Children of the Comet (11 page)

“Good question,” Chu said. “The answer is that they didn't randomly drift. Your grandfather can tell you about that.”

Joorn obliged. “They had light sails, and they had their plantlike volition,” he said. “All plants are phototropic, each in its own fashion. The poplar trees that these immense growths were derived from were no exception. But, with an assist from the genetic engineers of the day, they could utilize parts of the electromagnetic spectrum that ordinary plants can't—from the long radio waves below the infrared to the x-rays and gamma rays at the top. It didn't kill them, because they had reflective leaves that bounced the dangerous stuff back and forth till it was usable. And more to the point, the tropisms that made this possible turned their leaves into little light sails to seek promising sources of light—including supernova flashes in nearby galaxies. Trees are patient. They could build up their acceleration through light pressure over periods of hundreds of years, maybe even attaining modest relativistic speeds.”

Chu couldn't restrain himself. “Those early genetic engineers speculated that by the time of the Big Crunch—they believed in it then—Earth life in the form of those wandering trees could spread through the entire Universe.”

“And that's not all,” Joorn said. “Don't forget that all trees harbor commensal life—even those early moon-nurtured trees that first seeded the Oort cloud acquired it one way or another. You saw it on Rebirth and even in our little shipboard forest. Insects. The spiders that feed on insects. Moths—you can't escape them—and the bats that hunt moths. Tree snakes. Fungi of all types. Parasitic plants and symbiotic plants. Every tree has its own rich ecology, and the Bernal trees were in effect self-contained planetoids that provided water, nutrients, and the internal atmospheres that they manufactured for their own use out of cometary ice.”

Joorn could see that Nina was getting caught up in the speculation. “And the people who harvested the trees in the Oort cloud must have lived there while they worked on them,” she offered. “They would have brought plants and animals of their own.”

“Good point, princess. The lumberjacks they sent out from Earth would have had to live there for years at a time while they trimmed branches and operated the sawmills that made the giant boards, and otherwise prepared to send their products sunward. And of course they would have had to be fed. That means cattle and other meat animals. Chickens and turkeys—”

“Little dinosaurs at first,” Chu interjected.

“Of course that would have been hundreds of years after my time,” Joorn said. “There's no telling what might have developed afterward. But even before I departed Earth, they'd begun to employ dolphins as safety engineers on space habitats to search out leaks and cracks with their sonar and such. And they're awfully good at holding their breath, aren't they? As a lumber industry grew in the Oort cloud and Kuiper Belt, there must have been a need for dolphins among the personnel.”

“That's where I draw the line,” Chu said good-naturedly. “Their sonar would be no good in a vacuum. And no matter how long they could learn to hold their breath, they have no legs. Out of their tanks, how would they get around?”

“Six million millennia of reverse evolution,” Joorn retorted. “All cetaceans once were land animals, like hippos. They'd crawled out of the sea to become mammals, then, after some millions of years, crawled back and lost their legs. Did you know that whales have vestigial leg bones?”

Nina giggled. “Can you picture Jonah or Triton running around on legs? Wearing little booties? The two dolphin safety engineers were Martin's colleagues on his outside maintenance rounds, and Nina had become fast friends with them, even joining them in their tank for an occasional swim. Their ancestors would have populated Rebirth's seas long ago.

Chu shrugged. “We're getting a bit fanciful here. I'll grant you the bugs and spiders. We'll soon find out. We're well within the Oort cloud now, and that object in the viewscreen is within planetary distances. Let's have a closer look.”

He fiddled with the banks of keys, and the jiggling image jumped in size as it sprang into sharper focus.

Nina gasped. It was a tree all right. Just like the pictures she'd seen of trees on Rebirth and vanished Earth, or the tamed thirty-footers in
Time's Beginning
's forest compartment.

But not quite. It was a real tree, with the unmistakable natural shape of any plant responding to its environment. But it was designed to grow in the absence of gravity. It was almost perfectly symmetrical—two flattened spheres joined by a thick trunk, like a dumbbell. The green spheroid was the tree's crown. The balancing brownish spheroid, clutching an outmatched globe of dirty ice that had to be a comet, was the tree's root ball. But the root ball, too, was streaked with green—adventitious leaves that the tree had grown to take advantage of any quantum of electromagnetic energy that came its way.

“It's a rather conflicted tree, sweetheart,” Joorn lectured. “It knows that it's supposed to respond to gravity by growing straight up. Our ancestors chose poplar trees for their experiments. They're fast-growing, and they grow straight—good for lumber. But the comets didn't give them much help. Their gravity's too feeble. The tree's strategy was to use its rotation as a growth guide. Centrifugal force is a good substitute for gravity, right? The trees rotate along their vertical axis, and those two oblate spheres respond by growing into matching symmetrical shapes.”

