by Larry Niven
Sharon Levoy was lecturing for the record, nobody else was listening. "That solves that. Levoy's Star is an old neutron star, half a billion to a billion years beyond its pulsar stage. It's still hotter than hell, but it's only twenty kilometers across. The radiating surface is almost negligible. It must have been losing its spin and its residual heat for all of that time. We didn't see it because it isn't putting out enough light.
"The yellow dwarf star might have planets, but we can expect that their atmospheres were boiled away by the supernova event of which Levoy's Star is the ashes—"
Goldblatt snarled, "We're supposed to be the first expedition here! Prikazyvat Kendy!"
The crew were not supposed to be aware that the ship's computer and its recorded personality could eavesdrop on them. Therefore Kendy said, "Hello, Sam. What's up?"
Sam Goldblatt was a large, round man with a bushy, carefully tended moustache. He'd been chewing it ever since Levoy found and named the neutron star. Now his frustration had a target. "Kendy, do you have records of a previous expedition?"
"Well, check me out. Those are absorption lines for oxygen and water, here, aren't they? Which means there's green life somewhere in that system, doesn't it? And that means the State sent a seeder here!"
"I noticed the spectrum. After all, Sam, why shouldn't plant life develop somewhere on its own? Earth's did. Besides, those lines can't represent an Earthlike world. They're too sharp. There's too much oxygen, too much water."
"Kendy, if it isn't a planet, what is it?"
"We'll learn that when we're closer."
"11mph. Not at this speed. Kendy, I think we should slow down. Decelerate to the minimum at which the Bussard ramjet will work. We won't waste onboard fuel, we'll get a better look, and we can accelerate again when we've got the solar wind for fuel."
"Dangerous," said Kendy. "I recommend against it." And that should have been that.
For five hundred and twelve years Kendy had been editing clumps of experience from his memory wherever he decided they weren't needed. He didn't remember deciding to follow Goldblatt's suggestions. Goldblatt must have persuaded Captain Quinn and the rest of the crew, and Kendy had given in…to them? or to his own curiosity?
Kendy remembered:
Levoy's Star and T3 circled a common point in eccentric orbits, at a distance averaging 2.5 x l0^3 kilometers, with an orbital period of 2.77 Earth years. The neutron star had been behind the yellow dwarf while Discipline backed into the system. Now it emerged into view of Discipline's telescope array.
He saw a ring of white cloud, touched with green, with a bright spark at its center. The spectral absorption lines of water and oxygen were coming from there. It was tiny by astronomical standards: the region of greatest density circled the neutron star at 26,000 kilometers-about four times the radius of the Earth.
"Like a Christmas wreath," Claire Dalton breathed. The sociologist's body was that of a pretty, leggy blonde, but her corpsicle memories reached far back…and what was she doing on the bridge? Captain Dennis Quinn might have invited her, the way they were standing to gether. It indicated a laxity in discipline that Kendy would have to watch.
The crew of Discipline continued to study the archaic Christmas wreath. Until Sam Goldblatt suddenly crowed, "Goldblatt's World! Prikazyvat Kendy, record that, Goldblatt's World! There's a planet in there."
"I'm not close enough to probe that closely, Sam."
"It has to be there. You know how a gas torus works?"
It was there in Kendy's memory. "Yes. I don't doubt you're right. I can bounce some radar off that storm complex when we pass."
"Pass, hell. We've got to stop and investigate this thing." Goldblatt looked about him for support. "Green means life! Life, and no planet!
We've got to know all about it. Claire, Dennis, you see that, don't you?" The crew included twelve citizens and eight corpsicles. The corpsicles might argue, but they had no civil rights; and the citizens had less than they thought. For reasons of morale, Kendy maintained the fiction that they were in charge.
Goldblatt's suggestion was not worth considering. Kendy said, "Think. We've got fuel to decelerate once and once only. We'll need it when we reach Earth."
"There's water in there," Dennis Quinn said thoughtfully. "We could refuel. I bet the water's rich in deuterium and tritium. Why not, it's circling the ashes of a supernova!"
