[meteorite-list] Just Another Question

From: Jeff Grossman <jgrossman_at_meteoritecentral.com>
Date: Fri, 30 May 2008 06:29:32 -0400
Message-ID: <OF338A0238.726E885C-ON85257459.0039D103_at_usgs.gov>

Alan Rubin and I grappled with this issue in our article in
Meteorite! 10 years ago, "What is a meteorite? The pursuit of a
comprehensive definition." We wanted a definition that would exclude
things like tektites from being called meteorites. Our definition
then said that, to be called a meteorite, an object had to escape
the dominant gravitational influence of its parent body. In this
case, we would say that a terrestrial meteorite would be an object
ejected from earth by natural causes (i.e., by impact), which entered
an orbit around the sun and later was re-accreted by the earth.

Nothing like this has ever been found. Its distinguishing properties
might be a fusion crust, evidence for cosmic-ray exposure in space,
and lithology that is completely exotic for its find
location. Without an exposure history (or being an observed fall) it
would be a very tough sell... a Wingstar.

Jeff

At 12:24 AM 5/30/2008, Pete Shugar wrote:
>Hello list,
>I've given this more than just a passing thought as I think this is
>a very intreguing question.
>If an impactor smacks into the moon with enough energy, objects will
>be dislodged.
>If they make it to earth intact, we have a luner meteorite.
>Same goes for Mars and Astroid 4Vesta.
>So,.....suppose we have a very high speed impactor that hits earth,
>and dislodges material that is now in orbit. If the material crosses
>Earth's orbit again, and survives to the surface of earth, would it
>be modified in it's appearance to the extent that it would be seen
>as a meteorite and not just another rock?
>Has anything ever been found that might be in this class of material?
>Would there be anything that would set it apart as a different rock/meteorite?
>
>Pete
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Dr. Jeffrey N. Grossman phone: (703) 648-6184
US Geological Survey fax: (703) 648-6383
954 National Center
Reston, VA 20192, USA
Received on Fri 30 May 2008 06:29:32 AM PDT