During the lunar eclipse
the moon passes through the shadow of the Earth. As we look at the Moon from
the Earth, it looks to us as if the shadow of the Earth slowly covered the Moon.
Looking at the picture on the left, you may think that lunar eclipses happen
very often. The Sun, the Earth, and the Moon must be lined up in order for a
lunar eclipse to take place. This happens very rarely. In most of the cases there
are only two lunar eclipses that can be seen only from certain places on the Earth.