In the Footsteps of Carl Sagan: Neil Tyson of the Hayden Planetarium

Neil deGrasse Tyson, Director of the Hayden Planetarium in New York, talks about his work and his upcoming Origins television series on PBS. Emily Lakdawalla settles the question of densest planet, and Bruce Betts has a new trivia contest question on What's Up! Also, a space news update.