Pretty much an unknown Queen song.
Great lyrics if you can grasp the concept.
It's called "39", written by Brian May who has a doctorate in astral physics among other things.
Talks of "the volunteers" traveling in space 1 year at the speed of light, only to return to an Earth centuries older .
You may need to play it a couple times to catch all the words.

"In the land that our grandchildren knew"

http://nz.youtube.com/watch?v=Cai75quGNoM