Judging a Planet's Habitability With Abel Mendez

Nearly 400 exoplanets discovered so far, and a truly terrestrial planet may be found soon. Abel Mendez has proposed a system for evaluating any planet's ability to support life, including our own! Bill Nye on the elemental link between two stories in the news. Emily Lakdawalla's Q&A says there really ARE planets. A new space trivia quizon What's Up with Bruce Betts and Mat Kaplan.