We were tooling along at four nines to c, relative to the Hercules cluster, when our Captain came on the intercom to tell us we were being tailed.

The announcement interrupted my afternoon lecture on Basic Implosive Geometrodynamics, as I explained principles behind the Fulton’s star drive to youths who had been children when we hoarded, eight subjective years ago.

“In ancient science fiction,” I had just said, “you can read of many fanciful ways to cheat the limit of the speed of light. Some of these seemed theoretically possible, especially when we learned how to make microscopic singularities by borrowing and twisting spacetime. Unfortunately, wormholes have a nasty habit of crushing anything that enters them, down to the size of a Planck unit, and it would take a galaxy-sized mass to ‘warp’ space over interstellar distances. So we must propel ourselves along through normal space the old-fashioned way, by Newton’s law of action and reaction… albeit in a manner our ancestors would never have dreamed.”

I was about to go on, and describe the physics of metric-surfing, when the Captain’s voice echoed through the ship.

“It appears we are being followed,” he announced. “Moreover, the vessel behind us is sending a signal, urging us to cut engines and let them come alongside.”

It was a microscopic ship that had been sent flashing to intercept us, massing less than a microgram, pushed by a beam of intense light from a nearby star. The same light (thoroughly red-shifted) was what we had seen reflected in our rear-viewing mirrors, causing us to stop our BHG motors and coast, awaiting rendezvous.

Picture that strange meeting, amid the vast, yawning emptiness between two spiral arms, with all visible stars crammed by the Doppler effect into a narrow, brilliant hoop, blue along its forward rim and deep red in back. The Fulton was like a whale next to a floating wisp of plankton as we matched velocities. Our colony ship, filled with humans and other Earthlings, drifted alongside a gauzy, furled umbrella of ultra-sheer fabric. An umbrella that spoke.