The Eternal Flame

3

Carla opened the valve at the top of the lamp, allowing a trickle of liberator to fall onto the sunstone. She started at the sudden hissing sound and the dazzling eruption of radiance, and her hand moved quickly to the dousing lever that would bury the flame in sand. But after a moment the noise settled to a steady splutter, and though the beam escaping through the aperture in the lamp’s cover retained its formidable intensity, it appeared to be stable.

Carla had prepared the liberator herself, extracting the active ingredient from sawflower roots, then diluting it with crushed powderstone, checking the proportions three times and running the mixture through an agitator to be sure there were no clumps. But even these precautions couldn’t assuage her fears entirely. Fire of every kind crossed the Cornelio line into positive temperatures, but the act of igniting sunstone felt like summoning a malevolent creature out of the sagas. It might sit on the bench and amuse you with its tricks, but you knew that what it really wanted was to bring its whole world of bright chaos through the crack you’d opened up between the realms.

A lens over the lamp’s aperture partly countered the natural spreading of the light. Carla placed a small mirror in its path; mounted diagonally on a pegged holder, it sent the beam straight down through a hole in the bench-top. She knelt and fitted a triangular prism into place to intercept the vertical beam, then she ran an upturned hand through the space below it, to watch the brilliant spectrum glide over her skin. Sunstone disquieted her, but no other source produced such pure, intense colors.

A robust clearstone container sat on the floor beneath the bench. Apart from the corners, rounded for strength, it was almost box-like in shape, and the gravity here was strong enough to hold it in place by friction alone. At the bottom of the container was a flat rectangular mirror, freshly polished. The spectrum from the prism fell along the length of the mirror, with a thin strip of colors spilling off one edge onto a sheet of gridded paper, making it easy to see the position of every hue. Carla noted the locations of the red and violet ends; some space remained beyond them where the mirrorstone would be exposed to invisible wavelengths. Half of the spectrum reflecting off the mirror showed up on the underside of the bench-top, with the rest reaching an adjacent wall, but Carla felt no urge to contain the spilt light. It was no longer part of the experiment, and the streak on the wall made a cheerful decoration.

The prism she was using had been calibrated against a light comb by an earlier custodian of the workshop—the neatly written table was dated just a dozen and four years after the launch—allowing her to assign a precise wavelength to each line on the grid. She verified the overall calibration with half a dozen spot checks, then glanced at the clock. Going on what Marzio had told her, and accounting for the strength of the beam, she had planned for an initial exposure of one day.

Marzio was one of the most respected instrument builders on the Peerless. Four years ago, he’d been asked by the astronomers to construct a wide-field camera that could function in the void, in the hope of capturing sharper images than those taken behind the clearstone panels of the observatory domes. Like most such cameras his design had included a mirror to divert the light path, making it easier to keep the gas that activated the sensitized paper from leaving a residue on the lens. The device he’d built had been successful enough, but when Carla had run into him recently he’d told her something curious: the mirror had grown tarnished more rapidly than the corresponding part in any camera he’d built before. This was not what anyone would have expected; the gradual loss of reflectivity in polished mirrorstone had always been attributed to some kind of slow chemical reaction with the air.

Marzio had speculated that perhaps the activating gas, which seemed to cause no problems with the mirrors in air-filled cameras, was behaving differently in the vacuum—although it still did its job perfectly well. And the tarnish on the mirror, he admitted, bore no signs of being an entirely new phenomenon: it was indistinguishable from the patina that appeared under ordinary conditions. It merely arrived sooner in the absence of air.

Carla had had no good theories about any of this, but Marzio’s observation had nagged at her. If it wasn’t air that tarnished mirrors, what was it? Exposure to light, or simply the passage of time? It would have been absurd to ask Marzio to build a whole new camera for her to play with, so she’d set up this simple test. To measure the effect of time alone, a second mirror in its own evacuated container had been shut away in a light-proof box.

