Nearly half a century has passed since the day in 1965 when Arnold Penzias and Robert Wilson, two American astronomers, unwittingly discovered the fading whispers of the Big Bang. For months they had been using a radio antenna in Holmdel, New Jersey, to detect signals coming from outer space but were frustrated by a background noise similar to the “static” that can interfere with reception of a concert broadcast on a traditional (analogue) radio. The hiss was constant, unvarying, and seemed to come from all directions. At first they thought that pigeon droppings were causing it, but after cleaning the antenna, the noise continued.