What is so great about the Great Wall of China? Could it really be the only visible man-made structure from outer space? How is it visible, if it is visible; by camera, or telescope, or the naked eye? From what distance would it be visible from? Is the Great Wall really that great, even from outer space?
In order to bust this myth, a wide range of resources are needed, such as time, money, technology, and astronauts. There could be a wide range of technology used, such as lenses, digital cameras, and an imaging radar. Many obstacles also contribute to the ability to see the Wall, such as the age of the structure, the material it is built out of, and the condition of the atmosphere. Where you are in space also contributes to its visibility. There are so many man-made objects on Earth, so why would people think it was the only visible thing? A possibility could be that the Great Wall is so large, people just figured it was the only visible man-made thing. Is it?
The orange line shows the Great Wall through radar imagery.
The Wall is not the only visible man-made structure from space, although it is visible from space, to an extent. It cannot be seen from the moon, which was a theory that has dated back to 1938, and was disproved when astronauts landed on it. No man-made object is visible from the moon, but plenty are visible from different points in space. The most visible objects from low Earth orbit are cities at night. The Wall can be seen using the Spaceborne Imaging Radar, and a 180mm lens and a digital camera. No one knows for sure if the Wall can be seen with just the naked eye, because a lot of factors play into the visibility, such as the material. The Great Wall of China is built out of earthly materials, making it blend in with the Earth, and hard to spot. So using the right technology, the Wall can be seen from space, but it is not the only thing man-made structure.
These are the pyramids at Giza, and they are man-made structures that are visible from space.
All information and pictures in this post were found at NASA
