Kepler's Laws of Planetary Motion
• First law (Law of Orbit): Planet revolves in an elliptical path around the sun, the sun being at one of the two foci of the ellipse.
• Second Law (Law of Area): The radius vector of any planet relative to the sun sweeps out equal area in equal interval of time.
• Third Law (Law of Period): The square of the period of revolution (T) of any planet around the sun is proportional to the cube of semi-major axis (a) of the elliptical orbits.
T2 \(\propto\) a3
