Herschel Discovers Uranus Moons: Solar System Expands

William Herschel was not trained as an astronomer. He was a musician from Hanover, Germany, who emigrated to England and made his living as an organist and composer in Bath. But his obsessive hobby of building telescopes and scanning the night sky would reshape humanity's understanding of the solar system more than once. Herschel had already stunned the scientific world in 1781 by discovering Uranus, the first new planet found since antiquity. The discovery doubled the known size of the solar system and earned him a royal pension from King George III, freeing him to pursue astronomy full-time. Six years later, on January 11, 1787, he turned his massive 20-foot reflecting telescope toward Uranus again and spotted two faint points of light orbiting the planet: its largest moons, which he would later name Titania and Oberon after characters from Shakespeare's A Midsummer Night's Dream. The discovery was remarkable for both its scientific significance and its technical demands. Titania and Oberon are relatively dim objects orbiting a planet roughly 1.8 billion miles from Earth. Herschel's ability to detect them reflected the extraordinary quality of the telescopes he ground and polished by hand in his workshop. His mirrors were considered the finest optical instruments in the world, superior to anything produced by professional instrument makers. The two moons would not be seen again by another astronomer for nearly fifty years, until William Lassell confirmed them in 1851 using improved optics. Modern spacecraft finally revealed their surfaces in detail when Voyager 2 flew past Uranus in 1986, showing Titania scarred by enormous canyons and Oberon pocked with ancient craters. A musician who taught himself to grind mirrors ended up naming moons after literary characters, and the names stuck for centuries.