“Maybe it set already.”
“Maybe. Or maybe something happened to it.”
“This is bad shit, isn’t it, Side?”
Sidewise didn’t reply.
“Once I saw some Roman ruins,” Snowy whispered. “Hadrian’s Wall. It was like this. All grown over, even the mortar rotted away.”
“This was a different scale,” Sidewise murmured. “Even from Rome. We had a global civilization, a crowded world. Everything was linked up.”
“What do you think happened?”
“I don’t know. That fucking volcano, maybe. Famine. Disease. Refugees everywhere. War in the end, I guess. I’m glad I didn’t live through it.”
“Shut up, you two,” Ahmed murmured.
Snowy sat up. He peered out through a glassless window frame in the wall of the church. He could see nothing. The land was just a blanket of dark, no glimmer of lights, no glow of streetlights on the horizon. Maybe everywhere was dark like this. Maybe their fire was the only light in England — on the whole damn planet. It was a stupendous, unbelievable, unacceptable thought. Maybe Sidewise could grasp it properly, but Snowy sure couldn’t.
Some kind of animal howled, out in the night.
He threw a little more wood on the fire, and buried himself deeper in his mound of greenery.
Sidewise had been right. Mars was missing.
The replicators, Ian Maughan’s robot probes, had survived. The program had been designed as a precursor to human colonization of the planet. The replicating robots would have been instructed to build homes for human astronauts, to make them cars and computers, to assemble air and water, even grow food for them.
But the humans never came. Even their commands ceased to be received.
That wasn’t troubling, for the replicating robots. Why should it be? Until they were told otherwise, their only purpose was to replicate. Nothing else mattered, not even the strange silence from the blue world in the sky.
And replicate they did.
Many modifications were tried, incorporated, abandoned. It did not take long for a radically better design to converge.
The replicators began to incorporate the factory components within their bodies. The new kind looked like tractors, pilotless, trundling over the impassive red dust. Each weighed about a ton. It took each one a year to make a copy of itself — a much shorter reproduction time than before, because they could go where the resources were.
After a year, one of the new replicator types would become two. Which after another year had made two more copies, a total of four. And in another year there were eight. And so on.
The growth was exponential. The outcome was predictable.
Within a century the factory-robots were everywhere on Mars, from pole to equator, from the peak of Mons Olympus to the depths of the Hellas crater. Some of them came into conflict over resources: There were slow, logical, mechanical wars. Others began to dig, to exploit the deeper materials of Mars. If you mined, there was still plenty of resources to go around — for a while, anyhow.
The mines got deeper and deeper. In places the crust collapsed. But still they kept digging. Mars was a cold, hard world, rocky for much of its interior. That helped the mining. But as they dug deeper and encountered new conditions, the replicators had to learn quickly, adapt. They were capable of that, of course.
Still, the penetration of the mantle presented certain technical challenges. The dismantling of the core was tricky too.
Mars weighed one hundred billion billion times as much as any one of the tractor-replicators. But that number was small in the face of the doubling-every-generation rule. Because of the continuing conflicts, the pace of growth was a little slower than optimal. Even so, in just a few hundred generations, Mars had gone, all but a trace of its substance converted to the glistening bulks of replicators.
With the whole planet transformed to copies of themselves — using solar sails, fusion drives, even crude antimatter engines — the swarm of replicators had moved out through the solar system, seeking raw material.
The next day, roaming into the country around the town, Snowy saw birds, squirrels, mice, rabbits, rats. Once he thought he saw a goat; it fled at his approach.
Not much else. There didn’t even seem to be many birds around. The place was silent, as if all the living things had been collected up and removed.
Some of the rats were huge, though. And then there were the rat-wolves he thought he had glimpsed. Whatever they were, they fled at his approach.
Rodents had always been in competition with primates, Sidewise said. Even at the peak of their technical civilization, people had had to be content with keeping rodents out of sight, and out of the food. Now, with people out of the picture, the rats were evidently flourishing.
It was easy to hunt, though. Snowy set a few snares, in a spirit of experimentation. The snares worked. The hares and voles seemed peculiarly tame. Another bad sign if you thought about it, because it meant they hadn’t seen humans for a while.
At the end of the second day, Ahmed had them sit in the ruins of the church, in a rough circle on corroded stone blocks.
Snowy was aware of subtle changes in the group. Moon was looking down, avoiding everybody’s eyes. Bonner, Ahmed, and Sidewise were watching each other, and Snowy, with calculation.
Ahmed held up an empty ration packet. “We can’t stay here. We have to plan.”
Bonner shook his head. “The most important thing is finding other people.”
“We’re going to have to face it,” Sidewise said. “There are no other people — nobody who can help us, anyhow. We haven’t seen anybody. We’ve seen no sign that anybody has been in this area recently.”
“No contrails,” Ahmed said, pointing to the sky. “Nothing on the radio, on any frequency. No satellites. Something went wrong—”
Moon laughed hollowly. “You can say that again.”
“We can’t know how events unfolded. Before the end it must have become — chaotic. We were never recalled. Eventually, I suppose, we were forgotten. Until we were revived by chance.”
Snowy forced himself to ask the question. “How long, Side?”
Sidewise rubbed his nose. “Hard to say. If we had an astronomy almanac I guess we could figure it out from the changed positions of the stars. Failing that, your best guess is based on the maturity of the oak forest.”
Bonner snapped, “You’re so full of shit, you scrawny bastard. How fucking long? Fifty years, sixty—”
“Not less than a thousand years,” Sidewise said, his voice tight. “Maybe more. Probably more, actually.”
In silence, they let that sink in. And Snowy closed his eyes, imagining he was plunging off the deck of an aircraft carrier into the dark.
A thousand years. And yet it meant no more than the fifty-year gulf that he thought had separated him from his wife. Less, maybe, because it was just unimaginable.
“Some future this is,” Bonner said edgily. “No jet cars. No starships, no cities on the Moon. Just shit.”
Ahmed said, “We have to assume we are not going to find anybody else. That we’re alone. We have to plan on that basis.”
Sidewise snorted. “Civilization has collapsed, everybody is dead, and we’re stuck a thousand years in the future. How are we supposed to plan for that?”
“That river is probably clean,” Snowy said. “All the factories must have shut down centuries ago.”
Ahmed nodded gratefully at him. “Good. At last, something we can actually build on. We can fish, we can hunt; we can start that tomorrow. Sidewise, why don’t you use that brain of yours for something useful and think about the fishing? Figure out how we can improvise lines, nets, whatever the hell. Snowy, you do the same for the hunting. Further down the line, we’re going to have to find somewhere to live. Maybe we can find a farm. Start thinking about clearing the ground, planting wheat.” He glanced at the sky. “What do you think the season is? Early summer? We’re too late for a harvest this year. But next spring—”