Claire Dalton was gazing at the screen, at a perfect smoke ring with a tiny hot pinpoint in its center. "The neutron star has cooled off, lost most of its rotation and most of its heat and most of that ferocious magnetic field the pulsars have. It's bright, but it's too small to be giving off much real heat. We could probably live in there ourselves." She looked around her. "Isn't this what we came for? The strangeness of the universe. If we don't stop now, we might as well be back on Earth." The contempt in her voice was unmistakable.
Kendy's memory jumped at that point. Hardly surprising. That must have been the true beginning of mutiny.
He remembered reviewing and updating his files on gas torus mechanics.
Two planets circled wide around the twin stars: Jupiter-style gas giants with no moons. The old supernova must have blasted away anything smaller.
A body did circle the neutron star. One limb of the Smoke Ring was curdled, a distorted whirlpool of storm. Hidden within was a core of rock and metals at 2.5 Earth masses. There was s6me oxygen and some water vapor in its thick, hot atmosphere. Goldblatt's World was tidally locked, and uninhabitable. Strip away its atmosphere and it might have harbored Earthly life-but its atmosphere was tremendous, dwindling indefinitely into the Smoke Ring itself.
The strong oxygen-water lines were coming from the gas torus.
A gas torus is the result of a light mass in orbit around a heavy mass, as Titan orbits Saturn. It may be that the light mass is too weak to hold its atmosphere. The faster molecules of air escape-but they go into orbit about the heavy mass. Thus, Titan circles Saturn within a ring of escaped Titanian atmosphere, as lo orbits Jupiter within a ring of sulfur ionized by Jupiter's ferocious magnetic field.
A gas torus is thin. The gas must be so rarefied that each molecule can be considered to be in a separate orbit: it must reasonably expect to circle halfway round the primary mass without bumping another molecule. Under such circumstances, a gas torus is stable. The occasional stray photon will bump a molecule into interstellar space; but the molecules are continually reencountering the satellite body.
Titan-smaller than Mars, no larger than Ganymede-carries an atmosphere of refined smog at one and a half times Earth's sea level pressure. The atmosphere is continually being lost, of course, but some of it continually returns from the gas torus.
Levoy's Star was an extreme case, and a slightly different proposition too.
The Smoke Ring was the thickest part of the gas torus around Levoy's Star. At its median it was as dense as Earth's atmosphere a mile above sea level: too dense for stability. It must be continually leaking into the gas torus. But the gas torus was stable: dense, but held within a steep gravitational gradient. Molecules continually returned from the gas torus to the Smoke Ring, and from the Smoke Ring to the storm of atmosphere surrounding Goldblatt's World.
"Goldblatt's World must have started life as a gas giant planet like, say, Saturn. Probably it didn't fall into range until the pulsar had lost a good deal of its heat and spin." Sharon Levoy's crisp voice spoke within Kendy's memory. "Then it was captured by strong Roche tides. It may have dropped close enough to lose water and soil as well as gas. For something like a billion years Goldblatt's World has been leaking gas into the Smoke Ring, and the Smoke Ring has been leaking to interstel lar space. It's not stable, exactly, but hell, planets aren't stable over the long run."
"It won't be stable that much longer," Dennis Quinn interrupted. "Most of Goldblatt's World is already gone. Ten million years, or a hundred million, and the Smoke Ring will be getting rarefied."
Kendy remembered these things. The records ha
d been made while Discipline's instruments probed the Smoke Ring from close range. Already some of the crew were exploring the Smoke Ring via CARMs. Their reports were enthusiastic. There was life, DNA-based, the air was not only breathable, but tasted fine.
Kendy didn't remember bringing Discipline into orbit around Levoy's Star. He must have expended his onboard fuel, postponing by several years his arrival at the target stars along his course. Why?
Claire Dalton's voice: "We've got to get out of this box. It's running down. A little of what we recycle is lost every time around. There's more than water in there; there's air, there's probably even fresh fertilizer for the hydroponics tanks!"
