CELESTIAL MECHANICS A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site orbital period The time taken for a body to go once around a closed orbit. The orbital period of a planet is its "year". For a body in an elliptical orbit of semimajor axis a about a much more massive body of mass M the orbital period P is given by P = (2πa3/2) / √(gM). This is the mathematical formulation of the third of Kepler's laws of planetary motion. Related category    • CELESTIAL MECHANICS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP