Children of the Comet (20 page)

Parn sighed. “Everybody is saying that these days. I suppose that we humans are mere twigs in the grip of the Trees, and they can snap us in two or make us grow.”

“We have much to learn,” Torris said.

The two women had been whispering together. Firstmother made her way toward them and waited diffidently for a pause in the conversation. “Come over by the fire,” she said. “The meat is sufficiently cooked now.”

Irina had taken over one of the larger auditoriums for the infomeet report. She had expected maybe a few hundred people to show up. Most people, she thought, would watch it on their personal screens or catch up with it later on the Shipnet posting. But over a thousand people had filled the hall to overflowing, with an equal number clamoring outside to be let in. Joorn, to the dismay of the participants, had been given no choice but to announce that there would be a second live conference where questions could be asked.

Irina's specialists were sitting stiffly on straight-backed chairs on the platform, some half dozen of them, representing the departments that had burgeoned under them. One was Nina's friend Andrew, who had made himself the go-to expert on physical anthropology despite his youth. Another was Irina's original assistant, Laurel, who had just published a paper tracing similarities between the dialects of Torris's and Ning's tribes that suggested a common point of origin about a thousand years in the past.

“And so the field workers' report concludes that we've gone about as far as we can go in acculturation without causing mischief,” Irina was saying. “We can leave the Oort cloud and continue our exploration of the Sol-Centauri system with a clear conscience. Left to their own devices, they'll do just fine till we can check on them again. Torris and Ning, along with their priesthoods, will be the prime focal points of change, but they're bright people—they'd have to be to survive without technology in a space environment—and they're well on the road to developing beyond an aboriginal hunting society. I think Andrew has something more to say about that.”

Andrew replaced her at the lectern. He looked very young but thoroughly in command of himself and his audience. Nina, sitting in the front row between Joorn and Alten, looked at him with eyes aglow.

“Conclusions first, then the facts,” Andrew said mischievously. “Just the opposite of the way we do it in our little work groups when we're hammering out theories. We think we can now state with reasonable confidence where Torris's people came from, how long they've been here, and how they managed their miraculous survival with only an Eolithic culture.” He paused. “I say Eolithic rather than Paleolithic because they didn't even have stones to fashion into their first tools, as the australopithecines did.”

A hush fell over the audience. They were paying attention now.

“Their resources were only those of the ecology of vacuum-dwelling trees—wood; ice; the bone, sinews, and hides of the animal life that the tree supported; and the sugars and other products of the tree's metabolism. And oh yes, fire. They had fire when they started out. The australopithecines didn't. And I can assure you that fire-hardened wood has a cutting edge.” He held up a bandaged finger. “Our experiments proved that.”

Nina whispered to her grandfather, “Isn't Andrew marvelous? He actually made wooden knives and spearpoints just to be sure.” She added proudly, “I helped him when Laurel and the others belittled the idea. I was the one who had to bandage his finger.”

Joorn smiled benignly, but Alten maintained a stone-faced demeanor.

Now Andrew was using a cursor to trace a lot of confusing lines and arrows on an electronic easel he had illuminated, but nobody was bothering to follow the animation.

“We followed up the study of Torris's DNA with samples from those members of his tribe we could persuade to cooperate. Some thought the DNA swabs were part of a religious ritual, sanctioned by the priest, Claz. Other DNA, I'm sorry to say, we acquired surreptitiously. Some say unethically. We can debate that, but no harm was done, and given the sociometric circumstances, we can say that, objectively speaking, there was no invasion of privacy. What we found jibed with our study of Torris and Ning. The antigenic distance between us and them is no more than four hundred thousand years, give or take a hundred thousand years.”

A hand shot up. “How can that be? We come from six billion years in their past.”

Andrew smiled. “Good question. They were derived from the same genetic stock that we were, only about four hundred thousand years ago on our time scale.”

More hands were waving. “Time dilation,” someone offered.

