Relativity can be awful sometimes. You get in your spaceship, leave a planet, and you come back a few months later only to find that years have passed and your family is old or dead and all your plants died because YOU COULDN'T WATER THEM LIKE I ASKED, KEVIN?
Anyway, most science fiction stories use a trope, like faster-than-light travel, to avoid dealing with relativity. Not so R.W.W. Greene. In The Light Years, the…