If you are an astronaut I would hope you could easily see man-made objects, like your space ship and the inside of your space suit. There are also seventy or so large objects including ship modules and the lunar lander that humans have left on the moon's surface.
As for man-made objects on Earth, none are visible from that distance. The moon is 240,000 miles away, and while the Earth looks quite large, nothing other than basic outlines of the clouds and continents are visible against the background of the ocean. The Kaguya lunar satellite took this recording of the Earth while flying 100 kilometers (62 miles) above the moon:
As for the Great Wall of China, it's hard to see even in low Earth orbit, which is about 135 miles from the Earth's surface. While the Wall is over 3,800 miles long, it's only thirty feet wide at its broadest points. For comparison, astronauts often mention that major highways are relatively easy to see from space; an Interstate highway is a minimum of 108 feet wide. Cities, airports, and large ships are also visible. At the International Space Station, which orbits about 250 miles above the Earth, only cities are large enough to be noticeably with the naked eye.
The earlies claim that the Great Wall is visible from the moon comes from a book published in 1938. Richard Halliburton’s “Second Book of Marvels, the Orient” states that astronomers at the time thought the Great Wall would be the only man-made structure visible from the moon’s surface. If someone were to fly into outer space when the book came out cities would still be visible in orbit, but the ships and highways seen today hadn’t been built yet.
Posted 3341 day ago