The Earth-Moon system. It is only when you get right away from the Earth that it appears in its astronomical context. The Earth and Moon were first photographed together by the Voyager probe in 1977 as it left to explore the solar system, but this image from December 1992 is clearer. It was taken from 4 million miles out by the Galileo deep space probe. The Earth and Moon function as a binary system; if there were no Moon, there would probably be no complex life on Earth. (NASA)
For other NASA Earth images, see links.
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