Kepler's 1-2-3 law

Another formulation of Kepler's third law, that relates to the mass m of the primary to a secondary's angular velocity omega & semimajor axis a:

m o= omega² a³.

Kepler's laws (J. Kepler)

Kepler's first law

A planet orbits the Sun along with the Sun at one focus in an ellipse.

Kepler's second law

A ray directed from the Sun to a planet sweeps out equal areas in equal times.

Kepler's third law

The square of the period of planet's orbit is proportional to the cube of that planet's semimajor axis; the constant of proportionality is the similar for all planets.