Space Pioneer – Johannes Kepler

(Launchspace Staff)

Johannes Kepler, a German mathematician, astronomer and astrologer, was born in 1571 and died in 1630. He was a key figure in the 17th century scientific revolution, best known for the laws of planetary motion, based on his works *Astronomia nova*, *Harmonices Mundi* and *Epitome of Copernican Astronomy*. These works also provided one of the foundations for Isaac Newton’s theory of universal gravitation in the late 1600s.

During his career, Kepler was a mathematics teacher at a seminary school in Graz, Austria, where he became an associate of Prince Hans Ulrich von Eggenberg. Later he became an assistant to astronomer Tycho Brahe, and eventually the imperial mathematician to Emperor Rudolf II and his two successors Matthias and Ferdinand II. He was also a mathematics teacher in Linz, Austria, and an adviser to General Wallenstein. Additionally, he did fundamental work in the field of optics, invented an improved version of the refracting telescope (the Keplerian Telescope), and mentioned the telescopic discoveries of his contemporary Galileo Galilei.

Kepler lived in an era when there was no clear distinction between astronomy and astrology, but there was a strong division between astronomy (a branch of mathematics within the liberal arts) and physics (a branch of natural philosophy). Kepler described his new astronomy as “celestial physics”.

Tycho Brahe charted the motion of Mars over several years. Kepler later used Brahe’s data to develop his laws of planetary motion. Today we refer to ideal two-body orbits as Keplerian orbits.