“Exactly. Torris's ancestors got here the same way we did, only four hundred thousand years before our arrival.”

“Have you any theories to explain that?” somebody asked belligerently.

“We have. The relativistic math works out in any number of ways, depending on what assumptions we make about velocity and distance. What it boils down to is that Torris's distant ancestors either were returning from a galaxy closer than the galaxy that we were returning from or that they had a faster ship capable of crowding the speed of light another decimal point or two. They found Earth and the inner planets gone—engulfed by the sun. The sun was earlier in its red-giant phase, somewhat bigger than it is at present, its hydrogen gone, but still feasting on its helium reserves. The same stellar evolution had happened in the Alpha Centauri system, now within easy reach, but the primary star there was even earlier in its red-giant stage and correspondingly bigger. Perhaps their ship was in some kind of trouble—it wouldn't have been capable of another star hop, or perhaps it had run down its supplies. So with Earth gone, they did the only thing they could. They headed out to the Oort cloud, now augmented by Centauri's Oort cloud, containing plenty of real estate—trillions of comets with all the ingredients needed for life. And the Trees that grew on them.”

Another hand went up. “You mean the Trees were already there when they arrived?”

“We're getting ahead of ourselves, but yes. They'd had six billion years to evolve. Don't forget, Torris's forebears had only a four-hundred-thousand-year headstart on us—a mere drop in the bucket of time.”

He gave them time to digest that, then said, “I don't know how many generations it took for them to forget the star-hopping civilization they came from—it could have been fifty or a hundred thousand years—but eventually they hit bottom. They were the equivalent of the naked apes that we once were when early
Homo sapiens
and
Homo neanderthalensis
went their separate ways with the aid of the simple tools that were available to both of them in their common environment—chipped stone, wooden clubs, and so forth. The Neanderthals didn't make it, but
Homo sapiens
did. They became modern
Homo sapiens
—or
Homo sapiens sapiens,
as we paleoanthropologists like to say. Wise, wise apes. And at some point—about thirty thousand years before agriculture became a way of life and the first cities arose in Egypt and Mesopotamia—something quite wonderful happened.”

Nina grinned at her grandfather. “Guess what he's going to say next.”

Before Joorn could respond, someone in the front row impatiently yelled, “What?”

“Grandfathers,” Andrew said with a broad smile. “Grandfathers happened.” He regained his professorial tone. “That's the only way I can put it.”

He moved the cursor on the easel, and a procession of fossil skulls appeared, each with its own bar graph. A header helpfully proclaimed O-Y RATIO.

“Teeth are the reason we know this,” Andrew said. “In the early twenty-first century, a pair of paleoanthropologists had the bright idea of doing a statistical analysis of large numbers of fossil teeth. There were plenty of teeth—enamel is harder than bone. It was possible to tell from the wear of the teeth displayed how old the individual was at death.”

He paused for emphasis. “In other words, given an existence that was short, nasty, and brutish, had any of these individuals lived long enough to become a grandparent? And applying statistical methods that hadn't been used up until that time, it was possible to discover the O-Y ratio for any given population.”

There was an uneasy stirring in the audience, and Andrew anticipated the next question. “O-Y simply refers to the relative numbers of old and young individuals of breeding age—
old
being someone of thirty or more. And they discovered the remarkable fact that the O-Y ratio multiplied abruptly and dramatically about thirty thousand years before the onset of civilization. That was the turning point. We begin to see the sudden appearance of conceptual thought. Cave paintings. Ornamental necklaces, some of them quite elaborate. A new, more thoughtful method of chipping the flint weapons that had remained unchanged for hundreds of thousands of years, as far back as the pre-sapiens hominids. Tools changed from crude hand axes to quite sophisticated stone knives with long, thin blades. Man changed from a hunter-gatherer into a farmer. Of course there were cultural overlaps. In ancient Sumeria, well into the Bronze Age, there were peasants who were still using those Neolithic tools.”

