The University of Michigan's Nilton Renno leads a team that last week announced discovery of persistent liquid water on Mars...right on a leg of the Phoenix Mars Lander. He'll tell us what makes this possible. Bill Nye ties together a new electric car and space exploration. A classic Q&A shows Emily Lakdawalla isn't phased by the moon. Bruce Betts and Mat Kaplan cry at the first space wedding, just before giving away another Planetary Radio t-shirt in the space trivia contest.