Two-Headed Space Worms What in the world are Planarian Flatworms? Why in the world did scientists send them on a mission to outer space? And where in the world are their mouths if not on their heads?! Join Guy Raz and Mindy Thomas for a tale of two worms....in one body. It's the latest who, what, when, where, why, how, and WOW in the world of WORMSTRONAUTS! Originally aired August 24th, 2017.