Carla stood by the bench, eyeing the lamp warily. She’d had to beg Assunto to approve the use of sunstone, though this handful was nothing to the quantity the Peerless’s cooling system burned up every day. “What’s the purpose of this experiment?” he’d asked irritably. He’d have to justify his decision to the Council in person at the next meeting, so he needed as pithy a summary as possible.

“Understanding the stability of matter.”

“And how exactly will a tarnished mirror help with that?”

“If the surface of a mirror can change in a vacuum,” Carla had argued, “that’s not a chemical reaction, it’s something simpler. If the luxagens in the mirrorstone are rearranging themselves in response to light, that could provide us with a mildly unstable system that we’d have a chance to manipulate and study—”

“As opposed to the kind that explodes in your face.” Assunto was of the school that believed luxagens would turn out to be pure fiction—he preferred to think of matter as a continuum rather than a collection of discrete particles—but in the end he’d signed the requisition for six scroods of sunstone.

Carla had re-read and signed the safety regulations. A sunstone lamp could not be left unattended. She went and stood at her desk, but kept her rear eyes on the lamp’s fizzing crucible as she marked her optics students’ assignments. After the first half-dozen it was tedious work, but she forced herself to wait as long as she could before taking a break.

Carla had been told that she’d have to share this cramped workshop with Onesto, the archivist, until one of the senior experimentalists in the main facility retired and freed up a bench there. But she and Onesto usually managed to choose shifts with as little overlap as possible, to avoid disturbing each other, and there were advantages to working on her own.

When the clock struck the fourth bell she stopped to wind it, then she went to the cupboard and took out a bag of groundnuts. She cupped one hand and tipped three of the aromatic delicacies onto her palm, then closed her fingers over them to trap the exhilarating scent. Her whole body tingled with anticipatory pleasure, casting off the lethargy that had begun to afflict her. But Carla had the timing down to an art: just before the muscles in her throat threatened to start gulping down an unsatisfying emptiness, she tossed the nuts back into the bag and quickly returned them to the cupboard.

I did swallow them, she told herself, wiping her hand over her lips, slipping three fingers into her mouth. That’s the aftertaste.

She picked up the stack of assignments again, then glanced back over the ones she’d marked so far. The men were doing better than the women, she realized—not by a lot, and not in every case, but it was impossible to miss the pattern. Carla thumped the side of the desk angrily; the lamp three strides away hissed and flickered in response. After seeing so many women slip behind in her final year, she’d promised herself that the same thing wouldn’t happen to her own students. She always pushed the women in her class to participate, to ask and answer questions so they couldn’t glide through the lesson in a hunger daze, but she was going to have to pay more attention and pick out the ones who were losing focus.

The ones who might be headed where Silvana had gone.

“Yeah,” she muttered. “Then I’ll hand out bags of nuts. Problem solved.”

“Are you sure you’ll be all right with this?” Carla asked Onesto.

He looked over the apparatus, respectful but not intimidated. “If in doubt, I’ll just kill the flame,” he said, gesturing at the lamp’s dousing lever. “You can always complete the experiment with a second exposure, can’t you?”

“Of course,” Carla replied. It was kind of him to agree to take responsibility for the lamp; she could have enlisted one of her students, but since Onesto was going to be at his desk a few strides away regardless, it did make sense.

“Are you seeing your co tonight?” he asked, doing his best to make it sound as if he viewed the question as nothing more than ordinary small talk.

“In a couple of days.” Carla had been open about the arrangement; she was hoping more people would try the same strategy, but most of her colleagues had greeted the news with embarrassment or confusion.

“Ah.” Having broached the subject Onesto backed away from it. “I put my name down for the Gnat yesterday. For the lottery.”

“The Gnat?”

“That’s what they’re calling the little rocket now,” Onesto explained.

“Isn’t this all a bit premature? We still don’t even know how far away the Object is.” Carla caught the tone of irritation in her voice. Why should she be annoyed that the astronomers’ plans were progressing, as they waited for the tools they’d need to bring the project to fruition? When she’d first heard of the discovery she’d been thrilled.

