China News Service reports an article issued on the Science & Technology Review, co-written by research staff with the Academy of Opto-Electronics under the CAS, stating that people are able to see the Great Wall from the space only with the help of optical equipment.

The Science & Technology Review is a journal published by the China Association for Science and Technology. Established in 1980 by Dr. Yang Zhenning, the Chinese-American recipient of a Nobel Prize, the journal is able to eye science and technology research from all over the world.

According to the paper worked out by Dai Changda, Jiang Xiaoguang and Xi Xiaohuan, the range of human sight is actually limited by distance and by the size of the objects themselves.

People are able to see a 10 square meters object within the extreme distance of 36 kilometers, the paper says, much shorter than the 100 or more kilometers.

The paper said the general width of the Great Wall is two meters with the widest part on the watchtowers spanning up to five or six meters. According to such calculations, the human eye positioned in outer space and usually more than 100 kilometers away from the ground should be unable to discern the wall without recourse to special equipment.

Three taikonauts in China's manned space tours, Shenzhou V and Shenzhou VI, have also admitted that they couldn't see the Great Wall from the outer space.

Many Chinese believed people could only see the Great Wall by eyes from the outer space in addition to the sea walls in the Netherlands. However disputes have been triggered in recent years since controversial voices pledged it's untrue.

The researchers said that optical apparatus can extend human sight to catch Great Wall-like thin-and-long terrestrial objects.

The reports acknowledge that a Chinese-American astronaut only developed his pictures of the Great Wall through use of his digital camera's ultra-high-definition function.