[meteorite-list] dis-oriented

From: Robert Verish <bolidechaser_at_meteoritecentral.com>
Date: Tue Dec 7 01:03:40 2004
Message-ID: <20041207060339.59585.qmail_at_web51707.mail.yahoo.com>

Hello Darren,

You've made some interesting observations about your
23 gram NWA 869 piece. And, I really liked your
animated .GIF which does a good job of making your
point. Coincidently, I made similar observations
about a 73 gram Nevada chondrite that is depicted on
my most recent NevMetPOD:

<http://meteorite-recovery.tripod.com/nvmetpod/nvmetpix.htm>

And from that web page you can download a .MPG movie
which is my attempt to show which sides had primary,
secondary, or tertiary fusion crust(takes a VERY long
time to download - it will require some patience)

<http://meteorite-recovery.tripod.com/nvmetpod/mov00409.mpg>

Although your piece appears to have a curved surface
typical of oriented meteorites, there is no such
evidence on my fragment.

Bob V.

----------------------------
[meteorite-list] dis-oriented
Darren Garrison cynapse at charter.net
Sun Dec 5 23:31:44 EST 2004


I also have a question that involves oriented
meteorites-- or more generally the dynamics of meteor
[sic]
travel through the atmosphere.

Is there any research done on the amount of
time/distance during which a meteor [sic] is ablating
material? It would depend, I would assume, on speed
and angle of entry, but just a general idea?

Also, the minimum size a meteor [sic] must be to
survive to hit the ground, and minimum size at which a
meteor [sic] will shatter/explode in the atmosphere?
(Again, I'm aware that it would differ for different
classes of meteor, [sic] but just a general idea).

Also, a minimum size that a meteor [sic] could exist
as a "gravel" of smaller stones held together rather
than be a single piece?

I ask because I have just recieved a 23 gram NWA 869
piece that I think has to be a broken oriented
stone: one side is smooth and flat, one side is smooth
and rounded. If you imagine the curve of the
smooth, rounded part to continue, it would form a
stone that would look like the large oriented
stone Michael Farmer has up for auction right now,
except that this one would be only around 3
inches across. The other side is shapless but
smoothed by a lighter colored, thinner fusion crust.

So this stone has had time to become oriented, then
break, then have the broken edge form a thinner
fusion crust before it stopped being hot enough to
ablate. And this after the parent meteor itself
has had to shatter into smaller pieces, assuming that
it was a single stone instead of a cluster.

Here is an animated gif of the stone:

http://webpages.charter.net/garrison6328/disoriented.gif

Any insights or opinions are wanted. Also, anyone
happen to have anything that might be a candidate
for another piece of this broken piece?


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Received on Tue 07 Dec 2004 01:03:39 AM PST