Starfarers (16 page)

Sundaram stirred. “No,” he said. “First we should attempt contact with the second ship. It will be here in another hour, won’t it?”

“It will not,” Nansen declared. “I am about to launch a second missile.”

“Oh, no!” Yu screamed. “You cannot tell—”

“I can gauge probabilities,” Nansen answered, “and that robot brain yonder may have learned something from what has happened. It shall not get a chance to apply the information. I hope the rest of the fleet will take that as a lesson to leave us alone.”

“But, Captain—”

“I am the captain. Let any guilt fall on me. I am responsible for all of
us.
”

Sundaram parted his lips and closed them again.

Nansen’s fingers wrote a command. Another torpedo eased into space. It turned, searched, found its target, plotted its course, and spurted off. After a while, very briefly, a new star winked.

There was no further sound from the engine center. Perhaps Yu had turned her intercom off. Perhaps she wept.

Robots and
humans working together restored
Envoy
’s plasma thruster. It had not been too badly damaged, as short a time as the wreckers were granted. She came about onto a new path and at length took orbit around the planet that bore life.

No more raptors troubled her. “They must have passed word back and forth,” Kilbirnie said. “They’ve learned we’re bad medicine.”

“Yes, they aren’t conscious, but they can learn—within rather broad limits, I’d say—if my guess about them is right,” Nansen replied.

“Oh, what is your guess?”

“I’ll wait until we have more data.”

“Aweel, meanwhile the rest of us can have the fun of making our own.” After the brush with ruin, mirth ran high, if a trifle forced.

Moonless, a fourth again as massive as Earth, turning once in forty-two hours on an axis barely tilted, atmosphere more dense, the planet still looked familiar enough to rouse an ache in a human breast. Although ice caps were lacking, oceans shone sapphire and lands, sprawled dun beneath white swirls of cloud. The air was nitrogen, oxygen, water vapor, carbon dioxide; it knew rain, snow, sunshine. Life flourished. The reflection spectrum off plants was not that of chlorophyl, but the chemistry was of protein, and animals were abundant.

They included sentient beings. High resolution found large brown creatures with stumpy legs and six-digited hands in villages(?) that consisted mostly of dome-shaped dwellings. They cultivated fields, mined and milled and manufactured, shipped and traveled, with the help of domesticated beasts and modest machines. They crossed the seas under sail; sometimes they flew in lighter-than-air craft. Dams, windmills, and solar collectors supplemented fueled power plants to furnish a certain amount of electricity. Designs were exotic and often suggested sophisticated engineering, but the main energy source seemed to be the combustion of biomass, and apparently much land was given over to growing this. Local variations in everything were noticeable, but nothing like what Earth had known through most of its history. Here might well be a world united under one dominant culture.

It was the ruins that leaped out at eye and mind. Remnants of cyclopean walls and sky-storming towers reared above forest crowns, brush-grown plains, deserted islands. Lesser relics lay everywhere; some had been incorporated into later works. Other traces—old riverbeds, peculiarly shaped mountains, anomalous patterns of vegetation—likewise told of past grandeur.

“Did a war destroy what was here?” wondered Zeyd one evening in the common room. “Could the shipkillers be left over from it?”

“I doubt that,” said Dayan. “Nothing looks as if it was broken by anything but neglect and weather.”

“Besides,” Ruszek added, “those aren’t really shipkillers. They tried to dismantle us, is all. When we fought back, they went straightaway kaput.”

Mokoena shuddered. “Not straightaway.” She caught his hand. “If the captain had been one minute slower, you would be dead now.”

“But Lajos is right,” Yu said. “They had no real defenses, they were not military machines. Let us not project our psychology onto the souls here. Perhaps they have never made war.”

“That would be lovely,” Sundaram mused. “If we could get to know them—an enlightenment—”

Nansen dismissed
that idea at the formal meeting several days later. “We are pledged to go to the Yonderfolk,” he said starkly.

“But the science to do,” Mokoena demurred. “A whole new biology.”

“The beings,” Sundaram added in his quiet fashion. “Their thoughts, feelings, arts, their mysterious history.”

