Even though the Moon is 400 times smaller than the Sun, it's also about 400 times closer to Earth than the Sun is. So, when the Moon comes between Earth and the Sun during a total solar eclipse, the Moon appears to completely cover up the light from the Sun. However, it won't always be this way.
Also question is, what are eclipses of the sun and moon?
When the Moon's shadow strikes Earth, people within that shadow see the Sun at least partially covered by the Moon; that is, they witness a solar eclipse. When the Moon passes into the shadow of Earth, people on the night side of Earth see the Moon darken in what is called a lunar eclipse.
Subsequently, question is, what are the 4 types of eclipses?
Solar Eclipse
There are four types of solar eclipses: total, partial, annual and hybrid. Total solar eclipses happen when the sun is completely blocked by the moon. Why does the moon fit exactly over the sun?
The sun and moon appear the same size in Earth's sky because the sun's diameter is about 400 times greater – but the sun is also about 400 times farther away.
Why can't we go out during solar eclipse?
The moon is in the farthest orbit away from the Earth, which means that it will not be able to cover the sun completely. This will cause the outermost rim of the sun to be visible in the eclipse, which will form a 'ring of fire' during the solar eclipse.