She could smell Onesto’s last meal through his skin.

Onesto glanced down at the mirror in its container. “I don’t suppose that will be sensitive to infrared?”

Carla said, “If it is, it would still take half a year’s exposure to record any kind of color trail.”

“Right.” Onesto stretched his arms behind his back. “You seem tired, Carla. You should go. I’ll look after everything, I promise.”

Carla’s new apartment was six levels closer to the axis than the workshop. She climbed ladder after ladder in the walls’ red glow; all the shafts looked the same, and at some point in the journey she lost track of where she was, unsure how much of her growing sense of lightness was down to her location and how much to hunger.

At home she took her holin dose, chewing the green flakes slowly. Her body begged for something more, but she lay down in the sand of her bed and pulled the tarpaulin into place.

She woke a bell earlier than she’d intended, thinking about the loaf in the cupboard barely four strides away. What difference would it make, to eat the same meal a little earlier on the very same day?

But she knew the answer. She’d be hungry again, from habit alone, at the time she was accustomed to eating. Then she’d be twice as hungry in the middle of the day, and so ravenous by the evening that she’d be struggling not to eat again. Her body had never experienced the home world’s cycle of plant light by night and sunshine by day, but it could still be pushed to follow a diurnal schedule more easily than any other routine. If she let the timing of her meals slip out of synch with that internal rhythm she would have lost her best and strongest ally.

She lay half awake beneath the tarpaulin, watching the clock in the moss-light, imagining Carlo beside her. Taking her in his arms, naming their children, promising to love and protect them as he drove her hunger away.

Onesto said, “No fireworks, no down-time, no problems at all.”

Carla was relieved. “Thank you. I hope the lighting didn’t distract you from your work.” The spillage from the lamp’s beam filled the room with patches of brightness and deep shadow, and though she’d become used to it the day before the contrast now made her eyes hurt.

“Not at all.” Onesto was trying to reconstruct a notebook belonging to one of the first-generation physicists, Sabino. It had turned up recently in a woeful state, and Carla didn’t envy him the days he was spending squinting at the torn sheets with their smudged dye.

Onesto put away his materials and left. Carla had no more marking to do, so she stood and reviewed her notes for the next optics lesson, trying to think of ways she could convey to the students the maddening intractability of the field’s unsolved problems without scaring them off completely. Most of what she taught hadn’t changed since Sabino’s day—and while much of that legacy possessed an indisputable elegance and consistency, and might well deserve to be passed unaltered down the ages, the rest was a perplexing mess.

No one had been able to improve on Nereo’s equation, which connected light to the “source strength” of the hypothetical particles he’d called luxagens, much as Vittorio’s equation connected gravity to mass. Sabino had demonstrated that the force implied by Nereo’s equation was real, by showing that it could hold two tiny mineral grains together, despite a visible gap between them. But taking all of Nereo’s ideas at face value soon led to predictions that simply weren’t true.

Whatever the fundamental constituents of a rock or a flower were, they either possessed the light-making property or they didn’t; it wasn’t something that could come and go. A few lines of mathematics proved that “source strength” was conserved, as surely as energy itself. So matter had to be made of something that possessed source strength, or no flower could glow, no fuel could burn. The trouble was, anything with source strength should give off some light, visible or invisible, all the time; only absolute stillness—or the equally unlikely contrivance of a pure high-frequency oscillation—could keep it from radiating. But a substance that emitted light could not be left unchanged by the process: the energy of the light had to be balanced by the creation of energy of the opposite kind. A flower could use its newfound energy to make food, but what was a rock to do? With a sprinkling of liberator a rock went up in flames, but why should it need that push? Why hadn’t every lode of sunstone simply blown itself apart, eons ago?

Carla disciplined herself not to so much as peek at the experiment before the exposure was complete. When the full twelve bells had passed, she knelt beside the clearstone container and checked that the spectrum had remained aligned with the same marks on the paper as before, then she stood and extinguished the sunstone lamp. Onesto had lit an ordinary firestone lamp in the corner of the workshop; now she turned up its light to help her see clearly.

