Kepler, Johannes
Kepler, Johannes (1571-1630), German astronomer and natural philosopher, noted for formulating and verifying the three laws of planetary motion. These laws are now known as Kepler's laws . Kepler was born on December 27, 1571, in Weil der Stadt in Württemberg and studied theology and classics at the University of Tübingen. There he was influenced by a mathematics professor, Michael Maestlin, an adherent of the heliocentric theory of planetary motion first developed by the Polish astronomer Nicolaus Copernicus . Kepler accepted Copernican theory (see Copernican System ) immediately, believing that the simplicity of Copernican planetary ordering must have been God's plan. In 1594, when Kepler left Tübingen for Graz, Austria, he worked out a complex geometric hypothesis to account for distances between the planetary orbits—orbits that he mistakenly assumed were circular. (Kepler later deduced that planetary orbits are elliptic; nevertheless, these preliminary calculations agreed w