YEARS ago, on one of my first assignments for New Scientist, I was sent to London’s Dorchester Hotel to interview Carl Sagan, the American astronomer. Sagan was famous for his popular science books, the blockbuster TV series Cosmos, and his science fiction novel Contact, which was turned into a film starring Jodie Foster. Rather overawed by Sagan’s palatial suite and by meeting the man himself, I asked him which he preferred – science or science fiction? “Science,” he replied without hesitation. “Because science is stranger than science fiction.”

That was two decades ago. Since then, we have discovered that 73 per …