Much is being said about the total solar eclipse on August 21, 2017. This will be an extremely rare opportunity for Americans to enjoy the spectacle of the Sun being completely covered by the Moon, certainly one of the most awesome celestial events visible to the unaided eye.The darkest part of the Moon's shadow, called the umbra, extends behind the moon, in a long cone. The shadow reaches out into space approximately 235,000 miles. Usually, in its orbit around the Earth, the Moon's shadow [...]
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