How do solar eclipses happen?

Solar eclipses occur when the Moon’s shadow falls on Earth during a new moon. If the alignment is precise enough, observers in the path of the Moon’s darkest shadow, called the umbra, can see a total eclipse. Partial and annular eclipses happen when the alignment is slightly off or the Moon appears too small to cover the Sun completely. A total solar eclipse typically lasts only a few minutes at any one location because the Moon’s shadow moves rapidly across Earth. The geometry of eclipses is why they do not happen every month, even though new moon occurs monthly.