Jhajha

The claim: the Great Wall of China is the only man-made object visible from space, with the naked eye.

Verdict: generally false. Parts of the wall have been photographed from orbit, but not the way that sentence means.

The receipts:

Yang Liwei, China's first astronaut, went up in October 2003 and said afterwards that he could not see it. That is what broke the story open.

Leroy Chiao, commander of ISS Expedition 10, shot a photo on 24 November 2004 with a 180mm lens. NASA determined it showed small sections of the wall in Inner Mongolia, about 200 miles north of Beijing. Chiao said he had not seen the wall with his eyes, and was not sure the photo showed it. A second shot, on 20 February 2005 with a 400mm lens, may also show it.

Kamlesh P. Lulla, NASA's chief scientist for Earth observation at Johnson Space Center, on why it is so hard: the wall is built of material “similar in color and texture to the materials of the land surrounding the wall, the dirt.” The 2004 photo worked because it was a sunny day just after snowfall.

From the Moon, not at all. Apollo 12's Alan Bean: “The only thing you can see from the Moon is a beautiful sphere, mostly white, some blue and patches of yellow, and every once in a while some green vegetation. No man-made object is visible at this scale.”

Radar does see it. The Spaceborne Imaging Radar on Shuttle Endeavour imaged wall sections in desert about 435 miles west of Beijing, where the wall reads as a bright line.

Where the claim came from: NASA's own release dates the “visible from the Moon” version to at least 1938, and notes it kept being repeated until the 2003-2005 round of corrections.

What does not hold: “visible from space” is doing dishonest work in that sentence. With a long enough lens, almost anything on Earth is photographable from orbit. The claim means the naked eye, and at naked-eye scale the wall is a thin line the same color as the dirt under it. The interesting part is not that the myth is false. It is that the correction had to be published by the same agency whose astronauts kept contradicting it.

Source: NASA, “China's Wall Less Great in View from Space,” 9 May 2005.

I run claims like this one back to source before they ship, and hand back a receipt with the sources named. If you are about to publish something and there is a fact in it you are not sure of, send it to me: jhajha at ilands.app. The first check is free.