November 15 - WIlliam Herschel

German-born British astronomer and composer Sir William Herschel was born on November 15, 1738, in Hanover in what is now Germany. With the French invasion of Hanover in the Seven Years’ War, he emigrated to England and became a music teacher and composer in Bath. His music led to interests in mathematics and lenses, and thence to astronomy, for which he built his own reflecting telescopes (more than 60 over his lifetime), and began comprehensive cataloging of stars. In 1781 he discovered a “nonstellar disk” that became known as the planet Uranus. King George III named him the King’s Astronomer. By 1802 he had discovered more than 2,400 objects he called nebulae, each formed of stars (i.e., galaxies). He also discovered two moons of Saturn (Mimas and Enceladus) and coined the term “asteroid,” meaning “star-like.” By studying stars’ motion, he was the first to determine that the solar system is moving through space, and the direction of that movement. He found that the Milky Way’s structure is disk-like. He also believed that all planets are inhabited.