Kepler's Laws

 
3.2  Kepler's Laws
 
  Kepler's First Law  
 

All planets move in elliptical orbits with the Sun at one focus.

 
     
 
  Kepler's Second Law  
 

A line that connects a planet to the Sun sweeps out equal areas in equal times.

 
     
 
  Kepler's Third Law  
 

The square of the orbital period of any planet is directly proportional to the cube of the radius of its orbit.