[meteorite-list] dis-oriented

[Darren Garrison]

I also hae a questions that involves oriented meteorites-- or more generally the dynamics of meteor
travel through the atmosphere.

Is there any research done on the amount of time/distance during which a meteor 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 must be to survive to hit the ground, and minimum size at which a
meteor will shatter/explode in the atmosphere?  (Again, I'm aware that it would differ for different
classes of meteor, but just a general idea).

Also, a minimum size that a meteor 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?