Kepler's laws of planetary motion are three laws describing how planets move around the Sun, worked out by the German astronomer Johannes Kepler. The first two were published in 1609 in his Astronomia nova, based on the careful observations of Mars made by the Danish astronomer Tycho Brahe. They state that planets travel in ellipses with the Sun at one focus, and that a line from the Sun to a planet sweeps out equal areas in equal times. The third law, published in 1619, links the time of a planet's orbit to its distance from the Sun. The laws broke with the ancient belief in circular orbits and later gave Isaac Newton key evidence for his theory of universal gravitation.
Before and after
- 1608Publication of King Lear
- 15 October 1608Birth of Evangelista Torricelli
- 9 December 1608Birth of John Milton
- 1609The Elevation of the Cross
- 1609Kepler's laws of planetary motion
- from 1609 to 1924American Indian Wars
- 1609Kepler publishes Astronomia Nova
- from 7 March 1609 to 5 April 1609Invasion of Ryukyu
- from May 1609 to October 1646Anglo-Powhatan Wars
More in Science & technology
- 1543De revolutionibus orbium coelestium
- 27 December 1571Birth of Johannes Kepler
- 1637Descartes publishes La Geometrie: algebra meets geometry
- 8 January 1642Death of Galileo Galilei
- 21 June 1646Birth of Gottfried Wilhelm Leibniz
- 1656Pendulum clock
The era
This moment belongs to the Early modern world (1500 CE to 1760 CE), voyages, printing and new ideas. You can also browse everything in the 17th century.