[meteorite-list] Re: lunar meteorites

From: AL Mitterling <almitt_at_meteoritecentral.com>
Date: Mon Mar 21 13:24:56 2005
Message-ID: <4234836B.3090904_at_kconline.com>

Hi List,

I put together a list of interesting (to me anyway) Lunar bits of
information. Here they are.

--AL Mitterling


Lunar Tidbits Of Interest

*The finding of the ALH81005 (lunar meteorite) was an important find and
  help to establish the existence of lunar meteorites on Earth. It was
  picked up at the last minute by an antarctic researcher who was
  trained in recognizing meteorites on the ice as he headed for shelter
  before a bad storm.

*Lunar Meteorites provide very important science as they sample areas
that the Apollo missions didn't get to from other areas of the Moon.
Some areas are not real safe to land on or near due to the rugged
terrain. By impacts we sample some of those areas. Lunar meteorites
compliment the Apollo material that is out there for continued science.


*Apollo Missions brought back 382 kg of rock, soil and samples. A total
of 12 kg (I have heard 17 kg) of lunar Meteorites have been found. One
of the largest is DAG 400 which weighs a bit over 3lbs. Soviets brought
back 300 grams of material.

*The average lunar meteorite specimen weighs 197.02 gm.

*Lunar Meteorites have been found on three continents. (Antarctica,
Australia, Africa). No doubt they exist in other places but due to the
"look" of regular terrestrial rocks often get overlooked.

Lunar Meteorites reach the Earth by impactors on the Moon which cause
lunar material to be ejected. Some of that material falls back on the
Moon, Some escapes the Earth/Moon system and a percentage falls to the
Earth. Sadly 3/4 of them fall into the oceans. There are 20 or less
impact events that have provided the lunar specimens so far found (32).

* Lunar escape velocity is 1.48 miles per second, only a few times the
muzzle velocity of a rifle. Some ejected material becomes captured by
the Earth?s gravitational field and lands on Earth within a few hundred
thousands of years or even shorter. Other ejected material, however,
assumes an orbit around the Sun. Some of that material may eventually
strike Earth. This can take a long time. Lunar meteorites
Yamato-82192/82193/86032 and Dhofar 025 remained in space for 10-20
million years before finally landing on Earth.


*Lunar Meteorites tend to be broken from repeated impacts and are
breccias. Also impacts cause surrounding materials to fly with hyper
velocities and become embedded in lunar surface rocks.
This is a distinguishing characteristic of Lunar Meteorites.

*Of the 22,507 meteorites listed in the Catalog of meteorites only .08%
are lunar.

Sources: Washington University at St. Louis

--AL
Received on Sun 13 Mar 2005 01:16:11 PM PST