Answer
Kepler's laws of planetary motion
Work Step by Step
Kepler’s three laws of planetary motion
1. All planets move around the Sun in elliptical orbits, having the Sun as one of the foci
2. A line joining the Sun and a planet sweeps out equal areas in equal interval of times
3. The square of a planet’s orbital period T is proportional to the cube of the semi-major axis (A)of its orbit.
$ T^2 = kA^3$
Kepler has an important place in the history. His discovery was a key step in the revolution which moved the center of the universe from the Earth (geocentric cosmology) to the Sun (heliocentric), and they laid the foundation for the unification of heaven and earth, by Newton, a century later