Link #114: Is the Great Wall of China Really Visible From Space?

Link #114: Is the Great Wall of China Really Visible From Space?

 

Chain of Facts - A Connection of Facts

Link #114: Is the Great Wall of China Really Visible From Space?

Great Wall of China
Great Wall of China, Mutianyu. Image credit: capelle79, (CC BY 2.0)

One of the oldest civilisations in human history is the Chinese civilisation. In all the years of their existence, the Chinese managed some great feats. In our last post, we spoke about one of their great feats, namely the Forbidden City.

However, the Forbidden City isn’t even the most well-known achievement of the ancient Chinese culture. That accolade goes to the Great Wall of China. In fact, some people even say that the Great Wall of China is the only manmade structure that can be seen from space.

This has undoubtedly added to the fame of the Great Wall of China. However, is it true? Can you really see the Great Wall of China from space?

Previous Link in the Chain of Facts
Next Link in the Chain of Facts




Can Astronauts See the Great Wall of China From Space?

Astronaut on Space
Image credit: WikiImages

Let’s get the basic question out of the way. Can astronauts see the Great Wall of China from space? The answer is no. The Great Wall of China is not visible to the naked eye from space even from a lower orbit.

Why Is the Great Wall of China Not Visible From Space?

Satellite image of the Great Wall of China
Satellite image of the Great Wall of China. Image courtesy NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

The Great Wall of China is actually one of the most remarkable man-made structures in the world. It is, after all, a structure whose construction began as early as 250 BC. Moreover, by the time it was completed, the Great Wall of China ran for an unbelievable 8,850 kilometres.

While the greatness of the Great Wall of China cannot be questioned, it still isn’t great enough to be easily visible by the naked eye from space, leave alone the moon. The Great Wall of China is actually very difficult to make out from space.

The main reason why the Great Wall of China isn’t visible from space is that it is built from local materials and follows natural changes in the terrain that it is built on. This makes it extremely difficult to distinguish the Great Wall from its surrounding terrain from space.

Various conditions need to come together for there to be any chance that a person can see the Great Wall of China from space. These conditions include things like favourable climatic conditions over the Great Wall, such as a sunny day followed by snowfall.

What Else Is Visible From Space On Earth?

Pyramids at Giza, Egypt.
Pyramids at Giza, Egypt are featured in this image photographed by an Expedition 32 crew member on the International Space Station. Author: NASA, PD image.

It is so difficult to see the Great Wall of China from space that China decided to remove this fact from the text books in the country. However, there are other man-made structures that can be seen from space. The oldest of these are the ancient pyramids at Giza.

At the same time, man-made structures easiest to see from space are modern such as roads and bridges over water. These modern structures tend to follow straight lines and are made from materials different from their surrounding terrain which makes them stand out.




Can you Guess the Next Link in the Chain?

What will be the next link in our Chain of Facts? Think you might know? Scroll down to add a comment below with your best guess.

Previous Link in the Chain of Facts
Next Link in the Chain of Facts

You can view the full list of links in the chain here.


Sources:

http://en.wikipedia.org/wiki/Great_Wall_of_China
http://www.snopes.com/science/greatwall.asp
http://www.nasa.gov/vision/space/workinginspace/great_wall.html
http://www.theguardian.com/science/2003/oct/23/thisweekssciencequestions

Click here to view the complete list of sources…

NO COMMENTS

Leave a Reply