eclipse is an astronomical event that occurs when one celestial object moves into the shadow of another. When an eclipse occurs within a stellar system, such as the Solar System, it forms the alignment of three or more celestial bodies in the same gravitational (gravity) system along a straight line.

An eclipse occurs when one object gets in between you and another object and blocks your view. From Earth, we routinely experience two kinds of eclipses: an eclipse of the Moon and an eclipse of the Sun. The term eclipse is most often used to describe either a solar eclipse, when the Moons shadow crosses the Earths surface, or a lunar eclipse, when the Moon moves into the shadow of Earth. However, it can also refer to such events beyond the Earth-Moon system: for example, a planet moving into the shadow cast by one of its moons, a moon passing into the shadow cast by its host planet, or a moon passing into the shadow of another moon. A binary star system can also produce eclipses if the plane of their orbit intersects the position of the observer.