Don't know when to rise; “The Great Wall of China is the only man-made structure visible from space” has been widespread all over the world. Is the Great Wall visible from space?
The first spaceman of China, Yang Liwei, received an interview after he came back from
the space. A journalist asked him curiously, “Do you see the Great Wall from the Space?” Yang Liwei answered quickly “No!”
Theoretically speaking, it is impossible to see the Great Wall of China from the space. Because the Great wall is narrow and irregular, and it is hard to observe something irregular from the space. In addition, the average width of the great wall in less than 10m which make the Great Wall easily merging with the environment, so that the Great Wall actually can hardly be distinguished from the environment when it is been seen from the height of 20 km and it will be totally invisible for human eyes from the height of 60m. To see the Great Wall from the Moon is the same as to find a hair from a distance of 2688m, and this is obviously unreal.
Actually, many spacemen said that the widespread rumor about the Great Wall was not true. Edwin Aldine, one of the first two spacemen who arrived at the Moon, said that the rumor was a misunderstanding in an interview. And the first space visitor Tito also denied this view.