Yatima had arranged to meet Orlando in a scape of Lilliput Base, a twenty-meter dome full of scientific instruments located on an equatorial plateau, far from the temperate lowlands where the oases formed. The dome and everything in it had been built by conventional nanomachines, but the raw materials would have been impossible to obtain in situ without far more sophisticated technology. A former Star Puppy called Enif, who'd switched outlooks upon reaching 51 Pegasus and taken up nuclear physics with a vengeance, had succeeded in constructing the first femtomachines about a century before C-Z Voltaire's arrival. Using the loosely-bound neutrons of halo nuclei in a manner analogous to the electron clouds of a normal atom, he'd managed to build "molecules" five orders of magnitude smaller than those with electron bonds, and then worked his way up to femtomachines able to ferry neutrons and protons to and from individual nuclei, holding the necessary increments of binding energy as deformations in their own structure. The invention had turned out to be priceless on Swift; not only were the normal, light isotopes of the five transmuted elements essential for some experiments, many other elements were rare on the planet's surface in any form.
They'd had to wait two days for a bay to become free. Yatima entered the scape just as the previous apparatus, designed to search for traces of oxygen-16 in ancient mineral grains, was dissolving back into reservoirs of its constituent elements. Scaled at one centimeter to a delta, the meter-square hay looked big enough for any conceivable experiment, but in fact it was going to be a tight fit. Yatima had found plans for a neutron phase-shift analyzer in the library, designed by Michael Sinclair no less, a former student of Renata Kozuch. When Blanca's proposed extensions to Kozuch Theory had reached Earth, most physicists had simply dismissed the new model as metaphysical nonsense, but Sinclair had scrutinized it carefully, hoping to devise an experimental test that would go beyond its success in explaining, after the fact, the length of the Forge's traversable wormholes.
Orlando appeared. The scape software didn't seem to know quite what to do with his exhalations; the Lilliput dome was maintained at high vacuum, and at first a faint cloud of ice crystals materialized and fell in front of him as his breath expanded and cooled, but after a moment some subsystem changed its mind and starred magicking the apparent contamination out of existence as soon as it left his mouth.
After raising a lattice of scaffolding, the bay's nanomachines began work on the analyzer, drawing threads of barium, copper, and ytterbium from the reservoirs and spinning them into delicate gray coils of superconducting wire for the magnetic beam splitter—an odd name for the component, when the "beans" in this case would consist of a single neutron. Orlando regarded their handiwork dubiously. "You really think the Transmuters were relying on someone doing an experiment as subtle as this?"
Yatima shrugged. "What's subtle? The shift between the spectrum of deuterium and hydrogen is a few parts in ten thousand, but we can't imagine anyone missing it."
Orlando said dryly, "Deuterium at six thousand times the normal abundance isn't subtle. Water vapor weighing twenty percent extra isn't subtle. But particles that behave exactly like neutrons until you split them into two quantum states, rotate one by more than 720 degrees, then recombine them to check their relative phase? Somehow I think that might qualify."
"Maybe. But the Transmuters didn't have much choice; you can't make neutrons twenty percent heavier. All they could do was wrap them in other layers that would draw attention to them. What makes Swift special? The heavy isotopes in the atmosphere. What makes those isotopes special? The extra neutrons they contain. What makes those neutrons special? There's only one thing you can change about a neutron, without turning it into something else entirely. The length of the wormhole."
Orlando seemed about to object, but then he raised his hands in a gesture of resignation. There was no point arguing; they'd soon have an answer, one way or the other.
In Blanca's extension of Kozuch Theory, as in the traditional version, most elementary particle wormholes were as short as they were narrow; the two mouths, the two particles, shared the same microscopic 6-sphere. That was the most probable state for a wormhole created out of the vacuum, and unlike traversable wormholes they weren't free to adjust their length once they were formed. But there was no theoretical reason why longer ones couldn't exist: chains of short ones joined end-to-end, a string of linked microspheres looping out into the extra six macroscopic dimensions. Once created, they'd be stable; it was just a matter of knowing how to make them in the first place. Ordinary splicing methods—brute-force collisions—simply merged the two microspheres into one.
