When Stephen Hawking postulated in the mid-1970s that black holes leak radiation, slowly dissolving like aspirin in a glass of water, he overturned a core tenet of the Universe. Ever since Albert Einstein published his theory of general relativity in 1915, predicting the existence of black holes, it was thought they devour everything in their vicinity, including light. Black holes, it was thought, were bottomless

According to Professor Stephen Hawking, humanity is at risk from a series of dangers of our own making.