Other Worlds Than These

in the receiver set.

But there were problems.

If there were small nonlinearities in the quantum-mechanical operators—and there couldn’t be more than a billion-billion-billionth part, according to Bado’s researchers—those parallel worlds, underlying the Uncertainty Principle, could short-circuit.

The Moon Five Brits had tried to build a cheap-and-dirty teleport machine. Because of the huge distances involved, that billion-billion-billionth nonlinearity had become significant, and the damn thing had leaked. And so they had built a parallel-world gateway, by accident.

This might be the right explanation, Bado thought. It fit with Captain Richards’s vague hints about “nonlinear quantum mechanics.”

This new understanding didn’t make any difference to his position, though. He was still stranded here. The teleport devices his researchers had outlined—even if they’d got the theory right, from the fragments he’d given them—were decades beyond the capabilities of the mundane world Bado found himself in.

Reentry is easy. Bado estimates the peak acceleration is no more than a couple of Gs, no worse than a mild roller-coaster. Even so, many of the passengers looks distressed, and those spindly lunar-born children cry weakly, pinned to their seats like insects.

After the landing, Alpha’s big doors are flung open to reveal a flat, barren desert. Bado and Williams are among the first down the rope ladders, lugging their pressure suits, and Bado’s tool carrier, in big net bags.

Bado can see a small town, laid out with the air of a military barracks.

Staff are coming out of the town on little trucks to meet them. They are processed efficiently; the crew of the Prometheus gives details of where each passenger has been picked up, and they are all assigned little labels and forms, standing there in the baking sunlight of the desert.

The spindly lunar children are lowered to the ground and taken off in wheelchairs. Bado wonders what will happen to them, stranded at the bottom of Earth’s deep gravity well.

Williams points. “Look at that. Another Prometheus.”

There is a launch rail, like a pencil line ruled across the sand, diminishing to infinity at the horizon. A silver dart clings to the rail, with a slim bullet shape fixed to its back. Another Beta and Alpha. Bado can see protective rope barriers slung around the rail.

Taine comes to greet Bado and Williams. “I’m afraid this is goodbye,” he says. He sticks out a hand. “We want to get you people back as quickly as we can. You alternates, I mean. What a frightful mess this is. But the sooner you’re out of it the better.”

“Back where?” Bado asks.

“Florida.” Taine looks at them. “That’s where you say you started from, isn’t it?”

Williams shrugs. “Sure.”

“And then back to your own world.” He mimes stirring a pot of some noxious substance. “We don’t want to muddy the time lines, you see. We don’t know much about this alternating business; we don’t know what damage we might do. Of course the return procedure’s still experimental but hopefully we’ll get it right.

“Well, the best of luck. Look, just make your way to the plane over there.” He points.

The plane is a ramjet, Bado sees immediately.

Taine moves on, to another bewildered-looking knot of passengers.

The Russian cosmonaut is standing at Williams’s side. He is hauling his stiff pressure suit along the ground; it scrapes on the sand like an insect’s discarded carapace. Out of the suit the Russian looks thin, young, baffled, quite ill. He shakes Bado’s hand. “Do svidanya.”

“Yeah. So long to you too, kid. Hope you get home safely. A hell of a ride, huh.”

“Mnye nada k zoobnomoo vrachoo.” He clutches his jaw and grins ruefully. “Schastleevava pootee. Zhilayoo oospyekhaf.”

“Yeah. Whatever.”

A British airman comes over and leads the Russian away.

“Goddamn,” Williams says. “We never found out his name.”

He got a report in from his meteorite studies group.

Yes, it turned out, there was a large object on its way. It would be here in a few years time. Bado figured this had to be this universe’s edition of that big old Imbrium rock, arriving a little later than in the Moon Five world.

But this rock was heading for Earth, not the Moon. Its path would take it right into the middle of the Atlantic, if the calculations were right. But the margins of error were huge, and, and…

Bado tried to raise public awareness. His money and fame got him onto TV, even, such as it was. But nobody here took what was going on in the sky very seriously anyhow, and they soon started to think he was a little weird.

So he shut up. He pushed his money into bases at the poles, and at the bottom of the oceans, places that mightn’t be so badly affected. Somebody might survive. Meanwhile he paid for a little more research into that big rock in space, and where and when, exactly, it was going to hit.

The ramjet takes ten hours to get to Florida. It is a military ship, more advanced than anything flying in Bado’s world. It has the bull’s-eye logo of the RAF painted to its flank, just behind the gaping mouth of its inlet.

As the ramjet rises, Bado glimpses huge atomic aircraft, immense ocean-going ships, networks of monorails. This is a gleaming world, an engineer’s dream.

Bado has had enough wonders for the time being, though, and, before the shining coast of Australia has receded from sight, he’s fallen asleep.

They land at a small airstrip, Bado figures somewhere north of Orlando. A thin young Englishman in spectacles is there to greet them. He is wearing Royal Air Force blue coveralls. “You’re the alternates?”

“I guess so,” Williams snaps. “And you’re here to send us home. Right?”

“Sorry for any inconvenience you’ve been put through,” he says smoothly. “If you’ll just follow me into the van…”

The van turns out to be a battered diesel-engined truck that looks as if it is World War Two vintage. Williams and Bado with their bulky gear have to crowd in the back with a mess of electronic equipment.

The truck, windowless, bumps along badly finished roads.

Bado studies the equipment. “Look at this stuff,” he says to Williams. “More vacuum tubes.”

Williams shrugs. “They’ve got further than we have. Or you. Here, they’ve built stuff we’ve only talked about.”

“Yeah.” Oddly, he’s forgotten that he and Williams have come from different worlds.

The roads off the peninsula to Merritt Island are just farmers’ tracks, and the last few miles are the most uncomfortable.

They arrive at Merritt Island in the late afternoon.

There is no Kennedy Space Center.

Bado gets out of the van. He is on a long, flat beach; he figures he is a way south of where, in his world, the lunar ship launch pads will be built. Right here there will be the line of launch complexes called ICBM Row.

But he can’t see any structures at all. Marsh land, coated with scrub vegetation, stretches down towards the strip of beach at the coast. Further inland, towards the higher ground, he can see stands of cabbage palm, slash pine and oak.

The place is just scrub land, undeveloped. The tracks of the British truck are dug crisply into the sand; there is no sign even of a road near here.

And out to the east, over the Atlantic, he can see a big full Moon rising. Its upper left quadrant, the fresh Imbrium scar, still glows a dull crimson. Bado feels vaguely reassured. That is still Moon Five; things seem to have achieved a certain stability.

In the back of the truck, the British technician powers up his equipment. “Ready when you are,” he calls. “Oh, we think it’s best if you go back in your own clothes. Where possible.” He grins behind his spectacles. “Don’t want