Hunted Earth Omnibus

by Roger MacBride Allen

  “Will you please quit saying ‘von Neumanns’ and explain what they are?” Sondra demanded.

  “It’s very simple,” Marcia said. “How did we miss it? A von Neumann machine is any device that can exactly duplicate itself out of locally available raw materials. A toaster that could not only toast bread but build more toasters out of things found in the kitchen would be a von Neumann toaster. It’s a very old concept, named for the scientist who dreamed it up.

  “But von Neumann’s real idea was to build a von Neumann starship,” Marcia said. “A robot explorer that could fly from one star system to another, explore the system—and then duplicate itself a few dozen times, maybe mining asteroids for materials. It would send out new von Neumanns, duplicates of itself, from there. Then each new exploration robot would travel on to a nearby star, duplicate itself, and start the cycle again. Each machine would report back to the home planet on what it found. Even given a fairly slow transit speed between stars, you could explore a huge volume of space in just a few hundred years. Travelling, exploring, reproducing, over and over again.”

  “Wait a second,” Sondra protested. “The Charonians haven’t done any of those things. They’re not travellers, and they’re not explorers, and they aren’t reproducing—”

  “Oh yes, they are,” Marcia said. “Remember, the labs found three different alien genetic codes in their genes? Maybe these Charonians haven’t gone anywhere, but that means they and their ancestors have been to at least three other star systems that had life. Finding them all would take a lot of travelling and exploring. And look how many of them there are—they’ve certainly done some reproducing!”

  Sondra sat down at the comm console and thought about it. “Okay, okay. I can see that. But that’s not the whole story. There has to be something more. It doesn’t quite fit. Why is the Wheel hidden in the Moon? What were the Landers doing riding around in asteroids all this time? And how does stealing Earth and attacking the planets fit in? Wait a second. Old starship ideas. That reminds me of something else. Another old idea.”

  She thought about it for a moment. At last she remembered. “Seedships. That’s it. It was a starship concept intended more for colonising planets than for exploration. The logic was that a life-support system would be the biggest, heaviest part of a spacecraft—so you eliminate it. Instead, you freeze down a bunch of genetically perfect embryos, or fertilised eggs—or just sperm and ova. Maybe not just of the intelligent life-form, but the local equivalent of dogs and pigs and cats and chickens, or maybe Tyrannosaurus rex, if that suits your fancy. Any life-forms that might be handy at the other end. You pack them all up and launch them off.

  “When the seedship finds a habitable planet, it lands, thaws out the embryos, and decants them. Then the ship—or its robots, or whatever—educates the kids as they grow. It raises the first generation of settlers. And if your designers were good enough, the ship could be programmed to do gene engineering, modify that first generation to survive better on whatever sort of world they end up on. Directed evolution.”

  “But that doesn’t have anything to do with what’s happened here, either.” Marcia protested.

  “No. But suppose you combined the ideas,” Sondra said. “Suppose you decided to build a von Neumann seedship. A seedship that knew how to do genetic tinkering, not only on gene codes from its homeworld, but smart enough to analyse other codes as well and use whatever was useful in them. Like Earth-style DNA. A machine that could duplicate itself, a machine programmed to duplicate itself and to send new seeds out among the stars, spreading out in all directions. A machine that was capable of modifying, improving itself, and modifying the life-forms it carried. Mining not asteroids, but living worlds, like Earth. Not just mining metal and fuel as raw materials, but life itself.”

  Marcia nodded. “I can see that. But the present-day Charonians aren’t like that. Seedships like the ones you’ve described wouldn’t have a reason to hide in asteroids.”

  “Maybe they do, and we don’t know what it is,” Sondra said. “Maybe they’ve just been in a dormant phase for a while and the gravity-wave beam woke them up.” But then she frowned and shook her head. “Wait a second. Their use of gravity waves and wormholes. We haven’t accounted for that.”

