Johannes Kepler was a German astronomer and mathematician who is best known for his laws of planetary motion. 
Kepler formulated three fundamental laws that describe the motion of planets around the Sun:
        First Law (Law of Ellipses): Planets move in elliptical orbits with the Sun at one focus.
        Second Law (Law of Equal Areas): a planet moves faster when it is closer to the Sun.

And the Third Law (Law of Harmonies): The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.  - very complex and difficult