Ancient astronomers subscribed to the geocentric model of the Universe, believing that all heavenly objects revolved the Earth. These observers knew that five objects moved relative to the fixed stars, and they named them "planets," after the Greek...

Orbits are the pathways taken by objects under the influence of the gravity of another object. These trajectories are governed by the fundamental laws of gravity and the motion of the object. The ability to calculate the orbit of an object, be it a...

See Phase...