Fact Check: The Great Wall of China is visible from space

Fact-Check: "The Great Wall of China is visible from space"

What We Know

The claim that the Great Wall of China is visible from space has been widely circulated and often repeated in popular culture. However, this assertion has been challenged by various sources. Notably, Chinese astronaut Yang Liwei stated after his mission in 2003 that he could not see the Great Wall from space. This contradicts earlier claims that suggested otherwise. Following his statement, the European Space Agency (ESA) mistakenly published an image that was misidentified as showing the Great Wall, which was later corrected to reveal it was actually a river.

The Great Wall, while extensive at approximately 7,300 kilometers long, is quite narrow, typically less than 6 meters wide. According to scientific analysis, the limitations of human visual acuity make it impossible to see such a narrow structure from the vast distances of space. For instance, to see the Great Wall from a distance of 160 kilometers, one would need a visual acuity far beyond that of a normal human eye.

NASA has also addressed this myth, stating that the Great Wall is not visible from the moon and is difficult or impossible to see from low Earth orbit without the aid of high-powered lenses (NASA). Furthermore, Phil Plait, a science communicator, emphasizes that the resolution required to distinguish the Great Wall from space exceeds the capabilities of the human eye.

Analysis

The evidence against the claim that the Great Wall of China is visible from space is robust and comes from credible sources. The initial assertion made by Yang Liwei is significant because it comes from a firsthand account of an astronaut who has experienced space travel. His statement was later supported by scientific reasoning regarding human visual acuity and the physical characteristics of the Great Wall itself.

The ESA's initial error in identifying a river as the Great Wall highlights the potential for misinformation in space imagery and the importance of verifying claims with reliable data. The subsequent correction by the ESA, along with input from experts, reinforces the idea that the Great Wall's visibility from space is a myth.

NASA's confirmation that the Great Wall cannot be seen from the moon and is difficult to discern from low Earth orbit adds another layer of credibility to the argument against the claim. The scientific community, including sources like Scientific American, has consistently debunked this myth, emphasizing the limitations of human vision and the specific conditions required to observe such narrow structures from great distances.

While some sources suggest that under perfect conditions the Great Wall might be spotted from low altitudes, these claims are speculative and not supported by empirical evidence (South China Morning Post).

Conclusion

Verdict: False

The claim that the Great Wall of China is visible from space is false. Despite its impressive length, the wall's narrow width and the limitations of human visual acuity make it impossible to see from space without advanced optical equipment. Credible sources, including astronauts, scientific studies, and NASA, have consistently refuted this myth, confirming that the Great Wall cannot be seen from space with the naked eye.