[meteorite-list] Lunar capture theory

From: jumper_at_mit.edu <jumper_at_meteoritecentral.com>
Date: Thu Apr 22 10:21:03 2004
Message-ID: <1057969945.3f0f5719a06d2_at_webmail.mit.edu>

At 10:19 PM 7/11/2003 +0100, Ken O'Neill wrote:
Hi List,

Would there be anything in the geological comparison between Earth and Moon
that would lean toward the "capture" rather than "same debris" theory or
vice versa ?

Regards

Ken O'Neill

Just quickly ( I haven't read all the responses so apologies if this is a
repeat) - if the Earth and Moon had co-accreted in similar neighborhoods and
then the Earth captured the Moon, you would expect the ratio of core to
mantle+crust to be the same. The moons core is much too small for that. This
fits neatly into the impact scenario in which the cores of the impactor and
proto-Earth are fused, leaving little core material for what would become the
Moon. Also, the Moon is very depleted in volatile elements - Na, K, H2O.
Again, if they had co accreted in the same neighborhood they should have the
same make up. Again, this fits nicely into the impact scenario where the
volatiles are blown off.

Steven

Steven Singletary
54-1224
Dept. Earth, Atmospheric and Planetary Sciences
M.I.T.
Cambridge, MA, 02139
Tel-617.253.6398
Fax-617.253.7102

Blue Skies!
Received on Fri 11 Jul 2003 08:32:25 PM PDT