By - - BBC - RADIO 4
Added: Sat, 07 Jan 2012 16:52:45 UTC

To mark his 70th birthday, physicist Professor Stephen Hawking answered a selection of questions from listeners to Radio 4's Today Programme.

It seems clear that Professor Hawking believes we we will have to colonise space if we are to avoid catastrophe, but he is upbeat about the prospects for self-sustaining colonies on Mars and believes the human race will eventually spread out across the far reaches of the universe. Finding intelligent life elsewhere in the universe, he says, would be the greatest scientific discovery ever, but he is not optimistic about the likely outcome.

ORIGINS OF THE UNIVERSE

1. Was there a "time" when there was "nothing"? - Roland, Lagos

The origin of the universe can be explained by the laws of physics, without any need for miracles or Divine intervention.

These laws predict that the universe was spontaneously created out of nothing in a rapidly expanding state.

This is called inflation because it is like the way prices in the shops go up at an ever increasing rate.

Time is defined only with the universe, so it makes no sense to talk about time before the universe began, it would be like asking for a point south of the South Pole.
Read more and listen to BBC audio of the interview

TAGGED: INTERVIEWS, PHYSICS