It was Sharis Davis Kendy who ruled Discipline. Discipline's crew of twenty was hardly necessary to run a seeder ramship. The State had chosen them as a reservoir of humanity: a tiny chunk of the State, far removed from any local disaster. One planet, one solar system, were too fragile to ensure the survival of the State or humankind itself. Every ship in the sky had a crew large enough to begin the human race over again: their secondary mission, if it ever became necessary. The State expected no such disaster, ever but the investment was trivial compared to the reward.
When had he lost control? Perhaps they had threatened to bypass the computer and go to manual control. They couldn't; but morale would disintegrate if they ever learned how little control they really had. Kendy might have surrendered on that basis.
Or he might have been curious.
He did not remember any part of what must have been a mutiny. He must have been played for a fool; he might not want to remember that. The crew had departed with eight of the ten CARMs and rifled the hydroponics to boot! It should never have been allowed.
He was reasonably sure that seven of the CARMs were inoperable. Some equipment might have been salvaged…and the last CARM had now ceased its spray of incandescent water vapor. Kendy ceased beaming his message. The Smoke Ring glowed white and featureless beneath him.
One day he would know. Would they remember him at all?
Kendy waited.
Chapter Six
Middle Ground
THE PATCH OF OLD-MAN'S-HAIR SHOULD HAVE BEEN TENDED long since. It was fifty to sixty meters across and had eaten half a meter deep into live wood. Parasol plants had rooted in the resulting compost, and matured, and spread their brightly colored blossoms to attract passing insects.
Minya watched the fire spread in intersecting curves within the fungus patch. Breezes tossed the choking smoke in unpredictable directions. The smoke drove clouds of mites out of the fungus and into the open. She was wishing Thanya's triad would arrive with water.
There were three triads of the Triune Squad now on the trunk.
Minya, Sal, and Smitta were nearing the median. Jeel's triad traversed up and down the trunk, ferrying provisions from the tuft, while Thanya's brought water from the lee.
Fire was usually no problem, but mistakes could happen.
"I love these climbs," Smitta said. She floated with her toes gripping an edge of bark. This close to the median, it was enough to hold her against the feeble tide. "I like floating…and where else can you see the entire Smoke Ring?"
Minya nodded. She didn't want to talk. When a problem couldn't be solved and wouldn't go away, what could one do but run? She had run as far as a human being could go. It was working: she felt at peace here, halfway between infinities.
The tree seemed to run forever in both directions. The Dark Tuft, backlit by Voy and the sun, was a halo of green fluff with a black core. Outward, Dalton-Quinn Tuft was barely larger. A few drifting clouds, wisps of green forest, whorls of storm were all outward. Eastward was a point of bright light off-center in a dark rim: the same small pond that had been drifting tantalizingly closer for a score of days.
Maybe, maybe it would come. They didn't talk about it. Bad luck.
Between the drought and the recent political upsets, it had been too long since the Triune Squad had been free for treetending duty. They had been needed as police. One could hope that the executions had settled the troubles; but now the triads were finding parasites and patches of old-man's-hair everywhere on the trunk. Today they were burning virtually a field of the horrid stuff.
Motion caught Minya's eye, outward and windward. Blue-againstblue, hard to see, something big. The sun was nearly at nadir, glaring up. She held a hand beneath her eyes, and squinted, and presently said, "Triune."
Smitta snapped alert. "Interested in us? Sal!"
Sal sang out from behind the smoke cloud. "I see it."
Minya said, "They're interested. They're pretty close already."
Smitta had pulled herself against the trunk and was readying her weapons. "I fought a triune once. They're smarter than swordbirds. You can scare them off. Just remember, if we kill one, we'll have to kill all three."
The torpedo-shaped object was closer now. It was nearly the blue of the sky, slowly rotating. Six big eyes showed in turn around the circumference, and three great gauzy fins…one smaller than the other.
That would be the juvenile. Minya whispered, "What do we need?"
"Bows and arrows ready? Tether your arrow and scoop up some burning old-man's-hair on the point. Lucky we had a fire going. Know where your jet pods are, you may need them."
Minya could feel her heart pulsing in her throat. It was her second trip up the trunk…but Smitta and Sal had been up many times. They were tough and experienced. Sal was a burly, red-haired fortyyear-old who had joined the Triune Squad at age twelve. Smitta had been born a man; she was a woman by courtesy.
