It was, of course, impossible ever actually to reach the speed of light. But the great starships could come close. And the closer they came, the greater the contraction of time aboard ship.
It was all a matter of relativity. Time is relative to the observer.
Thus travel between the stars was possible. Without the Fitzgerald Contraction, the crew of a spaceship would age five years en route to Alpha C, eight to Sirius, ten to Procyon. More than two centuries would elapse in passage to a far-off star like Bellatrix.
Thanks to the contraction effect, Alpha C was three weeks away, Sirius a month and a half. Even Bellatrix was just a few years' journey distant. Of course, when the crew returned to Earth they found things completely changed; years had passed on Earth, and life had moved on.
Now the Valhalla was back on Earth again for a short stay. On Earth, starmen congregated at the Enclaves, the cities-within-cities that grew up at each spaceport. There, starmen mingled in a society of their own, without attempting to enter the confusing world outside.
Sometimes a Spacer broke away. His ship left him behind, and he became an Earther. Steve Donnell had done that.
The Fitzgerald Contraction does funny things. Alan thought of the brother he had last seen just a few weeks ago, young, smiling, his own identical twin—and wondered what the nine extra years had done to him.