Kepler Discovers How Planets Move
Johnnes Kepler Gesammelte Werke , C. H. Beck, 1937
Johannes Kepler used simple mathematics to describe how planets move. Kepler was an assistant to the most accurate astronomical observer of the
time,
Tycho
Brahe.
Kepler was able to use
Brahe's data to show that
planets move in
ellipses
around the
Sun (Kepler's First Law), that planets
move proportionally faster in their orbits when they are nearer the Sun
(Kepler's
Second Law), and that more distant planets take proportionally
longer to orbit the Sun
(Kepler's Third Law). Kepler lived from 1571 to
1630, during the time of discovery of the telescope. Kepler was one of the few vocal supporters of
Galileo's
discoveries and the Copernican system of planets orbiting the
Sun instead of the
Earth.