We're Back! Bill Nye Describes the LightSail Project

Come sailing with us! Bill Nye the Science and Planetary Guy satisfies your curiosity about The Planetary Society's LightSail project in a special conversation. First though, Emily Lakdawalla provides updates on the discovery of water hiding in the Moon's permanent shadows and Mars Exploration Rover Spirit's attempt to free itself from a sand trap. Puppies from space! Bruce Betts and Mat Kaplan will explain in this week's edition of What's Up as they offer a new space trivia contest.