Diaspora

"Apparently not." Gabriel pressed his hand inside ver again, deeper this time; pulses of warmth spread our from the center of vis torso. Blanca turned toward him and stroked his back, reaching for the place where the fur became, if he chose, almost unbearably sensitive. C-Z culture had its problems, but in Konishi a simple exchange of pleasure phrased in this manner would have been unthinkable. The two of them were not slavishly embodied; harm remained impossible, coercion remained impossible. But Konishi had sanctified autonomy in the same absurd fashion as the statics had sanctified the pitfalls of the flesh.

The FM arrived in the gamma-ray chamber, and a series of intense pulsed bombardments began. The gamma-ray photons had wavelengths of around ten-to-the-minus-fifteen meters, roughly the same as the FM's diameter. A photon's wavelength had nothing to do with the size of its wormhole mouth, but it did measure how precisely you could constrain its location and aim it at a chosen target.

Blanca protested, half-seriously, "Why couldn't you have positioned the Forge so the time lags were equal?" Gamma rays should have been emerging instantaneously from the wormhole's other mouth, but the far end of the accelerator was three billion kilometers further from Earth than the near end, so it would be another three hours before they'd know what had happened there, 68 hours earlier.

Gabriel defended himself almost absent-mindedly "It was a compromise. Comets to avoid, gravitational effects to balance…" Blanca followed his gaze into the flickering gamma-ray glow, and knew at once what he was thinking. What they were witnessing here opened up some very strange possibilities. According to a hypothetical observer flying along the axis of the Forge toward the far end, these photons, transported faster than light, would be coming out of the wormhole before they went in. That peculiar ordering of events was largely academic—the traveler wouldn't even know about it until photons from both ends had had time to reach ver—but if ve also happened to be carrying a wormhole mouth of vis own, linked to one in the hands of an accomplice in a second spacecraft following behind, then as the traveler flew past the far end of the Forge ve could signal the accomplice to destroy the gamma-ray source at this end… before the photons ve'd just seen emerging had ever been sent.

Once they had a second wormhole, the Forge group would be able to make this ancient thought experiment a reality. The most likely solution to the paradox involved virtual particles—the mouths of vacuum wormholes—traveling in a loop that included both the Forge wormhole and the ship-borne one. Virtual particles were constantly streaming along every available path through space-time, and though crossing ordinary space between the mouths of the two wormholes would take them a certain amount of time, moving through the ship-borne wormhole would carry them back into the past, reducing the total time needed to go around the loop. As the two spacecraft neared the point where signaling from future to past became possible, the transit time for the loop would approach zero, and each virtual particle would find an exponentially growing army of doppelgangers hard on its heels: future versions of itself which had already made the trip. As they slipped into perfect phase with each other, their rapidly increasing energy density would make the wormhole mouths implode into tiny black holes, which would then vanish in puffs of Hawking radiation.

Apart from ruling out time travel, this would have serious practical consequences: once the galaxy was crisscrossed with wormholes, there'd be loops of virtual particles threading them all, and any careless manipulation of the mouths could see the whole network annihilated.

Gabriel said, "It's almost time. Shall we…?"

They jumped to the far end of the Forge, where the scape was showing the most recent data available: still a few minutes before the gamma-ray bombardment had begun. The second FM sat in an observation chamber, under the scrutiny of a cylindrical array of gamma-ray detectors, nudged occasionally by UV lasers to keep it perfectly centered. The faint scatter from the lasers was the only sign that the thing was really there; with no electric charge or magnetic moment, it was a far more elusive object than a single atom.

"Don't you think we should be with the others?" Blanca had lived with the distant promises of the Forge for so long now that it was hard to be moved by this first, microscopic hint of what lay ahead. But if they really were on the threshold of a change that would shape the history of the Coalition for the next ten thousand years, it seemed like a fair excuse for public celebration.

"I thought you'd be pleased." Gabriel laughed curtly, offended. "At the end of eight centuries, we're together for this moment. Doesn't that mean anything to you?"