Picture of Johan Kepler Courtesy of The Bettman Archive. From engraving by MacKenzie

Johan Kepler was a German astronomer who lived between 1571-1630. He introduced three important laws of planetary motion and helped the Copernican model of the solar system gain general acceptance.

Kepler inherited Tycho Brahe's observational data on Mars following Brahe's death and showed, mathematically, that Mars followed an elliptical orbit. This new revelation contradicted the age old belief that heavenly bodies all moved in perfect circles.

During his life, Kepler also cast horoscopes and wrote science fiction novels.