Johannes Kepler

Johannes Kepler was a Lutheran schoolteacher from Swabia who became Tycho Brahe’s assistant in Prague and, from Tycho’s observations of Mars, found that the planets move in ellipses with the sun at one focus, sweeping equal areas in equal times, laws that Newton would explain. He was imperial mathematician to three emperors, defended his mother against a charge of witchcraft, and believed the planets sang. The Epitome of Copernican Astronomy is the textbook of the new system; The Harmonies of the World contains the third law and the music of the spheres, and Thomas Aquinas College reads the Epitome in sophomore year.