What the hell’s that mean? Killeen thought irritably. He was watching the hoop slowly cut through a slate-gray plain. Around him the control vault had fallen into numbed silence. His Arthur Aspect broke in:

I believe matters could proceed better if I translated from Grey for you. She is having difficulty.

Killeen caught the waspish, haughty air the Aspect sometimes took on when it had been consulted too infrequently for its own tastes. He remembered his father saying to him once, “Aspects smell better if you give ’em some air” and resolved to let them tap into his own visual and other sensory web more often, to stave off cabin fever. He murmured a subvocal phrase to entice the Aspect to go on.

Think of ice freezing on the surface of a pond. As it forms there is not quite enough area, perhaps, and so small crinkles and overlaps appear. These ridges of denser ice mark the boundary between regions which did manage to freeze out smoothly. All the errors, so to speak, are squeezed into a small perimeter. So it was with the early universe. These exotic relics are compacted folds in space, tangles of topology. They have mass, but they are held together primarily by tension. They are like cables woven of warped space-time itself.

“So what?”

Well, they are extraordinary objects, worthy of awe in their own right. Along their lengths, Grey tells me, there is no impediment to motion. This makes them superconductors!—so they respond strongly to magnetic fields. As well, if they are curved—like this one—they exert tidal forces on matter around them. Only over a short range, however—a few meters. I should imagine that this tidal stretching allows it to exert pressures against solid material and cut through it.

“Like a knife?”

Indeed—the best knife is the sharpest, and cosmic strings are thinner than a single atom. They can slide between molecular bonds.

“So it just slides right through everything,” Killeen mused to himself.

Yes, but, well—think of what we witness here! A flaw in the continuity of the very laws that govern matter. Nature allows such transgressions small room, and the discontinuity derives a tension from its own wedged-in nature—a stress that communicates along its stretched axis. And so we can see this incomparably slim marvel, because it is bigger than a planet along its length.

“So why’s this one cutting through New Bishop? It just fall in by accident?”

I sincerely doubt that such a valuable object would be simply wandering around. Certainly not at Galactic Center, where entities are sophisticated enough to understand their uses.

“Somebody’s usin’ it? For what?”

That I do not know.

Grey’s wispy tones sifted over Arthur’s:

I heard of astronomers…observed distant strings…but no record…of use. Were born…as relativistic objects…but slowed down…through collisions with…galaxies…finally came to rest…here…at Center…

When her voice faded Arthur said:

I would imagine handling such a mass is a severe technical difficulty. Since it is a perfect superconductor, holding it in a magnetic grip suggests itself. The sure proof of my view, then, would be fluctuating magnetic fields in the region near the outer part of the hoop.

Killeen recognized Arthur’s usual pattern—explain, predict, then pretend haughty withdrawal until Killeen or somebody else could check the Aspect’s prediction. He shrugged. The idea sounded crazy, but it was worth following up.

To Shibo he said, “Can Argo analyze the magnetic fields near that thing?”

Without answering, Shibo set up the problem. When she thought intensely, Shibo seldom spoke.

Toby stepped forward eagerly. “Magnetic fields! Sure, I shoulda thought. That magnetic creature, right? ’Member, back on Snowglade? It told us then—look for the Argo, it said. You think it’s maybe followed us here, Dad?”

His Ling Aspect spat immediately:

This is a grave crisis you face. Do not let crew get out of hand or you will have even greater difficulty.

Killeen understood Toby’s exuberance, but Ling was right: Discipline was discipline. “Midshipman, you’ll kindly remain silent.”

“Well, yessir, but—”

“What was that?”

“Uh…aye-aye, sir. But if it is the EM—”

“You’ll stand at attention, mister, against the wall.” Killeen saw that Besen and Loren were grinning at their mate’s dressing-down, so he added, “All three of you—attention! Until I say otherwise.”

He turned his back on them and Shibo was at his elbow. “Argo’s detectors report strong fields there. Changing fast, too.”

“Um-hmm,” Killeen murmured noncommittally. He outlined to Cermo and Shibo, and the eavesdropping midshipmen, what Arthur had conjectured. He resorted to simple pictures, describing magnetic fields as stretched bands that seized and pressed. Nothing more was needed; explanations of science were little better than incantations. None of them had a clear notion of how magnetic fields exerted forces on matter, the geometry of currents and potentials such a phenomenon required, or the arcane argot of cross vector products. Magnetic fields were unseen actors in a world unfathomable to humans, much as invisible winds had driven Snowglade’s weather and ruffled their hair.

Cermo said slowly, “But…but what’s it for?”

Killeen said tersely, “Keep a sharp eye.” Cap’ns did not speculate.

“Maybe caused those gray, dead zones on the planet.” Shibo pointed to the devastated polar regions, which the hoop was now approaching.

“Um-hmm,” Killeen murmured noncommittally.

He felt instinctively that they should not fasten on one idea, but leave themselves open. If New Bishop was not a proper refuge for them, he wanted to be damn sure of that fact before launching them on another voyage to some random target in the sky. Now that he had a moment to recover, even this gargantuan glowing hoop had not completely crushed his hopes that they might scratch out an existence here.

“Why’s it happening now?” Shibo mused.

“Just as we arrive?” Killeen read her thoughts. “Could be this is what the Mantis wanted us for.”

“Hope not,” Shibo said with a sardonic twist of her lips.

“We had plenty bad luck already,” Cermo said.

Shibo studied the board. “I’m getting something else, too.”

“Where?”

“Coming up from near the south pole. Fast signals.”

“What kind?”

“Like a ship.”

Killeen peered at the screen. The glorious squashed circle had cut slightly farther into the planet. It was still aligned with its flattened face parallel to the rotation. He estimated the inner edge would not reach the planet’s axis for several more hours at least. As it intruded farther, the hoop had to cut through more and more rock, which probably slowed its progress.

Shibo shifted the view, searching the southern polar region. A white dab of light was growing swiftly, coming toward them. It was a dim fleck compared with the brilliant cosmic string.

“Coming toward us,” she said.

“Maybe cargo headed for the station, if they’re still carrying out business as usual.” He cut himself short; it did no good to speculate out loud. A crew liked a stony certainty in a Cap’n; he remembered how Cap’n Fanny had let the young lieutenants babble on with their ideas, never voicing her own and never committing herself to any of their speculations.

He turned to Cermo. “Sound general quarters. Take up positions to seize this craft wherever it comes in.”

Cermo saluted smartly and was gone. He could just as easily have hailed the squads of the Family from the control vault, but preferred to go on foot. Killeen smiled at the man’s relishing this chance to take action; he shared it. Pirating a mech transport was pure blithe amusement compared with impotently watching the hoop cut into the heart of their world.