Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2002 July 20 Footprints on Another World Credit: Apollo 11, NASA Explanation: On July 20th, 1969, humans first set foot on the Moon. Taken from a window of their Apollo 11 lunar module, the Eagle, this picture shows the footprints in the powdery lunar soil made by astronauts Neil Armstrong and Buzz Aldrin. It has been estimated that one billion people on planet Earth watched Armstrong step from...