Orbit

In physics, an orbit is the gravitationally curved trajectory of an object. In astronomy, orbits are observed by the trajectory of a planet around a star or a natural satellite around a planet. Normally, orbits of this nature are repeating trajectories. To a close approximation, planets and satellites follow elliptic orbits, with the central mass being orbited at a focal point of the ellipse, as described by Kepler's laws of planetary motion.