The galaxies had turned into ships of fire, she thought.
Mark’s profile was picked out, now, in colors of blood. “Take a good look around, Lieserl,” he said grimly. “I’ve adjusted out the blue shift; this is how things really are.”
She looked at him curiously; his tone had become hostile, suddenly. Though he still held her hand, his fingers felt stiff around hers, like a cage. “What are you saying?”
“Here’s the result of the handiwork of your photino bird pets,” he said. “In the week since we arrived, we’ve been able to catalog over a million galaxies, surrounding this cavity. In every one of those million we see stars being pushed off the Main Sequence, either explosively as a nova or supernova or via expansion into the red-giant cycle. Everywhere the stars are close to the end of their lifecycles — and, what’s worse, there’s no sign of new star formation, anywhere.”
Suddenly she understood. “Ah. This is why you’ve set up this display for me. You’re testing me, aren’t you?” She felt anger build, deep in her belly. “You want to know how all this makes me feel. Even now — even after we’ve been so close — you’re still not sure if I’m fully human.”
He grinned, his red-lit teeth like drops of blood in his mouth. “You have to admit you’ve had a pretty unusual life history, Lieserl. I’m not sure if any of us can empathize with you.”
“Then,” she snapped, “maybe you should damn well try. Maybe that’s been the trouble with most of human history. Look at all this: we’re witnessing, here, the death of galaxies. And you’re wondering how it makes me feel? Do you think all this has somehow been set up as a test of my loyalty to the human race?”
“Lieserl — ”
“I’ll tell you how I feel. I feel we need a sense of perspective here, Mark. So what if this — this cosmic discontinuity — is inconvenient for the likes of you and me?” She withdrew from him and straightened her back. “Mark, this is the greatest feat of cosmic engineering our poor Universe will ever see — the most significant event since the Big Bang. Maybe it’s time we humans abandoned our species-specific chauvinism — our petty outrage that the Universe has unfolded in a way that doesn’t suit us.”
He was smiling at her. “Quite a speech.”
She punched him, reasonably gently, beneath the ribs, relishing the way her fist sank into his flesh. “Well, you deserve it, damn it.”
“I didn’t mean to imply — ”
“Yes, you did,” she said sharply. “Well, I’m sorry if I’ve failed your test, Mark. Look, you and I — by hook or by crook — have survived the decline and destruction of our species. I know we’re going to have to fight for survival, and I’ll be fighting right alongside you, as best I can. But that doesn’t remove the magnificence of this cosmic engineering — any more than an ant-hill’s destruction to make way for the building of a cathedral would despoil the grandeur of the result.”
Still holding her hand within his stiff fingers, he turned his face to the galaxy-stained sky. His offense at her words was tangible; he must be devoting a great deal of processing power to this sullen rebuke. “Sometimes you’re damn cold, Lieserl.”
Lethe, she thought. People. “No,” she said. “I just have a longer perspective than you.” She sighed. “Oh, come on, Mark. Show me the Ring,” she said.
The sculpture of string, driving itself into the heart of the scarred galaxy, was not symmetrical. It was in the form of a rough figure-of-eight; but each lobe of the figure was overlaid with more complex waveforms — a series of ripples, culminating in sharp, pointed cusps.
“Do you see it, Spinner?” Mark asked. “That is a loop of string nearly a thousand light-years wide.”
Spinner smiled. “That’s not a loop. That’s a knot.”
“It’s moving toward the galactic core at over half the speed of light. It’s got the mass of a hundred billion stars… Can you believe that? It’s as massive as a medium-size galaxy itself. No wonder it’s cutting this swathe through the stars; the damn thing’s like a scythe, driving across the face of this galaxy.”
Louise laughed. “A knot. Knot-making is a skill, up there in the forest, isn’t it, Spinner? I’ll bet you’d have been proud to come up with a structure like that.”
“Actually,” Mark said, “and I hate to be pedantic, but that isn’t a knot, topologically speaking. If you could somehow stretch it out — straighten up the cusps and curves — you’d find it would deform into a simple loop. A circle.”
Spinner heard Garry Uvarov’s rasp. “And I hate to be a pedant, in my turn, but in fact a simple closed loop is a knot — called the trivial knot by topologists.”
“Thank you, Doctor,” Louise said drily.
Spinner frowned, peering at the detailed image of the string loop; in the false colors of her faceplate it was a tracery of blue, frozen against the remote background of the galaxy core. She realized now that she was looking at one projection of a complex three-dimensional object. Subvocally she called for a depth enhancement and change in perspective.
The loop seemed to loom toward her, lifting away from the starry background, and the string was thickened into a three-dimensional tubing, so that she could see shadows where one strand overlaid another.
The image rotated. It was like a sculpture of hosepipe, rolling over on itself.
Mark commented, “But the string isn’t stationary, of course. I mean, the whole loop is cutting through this galaxy at more than half lightspeed — but in addition the structure is in constant, complex motion. Cosmic string is under enormous tension — a tension that increases with curvature — and so those loops and cusps you see are struggling to straighten themselves out, all the time. Most of the length of the string is moving at close to lightspeed — indeed, the cusps are moving at lightspeed.”
“Absurd,” Spinner heard Uvarov growl. “Nothing material can reach lightspeed.”
“True,” Mark said patiently, “but cosmic string isn’t truly material, in that sense, Uvarov. Remember, it’s a defect in spacetime… a flaw.”
Spinner watched the beautiful, sparkling construct turn over and over. It was like some intricate piece of jewelry, a filigree of glass, perhaps. How could something as complex, as real as this, be made of nothing but spacetime?
“I can’t see it move,” she said slowly.
“What was that, Spinner?”
“Mark, if the string is moving at close to lightspeed — how come I can’t see it? The thing should be writhing like some immense snake…”
“You’re forgetting the scale, Spinner-of-Rope,” Mark said gently. “That loop is over a thousand light-years across. It would take a millennium for a strand of string to move across the diameter of the loop. Spinner, it is writhing through space, just as you say, but on timescales far beyond yours or mine…
“But watch this.”
Suddenly the three-dimensional image of the string came to life. It twisted, its curves straightening or bunching into cusps, lengths of the string twisting over and around each other.
Mark said, “This is the true motion of the string, projected from the velocity distribution along its length. The motion is actually periodic… It resumes the same form every twenty thousand years or so. This graphic is running at billions of times true speed, of course — the twenty millennia period is being covered in around five minutes.