shows the shadow of the Moon cast upon the eastern Mediterranean Sea near Cyprus. NASA image.]]An eclipse (Ancient Greek noun ???????? (ékleipsis), from verb ??????? (ekleíp?), "I cease to exist," a combination of prefix ??- (ek-), from preposition ??, ?? (ek, ex), "out," and of verb ????? (leíp?), "I am absent") is an astronomical event that occurs when one celestial object moves into the shadow of another. The term is most often used to describe either a solar eclipse, when the Moon's shadow crosses the Earth's 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 parent planet, or a moon passing into the shadow of another moon. Syzygy An eclipse is