Stay clear of Smitta, Minya told herself. Smitta was slow to anger, but under pressure something could snap in her mind. Then Smitta fought like a berserker, even among her own, and the only way to at her was to pile on her.
Minya strung her hardwood bow and used an arrow point to dig a gob of burning fungus. Ready-?
The torpedo split in three. Three slender torpedoes flapped laz toward them, showing small lateral fins and violent-orange bellies. male and a female, forever mated, plus a single juvenile who would take on body mass fast, then mature more slowly. They divided only to ht or fight. The Triune Squad itself was named for the triune famil: interdependence.
The juvenile would be the smallest, the one hanging back a little. The adults swept forward.
"Aim for the male," Smitta said and loosed, the line trailing c behind the arrow. Which was male? Minya waited a moment to judge Smitta's target, then loosed her own weapon. She judged that U, weren't in range yet…and she was right; the male's body ripped him free of the arrows' paths, while the female bored in. Sal had hit back. Now she loosed, and the veering female caught an arrow in 1 fin.
She bellowed. She flapped once, and the arrow snapped free. appeared from the smoke, yanked into the sky. It didn't seem to boti her as she reeled in, her ancient metal bow slung safe over her should The smoldering old-man's-hair had been left on the female's tail, a she was flapping madly.
Smitta sent a tethered arrow winging at the juvenile.
Both adults screamed. The female tried to block the arrow. Too late. The juvenile didn't seem to see the arrow coming. Smitta yanked at the line and stopped it a meter short.
The female gaped.
The women were reeling frantically, but it wasn't necessary. The adults moved in alongside the infant, infinitely graceful. Small has reached out from their orange bellies to pull them together. Tb moved away like a single blurred blue ghost against the blue sky.
"See? They're smart. You can reason with them," Smitta said.
Sal pulled a teardrop-shaped jet pod from one of the cluster of pods that ran down and across the front of her tunic. She twisted the top and a cloud of seeds and mist spurted away from her, thrusting Sal back toward the bark.
She coiled line and stowed her weapons, including the valuable be Springy met4, it was, handed down from old to young within the Triune Squad for at least two hundred years. "Well done, troops, but I think the fire is getti
ng to the wood. I wish Thanya would get here. She couldn't have missed us, could she?"
To Minya's eye, the fire might have reached wood by now, or not.
Hard to tell where old-man's-hair shaded over into rotted wood. "It's not bad yet," she said.
"I hate to waste jet pods, but…treefodder. I want to look for them," Sal decided. She gathered her legs under her, hands gripping the bark to brace herself, and jumped. She waved her arms turn herself around until she could see the trunk. They watched her drift along the trunk, out toward Dalton-Quinn Tuft.
"She worries too much," Smitta said.
Seventy days had passed since Clave's citizens had departed Quinn Tuft.
The tree fed a myriad parasites, and the parasites fed Clave's team. They had killed another nose-arm, easily, chopping through its nose, then jabbing harpoons into its den. There were patches of fan fungus everywhere. Merril had slept a full eight days after eating from the red fringe of a fan fungus. The subsequent throbbing headache didn't seem to affect her climbing, and presently it went away. So the fan fungus served them as food, and they had found more of the shelled burrowers and other edibles.
The Grad saw it all as evidence of the tree's decline.
They had found a jet pod bush, like a mass of bubbles on the bark.
Clave had packed a dozen ripe pods in a pouch of scraped nose-arm hide.
They had taken to camping just outside the water-washed wood.
Clave laughed and admitted that they should have been doing that all along. They'd slept three times more on the tree: last night in a nosearm's den, twice before in deep wounds in the wood, cracks overgrown with "fuzz" that had to be burned out first. The char had turned their clothing black.
They had learned not to try to boil water. The bubbles just foamed it out in a hot, expanding mass.
Tidal gravity continued to decrease until they were almost floating up the trunk. Merril loved it. Recovering from the fan fungus hadn't changed that. You couldn't fall; you'd just yell for help, and someone would presently throw you a line. Glory loved it, and Alfin smiled sometimes.