One of the largest contributors to the field of astronomy was Johannes Kepler. His work was of utmost importance to the astronomy community as well as to other major fields of science. Using data collected by Tycho Brahe, to whom Kepler was an assistant, Kepler was able to formulate the three major laws of planetary motion. These laws give astronomers, physicists, mathematicians, and other scientists the basis for prevalent rules governing basic scientific principals.
Born on December 27, 1571 in Germany, Kepler went on to study theology at University of Tubingen. His education was the first step toward his revolutionary ideas. He was first influenced by his mathematics professor who was an ardent believer in the heliocentric theory of planetary motion (seen below-right). This theory was in itself revolutionary, as it based the solar system around the sun as opposed to all items in the solar system revolving around the earth. Likewise, Kepler accepted the Heliocentric model of planetary motion, originally developed by Copernicus, to be a simplistic explanation for the layout of the solar system. He soon left Germany to study in Austria where he began to work out complex equations which proved specific distances between planetary orbits, which at the time he believed to be circular. He went on to declare that the sun emitted some force that grew greater as objects approached the it. This force pushes the planets in the solar system into their orbits. These theories were first published in a composition called Cosmographic Mystery which became significant as it was the first account of the validity of the heliocentric model.
He later became the assistant to Tycho Brahe, a Danish astronomer in Prague. When Brahe died, Kepler took over his position as head mathematician and astronomer to Rudolf II, the Holy Roman emperor. During his time in this position Kepler released another major document known as Astronomia Nova which stated the first two of his three laws, regarding planetary motion.