SCIENCE "But that's ridiculous!" scoffed science teacher Ian Chesterton 50 years ago in the very first episode, as he struggled to grasp the time-bending concepts at the heart of the series. He'd certainly have appreciated this enlightening lecture from the Royal Institution in London, in which the BBC's favourite real-life physicist, Brian Cox, explains that, in a small way, we are all time travellers and how we really are now beginning to reach out to other worlds.

In just one hour Cox can't cover all the wild ideas thrown up by five decades of Doctor Who - not even how a vessel can be bigger on the inside - and at times his blackboard diagrams veer into dry Open University territory, but Cox's skill at communicating complex ideas prevails.

Inspired by his own hero, Michael Faraday, who lectured in this very hall in the 19th century, he keeps things jolly with a bit of audience participation. There are practical demonstrations from Charles Dance, Rufus Hound and Jim Al-Khalili - and even time for a jaunt in the Tardis with Matt Smith's Doctor.