She slid the container out from under the bench and tipped it for a better view; the clearstone caught the light and confused her with its own reflections, but she was almost certain that the mirror’s sheen had been diminished. She fetched a needle and made a tiny hole in the container’s resin seal, then waited impatiently while the air squealed back in.

With the pressure safely equalised, she cut the seal away completely, removed the lid and took out the mirror, careful not to detach the gridded paper that she’d glued beneath it.

Carla held the mirror up to catch the light. There was an unmistakable dull white patina, uniform and complete across the width of the mirror—but not its length. It stretched from one end of the rectangle to a point about halfway along, where it disappeared abruptly. She summoned the calibration notes for the grid onto her thigh. The tarnished region corresponded to a portion of the spectrum running from infrared to green.

Why stop at green? The intense light from the sunstone beam would have shaken the luxagens, making them vibrate, making them radiate their own light in turn… giving them the energy they needed to break out of the mirrorstone’s regular structure, damaging the surface, spoiling the sheen. But why should the color of the light have such a sharply delineated effect? The theory of solids held that a material’s only hope of stability was for its luxagens to sit in energy valleys whose natural frequency of vibration was greater than the maximum frequency of light—so at least that favored, resonant frequency couldn’t generate radiation and aid in the material’s destruction. So why should light have the power to shake luxagens loose on the red side of green but not the blue side? Since every color was far below the resonant frequency, the response should have varied smoothly across the spectrum, without any sudden jumps.

Carla turned the mirror back and forth in front of her eyes, wondering if it could all be an error, an artifact. Maybe an obstacle outside the container had intruded into the blue end of the spectrum—something Onesto had stashed under the bench for part of the night? But that was ridiculous; why would he have done that? And even if he’d set out deliberately to sabotage the experiment, she’d been present for the greater part of the exposure. Blue light had reached the mirror. The color-dependence was real.

As the mirror flared in the firestone’s light, a new feature marring the surface jumped out for an instant and then vanished. It was like glimpsing a white thread on a white floor, only to lose it again. Carla cursed and repeated the motion, over and over, until she found herself staring at a second, faint edge. In the half of the mirror that had seemed to her before to be uniformly shiny and new, there was in fact another, very subtle change in its reflectivity. The tarnish that she’d thought had ended completely at green actually continued—vastly diminished—along a section that stretched almost down to violet. And beyond that? She was no longer prepared to assume that the surface remained pristine; all she could be sure of was that she’d exhausted the discriminatory powers of her vision.

But there were at least two abrupt transitions in the density of the tarnish: two sudden changes in the damage the light had done, depending on its color.

Next to the calibration notes on her thigh, Carla wrote the wavelengths that marked these transitions. She committed them to memory, then started sketching luxagen arrays, doodling calculations, trying to make sense of the numbers. Maybe there was some kind of shift in the response of the mirrorstone when the light’s wavelength crossed some natural length scales dictated by its structure. Luxagens were expected to be separated from their nearest neighbors by roughly the same distance as light’s minimum wavelength, but other regularities showed up at greater distances.

There was no fit, though, between her two numbers and any of the known array geometries.

Carla paced the workshop. If not the wavelengths, what about the frequencies? She did the conversion: the green edge was at three dozen and three generoso-cycles per pause, the violet edge at two dozen and seven. But the frequencies at which luxagens were expected to vibrate, in mirrorstone or any other substance, could only be pinned down to within an order of magnitude—crudely constrained by the known properties of solids and the strength of Nereo’s force. So to what should she compare these frequencies?

To each other. They were in a ratio of five to four. Not exactly, but it was very close.

Carla remeasured the locations of the edges in the tarnish with scrupulous care, then recalculated everything.

Within the range of uncertainty imposed by the measurements, the ratio was indistinguishable from five to four.