A lunar eclipse can be total, partial or penumbral. The moon has two shadows, penumbra and umbra. The penumbra is the moon’s faint outer shadow. The umbra is the moon's dark inner shadow. A total lunar eclipse is when the entire moon passes through Earth's umbral shadow. A partial eclipse is when a portion of the moon passes through Earth's umbral shadow. A penumbral eclipse happens when the moon passes through Earth's penumbral shadow. Pictured here is a total lunar eclipse as seen on the winter solstice, Dec. 21, 2010, in Arlington, Va.