Space Alien Special

Richard is at SETI in California to hunt space aliens with the institute's chief astronomer, Seth Shostak. He also reports from the iconic Parkes space telescope in Australia on the Breakthrough Listen hunt for ET. And, in the search for aliens closer to home, he talks to the head of Cassini's imaging team and one of NASA's top astrobiologists about life on Saturn's moon Enceladus. Is the truth out there?