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This is a list of examples where an asteroid or meteoroid travels close to the Earth. Some are regarded as potentially hazardous objects if they are estimated to be large enough to do regional devastation. Near-Earth object detection technology greatly improved around 1998, so objects being detected as of 2004 could have been missed only a decade earlier due to a lack of dedicated Near-Earth sky surveys. As dedicated Near-Earth sky surveys improve, smaller and smaller asteroids are regularly being discovered. The small near-Earth asteroids and 2014 AA are the only two asteroids discovered before impacting into Earth. Scientists estimate that several dozen asteroids in the 6 to 12 meter size range fly by Earth at a distance closer than the moon every year, but only a fraction of these are actually detected.〔(Responding to Potential Asteroid Redirect Mission Targets )〕 ==Timeline of close approaches within one lunar distance to Earth== A list of examples of known close approaches.〔A more complete listing of near-Earth asteroids is published by the International Astronomical Union: ("Near Earth Asteroids (NEAs): A Chronology of Milestones" ).〕 (see also (NEO Earth Close Approaches )) The average distance to the Moon is about 384,400 km For lists of close approaches less than one lunar distance from Earth for a given year: * List of asteroid close approaches to Earth in 2015 * List of asteroid close approaches to Earth in 2014 * List of asteroid close approaches to Earth in 2013 * List of asteroid close approaches to Earth in 2012 * List of asteroid close approaches to Earth in 2011 * List of asteroid close approaches to Earth in 2010 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「List of asteroid close approaches to Earth」の詳細全文を読む スポンサード リンク
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