The impish look reappeared on his face, and he said, “So we can thank grandfathers for civilization.” Catching the look that Nina gave him, he added, “And grandmothers. They'd lived long enough to pass on what they'd learned. How to weave a better basket. How to make a sharper knife or improve your range with a throwing stick. How to paint shells to make prettier necklaces. In a word,
traditions
. The sense that there is a past.”

He became utterly serious. “We believe that Torris's people were at this point when we found them. Certainly our survey found plenty of grandfathers. And grandmothers too—excuse me, Nina. They've had traditions for an unknown number of generations. Torris fell afoul of at least one of them.”

He lifted his head and locked eyes with his audience. “We also believe that Torris's people are at this turning point now and have been since their O-Y ratio began to change. And we think we can help speed things up.”

The fellow in the first row, whom Joorn now recognized as a classmate of Andrew's, raised his hand. Joorn believed that Andrew was not above using him as a plant to keep things moving.

“This is all very interesting, Andrew, but what a lot of us would like to know is where did this full-blown ecology based on the Bernal trees come from?” he asked. “How is it that Torris's shipwrecked antecedents found a ready-made environment able to support them after they'd finished cannibalizing their ship and sunk into savagery?”

“I think I'd better let Jen answer that,” Andrew said. “Jen is our expert on evolutionary theory.”

He made way for a lanky young woman with straggling ash-blond hair. Nina nudged Joorn. “Jen's new to the team, but she knows more than some of them.”

The young woman began briskly rearranging Andrew's visuals. The hominid skulls, the teeth, and the Stone Age tools flashed by and disappeared. When the blur of images slowed down and stopped, there was only a picture of a tree growing out of a comet left on the screen. The tree was ten or twenty times taller than the comet's diameter, like a small potato sprouting a stalk bigger than itself. It looked very much like Torris's Tree seen from a distance.

“This is an artist's conception of a Bernal tree,” Jen began. “It was drawn in the early twentieth century, before there was space travel or genetic engineering—at a time when most scientists thought that space travel would forever be impossible and before the very concept of genetic engineering even existed.

“Bernal's tree was derided by most scientists at the time, but in the years that followed, it was championed by a few visionary thinkers, notably the evolutionary biologist J.B.S. Haldane and the physicist Freeman Dyson. Here's what Dyson had to say about Bernal's dream.”

The tree was replaced by the close-up of a face, presumably that of the physicist. Jen read from the text of an old book that was also displayed on the screen.

“‘How high can a tree on a comet grow? The answer is surprising. On any celestial body whose diameter is of the order of ten miles or less, the force of gravity is so weak that a tree can grow infinitely high. Ordinary wood is strong enough to lift its own weight to an arbitrary distance from the center of gravity. This means that from a comet of ten-mile diameter, trees can grow out for hundreds of miles, collecting the energy of sunlight from an area thousands of times as large as the area of the comet itself.'

“‘Countless millions of comets are out there, amply supplied with water, carbon, and nitrogen—the basic constituents of living cells. They lack only two essential requirements for human settlement, namely warmth and air. And now biological engineering will come to our rescue. We shall learn how to grow trees on comets.'”

She paused to let that sink in. A low murmuring had begun in the audience. Jen let it grow, then said, “And evidently the human race did just that. The process had already begun when
Time's Beginning
left Earth in pursuit of a quasar. Captain Gant and his contemporaries can remember the early stages personally. We already had forests on the moon. Now the lumber industry proposed moving to the relatively nearby comets of the Kuiper Belt—the Oort cloud still seemed impractically far away then. The trees could be bigger—big enough to make wooden spaceships and habitats. We don't know what happened in the next six billion years after our departure. The Others came and, evidently, went. Humanity—whatever was left of it in our little corner of the galaxy—undoubtedly became extinct too. But the trees flourished and spread—to the Oort cloud and beyond.”

Nina could no longer contain herself. She stood up, shaking off Joorn's restraining hand, and said, “Tell them about the animals, Jen.”