Professor Stephen Hawking delivers his BBC Reith Lecture on black holes. These collapsed stars challenge the very nature of space and time, as they contain a singularity - a phenomenon where the normal rules of the universe break down. They have held an enduring fascination for Professor Hawking throughout his life.

Rather than see them as scary, destructive and dark he says if properly understood, they could unlock the deepest secrets of the cosmos. Professor Hawking describes the history of scientific thinking about black holes, and explains how they have posed tough challenges to conventional understanding of the laws which govern the universe.

Professor Hawking then explains his own hypothesis that black holes may emit a form of radiation, now known as Hawking Radiation. He discusses about the search for mini black holes, noting that so far "no-one has found any, which is a pity because if they had, I would have got a Nobel Prize." And he advances a theory that information may remain stored within black holes in a scrambled form. Show less