The Planets S1, E3

Welcome to the greatest story that's never been told. In a new, ground breaking series we'll be telling the story of the planets as never before.

Cast:Brian Cox , Carolyn Porco , Edgard Rivera-Valentin , Fran Bagenal , Jennifer Eigenbrode , Heidi Becker , David Grinspoon , Nancy Chabot , Julie Webster , Hal Weaver , John Grotzinger , Cathy Olkin , Noah Hammond , Larry Nittler , Ashwin Vasavada , Carl Murray , Leigh Fletcher , Jeff Cuzzi