<P> The term is derived from the ancient Greek noun ἔκλειψις (ékleipsis), which means "the abandonment", "the downfall", or "the darkening of a heavenly body", which is derived from the verb ἐκλείπω (ekleípō) which means "to abandon", "to darken", or "to cease to exist," a combination of prefix ἐκ - (ek -), from preposition ἐκ (ek), "out," and of verb λείπω (leípō), "to be absent". </P> <P> For any two objects in space, a line can be extended from the first through the second . The latter object will block some amount of light being emitted by the former, creating a region of shadow around the axis of the line . Typically these objects are moving with respect to each other and their surroundings, so the resulting shadow will sweep through a region of space, only passing through any particular location in the region for a fixed interval of time . As viewed from such a location, this shadowing event is known as an eclipse . </P> <P> Typically the cross-section of the objects involved in an astronomical eclipse are roughly disk shaped . The region of an object's shadow during an eclipse is divided into three parts: </P> <Ul> <Li> The umbra, within which the object completely covers the light source . For the Sun, this light source is the photosphere . </Li> <Li> The antumbra, extending beyond the tip of the umbra, within which the object is completely in front of the light source but too small to completely cover it . </Li> <Li> The penumbra, within which the object is only partially in front of the light source . </Li> </Ul>

What is the largest shadow cast by the moon during a solar eclipse