"It took longer than that," Ruiz said. "The Cygnans have been traveling for six million years."

Chapter 24.

There was a commotion within the crowd, and Tu Jue-chen came pushing her way through. They parted to make way for her, the Americans with somewhat more alacrity than the Chinese. She stood panting on the step below Ruiz and the ship's officers, shaking a liver-spotted fist at him.

"You are lie!" she shrilled. "You are lie!"

Beside Jameson, Maggie whispered, "What's this all about?"

"I don't know," Jameson said. "She's got some ideological bee in her bonnet."

Ruiz's expression was absolutely correct. "Why do you say that, Comrade Tu?" he said.

She showed her horse's teeth. "Because," she said triumphantly, "after six million years they would be socialists!"

Ruiz appeared to ponder the matter. "How do you know they're not?" he said finally.

"No!" she spat. "They are degenerate society!"

"I should think so," Ruiz said, "after six million years in their circ.u.mstances."

"Six million years is impossible!" Tu insisted.

Maggie nudged Jameson. "I don't follow her logic. Either they've been around long enough to become degenerate, or they've been around long enough to be socialists."

"Don't bother about the logic, Maggie," Jameson said. "It's just her way of getting across to the troops that the Cygnans are no longer their socialist buddies from the stars. We're having a change of line.

"But why?"

"Comrades don't lock the chosen up in a cage. They can't communicate with the Cygnans, and they know it now." He frowned. "I wonder if they're planning some kind of action."

"They are not travel for six million years," Tu was screaming. "You tell them, Comrade Chu!"

The Chinese astronomer had been standing off to one side, going over figures on the lightpad with Maybury. He stirred uneasily and said: "You see, Comrade Tu, the interval of time-"

"Tell them, tell them!"

Dr. Chu looked unhappy. "Of course there is always the possibility of error in Dr. Ruiz's computations, bu-"

Unexpectedly, Captain Hsieh broke in. His round face was stern, his short stocky body stretched to full height. "We must listen to Dr. Ruiz," he said. "He has learned an important thing about thehsing-ch'ung ."

The word he'd chosen meant, literally, "star-worms." "We must try to understand, so that we may act correctly."

"What's happening?" Maggie whispered.

Jameson said, "There's some kind of shift in power going on. We're a long way from New Peking. I think Captain Hsieh and his supporters have decided they're never going to see it again."

People's Deputy Commander Yao Hu-fang spoke out from the crowd. "Go ahead, Dr. Ruiz. We would like to hear you."

Ruiz nodded at him. He waited until the tumult died down. Tu Jue-chen wormed her way through the milling crowd and went off to sulk.

"Comrade Tu is right, in a sense," Ruiz said, watching her go. "The Cygnans haven't beentraveling six million years. Theyleft six million years ago."

Dr. Chu put down the lightpad, took a nervous glance at Captain Hsieh for rea.s.surance, and said: "We can be sure about the figures. You see, after the supernova explosion it would have taken the system another six million years to become an X-ray source. The X-ray stage is brief. It could not last more than fifty thousand years. But we know that Cygnus X-1 is an X-ray sourcenow! "

"Orhas been within the last ten thousand years," Ruiz said.

"Of course," Chu said apologetically. "It is ten thousand light-years away."

"Go on, Dr. Chu," Ruiz said. "You're doing fine."

"When the helium star exploded, its remnant collapsed. It became a black hole. Cygnus X-1, in fact, was the first black hole to be positively identified, back in the twentieth century. Now, the black hole continued to circle its companion-waiting, as Dr. Ruiz might say, for a chance to take back its stolen ma.s.s. "It must wait for six million years, till its companion burns up its ill-gotten hydrogen and becomes a blue supergiant. Blue supergiants are almost always a.s.sociated with such X-ray sources. A blue supergiant some-oh, twenty times larger than the sun will begin to lose ma.s.s in the form of a solar wind, at the rate of about a millionth of a solar ma.s.s per year. Some of the ma.s.s falls into the black hole. It disappears from the universe forever. But during that fall to infinity, the gas accelerates to tremendous speed, and is heated to a temperature of tens of millions of degrees Kelvin. It is this envelope of falling gas that generates X-rays. For a brief period-not more than fifty thousand years-it will shed X-rays burning with the radiance of ten thousand suns."

Chu stopped and mopped his brow. His eyes roved toward Hsieh, then to the People's Deputy Commander.

"After that," Ruiz said, "the newly formed blue supergiant overflowsits Roche lobe and pours its ma.s.s down the black hole at a rate that extinguishes it as an X-ray source."

