Until the 2009 collision, the last known impact event on Jupiter was the famous "death" of Comet Shoemaker-Levy 9 in 1994.

2009年的碰撞之前，上一次已知的碰撞木星事件是著名的1994年苏梅克·列维9号彗星的死亡碰撞。

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That’s been observed twice before, when comet Shoemaker-Levy 9 crashed into Jupiter in July 1994, and when a large asteroid smacked the planet last summer.

这种黑羽碎片的现象已经观察到了两次了，一次是苏梅克-列维9彗星于1994年7月撞向木星，另一次是去年夏天一个比较大的小行星于撞击了这个行星。

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In July 1994, the Comet Shoemaker -levy collided with Jupiter.

1994年7月，慧星“皮鞋匠”——利维撞击了木星。

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But the object that struck Jupiter in July is estimated to have been much smaller and harder to see than comet Shoemaker-Levy.

VOA: special.2009.08.25

Comet Shoemaker-Levy Nine broke up and struck Jupiter.

VOA: special.2009.08.25

One answer might be that the two impacts were, in effect, simultaneous that the objects which created Shiva and Chicxulub were the daughters of a comet that had broken up in space and hit the Earth a few hours apart, as the pieces of comet Shoemaker-Levy 9 hit Jupiter in 1994.

ECONOMIST: Mass extinctions

That survey was requested by America's Congress nearly a decade ago, and was stimulated in part by the dramatic images of Comet Shoemaker-Levy, whose collision with Jupiter in 1994 generated a great deal of public awareness of the risk of asteroid impacts. (A couple of Hollywood films exploring doomsday scenarios also swayed opinion.) In 2005 Congress ordered the survey that is about to start.

ECONOMIST: The American Association for the Advancement of Science