A dramatic celestial phenomenon in which light from the Sun is blocked from the Earth by the Moon. In order for this to occur, the Earth, Moon, and Sun must be in a line in that order, which means that the phase of the Moon must be new. The Moon's shadow sweeps across the Earth's surface as the Moon moves over the face of the Sun. Totality occurs when the Sun is completely blocked by the Moon. The darkest part of the shadow is called the umbra, and it is surrounded by an area of partial shadow called the penumbra. Because the Moon's shadow stretches from the Moon to the Earth in a cone shape, only a small fraction of the Earth's surface experiences the eclipse. The solar eclipse alignment of Earth, Moon and Sun does not occur every month, because the Moon's orbit is tilted five degrees from a plane containing the Earth and Sun, so the Moon's shadow usually passes above or below the Earth.