Why do solar eclipses happen so rarely?

21 will attract a huge audience — and rightly so. The millions of people who are expected to witness the astronomical event won't show up just because solar eclipses are exceedingly beautiful — they're also exceedingly rare. Here's why. read more

An eclipse can only happen whenever the new moon coincides with the moon passing through the plane of the Earth's orbit around the sun. This kind of alignment can happen only so often, so the eclipses tend to be relatively rare. read more

Total solar eclipses happen when the moon crosses between the sun and Earth, but Earth doesn't experience a total solar eclipse every month. Exploratorium Senior Scientist Paul Doherty explains why not. read more

Solar eclipse happen only rarely because only rarely does the sun interact with the moon. Since the moon is closer to earth, the moon will cover the sun. read more