Original title: background links: more than 1640 asteroids pose a potential threat to the earth
Xinhua news agency, Nanjing, September 8, (reporter Jiang Fang, Cai Yugao) 8 reporters from the Chinese Academy of Sciences, Purple Mountain Observatory was informed that, according to the latest release of the Minor Planet Center website, through the global survey, the researchers found 1640 “ the potential threat of asteroid ”.
In 1994 the comet collision with Jupiter after the incident, the international astronomical community will gradually pay attention to risk of hitting the earth near earth objects. The international astronomical community in the United States National Aeronautics and Space Administration, the nearest to the asteroid observation system for the target two times, the first time in 1998 2008, through 10 years observed more than 90% more than 1 kilometers in diameter asteroid, this goal is completed; second times during 2005 2022 years in diameter 140 meters above all near Earth Asteroids observed, at present there is a large distance from achieving this goal.
In China the Chinese Academy of Sciences in 1999 to set up “ near earth object detection and solar system dynamics research group, established in October 2006 ” Purple Mountain Observatory near earth object observation station in Xuyi County of Jiangsu Province, and successfully installed 1.2 m Schmidt telescope near earth objects.
The chief researcher at the Purple Mountain Observatory near the astronomical telescope group Zhao Haibin introduced, the potential threat of near Earth Asteroids, because of their large diameter “ ”, at least 140 meters; the orbit and the earth orbit is very close, within 7 million 500 thousand km.
According to the statistical analysis, the 10 kilometer diameter asteroid hit the earth's energy in a second speed of 10 kilometers, the equivalent of 3 billion Hiroshima atomic bomb. Astronomers generally believe that the reason for the extinction of the dinosaurs about 65 million years ago, is about 10 kilometers in diameter asteroid hit the earth.
Astronomical experts said that there may be as space “ killer ” threats to the earth and humans are not only near Earth Asteroids, as there are near earth comets. In astronomy, the near Earth Asteroids and near earth comets are commonly referred to as near earth small objects.