[meteorite-list] Tektites and Meteorites of Terrestrial Origin

From: Rob McCafferty <rob_mccafferty_at_meteoritecentral.com>
Date: Sat Jun 3 21:00:42 2006
Message-ID: <20060603224031.89610.qmail_at_web50908.mail.yahoo.com>

This one's been niggling at me for a few weeks now and
I finally formulated my thoughts in the car today (no
radio since i put my car in a ditch upside down a few
moths back. My car is my think time)

I know during the early days of the space programme,
they glued some terrestrial rocks onto the ablative
heatshield of a rocket to see what earth rocks would
look like after a descent through an atmosphere and
although a few of them fell off they did get some
results. I've been unable to find anything on these
results. Is there somewhere I can find it? Pictures
would be nice if they exist.

It puzzles me what an object blasted from the earth
looks like after re-entry. They can't all look like
tektites. Some chunks of rock must make it out
relatively intact as the do from Mars and the moon.

How do the orbital dynamics work. Can something
achieve escape velocity only to come back later? I
think there are enough mechanisms in place to allow
it.

Would anyone even recognise a meteorite of terrestrial
origin as a meteorite at all (one presumes not if it
was weathered).

Considering that there are readily identified
meteorites from two other large bodies on earth, I
find it hard to believe that there are none from
Earth. The higher gravity and thicker atmosphere
cannot account for it all, surely.

Some Australian tektites are aged at 700,000yrs but
are found on much younger surfaces, still fresh and
not looking transported. Has anyone ever done a CRE
age on these things. It'd be interesting to know how
long they'd been up in space. Have they been there a
while and fallen back later. (Yes, Moldavites look
different from Australites, I know, I'm just asking)

Considering the vast multitude of rock types on the
earth, the equally fascinating origins of them, I'm
hoping someone can tell, difinitively why we don't
have a whole load of (or at least a few) achondrites
which don't match anything else and have isotopes
which label them as terrestrial.

This is knowledge for knowlede's sake. I just want to
know and I don't care how much detail the answer goes
into, I'll work it out.

Best regards

Rob McCafferty

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Received on Sat 03 Jun 2006 06:40:31 PM PDT