“I know,” Nansen replied. “But you know, all of us know, we could spend our lives here and not begin to understand it. We’re in search of a starfaring race. I only agreed to this diversion because it might somehow bear on”—he faltered—“on certain questions about the stability of high technology.”

“Well, doesn’t it?” Cleland made bold to ask.

“Yes and no,” Nansen said to the half-circle he faced. “Clearly, they never achieved the zero-zero drive. It does appear their time of glory was long ago. Perhaps the civilization we are bound for did not yet exist. Perhaps the haze in this cluster prevented their finding traces of any farther
off. It was discoveries like that which led us to the principles of the quantum gate.”

“Somebody had to do it first, independently,” Kilbirnie argued. “I suspect we would have regardless.”

Nansen shrugged. “Who can say? In any event, I have had a few thoughts about the situation here and how it came to be. I’ve discussed them with Engineer Yu and Physicist Dayan, who carried them further. We have what we believe is a reasonable hypothesis.”

Brent glanced at Yu, Kilbirnie at Dayan, with a flash of jealousy. Kilbirnie lost hers in fascination as talk continued.

“A high technology, including nucleonics and doubtless genetic engineering, arose on this planet, and evidently there was world peace, too,” Nansen said. “Perhaps there always was. They explored the planetary system. They began to use its resources: energy, minerals, industrial sites that did not harm the biosphere at home. In all this they were like us.

“Then why should they not do what our ancestors thought of doing, and would have done if zero-zero had not made it irrelevant? Send probes to the nearer stars—and in a cluster, every star is near. Robots to survey and study and beam their findings back.”

“Our ancestors did, a few times,” Cleland pointed out.

Nansen nodded. “True. But they never took the next step, which was to send von Neumann machines.”

“What?”

Nansen looked at Dayan. “Would you like to explain?”

“It’s simple enough,” she said. “We use the same principle every day in our nanotech, and in fact it’s the basis of life and evolution. Send machines that not only explore and report to you, but make more like themselves and dispatch those onward, programmed to do likewise.”

Brent whistled. “Whew! How long would they take to eat the galaxy?”

“It wouldn’t be that bad,” Yu told him. “It would be enough to make a few score in any given planetary system. An asteroid or two would suffice for materials.”

“A probe wouldn’t be a single unit,” Dayan added.
“We’ve seen. A carrier, housing the central computer and its program; a number of robots to do the actual work, including to build the next generation of machines.”

“But none ever reached us,” Ruszek argued, puzzled. “Why not? If it began here, oh, a million years ago—well, we’ve seen what kind of boost the carriers have. Sixteen hundred light-years, they should have spread through that before now.”

“High boost,” Brent said, “but limited delta
v
.” He had been pondering the recorded data, as well as starting to dissect the slain robots. “Maybe a fiftieth or a hundredth
c.
”

“Even so—”

Zeyd narrowed his eyes. “The shipkillers,” he hissed. “Can they be the reason?”

“Not that simple,” Dayan answered. “Our conjecture—But, Captain, you can probably explain it with the least technicalese.”

A smile tugged at Nansen’s mouth. “Thank you. I’ll try.

“Essentially, we think a von Neumann probe went to the double star soon after it had gone nova. We don’t know if that was the most recent eruption or an earlier one, but our guess is that it was the latest. The mission was a very natural one, to a remarkable thing, fairly nearby. And doubtless the system has kept a few planets, or at least solid debris in orbit, to use for construction material.

“Now, the von Neumann principle does not mean that immediately on arrival, a machine makes more machines to launch toward farther stars. First it will make more like itself to investigate the system that it has reached. They must cope with many unforeseeables. Their hardware must be complex. But even more, they need sophisticated software, programs capable not just of learning but of developing solutions to problems that arise—and programs that can take advantage of any opportunity they see to do things better, more efficiently.

“Well, our hypothesis is that in the dreadful radiation environment shortly after the nova outburst, a program imitated. Probably several did, in different ways, and perished.
It would make sense to take the useable parts of those machines for making new ones. But this mutant went beyond that. It found it could reproduce still more efficiently by actively assaulting others, or any machinery it found, and processing what it took.”

“My God, a predator!” Kilbirnie blurted. She stared before her. “No awareness to tell it this was wrong, a bad idea. Evolution, blind as wi’ life.”

