What is a solar eclipse?

A solar eclipse occurs when the Earth passes through the moon's shadow. As we can see in the illustration below, the moon casts a dark shadow, i.e. the umbra, and a less dark shadow known as the penumbra. The umbral shadow takes the shape of a cone. When the tip of that cone reaches the Earth's surface, observers at that location can view a total solar eclipse.

Eclipses are classified as total, partial, annular, or hybrid.

A decription of each of the eclipse types can be found here.