Time cycles signify a 360-degree circular or elliptical rotation, orbit or journey in time typically of an object such as a planet or moon. In the case of the precession of the equinoxes, the cycle is determined by the 360 degree shifting of the equinoctal axis. Time cycles can also refer to larger rotations or orbits such as the time it takes for the Earth to make one complete revolution about the Galactic Center of the Milky Way.