“I imagine the … cannibals … aren’t too specialized,” Yu murmured. “They must retain the ability to use raw materials. It is simply a loss of … inhibition. But in the end, they devoured all others in the nova system.”

“And then they went after new prey,” Dayan said, flat-voiced.

“Is that why no such machines ever reached Sol?” Mokoena asked. In her expression, shock struggled with professional interest.

“No,” Zeyd said. “How could they overtake the wave of exploration?”

“Wolves didn’t wipe out buffalo,” Brent added.

“Predator and prey developed an integral relationship,” Sundaram said. “We learned on Earth how unwise it is to interfere with the web of life.”

“Please,” Nansen said. “These are side issues. Argue them later.”

“The analogies to organic evolution are not exact,” Yu admitted.

“Our guess is that machines capable enough to be useful interstellar explorers are necessarily so complex as to be vulnerable to mutation in their programs,” Dayan said. “They need not visit a nova. Sooner or later, if nothing else, cosmic radiation will do it. Generally, they lose their ‘wits’ and just drift on aimlessly forever. Probably no line of von Neumanns gets beyond a few hundred light-years before it goes effectively extinct.”

“More speculation,” Nansen said. “We, our crew, will never know with certainty. But the suggestion is that this one mutation was successful in a way. And some of the predators
came back to this star. It may have been random, or they may have … remembered.

“By then, the civilization here was completely dependent on its industries in space. Suddenly they were wiped out. If the beings realized what was going on and tried to launch weapons against the invaders, those weapons were inadequate, perhaps gobbled up as they left atmosphere. Or perhaps the beings were too peaceful to think of weapons. Whatever happened, their technology collapsed. It must have been horrible.”

Mokoena winced. “Famines. Epidemics. Billions dying.”

“They seem to have rebuilt as best they could,” Nansen reminded her gently. “It looks like a stable population and ecology, a world that can last till the sun grows too hot.”

Kilbirnie grimaced. “But then? And meanwhile, ne’er to adventure again?”

“Not while the predators prowl,” Brent grated.

“I daresay they’ve reached an equilibrium, too,” Dayan said. “They probably reproduce from raw materials and from the parts of ones that, um, die. Maybe they have combats once in a while, but that can’t be the basis of their existence. Their programs remember, though. They remember. And when we arrived—Manna from heaven.”

Zeyd jumped to his feet. “Let’s hunt them down!” he shouted. “If we do nothing else, we can set these poor beings free!”

Ruszek sat bolt upright, his mustache quivering. Brent stifled a cheer.

“No,” Nansen said. “It would take years, if we can do it at all. And we can’t tell what the consequences could be. We are not God. We have our promise to keep.

“No, we have not really solved the mystery we found. We have what seems to be a good guess, no more. It is the best we can hope for. If no one finds an unanswerable reason to stay, we will continue on our proper mission within this week.”

Zeyd snapped air into his lungs, looked around at his crewmates, and sat down. Silence closed in.

Kilbirnie waved a hand aloft. “Bravo for you, skipper!” she called. “We’ve plenty ahead of us. Bring us there!”

She, at least, is wholeheartedly with me
, Nansen thought.
I’d like to confide in her—tell her why this irrational sense of urgency is riding me—if the thing I’m afraid of turns out to be true.

And then, looking at her:
Afraid? Why? Our mission is to discover the truth, whatever it may be.

His mind flew back across light-years, to what was less knowable than that which lay ahead.
May they at home still have a spirit like hers.

Earth was
the mother and her Kith Town the small motherland of every starfarer; but there were other worlds where humans dwelt. At those the ships were almost always welcome, bearers of tidings and wares that bridged, however thinly, the abysses between. It was not perennially so on Earth.

Thus, over the centuries, Tau Ceti became the sun which voyagers from afar often sought first. Its Harbor was as homelike as any known extrasolar planet, and usually at peace. News beamed from Sol arrived only eleven and a half years old; if you had felt unsure, you could now lay plans. Whether or not you went on to that terminus, here was a good place to stop for a while, do business, make fresh acquaintances and breathe fresh winds. A Kith village grew up, stabilized, and settled into its own timelessness.