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Space Academy NASA
  1. The law of ellipses: The orbit of a planet is an ellipse with the sun located at one focus.

  2. The law of areas: The line joining a planet to the sun sweeps out equal areas in equal times.

  3. The harmonic law: The square of the orbital period of a planet is proportional to the cube of its distance from the sun.

Updated August 23, 1996. Contacts