Kepler's laws describe the motion of planets: (1) Planets move in elliptical orbits with the Sun at one focus. (2) A line connecting a planet to the Sun sweeps out equal areas in equal times. (3) The square of a planet's orbital period is proportional to the cube of the semi-major axis of its elliptical orbit.

1. KEPLERS LAW FOR PLANETARY MOTION
M. KARTHIKA
Asst Professor,
Dept of Physics,
Bon Secours College for Women ,
Thanjavur Dt.

2. KEPLERS LAW
• The Law of Ellipses
• The Law of Equal Areas
• The Law of Harmonies

3. The Law of Ellipses
• The path of the planets about the sun is
elliptical in shape, with the center of the sun
being located at one focus.

4. The Law of Equal Areas
• An imaginary line drawn from the center of
the sun to the center of the planet will sweep
out equal areas in equal intervals of time.

5. The Law of Harmonies
• The square of the period of revolution of the
planet around the sun is proportional to the
cube of the semi_major axis of the ellipse.