MASS! (1)

Period/Size of orbits are related to MASS by Newton’s version of Kepler’s Third Law
Qualitatively, if two masses are orbiting about one another very rapidly, then the gravity between them must be stronger than if they were orbiting more slowly.
SUM of MASSES: Orbital Period + Orbital Size + GRAVITY

Period/Size of orbits are related to MASS by Newton’s version of Kepler’s Third Law