What is a solar eclipse?

Solar eclipses happen only when there is a new moon, and when the Moon is between the Earth and the Sun. The Moon casts a shadow on Earth, and blocks, or partially blocks the Sun. Solar eclipses are visible from small areas on Earth, so they are hard to see. During a solar eclipse, the Moon's shadow on Earth’s surface is about 300 miles wide. There are two parts to the shadow: the umbra, where the Sun is completely blocked, and the penumbra, where the Sun is partially obscured. People who are in the umbra will be able to see the total eclipse, but people in the penumbra will only be able to see a partial eclipse.