In an incredibly fun instance of worlds colliding, so to speak, rock star astrophysicist Neil deGrasse Tyson has joined the ranks of Batman, the Flash and Spider-Man in teaming up with Superman in the latest issue of "Action Comics." In the issue, he helps the Man of Steel observe his home planet—just before its destruction.
DC Comics, Tyson explains, approached him for permission to use the Planetarium — as well as his likeness — in a story where Superman witnesses the destruction of Krypton, since the light from the distant planet is just now arriving on Earth. Tyson told DC Comics that he was happy to help, and that instead of just making up the story of Superman seeing Krypton, he could help them ground it in at least some actual science.
OK, so here's how Tyson explains it: Superman didn't age during his trip to Earth, because he was still an infant upon arrival, meaning he must have traveled here through a wormhole with his little ship. If he's in his late 20s now (the estimate DC provided) and this is the time when he can witness the explosion of his home planet, then the planet is 27 or so light years away.
The story glosses over deGrasse's explanation of the science during the actual interview (which itself was simplified for a drive-time radio audience), but it's fun bit of actual science making its way into a world that's generally filled with improbable, if not outright impossible, happenings. Check out the audio on NPR's website (which I unfortunately can't embed) here.