Stephen Hawking reflects on the Earth's chances of sustaining life – video

Physicist and cosmologist Prof Stephen Hawking, at his first Australian public lecture, appears at the Sydney Opera House from Cambridge University in England via hologram technology. Hawking reflects on the state of the universe and why he believes we need to set up colonies in outer space. Before his BBC Reith Lecture on black holes, Hawking discusses the danger inherent in progress and the chances of disaster on Earth