"So what you are saying-" said Yaeger.

"Is that there is no emergency."

Pitt looked at Friend. "Come again."

"The event in seven thousand B.C.," explained Friend, "was a million-to-one chance occurrence. The comet that struck Earth, and the comet that arrived a few days later and missed, were not twins. They were separate objects in different orbits that happened to cross paths with Earth at almost the same time. An incredible coincidence, nothing more."

"How soon is the second comet due to return?" Pitt inquired warily.

Friend thought a moment, then said, "Our best guess is that it will fly by no closer than eight hundred thousand miles from us-in another ten thousand years."

35

THERE CAME SEVERAL MOMENTS of stunned silence, as perplexity flooded the minds of the people seated around Dr. Friend. Pitt swore softly under his breath. He stared steadily at Friend, as if attempting to read something in the astronomer's eyes, an uncertainty maybe, but there was none.

"The comet-" he began.

"Its name is Baldwin, after the amateur astronomer who rediscovered it," Friend interrupted.

"You say the Murphy comet and the second comet that the Amenes recorded are one and the same?"

Friend nodded vigorously. "No doubt about it. Calculations confirm that its...o...b..t coincided with the comet that caused the cataclysm of seven thousand B.C."

Pitt glanced at Sandecker and Pat, then back to Friend. "There can be no mistake?"

Friend shrugged. "A margin of error of perhaps two hundred years, but certainly no more. The only other large object to enter Earth's atmosphere in recorded history was the one that flattened those eight hundred square miles in Siberia. Only now are astronomers beginning to believe that, instead of a colossal impact, it was actually a near miss."

"Surely the Wolfs must have had access to the same data," said Loren, looking bewildered. "It doesn't make sense for them to liquidate every a.s.set of the family after having spent billions of dollars building a fleet of ships to survive a cataclysm they know is not about to happen."

"We all agree with you," said Sandecker. "It may simply be that the Wolf family is nothing more than a bunch of fruit-cakes."

"Not only the family," said Giordino, "but two hundred and seventy-five thousand other people who work for them and look forward to the voyage to nowhere."

"That doesn't sound like an insignificant cult of crazies to me," said Loren.

"Very true," Pitt agreed. "When Al and I infiltrated the supership, we found a dedicated fanaticism with surviving the deluge."

"I reached the same conclusion," added Pat. "The conversations I overheard regarding the coming cataclysm were resolute. There was not the slightest doubt in their minds that disaster would overtake the world and that they had been given the gift of rebuilding a new civilization without the handicaps of the old."

Giordino looked at Pat. "An echo of Noah and his ark."

"But on a far grander scale," Pitt reminded him.

Sandecker shook his head slowly. "I have to admit that this whole dilemma is a mystery to me."

"The Wolf family must have a solid motive." Pitt paused, as everyone stared at him in silence. "There can be no other answer. If they are convinced the civilized world is going to be swept away and buried for all time, they must know something no one else on Earth knows."

"I can a.s.sure you, Admiral," said Friend, "that disaster is not soaring in from the solar system. Certainly not in the next few days. Our tracking network sees no large asteroids or comets coming anywhere close to Earth's...o...b..t in the foreseeable future, certainly not before the end of the next century."

"So what else could produce such a disaster? Is there any way of predicting a crust displacement or a polar shift?" Yaeger asked Friend.

"Not without the opportunity to study such a phenomenon at first hand. Earthquakes, volcanic eruptions, and tsunami waves have been witnessed and recorded. But no crust movements or polar shifts have occurred since earth science emerged from the Greeks. So we have no solid data upon which to draw enough conclusions to even attempt predictions."

"Are there conditions on Earth that could cause the crust and poles to shift?" asked Pitt.

"Yes," Friend answered slowly. "There are natural forces that could upset Earth's balance."

"Such as?"

"The most likely scenario would be an ice shift at one of the poles."

"Is that possible?"

"Earth is like a giant child's top or gyroscope rotating on its axis, as it spins every year around the sun. And, like a top, it is not in perfect balance, because the landma.s.ses and poles are not ideally placed for perfect stabilization. So Earth wobbles as it rotates. Now, if one of Earth's poles grows until it becomes oversize, it affects the wobble, like an unbalanced wheel on your car. Then it could cause a crust displacement or polar shift. I know respected scientists who believe this happens on a regular basis."

"How often?"

"Approximately every six to eight thousand years."

"When was the last shift?"

"By a.n.a.lyzing cores pulled from deep beneath the seas, oceanographers have dated the last shift at nine thousand years ago, the approximate age your comet struck Earth."

"So you might say we're due," said Pitt.

"Actually, overdue." Friend made a helpless gesture with his hands. "We can't say with any confidence. All we know is that when the day comes, the shift will be very sudden. There will be no warning."

Loren stared at Friend uneasily. "What will be the cause?"

"The ice formation that acc.u.mulates on top of Antarctica is not distributed equally. One side of the continent receives much more than the other. Every year, over fifty billion tons of ice are added to the Ross Ice Shelf alone, a growing ma.s.s which increases Earth's wobble. In time, as the weight shifts, so will the poles, causing, as Einstein himself predicted, trillions of tons of water and ice thousands of feet high to race from both poles toward the equator. The North Pole will sweep south and the South Pole will sweep north. All the forces that were unleashed by a comet strike will be repeated. The major difference is that instead of a world population of about a million people nine thousand years ago, now we're looking at a world populated by seven billion people who will be swept to their deaths. New York, Tokyo, Sydney, Los Angeles will be completely inundated, while cities far inland will be leveled to the ground and disappear. Hardly a slab of concrete would be left where millions walked only a few days earlier."

"And if the Ross Ice Shelf were suddenly to detach itself from the rest of the continent and drift out to sea?" Pitt put to Friend, leaving the question hang.

Friend's face turned grim. "It's an event we've already considered. A simulation shows that a drastic movement by the Shelf would cause an imbalance broad enough to trigger a sudden shift of Earth's crust."

"What do you mean by drastic movement?"

"Our simulation demonstrated that should the entire ice shelf break away and drift sixty miles to sea, its relocated ma.s.s would increase Earth's wobble enough to trigger a pole shift."

"How long do you estimate it would take to drift sixty miles?"

Friend thought a moment, then said, "Taking into account the sweep of the currents in that part of the Antarctic, I should say no more than thirty-six hours."

"Is there no way to stop the drift?" asked Loren.