CAS confirmed that the naked eye can not see the Great Wall from space.

<P> What the naked eye in space can see the Great Wall of China? .This topic has long been concerned about the controversial. .Chinese Academy of Sciences recently completed a research team to study further confirmed: the naked eye can not see the Great Wall from space, only up to a certain spatial resolution satellite remote sensing images to get the Great Wall. .</ P> <P> by the CAS Institute of Opto Prachanda researchers and Jiang Xiaoguang Dai, Xiao-ring study's completion of the research published in the latest issue of "Technology Review" on. .They argue, human visual perception from the light, color vision progress to "shape perception," the emergence of a certain objective things to see, will observe the objects subject to size and distance. .The general inclination of the human eye pupil center is equivalent to a circle 1 / 3600. .</ P> <P> this basis, even in the case through as excellent condition, ordinary people can see the meter sized objects, the formation of flat "form sense," the limit distance of about thirty-six km, much lower than the general .hundred kilometers away to the public that as a starting point of the space height. .The Great Wall was basically two meters wide, in addition to pass a large tower, in general, the city station (beacon) is only five to six meters wide, it can be concluded that astronauts in space can the naked eye can not see the Great Wall .. .Three Chinese astronauts into space successfully confirmed that they did not see the Great Wall in space. .</ P> <P> the same time, most people can produce three-dimensional vision, feel the three-dimensional shape of the limit of observation of the object distance of about four hundred and fifty meters, beyond this distance will not lose the three-dimensional object recognition of three-dimensional form, can not distinguish between .objects near and far. .</ P> <P> researchers also noted that the use of remote sensing techniques will greatly extend the human visual function. .Chinese-American astronaut Chiao photographed from space, the Great Wall with a digital camera image, and the recent American Aerospace Museum's "space to see the Earth image," another example of validation of satellite remote sensing to carry out their test results the Great Wall, the spatial resolution .reached a certain degree of remote sensing images to display the Great Wall or other appropriate surface material, less than a certain level of resolution of remote sensors to the Great Wall will not be able to capture these objects were thin on the planet. .</ P> </ p>.