You can see the Great Wall of China from the Moon
This would be a myth even if an astronaut used a telescope.
By
Michael E. Bakich The Great Wall of China is invisible from space. It’s just too narrow for astronauts to see.
Photo by Holley Y. Bakich
When thinking about how feasible making this observation is, most people account for the Great Wall's length — a whopping 5,500 miles (8,850 km) — but not its width, which at maximum spans a mere 30 feet (9.1 meters). From the average distance of the Moon, some 238,000 miles (383,000 km) from Earth, a feature on our planet would have to be roughly 70 miles (113 km) across for the unaided human eye to discern it.
OK, then how about the follow-up question: Can an astronaut see the Great Wall of China from Earth orbit? Again, the answer is no. Although some scientists have argued that this observation is theoretically possible under the best conditions of atmospheric clarity and Sun angle, it requires a resolving power (visual acuity) more than 5 times that of the human eye. |
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