The Great American Eclipse

While the Moon is about 239,000 miles away with a radius of about 1,000 miles, and the Sun is about 93 million miles away with one of about 432,000 miles, they have a similar angular size in the sky. Yes, that is right, they both take up about half a degree on the sky as seen from Earth. Solar eclipses occur when the New Moon comes between the Sun and Earth, and casts the darkest part of its shadow, the umbra, on the latter.

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