You Cannot See the Great Wall of China from Space

April 4, 2013 at 2:00 am Chad Upton 1 comment

By Chad Upton | Editor

Before we could even go to space, the myth was the great wall is visible from the moon. Ever since we got to space, astronauts have been looking for it.

Mathematically, the wall would have to be at least 70 miles (110 km) wide to be seen from the moon with unaided eyes. Since the wall has a maximum width of 30 ft (9.1 m), this is easily dismissed as myth. The moon legend came from a 1754 letter by William Stukeley; his remarks on the massive size of the wall could have been literary hyperbole. But, some people took it literally.

In his defense, there have been a few claims that the great wall can be seen from low earth orbit — as little as 100 miles (160 km). A number of astronauts have claimed they have seen it. Even the European Space Agency claimed it was visible and published a picture. A week later they issued a press release indicating it was actually a river and not the Great Wall of China.

NASA claims it, “generally isn’t [visible], at least to the unaided eye.” Mathematically, it’s the same answer, unless you have 20/3 or better vision. But, according to the Journal of Optometry, “Not even the best of human eyes at a simple glance could see the Great Wall of China from Space.” That’s because the anatomy of the eye limits vision to an acuity no greater than 20/9. So, 20/3 is impossible.

The gaza pyramids on the other hand are about 22 times wider than the Great Wall of China; they are visible from low earth orbit.

Broken Secrets | Facebook | Twitter | Email | Kindle

Photo: Keith Roper (cc)

Sources: wikipedia (Great Wall of China), Journal of Optometry, NASA