Nina's face was glowing. “Grandfather!” she exclaimed. “This is where a really, really dull subject like botany becomes an actual branch of astronomy!”

“Precisely, princess. Bear that in mind when you go back to class. Biologists are scientists too. And watch those puns.”

“I wish Martin were here to see this,” Nina said.

“He's getting a better view,” Chu said. “Or will be. Hanging by his heels from one of the dolphin pods.”

Some of the color drained from Nina's face. “Uncle Chu, you won't …”

“Don't worry, sweetheart. The Higgs drive will be turned off while Martin's working outside, the way it always is. We'll coast without gaining any gamma. What's a few hours out of a billion and a quarter years, right?”

“You mean losing, not gaining,” Nina pointed out tartly. “We've been decelerating since midpoint.”

“Touché, little genius,” Chu said. “That's what I meant to say.”

“We ought to be switching to the fusion drive soon anyway,” Joorn said. “We're in the outer fringes of the Oort cloud now, but we'll be within planetary distances before you know it. We didn't come all this way to sterilize the planets of Sol and Alpha Centauri, assuming that some sort of bacterial life survived. And now, with these trees …”

“We don't want to sterilize the comets either,” Chu finish­ed for him. “I'm way ahead of you, Skipper. I've already warmed up the deuterium-helium-3 reaction, and it's on standby.” He checked the figures unreeling on his screen. “And weren't we lucky that Rebirth's oceans turned out to be full of deuterium?”

“And that the deuterium-helium reaction turned out to be a lot less lethal than deuterium-tritium fusion. What's our gamma now, Chu?”

“We're down to about one-tenth of the speed of light, Skipper. We're practically in real time now.”

“All right. Keep track of our distance from that tree. I don't want to get any closer than twenty astronomical units with the Higgs drive still on.”

“You've got it, Skipper,” Chu said.

“What's happening, Uncle Chu?” Nina said.

“We're about to get a closer look, sweetheart,” Chu said. He punched in further instructions, and the image bloomed again. You could see that the smooth ball of the crown was actually composed of individual branches.

Nina gasped. “What are those things like midges hovering over the edge of the green ball?” She squinted. “They look like they're sort of …
flapping
! Like bats.”

“That's crazy, Nina,” her grandfather said. “Nothing can fly in a vacuum.”

“There! Look at that one down near the rim! It's after some kind of little speck that I can't make out! It is too! It's flapping!”

“We're about to find out, sweetheart,” Chu said. His hands flew over the board. The deep thrum of the Higgs drive stopped abruptly. Weight disappeared, and Nina grabbed for her armrests.

Chu tapped at the keys again. Weight returned. “It's all yours, Skipper,” Chu said. He turned to Nina. “Hang on to your hat, sweetheart,” he said. “It's going to be a downhill ride.”

CHAPTER 17

6,000,000,000 A.D.

The Oort Cloud

A small boy in a skinsuit that was too big for him threw an iceball at Torris as he headed for the cave mouth. He ducked without haste, and it missed him, but then two or three of the other children who were playing outside joined the sport. Another iceball grazed him, dangerously close to his airbag gasket, but by then the mothers were hauling their children back to keep them from becoming contaminated by Torris. Being Shunned meant not being noticed by other people at all, either for good or ill.

He shifted the towering load of firewood on his back for better balance. He was not banned from the communal fire, but nobody made way for him either. He'd also been lucky enough to snare a couple of fat stovebeasts, which were trying to escape from a sack dangling from his waist. Other than that, he hadn't had much luck on his foraging expedition: a few bark hoppers that would barely fill his stomach, a small pouch of thin syrup from a worn-out stretch of root that the tribe no longer bothered to tap, and some edible seed pods from the vegetation growing on the lower branches.

He could smell roasting meat as he made his way down the main passageway, his helmet tilted back as he breathed the communal air. His mouth watered as he thought of the feast his father would be having at this hour. His father, particularly, made a point of avoiding him. He understood that, but it bothered him all the same. Neither Firstmother nor Secondmother would dare try to sneak food to him; it would be too dangerous. He understood that too.

A group of rowdy young men was blocking his way. They made no attempt to move aside for him, but some sneaked glances as he edged past them. He heard someone whisper “heretic,” followed by a whispered reply about “a woman” that sounded envious.

They resumed the loud discussion they'd been having. They were talking excitedly about the coming bride raid and the approaching foreign Tree, speculating about when it would be close enough for Claz to give his approval. All of them were armed, and they were comparing weapons and boasting about their prowess.

He longed to tell them that the people of Ning's Tree were far more advanced than their own tribe and would probably prove to be formidable adversaries. The talk that would be generated by Ning's return would probably spur the young bloods there to launch their own bride raid sooner than Torris's tribe would dare risk it.

