[meteorite-list] Re: Scientists Find Mars Met. (NWA 1950)

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Thu Apr 22 10:31:58 2004
Message-ID: <3FF8DD46.B48F7965_at_bhil.com>


    What the computer models which lead to the "big-impactor" theory of the
Moon's origin show is that the Moon ends up being composed of most of the
impactor's mantle, and that portion of the Earth's mantle that is blown off
by the impact. The impactor's denser core material mostly remains with, or
falls back to, the Earth, and some of the impactor mantle is also
incorporated in the Earth's crust.
    This is why the bulk density of the Moon is identical to the bulk
density of the Earth's crust, since both are a mixture of the crustal
material of the two original bodies before impact. This fortuitous
correspondence was the chief argument for the old theory that the Moon was
"spun off" from the Earth's Pacific basin. This theory, formulated by
Darwin (no, not that Darwin, but a nephew or grandson), was still being
vigorously supported by some as late as 1963!

Sterling K. Webb

David Weir wrote:

> Hello Pekka,
> I believe the Moon is in large part composed of the impactor material,
> the remainder is material from the Earth's early composition.
> David
> Pekka Savolainen wrote:
> >
> > Well, at the moment it´s belived, that the moon has separeted the
> > earth
> > after a collision with a Mars-sized body. So in fact all lunar ones
> > are "earth meteorites" ... And in fact the moon is the biggest "earth
> > meteoroid".
Received on Sun 04 Jan 2004 10:43:03 PM PST

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