Stephen Baxter: Ring

“Tell me what you see through there right now,” she said. “Tell me about the universe on the other side of the Kerr interface.”

“Now?” Mark looked doubtful. “Louise, you’re asking me to come up with an analysis of a whole cosmos — based on a few muddled glimpses — in a few seconds. It’s taken all of human history even to begin a partial — ”

“Just do it,” she snapped.

He studied her briefly, his expression even. “Some of the twin universes feature a degree of variation to our physical laws. That’s no great surprise; the constants of physics are just an arbitrary expression of the way the symmetries at the beginning of time were broken… But even those universes with identical laws to ours can be very different, because of changed boundary conditions at the beginning of time — or even, simply, from being at a different stage of their evolutionary cycles to ours.”

“And in this particular case?” she asked heavily.

He closed his eyes. Louise could see that stray pixels, yellow and purple, were again migrating across the Virtual images of his cheeks. His eyes snapped open, startling her. “High gravity,” he said.

“What?”

“Variation of the laws. In the neighboring universe, the constant of gravity is high — enormously high — compared to, uh, here.”

Morrow looked nervous. “What would that mean? Would we be crushed?”

More pixels, glitches in the image, trekked across Mark’s cheeks. “No. But human bodies would have discernible gravity fields. You could feel Louise’s mass, Morrow, with a pull of about half a gee.”

Morrow looked even more alarmed.

“Stars could be no more than a mile wide, and they would burn for only a year,” Mark said. “Planets the size of Earth would collapse under their own weight immediately…”

Lieserl frowned. “Could we survive there?”

Mark shrugged. “I don’t know. The lifedome would implode immediately under its own weight. We’d need to find a source of breathable air, and fast. And we’d have to live in free fall; any sizeable mass would exert unbearably high gravitational forces. But maybe we could make some kind of raft of the wreckage of the Northern…”

Lieserl looked up into the singularity plane, and her expression softened. “We know there have been human assaults in the Ring — like the neutron star missile. So perhaps we are not the first human pilgrims to fall through the Ring. Mark, you said the bridge to the other universe goes through cycles. I wonder if there are humans on the other side of that interface even now, clinging to rafts made from wrecked warships, struggling to survive in their high-gravity world…”

Mark smiled; he seemed to be relaxing. “Well, if there are, we won’t meet them. That continuation has closed off; a new one is opening… Wherever we’re going, it won’t be there.”

Louise glanced up at the false-color sky. “…I think it’s time to find out,” she said.

The Northern reached the zenith of its arc, high over the plane of the Ring.

Spinner felt as if she were suspended at the top of some huge cosmic tree, a million light-years high. The ship was poised above the singularity’s central, glittering pool of muddled starlight, and beyond that, at the edge of her field of view, was the titanic form of the Ring itself.

The flock of nightfighters hovered in a rough cap around her and above her, their wings spread. The ’fighters were sharp, elegant forms, filling space.

Spinner-of-Rope closed her hands over the hyperdrive waldo.

Now, it was like tumbling out of the tree.

The nightfighter fell through space, covering ten thousand light-years every second.

The singularity is a gateway to other universes, Michael Poole said. Who knows? — perhaps to better ones than this.

In fact, Poole told her, there had to exist further gateways, in the universe beyond, to still more cosmoses… He painted a picture of a mosaic of universes, connected by the glowing doorways of positive and negative Kerr singularities. It’s wonderful, Spinner-of-Rope.

Spinner stared down at the singularity. “Is this what they intended? Did the Xeelee mean to construct the singularity as a gateway?”

Of course they did. Why do you think they made the singularity so damned big?… So that ships could pass through it, without being destroyed by tidal forces from the singularity thread.

Spinner-of-Rope, this is the Xeelee’s most magnificent achievement. I would have liked to tell you some day how this Ring was built… how the Xeelee returned through time and even re-engineered their own evolution, to give themselves the capabilities to achieve this.

“You would have liked to tell me… ?”

Yes. Poole sounded sad. Spinner, I’m not going to get the chance… I can’t follow you.

“What?”

It was as if she descended through an immense tunnel, walled by the distant, irrelevant forms of blue-shifted galaxies. The singularity was the starlit open base of that tunnel, out of which she would fall into -

Into what?

Still, the starling flocks of nightfighters swirled around the ship.

“You know,” she said, “the Xeelee could have stopped us at almost any point. I’m sure they could destroy us even now.”

I’m sure they could.

“But they haven’t.”

Perhaps they are helping us, Spinner-of-Rope. Maybe there is some residual loyalty among the baryonic species, after all.

“…Spinner-of-Rope.”

“Yes, Lieserl.”

“Listen to me. The trip through the singularity is going to be — complicated.”

“Oh, good,” Spinner said drily.

“Spinner, the spacetime manifold around here isn’t simple. Far enough out the singularity will attract us — draw us in. But close to the plane of the singularity, there is a barrier of potential in the gravitational field.”

She sighed. “What does that mean?”

“…Antigravity, Spinner-of-Rope. The plane will actually repel us. If we don’t have enough kinetic energy as we approach the plane, we’ll be pushed away: either back to the asymptotically flat regions — I mean, to infinity, far from the plane — or else back into the zone of attraction. We could oscillate, Spinner, alternately falling and being repelled.”

“What happens on the other side? Will we be drawn back into the plane?”

“No.” Lieserl hesitated. “When we pass through the plane, there is a coordinate sign change in the metric… The singularity will push us away. It will hurl us on, deep into the new universe.”

“So what do I have to do?”

“To get over the potential barrier, we need to build up our kinetic energy before we hit the plane of the singularity. Spinner, you’re going to have to operate your discontinuity drive in parallel with the hyperdrive. The fractions of a second between jumps, when we’re in normal space, will be enough to let us begin our normal-space acceleration.”

Spinner felt sweat trickle over her face, pooling under her eyes behind her spectacles. She was afraid, suddenly, she realized: but not of the singularity, or what might lie beyond, but of failing. “That’s ridiculous, Lieserl. How am I supposed to pull that off? What am I, a spider-monkey?”

Lieserl laughed. “Well, I’m sorry, Spinner-of-Rope. We’re making this up as we go along, you know…”

“I can’t do it.”

“I know you can,” Lieserl said calmly.

“How do you know?”

Lieserl was silent for a pregnant moment. Then she said, “ Because you have help. Don’t you, Spinner-of-Rope?”