Kepler's laws of planetary motion are three mathematical laws that describe the motio of the planets in out solar system. The three laws are:
- The orbit of every planet is an ellipse with the sun at a focus.
- A line joining the a planet and the sun sweeps out equal areas during equal intervals of time.
- The square of the orbital period of a planet is directly proportional to the cube of a semi-major axis of its orbit.