  “So let’s go back a bit,” Marcia said. “Let’s talk about earlier stages in their development. Not the way the Charonians are now, but an intermediate stage between the way they were first made and the way they are now. Millions, tens or hundreds of millions of years ago.” She thought for a second. “Suppose, way back when, the Charonians were von Neumann seedships. Suppose a few things went wrong—at least from the viewpoint of the original designers. Suppose the ships just evolved off in an unexpected direction?”

  Marcia put the message sheets down on the comm unit and walked back to sit on the couch she had been sleeping on. “The plan when the first ship was sent out was to spread life, and the duplication of the ships and so on was subordinate to spreading life. Then that point got lost, or changed. After all, it’s the machines doing all the work. Suppose the machines decided it was more important that they be duplicated—and then subordinated spreading life to spreading machines?

  “Suppose the ships started modifying their passengers, started breeding them so they were genetically driven to build more seedships?” Marcia asked. “They could hardwire building skills into the passengers, so that building new seedships becomes an instinct, a primal need. Maybe they start cutting and pasting DNA, or whatever they use instead of DNA. Take some T. rex genes, some dog and cow genes, combine them with the intelligent life-form’s genome. They land on a new world full of life and find some handy codings there. They cut and paste those in, too.”

  “Wait a second,” Sondra protested. “No human would let a machine loose to modify human DNA.”

  “We wouldn’t. Humans wouldn’t do it, no. The very idea is repellent to us. But we’re not talking humans here. Suppose there were aliens with no taboos against such things? The idea disgusts me too, but imagine how fast things could change, how dramatically a species could evolve, if such things were permitted.

  “They kept evolving,” Marcia went on. “The machines modifying themselves, the organic forms breeding themselves, machines tinkering with their own programming, and modifying the descendants of the organic Charonian passengers and their worker-animals. The seedships developed machines that worked with special-bred animals, and bred animals that needed mechanical implants, that couldn’t survive without them. Until the line between living and machine was completely blurred, until the Charonians didn’t even bother with the distinction anymore, until there was no clear line anymore between the Charonians, their machines, and their worker-animals. They all merged into one hugely complex entity. All the forms rely on each other to survive. Call it a multispecies.”

  “Okay, good,” Sondra said. “But the ships were still the key. The seedships become the dominant form of the Charonians,” Sondra said. “They didn’t need organic-style intelligence to tell them what to do anymore. Somewhere along the line, the original Charonians lost out. That must be true, because they’re not there anymore. After all, it had to be living, sentient creatures who built the first ships.”

  “It makes sense,” Marcia said. “I doubt we have it precisely right, but if we accept the idea that the Charonians of today started out as von Neumann seedships, built by creatures something like us, then they’ve certainly changed, mutated along the way to get to be what they are now. But that wasn’t the end of their development. We haven’t explained the Lunar Wheel, or the Multisystem. How do they fit in?”

  Sondra scratched her head. “Let’s take a pass at it from another direction. Let’s think of their biology, their technology, the ages that went by in a breeding cycle. The ages of their lives and deaths. A ship with a computer full of machine blueprints and a hold full of dormant animals or dormant embryos would launch from a system, and drift between the stars for centuries, maybe for tens or hund
reds of thousands of years, until it found a star system with a life-bearing world. Maybe the ship would pass the time during the flight by tinkering with the genes of the animals and blueprints of the machines. Finally the ship would land, and if need be, it would genetically modify its animals once again so they could survive on the new world.

  “The animals—some of them descended from the ship’s designers—would go out into the world, breed as fast as they could, while mining that planet for raw materials and building more ships—perhaps thousands of ships, or millions. The shipbuilding would be like everything else—a reflex action, a complex instinct.

  “The new ships would take their passengers aboard and launch out into space, out to search for new worlds. Maybe one ship in a thousand, one in a million, would manage to cross the sky, reach a new star and survive to reproduce, but that would be enough for the whole cycle to repeat, over and over again.”

