Before the Big Bang

Stephen Sackur talks to Sir Roger Penrose about his latest theory on what may have existed before the Big Bang.

The universe began with a big bang.

That's the most popular, though by no means the unanimous view of the world's leading physicists.

Sir Roger Penrose has devoted his life to the biggest questions; from the origins of the universe to human consciousness.

Stephen Sackur asks if his latest theory is perhaps a step too far?

HARDtalk can be seen on BBC World at 04:30 GMT, 0830 GMT, 1130 GMT, 1530 GMT, 1930 GMT, 0030 GMT

It can also be seen on BBC News 24 at 04:30 and 23:30