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(also written 2007 VK184) is a near-Earth asteroid estimated to be about in diameter.〔 It was listed on the Sentry Risk Table with a Torino Scale rating of 1.〔 A Torino scale rating of 1 is a routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger.〔 was discovered on November 12, 2007, by the Catalina Sky Survey.〔 It was recovered on March 26, 2014 by Mauna Kea,〔〔 and removed from the Sentry Risk Table on March 28, 2014.〔 By January 4, 2008, with an observation arc of 52 days, there was a 1 in 2700 chance of an impact with Earth on June 3, 2048.〔 The Sentry Risk Table, using an observation arc of 60 days, showed the asteroid had a 1 in 1820 chance (0.055%) of impacting Earth on June 3, 2048.〔 Since the March 2014 recovery, it is known that the asteroid will pass from Earth on June 2, 2048.〔 == 2014 passage == Before the 2014 close approach, the asteroid had a modest observation arc of 60 days,〔 and the imprecise trajectory of this asteroid was complicated by close approaches to Earth, Venus and Mars.〔 On May 23, 2014, the asteroid passed from Earth〔 and reached an apparent magnitude of ~20.8.〔 As expected the close approach allowed astronomers to recover the asteroid on March 26, 2014 and refine the odds of a future collision.〔 As the asteroid gets closer to Earth, the positional uncertainty becomes larger.〔 By recovering the asteroid well before closest approach you can avoid searching a larger region of the sky.〔 Most asteroids rated 1 on the Torino Scale are later downgraded to 0 after more observations come in. Risk assessments were calculated based on a diameter of 130 meters.〔 It was estimated that, if it were ever to impact Earth, it would enter the atmosphere at a speed of 19.2 km/s and would have a kinetic energy equivalent to 150 megatons of TNT.〔 Assuming the target surface is sedimentary rock, the asteroid would impact the ground with the equivalent of 40 megatons of TNT and create a impact crater.〔 Asteroids of approximately 130 meters in diameter are expected to impact Earth once every 11000 years or so.〔 On March 26–27, 2014, additional observations were made which ruled out the chance of an impact in 2048.〔 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「2007 VK184」の詳細全文を読む スポンサード リンク
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