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 is often regarded as a popular myth. According to Norberto López-Gil, after Chinese astronaut Yang Liwei's mission in 2003, he stated that he could not see the Great Wall from space, contradicting previous beliefs. This statement was later supported by various sources, including NASA, which confirmed that the Great Wall is not visible from the moon and is difficult to see from Earth orbit without high-powered lenses (NASA).

The Great Wall, while extensive at about 7,300 kilometers long, is relatively narrow, with most sections being less than 6 meters wide. This width poses a significant challenge for visibility from space, as the human eye has limitations in resolving such small features from great distances. As noted by López-Gil, even under optimal conditions, the visual acuity required to see the Wall from space exceeds what the human eye can achieve (López-Gil).

Further corroboration comes from Phil Plait, who explains that the resolution required to distinguish an object like the Great Wall from space is far greater than what the human eye can provide. The Wall's dimensions do not allow it to stand out against the surrounding terrain, making it virtually invisible from orbit.

Analysis

The evidence against the claim that the Great Wall of China is visible from space is robust and comes from multiple credible sources. The initial assertion by astronaut Yang Liwei is critical, as it directly challenges the myth with firsthand experience. NASA's confirmation that the Wall is not visible from the moon and is difficult to see from Earth orbit adds further credibility to the argument (NASA).

López-Gil's detailed analysis of human visual acuity provides a scientific basis for understanding why the Great Wall cannot be seen from space. He explains that the necessary visual acuity to see the Wall from a distance is significantly higher than what is biologically possible for humans (López-Gil). This is echoed by Plait, who discusses the concept of resolution in optics, emphasizing that the Great Wall's narrow width makes it indistinguishable from the surrounding landscape when viewed from space (Plait).

Other sources, such as Britannica and Snopes, also confirm that the Great Wall is not visible from space, reinforcing the consensus among experts. While some sources mention that shadows of the Wall might be seen under specific conditions (Grunge), this does not equate to visibility of the Wall itself.

Conclusion

The claim that the Great Wall of China is visible from space is False. Despite its length, the Wall's narrow width and the limitations of human visual acuity make it impossible to see from space without aid. The consensus among astronauts, scientists, and credible sources supports this conclusion, debunking the myth that has persisted for years.