So if an object were to be taken into orbit and given excape velosity from
earth's gravitational well such that it was not in orbit around earth, but
in orbit around the sun and at a later time reentered earth's gravity well,
passed thru the atmosphere and survived to impact the earth, it would not be
a meteorite simply because it was not ejected fron terra firma by natural
means? Granted that man made debri isn't classed as a meteorite but non man
made material shouldn't be penalized because an astronaught
decided to impart excape velosity to a rock,puting it into orbit around the
sun.
I say material surviving to impact from any source (excluding man made)
would and should be called a meteorite.
Pete
----- Original Message -----
From: "Jeff Grossman" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, May 30, 2008 5:29 AM
Subject: Re: [meteorite-list] Just Another Question
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
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