A solar eclipseThe passage of the new moon directly between the Sun and the Earth when the Moon's shadow is cast upon the Earth. The Sun appears in the sky either partially or totally covered by the Moon. More seen from within the Moon’s penumbraThe part of a shadow (as of the Moon or the Earth) within which the source of light (the Sun) is only partially blocked. Also, the lighter outer area of a sunspot. More. The Moon appears to block part (but not all) of the Sun’s photosphereThe bright, visible surface of the Sun. More.