http://www.npr.org/sections/thetwo-...ign=npr&utm_term=nprnews&utm_content=20160502 All three planets have one side that's always facing the star, and one side that's always facing away. That means one side is frigid and one side is scorching hot — but the regions in between might be downright cozy. I'm pretty sure I've read a science fiction story or novel taking place on that kind of planet. Or was it an episode of one of the Star Trek shows? Kind of bothering me a bit that I can't remember which sci-fi work it was.