Torris wondered if Ning would be in the vanguard, if she would come looking for him, as a man might target a particular woman. He shook his head to rid himself of the insane thought. A thought as far from the natural order of things as wishing for a world without caves, where you could walk around on the surface and yet somehow breathe.

He pushed aside the translucent gut curtain that sealed the third of the three airlocks and stepped through into the communal chamber. Nobody noticed him at first; they were all gathered around the big central fire, busy eating, talking, minding the children, and jockeying for places closer to the warmth, so he was able to catch fragments of the evening's chitchat.

“… and this new star is bright enough to cast its own shadows. So it is clear that the Tree has created it as a fourth holy object to be worshipped and propitiated in its name. …”

“Nonsense, it's only a wandering star like those we've seen before, and one day it will be gone. It's not like our own stars that move, which never vary from their fixed courses, showing that they each have a holy purpose. …”

“Still, it moves. …”

“Not anymore,” a new voice cut in. “It suddenly stood still in the sky five sleeps ago and changed its color. Now it grows brighter and brighter every day. …”

“I've been telling you, it's a Sign. …”

A few people had begun to notice him as he made his way across the cave. He was supposed to be treated as if he were invisible. As if he didn't exist. But people couldn't help themselves. The talk stopped, and an uneasy silence took its place. People unconsciously moved a little closer to one another, barring access to the fire. They studiously avoided looking at him. Torris was doing the same. He looked straight ahead, as if they were the ones who were invisible. But he couldn't avoid hearing the person who lost all self-control and burst out, “It's an omen, that's what it is! A Sign that we must propitiate the Tree by offering the heretic as a sacrifice.”

There was a low muttering of agreement. “Cast him into the outer dark,” someone said.

Torris tightened his lips. Claz had stopped short of that. The prescribed penalties for each degree of heresy had been passed down through the ages and were law.

He hurried his steps a little and escaped down the dank passageway, where he had found a cramped hollow to sleep in.

His little fire still flickered, sending greasy smoke into the corridor. He'd cooked his meager supper of bark hoppers on it and tethered the two captured stovebeasts nearby. He piled more wood on the fire and was debating with himself whether or not to sleep in his airsuit when a sodden sleep overtook him.

He woke in the middle of the night, hearing voices down the corridor coming closer. Angry voices.

They stopped outside his cubbyhole. A hand thrust aside the skin he'd hung to conserve heat and ripped it down. The small space was suddenly crowded with a half dozen men, all of them shouting at him.

They hauled him violently to his feet. A fist smashed into his mouth, catching him unawares. He only had time to think,
They can't do that; you're not supposed to touch a Shunned person
.

They hustled him down the passageway, handling him roughly. One of them was leading the way with a torch. Someone growled, “We're taking you to see Claz, murderer,” and Torris, confused, could only think,
You're not supposed to talk to a Shunned person either
. His mouth was bleeding, and his head was spinning. He tried to wipe away the blood on his chin, but two young bruisers were pinning his arms.

He could recognize some of them now. They were all unattached young men of an age to band together for a bride raid. A couple of them were part of the same catechism class that had made the ill-fated Climb with him and Brank.

People usually slept at this hour, but the commotion had roused a couple handfuls of the curious. More people were straggling into the common chamber, staring after Torris as he was dragged toward Claz's cubicle.

Claz was waiting for them, along with two elders—Igg the lame Spearmaker and Cleb the Chronicler, Brank's father. All three of them were looking grim and bleary-eyed, as though they'd been roused from a sound sleep and weren't too happy about it. A few small objects were spread across the horizontal root Claz used for a table and bench: some scraps of quilted fabric from an airsuit, a bone toggle for fastening a helmet, and a glove. Claz was holding an arrow, and Torris could see that the arrowhead was flecked with dried blood.

“His skeleton was picked clean,” Claz said without preamble, “but this was lodged between the ribs.”

He held out the arrow as if it were something distasteful. Torris could see that it was his, one of the arrows that Claz had inscribed with a blessing for success in the Climb.

“What was left of him came to rest at the bottom of the Tree in the middle of the night. The body must have been caught in the branches many miles above, until the carrion creatures that were feeding on it finally dislodged it. It was Brank, no question about it.”

He gestured at the scraps of airsuit fabric, and Torris could see that some of them were festooned with the colored beads that were Brank's trademark. Cleb made a wordless sound in his throat, but Claz ignored it.

“And this,” Claz continued with naked fury, “is your arrow. No question about that either!”

Torris stood dumbstruck. There was nothing he could possibly say. One of the surly guardians who was holding him gave him an angry shake.

“If it hadn't been for Uz here,” Claz was saying with a nod at Torris's captor, “the murder might never have been discovered.” He'd mastered his anger, and now his tone was merely severe. “He happened to be wandering about in the middle of the night with his idle companions, for what purpose I don't know, and I will have a talk with them about that.”

