura.n.u.s deep into the moon system. The idea was to stop Ganymede almost dead in its tracks. Of course the maneuver fouled up a lot of lunar orbits."

"What went wrong?"

"I'm not sure. The Girls wanted a grazing orbit. Instead the moon dropped straight in. But so what?"

Skatholtz made no answer.

It was hard to think. The deep knowledge of giant fusion pulse-jets and Ura.n.u.s's atmosphere and interstellar war hadn't been in his head until now. It let him understand the history tape, but when he tried to think with the new data it came out all jumbled. d.a.m.n Skatholtz anyway: Why should Corbell tell him anything? But the problem fascinated him. The RNA carried that fascination... and Corbell knew it... and couldn't bring himself to care.

"Let's see. Jupiter puts out more heat than it gets from the sun.

That's heat left over from when the planet fell in on itself out of the original dust cloud, four billion years ago-my years. So the planet could hold heat and leak it out for a long, long time. But the energies should be the same no matter what angle the moon fell at."

"This impact, would it cause fusion? Would Jupiter b.u.m?"

"Jupiter's too small to burn like a star. Not enough ma.s.s, not enough pressure. But yeah, there'd be a h.e.l.l of a lot of pressure in the shock wave ahead of Ganymede. And heat."

"Difficult to add up?"

"What?"

Skatholtz said, "The numbers of the heat made by a grazing fall should be simple. They knew the ma.s.s of Ganymede and the height of the fall. The Girls could add up just how much hotter Jupiter would become to warm the world just enough. But. The heat made by fusion is too complicated to add. The Girls made their numbers simple with the grazing orbit. Would the heat added be great?"

Corbell was nodding. "Look: The center of Jupiter is compressed hydrogen, really really compressed, to where it acts like a metal. Ganymede drops straight in. The fusion goes on in the shock wave, and it adds, it builds up: The continuous fusion explosion makes the shock wave greater and greater. The heat has been leaking out ever since." compressed, to where it acts like a metal. Ganymede drops straight in. The fusion goes on in the shock wave, and it adds, it builds up: The continuous fusion explosion makes the shock wave greater and greater. The heat has been leaking out ever since."

"I can't picture this, Corbell. Does it make sense to you?"

"Yeah. They lost a moon, and it killed them. Ura.n.u.s was on its way into interplanetary s.p.a.ce. The Girls couldn't bring it back in time. Their territory was too hot. They tried to take Boy territory."

Corbell became aware that the show had ended. New memories settling in his brain still dizzied him. But he felt like Jaybee Corbel. His personality seemed intact.

Skatholtz said, "Then the new moonlike object is Ura.n.u.s. Some Girls must have survived. What can we do? We don't have s.p.a.cecraft. We can't build them fast enough. Corbell, could we use your landing craft?"

"No fuel." Corbell laughed suddenly. "What would you do with a s.p.a.cecraft? Ram Ura.n.u.s? Or learn to fly it?"

"You're hiding something."

"I don't believe in your Girls. If they survived this long, they would have done something long ago." Ura.n.u.s's arrival was too dramatically fortuitous. Such a coincidence had to be explained away; and Corbell had thought of an explanation. Well... try misdirection. "Could they have held out in the Himalayas? There's life in some of the high valleys. They'd be a long time building industry there."

"Your place names mean nothing." Skatholtz helped him stand up. "Can you point out this Himalayas place on a picture of the world? There was one downstairs."

CHAPTER EIGHT:

DIAL AT RANDOM.

I.

The stairway was a long diagonal across the building's gla.s.s face. The bannister jogged to horizontal at six landings; otherwise it ran straight down to the admissions room.

Skatholtz and Krayhayft spat Boyish at each other. Corbell caught some of the exchange: Skatholtz telling the tale as it had come from Corbell, Krayhayft checking it against "tales" memorized over several hundred years of life. There was something Italian in the way their hands jumped and their mouths spat syllables; but their faces were blank. Scared Scared, Corbell thought. The "tales" matched too well.

Corbell tried to set his thoughts in order. He'd been given far too much to a.s.similate all at once.

Girls could could have survived this long. Peerssa had found pockets of life in isolated places. But they would have acted! Unbelievable, that Corbell could have returned just in time for their million-year delayed vengeance. have survived this long. Peerssa had found pockets of life in isolated places. But they would have acted! Unbelievable, that Corbell could have returned just in time for their million-year delayed vengeance.

He had to escape. It had been urgent. It was more urgent now. Could Boys slide down a bannister? Unlikely that they'd ever practiced. But Corbell hadn't practiced recently...

"They were fools," Krayhayft was saying. "They should have chosen several smaller moons to drop one by one."

"You're the fool," Corbell snapped, surprising himself. "It would have taken too long to bring Ura.n.u.s back each time. It would have fouled up too many orbits. We're talking about a planet ten times as big as the world!"

"So big that the Girls lost track of its path," Krayhayft sneered.

Skatholtz was saying, "The dance of Jupiter's moons is very complex-"

While Corbell was saying, "You arrogant ball-less idiot-"

Casual, contemptuous, Krayhayft's backhand swipe caught him under the jaw and lifted him and flung him back on the steps. "The bottled memory has given you too much of the Girls' view," Krayhayft said.

"And whose fault is that?"

Skatholtz pulled Corbell to his feet. His elbow hurt furiously, but he thought he hadn't broken anything, and that was fiercely important now. Still, it was just as well he hadn't tried the bannister. Two Boys were waiting below them in the admissions room.

They waited for the leaders to descend. One was young, two or three Jupiter years old by Corbell's estimate. He burst into speech as if he wanted to get it over with: "Gording is still loose. He has not used a prilatsil. The thread he took was mine. He must have brushed against me and taken it from my belt. I didn't notice."

"Where is he?" Skatholtz demanded.

"He went north and east, until we lost his track. Toward the edge of Parhalding."

"It may be he doesn't know about the-" something Corbell couldn't catch. "Search the streets but not the buildings. That way he cannot trap you with thread. He may be trying to reach the Dikta Place on foot. We can stop him then. Or he may try to take a tchiple tchiple-" an unfamiliar word. "Look for undamaged tchiples. Damage them. Tell the others now."

The younger Boy ran, eager to be gone.

What was a tchiple? A bubble-car? How did the Boys know whether Gording had used a "phone booth"?

"You must retrace our path," Skatholtz told the other Boy. "Warn all you meet that a dikt is loose. Gording must not return to the Ditka Place." He wheeled suddenly and barked, "You are staring, Corbell. Do we fascinate you?"

"Very much. Couldn't Gording use a prilatsil without your knowing?"

"No." Skatholtz smiled. He pointed at the wall map. "That is a picture of the world, isn't it? An old one, made when ice still covered this land."

"Yes. Can I use your spear?"

That was sheer bravado; he wanted to see what would happen. What happened was that Skatholtz handed Corbell his spear. The younger Boys were gone, but Skatholtz and Krayhayft betrayed no obvious tension. Corbell pointed with the haft. "These are the Himalayas, mountains. There are valleys high up, where it is cooler. From orbit I saw green things growing there. Further north, here on the Sea of Okhotsk, energy is being used for industry. It may be only machines left running, but-"

"It could be Girls. Would it be too hot for them? No, the pole is near enough. But you don't think so, Corbel."

"No. Why would they wait so long? How would they build s.p.a.ceships?"

"We don't know how s.p.a.ceships are built." Skatholtz looked through the broken picture window, toward where the new planet would appear at dark. "If Ura.n.u.s is falling free, we can do nothing. If the Girls are guiding it... what will they do? Smash the world? Make it cold again and take back their land? You knew Girls, Corbell."