IN THE millennia before street lights and smartphones, humans could, on rare occasions, walk around on a moonless night and see clearly. Looking up, they could see broad luminous patches of light stretching across the sky, which brightened the heavens in all directions as though it were daylight. People could read without candlelight, view small details in their surroundings, and make out landscapes in the distance. It was as if the world were illuminated by a hidden night-time sun.
The existence of bright nights is well accepted, but their cause remains a mystery. Frustratingly, sightings have almost entirely faded away in the past few decades, making it seem that any hope of solving the riddle was dimming. Now, though, one man says he has seen the solution.
The earliest account of a bright night comes from Pliny the Elder, a Roman army commander who studied nature in his