The Eternal Flame

was essential to the success of the procedure. When his rear gaze fell on her she quickly averted her eyes, afraid she might distract him and end up turning the whole chamber into an inferno.

Ivo switched to a cross-rope that took them to his own bench, where he slipped into the harness. A large lightproof box was attached to the bench-top; he swung up the lid to allow Tamara, still hanging on the cross-rope, to inspect the contents.

“That’s just an ordinary lamp in there,” he explained, gesturing at a spherical hardstone enclosure. “Lens, prism… it’s all standard equipment.” Ivo pulled the prism out of its slot and passed it to her for approval, as if he feared she might suspect him of some sleight of hand. The prize she was offering wouldn’t be much use to a cheat: any attempt to visit the Object would be an awful anticlimax if they failed to calculate its distance correctly. But Tamara obliged her host out of courtesy, and held the prism up to the light of the nearest lamp. The shimmering sequence of colors that appeared in front of her as she rotated it around its axis was no different from that produced by any piece of clearstone similarly cut.

She returned the prism to Ivo. He replaced it, then pointed out an unprepossessing piece of yellowish, resin- coated paper, positioned about a span from the light source. “This won’t make a permanent record itself; it will need to be supplemented with an ordinary camera. It doesn’t need any activating gas, but it only retains its potency for a few days after preparation.”

“I see.” Tamara made a mental note to start factoring that into her plans, hoping it wouldn’t lead to the Gnat having to carry a lizard-press.

Ivo tapped the lamp’s enclosure, shaking some liberator into contact with the firestone until the hot gas from the flames themselves started scattering the powder back onto the fuel. He closed the lid, then gestured to Tamara to peek through a slit in the box, opposite the lamp.

She moved back along the rope so she could bring her head down closer, self-conscious for a moment at her contortions. When she was in place, the first thing she noticed was an ordinary spectrum, muted by the paper through which she was seeing it but no different in scale and orientation than she would have expected from the prism’s geometry.

She closed all her eyes but one, ridding herself of distractions. Ivo said, “If you want to block the visible spectrum, there’s a lever on your right.” She found it, and slid an opaque screen across the band of colors. Then she waited while her vision adapted to whatever remained.

Out of the grayness, a blurred vertical bar of shimmering yellow light appeared—far beyond the red end of the hidden spectrum.

Tamara gauged the strength of the fluorescence. Assuming the effect scaled linearly, infrared light from the Object would produce far too weak a response in this lizard paper to see with the naked eye, but they could probably capture it with a camera and a long enough exposure.

“What wavelength is this?” she asked Ivo, without moving away from the slit. She was prepared to take his word for it, and hoped he wouldn’t insist on her verifying his answer immediately with protractors and calibration curves.

“About two scarso-scants.”

She did some quick calculations on her forearm. Light of that wavelength traveled at about an eighth the speed of red light, and it would extend a visible color trail by a factor of a dozen. If that wasn’t good enough to let them measure the Object’s speed, it would have to be moving at little more than a jogging pace. Any slower—and nearer—and they’d be able to toss a rope out to it and make the whole journey by hand.

“Congratulations,” Tamara said. “You’ve won yourself a trip into the void.” She drew away from the box, and Ivo opened it and shut off the lamp, contemplating her announcement in silence. Everyone had been outside the Peerless for at least a few shifts of fire watch, but traveling across the void until the mountain vanished from sight had to be a daunting prospect for anyone.

“More immediately,” she added, “we’ll be needing you at all the planning meetings, to ensure that the Gnat’s capable of supporting whatever experiments you have in mind. There’s only going to be one chance to get this right.”

“Only one chance?” he replied. “I hope not.”

“The Object’s on a linear trajectory,” Tamara said. “Once it passes us, it’s never coming back.”

Ivo said, “Exactly. And this might be the only substantial body of orthogonal matter to come within our reach for generations. However diligently we prepare for this trip, however large the samples we’re able to bring back, it’s not going to be enough for everything we need to do.”

Tamara said, “What do you suggest then? If the Peerless matches velocities with the Object we’ll slip out of orthogonality with the home world. Not by much—but do we really want to be under pressure to solve their problems any faster?” The whole point of the Peerless was to grant its inhabitants as long as they needed to find a way to deal with the Hurtlers. If time on the endangered planet began to creep forward for the travelers, however slowly, that advantage would be lost.

“I don’t want the Peerless changing course,” Ivo said. “But that doesn’t mean we can’t match velocities.”

Tamara gazed at him uncomprehendingly for a moment, but then she grasped his meaning.

She said, “Why is it that whatever you ask a chemist, the answer invariably entails an explosion?”

Ivo buzzed delightedly. “A small explosion,” he said, “could correct the Object’s course, transforming it from a fleeting marvel whose passing we might recount to our grandchildren into a resource that they can study and exploit for as long as they wish. And if this thing is made of the same material that caused spot ignitions on the mountainside before spin… all we’ll need to do is toss the right amount of calmstone at the Object and it will become a kind of rocket in its own right.”

“No doubt,” Tamara replied. “But how do we discover what the right amount is— without blowing the whole thing into fragments, or creating a brand new star?”

“Calorimetry,” Ivo replied. “We’ll need to take samples and carry them a safe distance away from the Object itself, then determine just how much energy is released in the reaction with calmstone.”

Tamara had a vision of the two of them in the void, drifting along beside a jagged mountain of orthogonal matter. While she struggled to steer the Gnat, Ivo would be juggling vials of reagents— trying to calibrate a detonation that would either kill them both and obliterate their quarry, or grant their descendants a storehouse of energy that could pave the way for their return from exile.

6

Patrizia took the guide rope to the front of the room, then turned and addressed the class. “Suppose there are some luxagens in the mirrorstone that are bound so loosely that they can easily be freed from their energy valleys by a light wave. Suppose they get swept along by that wave, until they’re moving as fast as the light itself. If you compare the geometry of the light with the geometry of the luxagens’ motion, you can see that each of these luxagens ends up with an energy that’s proportional to the frequency of the light.”

Carla watched as the usually shy student sketched a diagram on her chest illustrating the relationship.

“To tarnish the mirrorstone at a given location,” Patrizia continued, “will require a certain amount of energy. Suppose that for light of the highest frequency, four luxagens can deliver that amount—so if a site in the mirrorstone is struck four times by these luxagens it will suffer the damage that we see as tarnishing. But as the frequency of the light falls, the energy per luxagen will fall too, so there’ll come a point where five luxagens would be needed to reach the same threshold. The tarnishing will still occur—but it will suddenly take much longer, and for a given exposure time it will be much fainter.”

Patrizia drew four stacked energy vectors for luxagens at the transition point, then added a second stack that