An answer in my board game states that the Great Wall of China is the only manmade object on Earth visible from the Moon. Is this true? —P. Saunders, Silverdale, Wash. No. The Great Wall is one of the largest structures ever built—up to 30 feet wide and about 4,000 miles long—but it isn’t any easier to see than the U.S. interstate highway system. Both of them, and plenty more, are visible with binoculars from a low orbit of 200 miles.
Yet astronaut Alan Bean noted in 1969 that when his spacecraft was only a few thousand miles from Earth, no sign of civilization could be seen. So from the Moon itself, which is 239,000 miles away, forget it. With an unaided eye, you couldn’t even see the state of Texas.