Kepler's Laws (orbits)
  1. planets orbit the sun in ellipses with the sun at one focus.

  2. simulator | sample calculation
     
  3. the line between the sun (primary) and a planet (secondary) sweeps out equal areas in equal times

  4. (the law of areas).
    simulator | sample calculation
     
  5. the ratio of the cube of the semi-major axis to the square of the orbital period is a constant (the

  6. harmonic law).
    simulator | sample calculation