The contamination was an uncharacteristic lapse. Carla had seen Ivo inspecting the air filters with a microscope, to ensure that there were no tears in them. But if the problem hadn’t arisen through carelessness, what had been its root? A misunderstanding of some kind. Which process was better understood, though: the filtering of dust from air… or the behavior of air in the presence of orthogonal matter?
What if the air is pure? she wrote.
Ivo didn’t dignify that with a reply. There was no better established fact in all of chemistry than the inertness of air. Nobody had a perfect explanation for this, but it had long been conjectured that each particle of the gas was a spherical cluster of luxagens, arranged in such a way that Nereo’s force canceled almost perfectly outside the cluster.
Still, when air bounced against rock it was Nereo’s force that made it bounce. Once an air particle actually made contact with something, the luxagens within couldn’t hide themselves completely. So it wasn’t inconceivable that orthogonal rock could react differently to air built from positive luxagens than it would to its own, presumably innocuous, swapped version. Let everyone on the Gnat and the Peerless share the blame, then, for failing to imagine that possibility.
Carla hadn’t thought to try to get a spectrum of the flames their spilt air had summoned, but she’d have bet anything that the same dominant spectral line as they’d seen before would have been present. Every mineral’s structure was complicated in a different way, and even a particle of air had its own elaborate geometry, but that one line screamed simplicity.
What was the UV frequency? she wrote.
Ivo gave her the wavelength.
No, the frequency.
I have no idea, he replied. His spectrograph was calibrated for wavelengths; it was the convention among chemists to express all their results in those terms.
You can’t work it out? Carla wasn’t so rattled that she couldn’t do it herself, but she wanted to keep Ivo engaged.
He humored her, carrying out the calculations on the patch of skin they shared. The spectral line’s wavelength wasn’t much greater than the minimum wavelength of light. Yalda’s formula put the frequency at near enough to three tenths the maximum; Ivo dutifully multiplied this out to get roughly a dozen and three generoso-cycles per pause.
Carla didn’t care about the final number; it must have been nice for the ancestors that a “pause” was a convenient fraction of the rotational period of the home world, but it had no bearing on anything else in the cosmos. All the real physics was in the pure ratios of numbers, untouched by the whims of history and convention.
The UV line they’d seen in every fire on the Object was three tenths the maximum frequency of light. Every photon of that frequency was traveling at a speed that tilted its energy-momentum vector steeply enough to make it lie at three tenths its original height.
But three to ten was the ratio Patrizia had found, when she’d fitted her curves for colliding particles to the data for light scattering off luxagens. A luxagen’s mass was three tenths the mass of a photon. So every photon in this ultraviolet line possessed the same energy as a stationary luxagen.
What if a luxagen became a photon? Carla wrote.
She could feel Ivo’s body shaking as he buzzed with mirth. Source strength? he replied.
He was right to object; a luxagen carried one unit of source strength, a photon had none. And from Nereo’s equation you could prove with mathematical certainty that source strength could never simply vanish.
Mathematically, though… it could cancel.
One positive luxagen, one negative, Carla suggested. Strictly speaking, the only quantity that had to remain unchanged was the total source strength: the count of positive particles minus the count of negative ones. The individual numbers didn’t need to stay fixed.
Ivo didn’t respond. Carla looked to his face; he appeared to be mulling it over.
She tried to imagine the process. Two luxagens came together, one of each sign… but instead of them simply bouncing off each other, the original particles were destroyed and two photons emerged.
It sounded absurd, but what principle did it violate? Source strength would be conserved, since the total was zero both before and after. Energy would be conserved, so long as each photon had the energy of a single luxagen. Momentum would be conserved if the photons were traveling in opposite directions, making the total zero before and after.
Is this charity? Ivo asked her.
Carla was taken aback. He thought she’d concocted the whole theory just to get him off the hook with Ada and Tamara. Of course not!
Luxagens vanish? Ivo’s face made it clear that he found this no more plausible than a conjuror’s claim to make a vole disappear from a sealed box.
Only in pairs, Carla replied, as if that were enough to make the idea respectable.
But no wonder it sounded preposterous: where else could they have seen positive and negative luxagens come together, with any hope of understanding the result? Not in the fleeting, uncontrollable events on the hull of the Peerless. Not in the light from the Hurtlers that menaced the ancestors; they hadn’t even known the luxagen’s mass or grasped the link between energies and frequencies.
Only here. Wherever this beautiful new physics carried them, it could only have begun here.
By the time the Gnat was fully re-pressurized and Carla had removed her cooling bag, she’d given Ada and Tamara a version of the Mite’s misadventures that never even raised the possibility of contamination in the air tanks.
“Air sets orthogonal rock on fire?” Tamara sounded every bit as skeptical as Ivo had been. “Are you sure there wasn’t some other—?”
“Air is made of positive luxagens,” Carla interjected. “Just like any other ordinary matter. That’s all it takes to set orthogonal matter on fire.”
She offered an illustration.
“The length of each line is the mass of the particle, and its height is the particle’s energy. Nereo’s arrow agrees with our time axis for positive luxagens, and opposes it for negative ones.”
Ada said, “Doesn’t a positive luxagen repel a negative one, close up?”
“It does,” Carla agreed.
“And the force pushing them apart goes to infinity as they get closer,” Ada added. “So how do they ever get to touch?”
“Luxagen waves don’t respect energy barriers absolutely,” Carla replied. “The wave for two luxagens with opposite signs will lie mostly in the energy valley where they’re far enough apart for Nereo’s force to become attractive—but it won’t be entirely confined to that valley, and it will allow some probability for the two luxagens to make contact. The fact that the probability is so small is why the process is relatively slow—why we had measurable delays before the flashes when we dropped the projectiles. But slow or not, once it happens, it happens.”
Ada looked dubious. Carla said, “Let me show you another process that’s worth thinking about.”