Get to know Professor Joseph Silk

From a channel Lumen includes in full: Gresham College has given free public lectures in London since 1597; its channel carries full hour-long lectures by professors and specialists on science, maths, history, law, medicine, music and the arts.

A 3-minute video from Gresham College's catalogue; the title names its topic.

Video by Gresham College, played through YouTube's embedded player.