She walked forward, hesitantly, her eyes slowly adjusting. When she looked down she saw that her feet were a little below the coal-black asteroid surface, as if she were paddling in a shallow pool. Of course, she felt nothing.
Cornelius said, “We papered the walls with softscreens. Not quite immersive VR. Much of the imagery comes directly from the various camera feeds we’re managing to operate up there. The rest is software extrapolation. I’ve been preparing our firefly robot probe. But—”
“But what?” Malenfant said.
Cornelius sighed. “An hour ago this happened.” He tapped at a desk surface.
A firefly robot materialized from a pixel hail in front of them. Using its cables and pitons to drag at the coarse surface, it made its painstaking way toward the artifact. Lines trailed back from it, out of their view.
Malenfant said, “That’s our robot?”
“No. Not ours. Just watch.”
And now an object like a huge beach ball, attached to the long lines, came washing into the virtual reconstruction, towed by the firefly. It was water, Emma saw: a droplet wrapped up in a shimmering golden blanket, complex waves molding its surface as it bounced gently on the regolith.
Within the blanket something was moving.
“It’s a squid,” Emma said.
“Yes.” Cornelius rubbed his nose. “We think it’s a Sheena. That is, from the faction that still inhabits the Nautilus. They, it, seem to retain some of the mission’s original imperative. Watch what happens now.”
The firefly, with a neat pulse of microrockets, leapt through the portal. It was briefly dwarfed by the great blue circle. Then it disappeared; Emma glimpsed a red flash.
The cables that trailed back to the beach ball oscillated, but they did not grow slack. The golden beach ball sat on the surface, quivering.
Malenfant stepped forward, hands on hips, studying the image. “Where did the firefly go? Did it come out the other side of the hoop?”
“We think so,” Cornelius said. “But the other side doesn’t seem to be on Cruithne.”
There was a long silence.
The squid in the golden beach ball jetted back and forth, patient. Then the cables grew taut again and began dragging the beach ball forward.
Watching the cables disappear into the artifact, apparently not connected to anything, was eerie.
It took just seconds for the beach ball to complete its series of awkward, slow bounces to the blue circle. Then, after a single liquid impact with the blue circle itself, the beach ball shimmered through the hoop. As the curved golden wall hit the dark disc, it seemed to flatten out, Emma thought, quickly reddening to darkness. At last the beach ball was squashed to an ellipse, dimmed to a sunset glimmer.
Then it was gone, not a trace remaining.
“Holy shit,” Malenfant said.
Cornelius held his hand up. “Wait.”
There was a screech, loud enough to sting Emma’s eardrums. “What was that?”
“A radio signal,” Cornelius said. “Very high intensity. Coming from the artifact. I cleaned it up, and got this.”
It was a TV image of a squid: coarse, the colors distorted, in golden gloom. She was repeating a simple sign, over and over.
“She’s saying reef” Cornelius said.
Cruithne’s wheeling black sky, legs crossed, sipping latte. bmma
watched Earth and Moon climb through Cruithne’s fifteen-
minute night, blue spark with pale gray-brown companion.
“I have only partial answers.” Cornelius’ face was heavily shadowed, its expression impossible to read. “The Sheena obviously survived. She used a camera in her hab bubble to send back that message. But she’s… somewhere else. I suspect we’re dealing with an Einstein-Rosen bridge here.”
“A what?”
“A multiply connected space.” He waved his hands. “A bridge between two points in space and time, otherwise separated. Or maybe even between two different spacetimes altogether, different levels of the manifold.”
“The manifold?” Emma asked.
“The ensemble of possible universes,” Cornelius said. He took his softscreen and folded it over, pinching two places together with thumb and forefinger. “You must be familiar with the principle. If I take this flat space, two-dimensional, and fold it over in the third dimension, I can connect two points otherwise far separated. And the point where they meet, the place between my thumb and finger, is a circle, a flat place.”
“So if you fold over our three-D space in four dimensions—”
“The interface you get is three-dimensional. A box of some kind, where the two spaces touch.”
“You’re talking about a wormhole,” Malenfant said.
Cornelius said seriously, “A wormhole is only one possibility. An Einstein-Rosen bridge is a generic term for any such interface, which is Lorentzian. That is, it transforms like special relativity—”
Malenfant snapped, “I thought you needed a lot of energy to make a wormhole. Funny physics.”
Cornelius sighed. “You do indeed. To keep their throats open, wormholes have to be threaded with exotic matter.” He looked at them. “That means negative energy density. Antigravity.”
“I didn’t see any antigravity machines out there on the asteroid,” Emma said.
Cornelius shook his head. “You don’t understand. General relativity is barely a century old. We haven’t even observed a black hole directly yet. And we believe that relativity is only a partial description of reality anyhow. We have no idea how a sufficiently advanced society might set up an Einstein-Rosen bridge: what it might look like, how it might behave. For example, it’s possible the ring itself contains something like cosmic string. Channels of unified-force energy. Very massive, very powerful gravity fields.”
“How could you manipulate such stuff?” Emma asked.
“I don’t know.” He smiled.
“How that thing works is less important right now than what it does,” Malenfant said. “If the ring is some kind of wormhole, a gateway to somewhere else—”
“Orsomewhen.”
“Then the Sheena isn’t dead. And if she stepped through that gateway, she can step back again. Right?”
Cornelius shook his head. “We think this particular bridge is one-way. That’s theoretically possible. The Kerr-Newman singularity, for instance—”
Emma faced him. “Why do you think our portal is one-way?”
“Because we can’t see through it. Because light falling on it, even sunlight, is absorbed completely.” He gazed at her. “Emma, if it was two-way, we’d be able to see Sheena. Wherever she is.”
Malenfant growled, “So what do we do?”
Cornelius smiled. “Why, we send through our firefly, as we planned.”
They invested another hour while Cornelius finalized the setup of his firefly robot. It had been loaded up with every sensor Cornelius could think of, mostly stuff Emma had never heard of.
Emma stretched, paced around this strange VR representation ofCruimne.
None of this is real, she thought. It is a light show from the sky. None of it matters, compared to the mountain of mails that must be mounting up in her “In” tray even now, compared to the complexities of the human world in which she had to survive. And when it all proves to be some dumb illusion, then we’ll get back to work.
Or not.
Without warning Cornelius collapsed the VR walls. Emma found herself in a bare, black-walled room illuminated by a single wall-mounted softscreen. The screen showed a slab of dark sky, a stretch of regolith; it was the single point of view returned by their firefly’s camera.