The Blue Marble. Whenever you see a picture of the whole Earth it’s usually this one. It was photographed by the geologist astronaut Harrison Schmitt as the last Apollo mission, Apollo 17, was leaving Earth in December 1972. Because of the unusual timing of the mission, this was the only time Apollo photographed the full Earth. It is the most widely reproduced single image in human history. (NASA)
For other NASA Earth images, see links.
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