China's Wall View from Space

China's Wall View from Space


 
It has become a space-based myth. The Great Wall of China, frequently billed as the only man-made object visible from space, generally isn't, at least to the unaided eye in low Earth orbit. It certainly isn't visible from the Moon. 

You can, though, see a lot of other results of human activity. 

The visible wall theory was shaken after China's own astronaut, Yang Liwei, said he couldn’t see the historic structure. There was even talk about rewriting textbooks that espouse the theory, a formidable task in the Earth’s most populous nation. 

Image to right: This photo of central Inner Mongolia, about 200 miles north of Beijing, was taken on Nov. 24, 2004, from the International Space Station. The yellow arrow points to an estimated location of 42.5N 117.4E where the wall is visible. The red arrows point to other visible sections of the wall. Credit: NASA. 






The issue surfaced again after photos taken by Leroy Chiao from the International Space Station were determined to show small sections of the wall in Inner Mongolia about 200 miles north of Beijing. Taken with a 180mm lens and a digital camera last Nov. 24, it was the first confirmed photo of the wall. A subsequent Chiao photo, taken Feb. 20 with a 400mm lens, may also show the wall. The photos by Chiao, commander and NASA ISS science officer of the 10th Station crew, were greeted with relief and rejoicing by the Chinese. One was displayed prominently in the nation's newspapers. Chiao himself said he didn't see the wall, and wasn't sure if the picture showed it. 



Image above: While the Great Wall of China is very difficult to see or photograph from low Earth orbit, sections of the wall can be seen readily in radar imagery. This image of sections of the wall in a desert about 435 miles west of Beijing was made by the Spaceborne Imaging Radar flown aboard the Space Shuttle Endeavour. The wall appears as an orange line extending the length of the image. Credit: NASA. 



Share on Google Plus

About muhammad qamar Shafiq

This is a short description in the author block about the author. You edit it by entering text in the "Biographical Info" field in the user admin panel.