Theory · proposed 1619 CE
Kepler's Laws of Planetary Motion
History of Astronomy
The theory
Three laws describing how planets move: orbits are ellipses with the Sun at one focus; a line from the Sun to a planet sweeps out equal areas in equal times; and the square of a planet's orbital period is proportional to the cube of its average distance. Derived from Tycho's observations between 1609 and 1619, they replaced circles with ellipses and made planetary motion exactly predictable.
Developed by
Presented in
Knowledge connections
- Introduced byAstronomia nova
- Introduced byHarmonices Mundi
- Developed byJohannes Kepler
- Part ofThe Scientific Revolution
- Associated withOrbital Elements
- Associated withOrbital Period (Kepler's Third Law)
- Associated withScientific Lineage
- Associated withObject Explanation
- Associated withScientific Summaries
Sources & references
The primary and reference sources this topic draws on.
- BritannicaEncyclopaedia Britannica
General reference for the history of astronomy, biographies, and cultural context.