科学美国人60秒 SSS 2014-08-29

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That’s not the plot of a new summer blockbuster. It’s the result of a study in the journal Nature. 

 

The asteroid in question is actually a kilometer-sized collection of rubble³. In most cases, such space-faring pebble⁴ piles are held together by a combination of gravity and friction⁵. But not so for our rocky interloper, dubbed⁶ “1950 DA.” This asteroid is rotating so rapidly that its pieces should have flung apart long ago.

 

Now, by analyzing⁷ the 1950 DA’s temperature and density⁸, researchers conclude that cohesive⁹ forces called van der Waals attractions must be keeping the pieces clustered. Van der Waals forces may sound mysterious, but they’re well known on the small scale for their weak influence within and between molecules¹⁰.

 

Blasting the asteroid, Hollywood style, could overcome these forces. But that might leave us with hundreds of smaller killer¹¹ space rocks to dodge¹². The good news is, the asteroid won’t be in our area until 2880. So we have some time to figure it out.

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