  Marcia looked up. “But that’s so inefficient,” she objected. “Breeding-planets would be light-years, dozens or hundreds of light-years apart. And they would chew up any life-bearing worlds they used. Look what they’re doing to Mars, outside that window, right now. If their ancestors were even half that size, the planetside breeding binges needed to stock a new generation of seedships would do tremendous damage to an ecosystem.”

  “You’re right. They’d eat everything in sight,” Sondra agreed. “None of the native animals would be able to find food. The Charonians would wreck everything, trying to breed as heavily as possible. And they’d be doing their mining and their shipbuilding at the same time. It’d be a hundred times worse than the way we polluted Earth. And look at the damage we did before we knew better. But it wouldn’t be a problem for the Charonians. They’d be leaving. They wouldn’t care about the mess they left behind.” Her eyes suddenly grew wide. “Jesus,” she said. “We’re talking about stuff that happened millions of years ago, and we know from the DNA they found in the carrier-bug that the Charonians landed on Earth sometime in the distant past. Do you think maybe the Charonians landed on Earth and wiped out the dinosaurs?”

  Marcia blinked in surprise. “It could be. It’s been pretty well nailed down that the dinosaurs were killed by an asteroid impact where Iceland is now. But if a Lander seedship malfunctioned and crashed, it would be just like a real asteroid crashing. Maybe two Lander seedships were travelling together. One crashed, and the other survived to breed. The impact killed most of the dinosaurs, and the breeding binge afterwards was more than the survivors could take.”

  Marcia rubbed her eyes and tried to think. “But getting back to the point at hand,” Marcia said, turning the conversation back, “the breeding binges were basically parasitic, sucking the life out of a world. That would not only deplete the animal and plant populations, it would wreck the ecosystem. But the Charonians would care about that. Life-bearing planets must be very rare. Some future seedship would need that world again for some future breeding binge. And mass extinctions would wipe out the genetic diversity the Charonians needed as raw material for their bioengineering.”

  Marcia paused for a moment, staring into space. “And we’re forgetting gravity again. We’re forgetting that somewhere along the line the Charonians learned how to manipulate gravity. How does that fit? Maybe the original Charonians knew how and taught the first seedship. Maybe a seedship landed on a planet and conquered a species that knew how. But somehow they learned how to use wormholes, how to use black holes as a power source.”

  Sondra thought for a long moment. “And that was important. Without it, they couldn’t have become what they are. They use gravity control for everything. It had to be a turning point. Maybe they were short of life-bearing planets, but in every other way, they were rich. They had all of space and time to work with, endless rock and metal and volatiles in free space. All that was holding them back was the planet shortage.”

  She paused for a long moment. Suddenly she slapped her palm down on the comm console. “So they decided to do something about the planet shortage. That’s it. That’s got to be it, the last piece in the puzzle, Once they had gravity control, they had power, incredible power. So they built the Sphere, the Multisystem, and stocked it with stars and planets. And now I think we know why.” Sondra looked at Marcia, let her come to the same answer she had found, if for no other reason than to convince herself she wasn’t crazy.

  Marcia’s face went pale. “It’s a nature preserve,” she said. “The Charonians built the Dyson Sphere, the Multisystem, as a nature preserve for wild planets, as a place for planets to heal between breeding binges, a central storage place where the seedships could always find breeding planets.

  “But don’t forget the Charonians would still be deliberately modifying themselves, directing their own evolution,” Marcia said. “How far would that go? How far could it go? Suppose the Sphere became the Charonians, the ruling intellect. Suppose the Sphere took over from the seedships, just as the seedships had taken over control from the original, organic intelligent life-form. If the Dyson Sphere took over, it would design a new life cycle, using the ancient patterns in a new way. It was built to store the life-bearing worlds of the Multisystem, for the convenience of the seedships. But if it started working for itself, for its own purposes, it would change that, take control of the life cycle and breed any independent streak out of the seedships. Which means the first, biological Charonians and the second, seedship Charonians are both extinct. So neither of those types are in charge.”

