A total solar eclipse happens when the Moon passes directly between the Earth and the Sun, blocking the Sun completely for a few unforgettable moments. Daylight fades, the temperature drops, and the Sun’s glowing corona appears around the dark Moon.

It all happens incredibly fast. The Moon’s shadow races across Earth at tremendous speed while the Earth, Moon, and Sun are all constantly moving. That is why totality usually lasts only a few minutes before the Sun suddenly returns.

The most amazing part is the cosmic coincidence that makes it possible. The Sun is about 400 times wider than the Moon, but also about 400 times farther away. Because of that, they appear almost the same size in our sky, allowing the Moon to cover the Sun almost perfectly. For a brief moment, everything lines up just right.