Lightspeed: Year One

Sol was half-way up the sky, a diamond of light. Charon hung directly over Lvov’s head, a misty blue disc, six times the size of Luna as seen from Earth. Half the moon’s lit hemisphere was turned away from Lvov, towards Sol.

Like Luna, Charon was tidally locked to its parent, and kept the same face to Pluto as it orbited. But, unlike Earth, Pluto was also locked to its twin. Every six days the worlds turned about each other, facing each other constantly, like two waltzers. Pluto-Charon was the only significant system in which both partners were tidally locked.

Chiron’s surface looked pocked. Lvov had her faceplate enhance the image. Many of the gouges were deep and quite regular.

She remarked on this to Cobh, at the Interface.

“The Poole people mostly used Charon material for the building of the wormhole,” Cobh said. “Charon is just rock and water ice. It’s easier to get to water ice, in particular. Charon doesn’t have the inconvenience of an atmosphere, or an overlay of nitrogen ice over the water. And the gravity’s shallower.”

The wormhole builders had flown out here in a huge, unreliable GUTship. They had lifted ice and rock off Charon, and used it to construct tetrahedra of exotic matter. The tetrahedra had served as Interfaces, the termini of a wormhole. One Interface had been left in orbit around Pluto, and the other had been hauled laboriously back to Jupiter by the GUTship, itself replenished with Charon-ice reaction mass.

By such crude means, Michael Poole and his people had opened up the Solar System.

“They made Lethe’s own mess of Charon,” Lvov said.

She could almost see Cobh’s characteristic shrug. So what?

Pluto’s surface was geologically complex, here at this point of maximal tidal stress. She flew over ravines and ridges; in places, it looked as if the land had been smashed up with an immense hammer, cracked and fractured. She imagined there was a greater mix, here, of interior material with the surface ice.

In many places she saw gatherings of the peculiar snowflakes she had noticed before. Perhaps they were some form of frosting effect, she wondered. She descended, thinking vaguely of collecting samples.

She killed the scooter’s jets some yards above the surface, and let the little craft fall under Pluto’s gentle gravity. She hit the ice with a soft collision, but without heat-damaging the surface features much beyond a few feet.

She stepped off the scooter. The ice crunched, and she felt layers compress under her, but the fractured surface supported her weight. She looked up towards Charon. The crimson moon was immense, round, heavy.

She caught a glimmer of light, an arc, directly above her.

It was gone immediately. She closed her eyes and tried to recapture it. A line, slowly curving, like a thread. A web. Suspended between Pluto and Charon.

She looked again, with her faceplate set to optimal enhancement. She couldn’t recapture the vision.

She didn’t say anything to Cobh.

“I was right, by the way,” Cobh was saying.

“What?” Lvov tried to focus.

“The wormhole instability, when we crashed. It did cause an Alcubierre wave.”

“What’s an Alcubierre wave?”

“The Interface’s negative energy region expanded from the tetrahedron, just for a moment. The negative energy distorted a chunk of spacetime. The chunk containing the flitter, and us.”

On one side of the flitter, Cobh said, spacetime had contracted. Like a model black hole. On the other side, it expanded—like a re-run of the Big Bang, the expansion at the beginning of the Universe.

“An Alcubierre wave is a front in spacetime. The Interface—with us embedded inside—was carried along. We were pushed away from the expanding region, and towards the contraction.”

“Like a surfer, on a wave.”

“Right.” Cobh sounded excited. “The effect’s been known to theory, almost since the formulation of relativity. But I don’t think anyone’s observed it before.”

“How lucky for us,” Lvov said drily. “You said we travelled faster than light. But that’s impossible.”

“You can’t move faster than light within spacetime. Wormholes are one way of getting around this; in a wormhole you are passing through a branch in spacetime. The Alcubierre effect is another way. The superluminal velocity comes from the distortion of space itself; we were carried along within distorting space.

“So we weren’t breaking lightspeed within our raft of spacetime. But that spacetime itself was distorting at more than lightspeed.”

“It sounds like cheating.”

“So sue me. Or look up the math.”

“Couldn’t we use your Alcubierre effect to drive starships?”

“No. The instabilities and the energy drain are forbidding.”