Re: Big Rocks

Mark L. Fergerson wrote:

Everybody else already heard about this?

http://www.physorg.com/news68455520.html

ISTR a thread some time ago about how large an impactor was required to cause plastic deformation of the mantle; does this thing qualify?

Either way, and granted that the article admits to being somewhat tentative since they still want to do local airborne magnetic and gravimetric surveys, any guesses how many of these in the Earth's history? I also vaguely remember an online chart relating impactor size to frequency.

That's interesting, it says it's hypothesized that it is caused the Permian mass extension. I thought scientists had pretty much dismissed the idea of an impactor for the Permian, instead opting for climatic change caused by other factors such as increased volcanism. Or is it that they opted for these other factors because they hadn't found the telltale crater, which would have had to have been huge, and so concluded there couldn't be one?

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Relevant Pages

  • Big Rocks
    ... ISTR a thread some time ago about how large an impactor was required to cause plastic deformation of the mantle; ...
    (rec.arts.sf.science)
  • Re: Pluto-Charon Origin May Mirror that of Earth and Its Moon
    ... > forming collision can be downloaded from ... offset between impactor and primary, ... stripping of the mantle from the impactor but not the fusion of the ...
    (sci.astro)