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The Blue Marble is a photograph of Earth taken on December 7, 1972, by either Ron Evans or Harrison Schmitt aboard the Apollo 17 spacecraft on its way to the Moon. Viewed from around 29,400 km (18,300 mi) from Earth's surface,[1] a cropped and rotated version has become one of the most reproduced images in history.[2][3]
In the original NASA image, named AS17-148-22727 and centered at about 26°19′49″S 37°25′13″E / 26.33028°S 37.42028°E with the South Pole facing upwards, The Blue Marble shows Earth from the Mediterranean Sea to Antarctica. This was the first time the Apollo trajectory made it possible to photograph the south polar ice cap, despite the Southern Hemisphere being heavily covered in clouds. In addition to the Arabian Peninsula and Madagascar, almost the entire coastline of Africa and most of the Indian Ocean are clearly visible, a cyclone in the Indian Ocean is also visible, the South Asian mainland and Australia is on the eastern limb, and the eastern part of South America lies on the western limb.
NASA has also applied the name to a 2012 series of images which cover the entire globe at relatively high resolution. These were created by looking through satellite pictures taken over time in order to find as many cloudless photographs as possible to use in the final images. NASA has verified that the 2012 "blue marble" images are composites, made from multiple images taken in low Earth orbit. Likewise, these images do not fit together properly and due to lighting, weather and cloud interference it is impossible to collect cohesive or fully clear images of the entire Earth simultaneously.[4]
By measurement of the size of Earth's image in these photographs (29mm), they were taken at a distance of about 29,400 kilometres (15,900 nautical miles).
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