Ten hours after leaving the crash scar, Lvov arrived at the sub-Charon point, called Christy. She kept the scooter hovering, puffs of gas holding her against Pluto’s gentle gravity.
Sol was halfway 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.
Charon’s surface looked pocked. Lvov had her face plate 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 face plate 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 space time. The chunk containing the flitter, and us.”
On one side of the flitter, Cobh said, space-time 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 space-time. 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 traveled faster than light. But that’s impossible.”
“You can’t move faster than light within space-time. Wormholes are one way of getting around this; in a wormhole you are passing through a branch in space-time. 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 space-time. But that space-time itself was distorting at more than light-speed.”
“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.”
One of the snowflake patterns lay mostly undamaged, within Lvov’s reach. She crouched and peered at it. The flake was perhaps a foot across. Internal structure was visible within the clear ice as layers of tubes and compartments; it was highly symmetrical, and very complex. She said to Cobh, “This is an impressive crystallization effect. If that’s what it is.” Gingerly she reached out with thumb and forefinger, and snapped a short tube off the rim of the flake. She laid the sample on her desk. After a few seconds the analysis presented. “It’s mostly water-ice, with some contaminants,” she told Cobh. “But in a novel molecular form. Denser than normal ice, a kind of glass. Water would freeze like this under high pressures — several thousand atmospheres.”
“Perhaps it’s material from the interior, brought out by the chthonic mixing in that region.”
“Perhaps.” Lvov felt more confident now; she was intrigued. “Cobh, there’s a larger specimen a few feet further away.”
“Take it easy, Lvov.”
She stepped forward. “I’ll be fine. I—”
The surface shattered.
Lvov’s left foot dropped forward, into a shallow hole; something crackled under the sole of her boot. Threads of ice crystals, oddly woven together, spun up and tracked precise parabolae around her leg.
The fall seemed to take an age; the ice tipped up towards her like an opening door. She put her hands out. She couldn’t stop the fall, but she was able to cushion herself, and she kept her face plate away from the ice. She finished up on her backside; she felt the chill of Pluto ice through the suit material over her buttocks and calves.
“…Lvov? Are you okay?”
She was panting, she found. “I’m fine.”
“You were screaming.”
“Was I? I’m sorry. I fell.”
“You fell? How?”
“There was a hole, in the ice.” She massaged her left ankle; it didn’t seem to be hurt. “It was covered up.”
“Show me.”
She got to her feet, stepped gingerly back to the open hole, and held up her data desk. The hole was only a few inches deep. “It was covered by a sort of lid, I think.”
“Move the desk closer to the hole.” Light from the desk, controlled by Cobh, played over the shallow pit.
Lvov found a piece of the smashed lid. It was mostly ice, but there was a texture to its undersurface, embedded thread which bound the ice together.
“Lvov,” Cobh said. “Take a look at this.”
Lvov lifted the desk aside and peered into the hole. The walls were quite smooth. At the base there was a cluster of spheres, fist-sized. Lvov counted seven; all but one of the spheres had been smashed by her stumble. She picked up the one intact sphere, and turned it over in her hand. It was pearl-gray, almost translucent. There was something embedded inside, disc-shaped, complex.