Five hundred years ago, Leonardo Da Vinci solved an ancient astronomical riddle: the mystery of Earthshine.

When you think of Leonardo Da Vinci, you probably think of the Mona Lisa or 16th-century submarines or, maybe, a certain suspenseful novel. That's old school. From now on, think of the Moon.

Little-known to most, one of Leonardo's finest works is not a painting or an invention, but rather something from astronomy: He solved the ancient riddle of Earthshine.

in The Da Vinci Glow by Tony Phillips