A total solar eclipse happens when the darkest part of the Moon’s shadow, the part called the umbra, touches the Earth’s surface. Because the Moon moves around the Earth, the umbra moves across a part of the planet during a total solar eclipse. Maybe you’ve seen a partial solar eclipse and think you know what I’m talking about. During a partial solar eclipse, you need certified eclipse glasses to safely view the Sun. When you are looking at a partial solar eclipse through eclipse glasses, you are seeing the part of the photosphere that is not blocked by the Moon.

Source: The Standard September 09, 2017 15:56 UTC