8:00pm Saturday, September 25 on C4
In the second programme of the series, Professor Hawking explores the world’s favourite “what if”: is time travel possible? With his trademark clarity, wit and humour, he considers a range of possibilities: could tiny worm holes hold the secret to travelling back in time? Might riding a black hole catapult us into the future? Hawking looks at the prospects, as well as the pitfalls – such as killing your own grandfather – of journeying through the fourth dimension.