That was the famous question posed by Italian American physicist Enrico Fermi in 1950. No, Fermi wasn’t trying to get through to the official Covid-19 hotline. He was pondering an even more puzzling question. If our galaxy alone contains billions of stars, each of them with orbiting planets, then the universe must be teeming with more life than on a private beach during lockdown. But if that’s the case, why haven’t we detected any up to now?