Mike Berry was facing the two astronomers, hands on hips. "So you say our six-legged friends left home six million years ago, before all this happened?"

"There's no doubt of it," Ruiz said.

"Then tell me this-if Cygnus X-1 is ten thousand light-years away, and they've been traveling at the speed of light,where have they been all this time? "

Ruiz looked pleased at the question.

"That's obvious," he said. "Making stops."

Mike was a very bright person. He chewed it over a few moments, then said: "Dr. Ruiz. You've deduced a h.e.l.l of a lot about our little buddies from the ma.s.s of a star and the ma.s.s of a black hole. Now this ought to give us a clue about how long-"

"It does," Ruiz said.

Boyle got to his feet. "Dr. Ruiz, I think-"

"Let him go on," Hsieh said. "Our people have a right to know."

"You're right," Boyle said. "Go on, Dr. Ruiz." He sat down.

Ruiz looked round the crowd. Almost the whole human colony was there now. In the artificial starlight their faces were a pointillist cobble of silver blobs. Here and there a firefly darted as a glowing joint was pa.s.sed from hand to hand.

"The average distance between stars in our part of the galaxy is about six light-years," he said. "If the Cygnans traveled a more or less straight line getting here, zigzagging from star to star, they encountered sixteen or seventeen hundred of them. If they stopped to refuel atevery star, they would have stayed for an average of three thousand six hundred years each time." He paused. "If they stopped at, let us say, every tenth, star each visit would have lasted some thirty-six thousand years."

"Butwhy? " Mike pushed away the joint that someone offered him. "Tod Jameson says the Cygnans aren'tinterested in the systems they visit! They never make planetfall. Even granting that they'd have to do some robot mining from time to time, refurbish their ships, they ought to be able to travel more than six light-years on a gas giant! Once they got coasting at close to light-speed, they ought to be able to reach anothergalaxy , for G.o.d's sake, without refueling-even with the inefficiency you mentioned before. Just shut off their robot siphon and let it careen away into infinity. Make another one when they want to brake. Why waste two years out of six accelerating and braking if they're going somewhere-"

"They're not going anywhere," Ruiz said.

"What do you mean?"

"They've forgotten. After six million years, they've forgotten. Their pattern of travel-hopping from star to star-made sense when they started out. They were looking for a new home. They didn't find one they liked soon enough. So after a few thousand years, I imagine, they got used to living in ships. They were safe in the ships. A real world might not be safe. But their pattern of travel persisted. Degenerate societies cling to old habits, just like degenerate organisms."

"Okay," Mike said. "Maybe you're right. But I'm still asking why they hang around a system they're not interested in for three thousand years."

Ruiz looked around at the dappled faces. He sighed. He turned back to Mike. "Maybe they're getting up their courage for the next jump."

There was a growing murmur in the crowd. Ruiz held up a hand.

"We don't know what it's like to travel between the stars," he said. "All that empty s.p.a.ce must be a terrifying thing. Our own mariners in the ancient world and Middle Ages never braved the open sea, even when they knew their destination. They island-hopped, stayed within sight of land, traveled coastwise from point to point."

"Scared? After six million years in s.p.a.ce?" Mike said. "Minus-how much time for time dilation? You figure it out, but even if they'd come nonstop, it couldn't have saved them more than ten thousand years."

"That's the point exactly," Ruiz said. "If they'd covered the ten thousand light-years at-let's say-ninety-eight percent of the speed of light, then time is slowed... hmm... fivefold, and they have to spend two thousand years in the empty s.p.a.ce between the stars. Even at ninety-nine point ninety-nine percent of light-speed, the jump takes them a hundred years.Lifetimes for millions of Cygnans who never get to come in out of the dark! But if they star-hop, then with a year to boost, a year to brake, hmm, a few weeks or months to cover the intervening light-years, then they never have to spend more than three years adrift. Then they spend the next three thousand years or more getting brave enough to do it again."

A tremulous voice came out of the silver dark: Liz Becqued "Dr. Ruiz, are you saying that we're-that the Cygnans are going to remainhere , inthis solar system, that long?"

Ruiz shrugged. "There's no reason to a.s.sume anything different."

Maggie turned quickly to Jameson. "I thought you said-"

"Shhh-the old fox knows what he's doing."

"But-"

Jameson leaned to whisper in her ear. "Something's up with the Chinese. I don't think Ruiz believes they'll do anything precipitous, but he's taking the pressure off anyway. This buys time for the Cygnans."

Maggie looked around, made sure no one was listening. Everybody was intent on Ruiz. "But what he said about their stopping and staying at almost every star... that's true?"

"It has to be," he said with an uneasy glance around. "Either that or they parked somewhere for the whole six million years."

