Starplex

Keith next ordered a probeship with a human and an Ib from Jag’s staff to fly through to the other side and do a more complete reconnaissance. They didn’t actually travel into the source of the twinkling stars. There was no way to communicate in real time through a shortcut, so if they got in trouble it might be too late to help before Starplex realized it. But they did do full-spectrum EM scans, a complete-sky search for artificial radio signals, and so on. They returned to Starplex, reporting that there was no apparent danger on the other side, although the cause of the twinkling starscape remained as elusive as ever.

Keith waited until all data from the two probes and the crewed reconnaissance had been reviewed by each department. Finally, satisfied that it would represent a low risk, he ordered Thor to take Starplex itself through the shortcut into the newly opened sector of space.

People occasionally used the terms “wormhole” or “tunnel” as synonyms for shortcut, but that wasn’t correct. There was no intervening space between the shortcut entrance and the exit. They were like doors between rooms in a house with paper-thin walls: as you walked through, you were partly in one room and partly in another. As simple as that—except that the rooms were separated by many light-years.

The Commonwealth had slowly worked out how to navigate the shortcut network. In normal space, a dormant shortcut is a point. But in hyperspace, that point is surrounded by a rotating sphere of tachyons. The tachyons move along millions of polar orbital lines, all of which are equally spaced, except that one is missing on one side, its tachyon looping back in a hemispherical path. That narrow tachyon-free gap is known as “the zero meridian,” and it means you can treat the sphere of tachyons just like a planetary globe, with a coordinate system of longitude and latitude.

To travel through a shortcut, you set a straight-line path toward the point at the center of the sphere. As you approach that point, you pass through the sphere at a specific latitude and longitude. Those coordinates determine which other shortcut you will exit from: where in the galaxy you come out depends on the direction from which you approached the local shortcut.

Of course, to get the ball rolling, there had to be one shortcut on-line at the outset that was not associated with any race—otherwise there’d be no location for the first emerging civilization to travel to with their shortcut. The initial shortcut—Shortcut Prime—was clearly a freebie, given by the shortcut makers. It was located in the heart of the Milky Way galaxy, within sight of the central black hole. Earth’s initial explorations of that sector had found no native life there, of course; the galactic core was far too radioactive for that.

At the beginning of the Commonwealth, there were only four active shortcuts—Tau Ceti, Rehbollo, Flatland, and Shortcut Prime. As more shortcuts were activated, the acceptable approach angles for each possible exit became smaller. After a dozen shortcuts were on-line, it became clear that to return to the Tau Ceti shortcut, one had to pierce the tachyon sphere surrounding another shortcut at about 115 degrees east longitude and 40 degrees north latitude. On Earth, that’s close to Beijing, which gave rise to the “New Beijing” nickname for the colony on Silvanus, Tau Ceti’s fourth planet.

When a ship touches the shortcut, the shortcut point expands—but only in two dimensions. It forms a hole in space perpendicular to the direction of the ship’s travel. The hole’s shape is the same as the cross-sectional profile of whatever part of the ship is passing through it. The opening is outlined in a violet ring of Soderstrom radiation, caused by tachyons spilling out around the edges and spontaneously translating into slower-than-light particles.

An observer looking at the shortcut from the front would see the ship disappearing into the violet-limned entrance. Looking from the back, he or she would only see a black void blocking the background stars; the void would have the same silhouette as the disappearing object.

Once the ship is all the way through, the shortcut loses its height and width, collapsing back down to nothingness—awaiting the next galactic traveler…

* * *

Thor sounded the pretransfer alarm, five successively louder electronic drumbeats. Keith touched keys, and his number-two monitor switched to a split-screen mode. One side displayed normal space, in which the shortcut was invisible; the other, a computer simulation based on hyperspace scans, showing the shortcut as a bright white point on a green background surrounded by a glowing orange sphere of field lines.

“All right,” said Keith. “Let’s do it.”

Thor operated controls. “As you say, boss.”