The gravitational keyhole they mention is a precise region in space, only slightly larger than the asteroid itself, in which the effect of Earth's gravity is such that it could tweak Apophis' path.

他们提到的引力关键点是天文上的一个精确地带，仅仅微大于小行星本身，在那个点上地球引力的影响可以改变小行星运行的轨迹。

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In 2004, NASA scientists announced that there was a chance that Apophis, an asteroid larger than two football fields, could smash into Earth in 2029.

在2004年的时候，美国航空航天局的科学家们宣布阿波菲斯这个比两个足球场还大的小行星，可能会在2029年撞击地球。

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The asteroid hurtled back into the news when Russia recently predicted 99942 Apophis may hit Earth on April 13, 2036.

当俄国最近又预测阿波菲斯99942可能于2036年4月13日撞击上地球时，该小行星再次引起媒体关注。

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To test out this idea, Paek simulated the asteroid Apophis, which will pass nearby the Earth in 2029.

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Science editor Alan Boyle's blog: Radar observations made during this week's close encounter with the asteroid Apophis have ruled out the risk of a collision with Earth in 2036, NASA says.

MSN: How to confirm we've found another Earth - Technology & science - Space - Space.com | NBC News

Asteroid 99942 Apophis is a primordial relic from the formation of our Solar System.

BBC: Foresight mission spacecraft Image