[meteorite-list] Too Few Lunar Meteorites

From: Julien.Courtois_at_gr.admin.ch <Julien.Courtois_at_meteoritecentral.com>
Date: Thu Apr 22 10:23:49 2004
Message-ID: <EAB746AD969AA24C9EBBF84B28065B8825C702_at_ber-ex-05.ber.gr.admin.ch>

>From Sky and Telescope!

March 20, 2003 | It's been 20 years since planetary scientists first
realized that chunks of the Moon and Mars were practically falling into
their laps as meteorites. And, while thankful for the free samples, they've
always puzzled over why these two worlds are represented roughly equally on
Earth. To date collectors have snatched up 24 distinct meteorites from the
Moon (some of which were found in multiple pieces or paired with other
finds) and 28 from Mars.

The puzzle arises because the lunar specimens should outnumber their Martian
counterparts by more than 100 to 1. For one thing, the Moon's weaker gravity
means that a much smaller impact will accelerate lunar debris to escape
velocity, compared to the more energetic (and thus rarer) blasts necessary
to eject something from Mars. Calculations performed several years ago by
Brett Gladman (University of British Columbia) show that, once launched into
space, a chunk of lunar rock has about a 50-50 chance of ending up on Earth
- 10 times better odds than for an arrival from Mars.

Full Article here:
<http://skyandtelescope.com/news/current/article_905_1.asp>
Received on Fri 21 Mar 2003 10:02:51 AM PST