Notes: Kepler proposed Laws of planetary motion. These three laws describes the behavior of planets in the heliocentric model;
The three laws of Kepler can be stated as follows:
1. Law of orbits: All planets move in elliptical orbits with the Sun situated at one of the foci of the ellipse
2. Law of areas: The line that joins any planet to the sun sweeps equal areas in equal intervals of time.
3. Law of periods: The Square of the time period of revolution of a planet is proportional to the cube of the semi-major axis of the ellipse traced out by the planet. The law of areas can be understood as a consequence of conservation of angular momentum which is valid for any central force