“We were just …” Uz started to mumble, but a glance from Claz silenced him.

“You are not needed here,” Claz said. “Go.”

Reluctantly, the two who were holding Torris released him and left with their friends. Claz stared at Torris for a long time in silence as if he were something strange and remarkable, like a two-headed tree snake. Finally he spoke one word.

“Why?”

Torris struggled to say something, but nothing would come out of his mouth. What was the point? He could tell them that Brank had been stalking him, but then he would have to tell them that Brank was stalking Ning too, and where would that lead? Nowhere. Or could he reveal Brank as a criminal who had violated every sacred precept when he stole another Climber's supplies and destroyed what he couldn't carry off? That Brank had attempted to kill a Dreamer freshly emerged from his calyx, when one of his judges was Brank's enraged father? Or try to explain that Brank was attempting to rape and kill an impious woman from another Tree? That wasn't even an offense. What did all that count against an arrow with his name on it in the rib cage of a murdered Climber?

Claz and the two elders whispered together in a corner for long minutes while Torris stood and stared at the ice walls with their network of root filaments. At last they turned and looked at him impersonally, the way one might regard a used-up stovebeast that had to be gotten rid of.

His knees went weak, but he managed to stay upright. Claz said sorrowfully, “I expected much from you, Torris. My disappointment is all the greater.”

“Get on with it, Claz,” Igg said impatiently, breaching protocol.

Claz thumped his staff on the ground twice. “You have committed an unspeakable murder,” he said. “It is the will of the tribe that you be expelled from the Tree.”

There were three days of purification rites. Torris was confined to his little cubbyhole, with two or three guards always stationed just outside, as much to keep impulsive people from getting at him as to keep him from getting out. His guards would not talk to him, but they'd talk at him when hostility and frustration got the better of them.

“I'd like to put my spear through you, unbeliever! Brank was a friend of mine.”

“Shut up, Uz. Claz said not to talk to him. He's still Shunned.”

“Igg said it too,” Uz grumbled. “He told me he'd like to talk to him with his spear.”

He was fed once a day, an undercooked haunch of meatbeast or a bone with enough scraps of flesh still on it to make a meager meal. He had to be kept alive until the day of his expulsion, he heard one guard explain to the other, so that his sacrifice could proceed properly and remove the stain of apostasy from the tribe. There were rules about that handed down from priest to priest since time out of mind.

They didn't bother to provide him with water; the cloudy drippings he was able to lick from the ice walls of his niche were considered to be sufficient to sustain him.

The traffic past his little cul-de-sac was uncommonly heavy for this little-used branch of a side tunnel. Everyone wanted to get a look at the heretic who was to be sacrificed, the first casting-out in years. The guards kept them moving, but Torris noticed that when Uz was on duty he tended to be lenient to those who had come to heap abuse on the heretic.

His father and his two mothers were not among those who filed past. His father's tenure as Facemaker would be shaky now, and a couple of likely aspirants for that position had already declared themselves—younger men whose qualifications Parn had always dismissed. He could not risk having Firstmother lose her self-control and attempt to speak to Torris as he hustled her past.

On the third day, they let him put his airsuit on and gave him a skin of air. He took the more robust of the two stovebeasts with him; it was near the end of its endurance now, but it would last long enough to see him through till his air gave out.

They prodded him with the butts of their spears and herded him down the corridor without speaking. The common cave was strangely deserted; they'd left some children behind to tend the central fire, but everybody else would be waiting out by the launch point to witness his expulsion.

It was the same low hillock that was traditionally used by departing bride raiders. There hadn't been an expulsion since Torris had been a small child. A lone flutterbeast was hovering motionless in the sky, too far away for arrows. It couldn't possibly know what was about to happen, but some instinct had brought it here, perhaps from its hunting ground at the crown of the Tree.

The ground was trampled for many man-lengths around the hillock, the packed snow turned into dirty ice by all the footprints. The hillock itself was barely a man-length in height, but it was the highest point around.

Torris's jailers hustled him forward. The crowd parted easily to let them through. If any of them was shouting imprecations at him, Torris couldn't hear it; all sound was damped by the eerie silence of Outside.

The scene was lit by the unnatural brightness of the new star, now brighter than either the red giant or the white dwarf. It hung motionless overhead, in the same spot where it had stopped abruptly a dozen sleeps ago, burning fiercely against the black sky. It was a frightening sight, and perhaps that was the reason the crowd seemed so subdued.

Torris tried to drag his feet, hoping to see his father and mothers somewhere in the crowd yet knowing that they wouldn't be there. His guards pushed him along relentlessly.

Two of the tribe's biggest men were waiting with a fur blanket at the crest of the hillock. Claz and the two elders were there too, but Claz didn't attempt to address the crowd in finger talk or no-air talk. He'd probably done that earlier.