The five of them sat together by a little tide pool. The breaking of the surf generated a soft white noise that reminded her of Argus and her years of listening to cosmic static. The Sun was well past the zenith, over the ocean. A crab scuttled by, sidewise dexterous, its eyes swiveling on their stalks. With crabs, coconuts, and the limited provisions in their pockets, they could survive comfortably enough for some time. There were no footprints on the beach besides their own.
“We think they did almost all the work.” Vaygay was explaining his and Eda’s thinking on what the five of them had experienced. “All the project did was to make the faintest pucker in space-time, so they would have something to hook their tunnel onto. In all of that multidimensional geometry, it must be very difficult to detect a tiny pucker in space-time. Even harder to fit a nozzle onto it.”
“What are you saying? They changed the geometry of space?”
“Yes. We’re saying that space is topologically non-simply connected. It’s like–I know Abonnema doesn’t like this analogy–it’s like a flat two-dimensional surface, the smart surface, connected by some maze of tubing with some other flat two-dimensional surface, the dumb surface. The only way you can get from the smart surface to the dumb surface in a reasonable time is through the tubes. Now imagine that the people on the smart surface lower a tube with a nozzle on it. They will make a tunnel between the two surfaces, provided the dumb ones cooperate by making a little pucker on their surface, so the nozzle can attach itself.”
“So the smart guys send a radio message and tell the dumb ones how to make a pucker. But if they’re truly two-dimensional beings, how could they make a pucker on their surface?”
“By accumulating a great deal of mass in one place.” Vaygay said this tentatively. “But that’s not what we did.”
“I know. I know. Somehow the benzels did it.”
“You see,” Eda explained softly, “if the tunnels are black holes, there are real contradictions implied. There is an interior tunnel in the exact Kerr solution of the Einstein Field Equations, but it’s unstable. The slightest perturbation would seal it off and convert the tunnel into a physical singularity through which nothing can pass. I have tried to imagine a superior civilization that would control the internal structure of a collapsing star to keep the interior tunnel stable. This is very difficult. The civilization would have to monitor and stabilize the tunnel forever. It would be especially difficult with something as large as the dodecahedron falling through.”
“Even if Abonnema can discover how to keep the tunnel open, there are many other problems,” Vaygay said. “Too many. Black holes collect problems faster than they collect matter. There are the tidal forces. We should have been torn apart in the black hole’s gravitational field. We should have been stretched like people in the paintings of El Greco or the sculptures of that Italian….” He turned to Ellie to fill in the blank.
“Giacometti,” she suggested. “He was Swiss.”
“Yes, like Giacometti. Then other problems: As measured from Earth it takes an infinite amount of time for us to pass through a black hole, and we could never, never return to Earth. Maybe this is what happened. Maybe we will never go home. Then, there should be an inferno of radiation near the singularity. This is a quantum-mechanical instability. …”
“Ana finally,” Eda continued, “a Kerr-type tunnel can lead to grotesque causality violations. With a modest change of trajectory inside the tunnel, one could emerge from the other end as early in the history of the universe as `you might like–a picosecond after the Big Bang, for example. That would be a very disorderly universe.”
“Look, fellas,” she said, “I’m no expert in General Relativity. But didn’t we see black holes? Didn’t we fall into them? Didn’t we emerge out of them? Isn’t a gram of observation worth a ton of theory?”
“I know, I know,” Vaygay said in mild agony. “It has to be something else. Our understanding of physics can’t be so far off. Can it?”
He addressed this last question, a little plaintively, to Eda, who only replied, “A naturally occurring black hole can’t be a tunnel; they have impassable singularities at their centers.”
With a jerry-rigged sextant and their wristwatches, they timed the angular motion of the setting Sun. It was 360 degrees in twenty-four hours. Earth standard. Before the Sun got too low on the horizon, they disassembled Ellie’s camera and used the lens to start a fire. She kept the frond by her side, fearful that someone would carelessly throw it on the flames after dark. Xi proved to be an expert fire maker. He positioned them upwind and kept the fire low.
Gradually the stars came out. They were all there, the familiar constellations of Earth. She volunteered to stay up awhile tending the fire while the others slept. She wanted to see Lyra rise. After some hours, it did. The night was exceptionally clear, and Vega shone steady and brilliant. From the apparent motion of the constellations across the sky, from the southern hemisphere constellations that she could make out, and from the Big Dipper lying near the northern horizon, she deduced that they were in tropical latitudes. If all this is a simulation, she thought before falling asleep, they’ve gone to a great deal of trouble.
She had an odd little dream. The five of them were swimming–naked, unselfconscious, underwater– now poised lazily near a stag horn coral, now gliding into crannies that were the next moment obscured by drifting seaweed. Once she rose to the surface. A ship in the shape of a dodecahedron flew by, low above the water. The walls were transparent, and inside she could see people in dhotis and sarongs, reading newspapers and casually conversing. She dove back underwater. Where she belonged.
Although the dream seemed to go on for a long time, none of them had any difficulty breathing. They were inhaling and exhaling water. They felt no distress–indeed, they were swimming as naturally as fish. Vaygay even looked a little like a fish–a grouper, perhaps. The water must be fiercely oxygenated, she supposed. In the midst of the dream, she remembered a mouse she had once seen in a physiology laboratory, perfectly content in a flask of oxygenated water, even paddling hopefully with its little front feet. A vermiform tail streamed behind. She tried to remember how much oxygen was needed, but it was too much trouble. She was thinking less and less, she thought. That’s all right. Really.
The others were now distinctly fishlike. Devi’s fins were translucent. It was obscurely interesting, vaguely sensual. She hoped it would continue, so she could figure something out. But even the question she wanted to answer eluded her. Oh, to breathe warm water, she thought. What will they think of next? Ellie awoke with a sense of disorientation so profound it bordered on vertigo. Where was she? Wisconsin, Puerto Rico, New Mexico, Wyoming, Hokkaido? Or the Strait of Malacca? Then she remembered. It was unclear, to within 30,000 light-years, where in the Milky Way Galaxy she was; probably the all-time record for disorientation, she thought. Despite the headache, Ellie laughed; and Devi, sleeping beside her, stirred. Because of the upward slope of the beach–they had reconnoitered out to a kilometer or so the previous afternoon and found not a hint of habitation–direct sunlight had not yet reached her. Ellie was recumbent on a pillow of sand. Devi, just awakening, had slept with her head on the rolled-up jump suit.
“Don’t you think there’s something candy-assed about a culture that needs soft pillows?” Ellie asked. “The ones who put their heads in wooden yokes at night, that’s who the smart money’s on.” Devi laughed and wished her good morning. They could hear shouting from farther up the beach. The three men were waving and beckoning; Ellie and Devi roused themselves and joined them.
Standing upright on the sand was a door. A wooden door–with paneling and a brass doorknob. Anyway it looked like brass. The door had black-painted metal hinges and was set in two jambs, a lintel, and a threshold. No nameplate. ft was in no way extraordinary. For Earth. “Now go `round the back,” Xi invited. From the back, the door was not there at all. She could see Eda and Vaygay and Xi, Devi standing a little apart, and the sand continuous between the four of them and her. She moved to the side, the heels of her feet moistened by the surf, and she could make out a single dark razor-thin vertical line. She was reluctant to touch it. Returning to the back again, she satisfied herself that there were no shadows or reflections in the air before her, and then stepped through.
“Bravo.” Eda laughed. She turned around and found the closed door before her. “What did you see?” she asked. “A lovely woman strolling through a closed door two centimeters thick.”