Maggie wouldn't let go. She seemed agitated. She tugged at his hand. "But yousaid they're leaving in a few days. Why isthis solar system any different?"

Jameson said, "Maybe the Cygnans have finally got their courage back."

"Tod,answer me!"

"All right. Maybe they're afraid of people. Maybe every once in a while, when they run across a system that looks unhealthy, they grab their hydrogen planet and hightail it out of there."

"The nuclear bombs we brought with us?"

Jameson glanced around again. "Perhaps. Or whatever else the human race might dream up in the next few thousand years."

Up on his platform, Ruiz was still talking. "... So perhaps the Cygnans aren't the formidable civilization we thought they were. As Dr. Berry pointed out, even their ma.s.s conversion engine might not be beyond our own capabilities in a century or two. We're still developing. They stopped, long ago. They're beginning to look like timid, fearful creatures. But fear can be more dangerous than confidence. We mustn't forget that the Cygnans have great powers, the capacity to do great mischief. So I'd urge us all not to do anything to panic them. Earth is still in a vulnerable position."

Maggie was nodding in agreement. "Their orbit out of here..." she began.

"Maggie, shut up," Jameson said. He gave her hand a warning squeeze. Klein was shouldering his way through the crowd, about to pa.s.s close to them. There was movement in other parts of the crowd as three or four people tried to maneuver themselves to the forefront to get closer to Ruiz. There was the sound of good-natured protest as people got shoved.

Ruiz had a debate going with young Dmitri Galkin. Dmitri was going on ponderously about fear and aggression in gray lag geese. "The mechanism of redirected behavior..." he was saying.

Klein had reached the front of the crowd. With a lithe movement he vaulted the final terrace and sprang to his feet in front of Ruiz.

"That's enough talk," Klein said. He faced the crowd. "Everybody listen to me!"

Dmitri started forward. "Now just a minute," he began.

"I said shut up!" Klein said. He gave Dmitri a shove that sent him sprawling. Dmitri was saved from toppling over the edge of the step by two or three people who caught him and propped him on his feet.

There was a growl from Omar Tuttle, who let go of Liz and started forward. Omar stopped in mid-stride.

Klein was standing in a little cleared s.p.a.ce where Ruiz and the ship's officers had backed off from him.

He was waving a flat, ugly object whose silhouette was unmistakable, even in the dim light. How he had obtained it was a puzzle.

It was a gun.

"All right," Klein said. "Everybody calmed down?"

He stood rocking on the b.a.l.l.s of his feet, the gun held dangling at his side. He looked remote and feral, with the narrow face and the sleek ferret head and the oversize arms meaty as thighs, sticking out of the chopped-off sleeves.

The packed throng was silent except for the whisper of shuffling feet. n.o.body moved.

"Better," Klein said. "I'm taking command of all American personnel here under the provisions of the National Security Act and the authority vested in me by Articles 42b, 46a, and subsections C and D." He delivered the words in a mechanical, singsong tone. "I am officially identifying myself as a special surveillance officer of the Reliability Board, with full authority over all SRA employees for the duration of this emergency."

"An arbee fink!" Omar spat. A murmur went through the crowd.

Klein flinched, but stood his ground. "Full compliance with my lawful orders is enjoined on this group under penalties of the Act. I will deputize such persons as I deem suitable. I will be a.s.sisted in these endeavors by security personnel attached to the Chinese crew under treaty provisions between the United States and the People's Republic."

Little Chia Lan-ying was making her way to Klein's side, followed by the hulking form of Yeh Fei.

"Hear me," she said stridently. "I am cultural officer ofShe-hui pu, the Social Affairs Department, and chief loyalty fighter here. Comrade Yeh knows this. Remember the Four Bigs! Grasp the Revolution!

Obey the People!"

The Chinese contingent looked at one another uneasily and began to draw together in little groups. One of Tu Jue-chen's people nodded vigorously and shouted, "Grasp the Revolution! Obey the People!" The cry was taken up by others.

Jameson said angrily to Maggie: "Caffrey and Tu weren't enough. They had to send types like those to keep an eye on us!"

He started forward. Maggie grabbed his sleeve. "Wait."

Several more people emerged from the boundary of the crowd and formed a loose phalanx around Klein and Chia. Jameson recognized the spare, lean form of Yao Hu-fang and one of the members of his bomb crew. One of the maintenance engineers, Fiaccone, was there with some kind of pipe in his hand.

Gifford took his place with the group, bouncing and clowning around, his clasped hands raised above his head like a boxer.

"The Giff?" Jameson said. "I don't believe it!"