Asaph Hall

Asaph Hall III was born October 15, 1829, and spent decades mapping the mechanics of the solar system — calculating satellite orbits, measuring Saturn's rotation, weighing Mars itself. In August 1877, working at the U.S. Naval Observatory, he turned a telescope on Mars and spotted what no one else had: two tiny moons wheeling close to the planet, which he named Deimos and Phobos. The discovery made him one of the era's most prominent astronomers, a specialist in double stars and planetary systems. He died November 22, 1907, having proven that even well-watched worlds can hide something in plai…