The most widely circulated panoramic photo of the earth: "The Blue Marble" (The Blue Marble).
This is a picture taken by astronaut Harrison Schmidt at an altitude of nearly 45,000 kilometers for the earth on December 7, 1972. At that time, he was riding on the Apollo 17 spacecraft flying to the moon. He glanced back at the earth and pressed the camera's shutter to freeze this classic image of 40 years.
ESA astronaut Thomas Pesquet said: "The beautiful curvature, with the sun's rays, we have been floating on the sea for a long time in the space station. Because 71% of our planet is ocean, we call it blue. There is a reason for the blue marble".