  “It’s the Sphere,” Sondra said, almost whispering. “The Sphere itself is running things. We’ve been wondering who’s been running it, when all the time it’s been running everything.”

  “Hold it a second,” Marcia said. She got up and sat next to Sondra at the comm unit. She grabbed a pencil and a sheet of paper and started taking notes. “So we’ve got a Dyson Sphere using its stock of breeding worlds to grow new forms. It puts them aboard seedships—though now it’s only one creature to a seedship, because the creatures are so big. The seedships go out, just as they always have. They find a world, use it for breeding stock, and then what?”

  “That’s where the change comes,” Sondra said, grabbing a keyboard to make her own notes on the computer. Maybe Marcia could think with a pencil, but she needed a set of keys. “They launch themselves off the planet after they’ve chewed it up, but instead of scattering amid the stars, the mutated seedships—the things we’ve been calling Landers and gee-point asteroids—go into hibernation in deep space, and wait. One of them grows into something like the Lunar Wheel. Once it’s matured, it sends a message that all is in readiness and waits for a return signal from the home Sphere that sent it out in the first place. A return signal is simply any sort of modulated gravity beam. The signal Larry sent by accident.”

  “But what’s the signal supposed to mean?” Marcia asked.

  “It’s the Sphere saying ‘I’m ready for a new world,’ ” Sondra said excitedly. “Maybe because it’s caught a new star and has more room for worlds.”

  Marcia nodded. “Okay, so that explains why they stole the Earth, and why they’re taking such good care of it. But why are they mining the other worlds here?”

  Sondra considered that for a moment. Try to think like the Dyson Sphere, she thought. What would be important to the Sphere? And then it hit her. Sondra’s heart started pounding in her chest, and her palms went damp with sweat. “Think for a second,” she said. “The original Charonians built the seedships to carry their offspring to new worlds, to make new Charonians. Then the seed-ships took power for themselves, and decided the important thing was to make more seedships, spread themselves out among the stars.

  “And then the seedships built a Dyson Sphere, and it took over, and it decided…”

  The two women were deadly silent as the thought sunk in. “The Dyson Sphere decided the important thing was to make more Dyson Spheres,” Sondra said at last. “So, millions of years ago, it modified the seedships’ programs one more time, p
layed with the gene pool one more time. To make all the other forms into part of a Sphere-reproduction system. And what the hell did we think Dyson Spheres were made out of?”

  Marcia shook her head numbly. “My sweet God. And we were rushing to save Earth. It’s every other world in the Solar System that’s in trouble.”

  “Planets,” Sondra said, not hearing Marcia. “You make them out of disassembled planets.”

  Marcia spoke very quietly. “That’s what the Landers are doing. Now that they’ve got Earth out of harm’s way, they’re taking the Solar System apart to build a new Dyson Sphere. They’ll shred the planets, the moons, the asteroids down to nothing, take them apart and use that material as raw material to build a shell around the Sun. They’ll start up a new Multisystem here.”

  Sondra stared blankly at the computer screen for a long moment and then came back to herself. “We have to tell them,” she said. “Before the dust clouds thicken again and all the radio wavelengths are jammed. We have to get the word out.” She started typing furiously.

  But Marcia wasn’t paying attention. She stood up and returned to the window, back to the sky full of fire. Out there, the Landers were tearing Mars apart, blasting its stones and sand up into the sky. Now she understood. But would understanding do any good? They were as far as ever from being able to stop it, from being able to do anything about it. Mars was still being torn to shreds.

  It wasn’t fair. She did not want to die like this. Not alone. “Oh, Gerald,” she said to the sky. “Gerald my love.” He was alive, and he had reached out across unimaginable distances, sent his words to her. That should have been some comfort, some solace.

  But it was not. Instead anger flared inside her.

  Gerald lived. How could she die, when she suddenly had a new reason to live?