Kepler's laws of planetary motion:
1. Planets move on elliptic orbits with the sun at a focal point. More generally: satellites of the sun (planets, comets, asteroids) move on conic sections (ellipses, parabolae, hyperbolae) with the sun at a focal point.
2. The line connecting a planet with the sun sweeps out equal areas in equal periods of time.
3. Comparing different planets, the squares of their orbital periods are proportional to the cubes of the long axes of their orbits.
Johannes Kepler (1571-1630) Biographic details
 |
Kepler's reconstruction of the orbit of Mars based on the data of Tycho Brahe. |
| Back to the beginning of the page | Comments and questions | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||