Sir Roger Penrose: The man who proved black holes weren’t ‘impossible’

We take for granted today the ability of telescopes to image black holes, or at least their immediate vicinity. And we’ve become a little blasé, it has to be said, when laser interferometers “hear” yet another pair of black holes bump into each other and merge. And, yet, go back just a few decades and the debate around the reality of black holes was a heated one.