This week's Radio Times cover star is none other than celebrated scientist Stephen Hawking. The theoretical physicist – who was diagnosed with motor neurone disease aged 21 – is delivering this year's Reith Lecture series, and to celebrate we've got an exclusive extract – plus his response to some of the burning questions everyone wants to ask.

But there was one answer in particular that made us think. When asked what motivates him to keep going, Hawking offered this inspiring reply...

Read the full interview with Stephen Hawking – plus extracts from his Reith Lecture on black holes (broadcasting Tuesday 26th January at 9am on Radio 4) in the new edition of Radio Times, available in shops and on the newsstand now.