[meteorite-list] Meteorites - warm or hot to the touch?

From: Jeff Kuyken <info_at_meteoritecentral.com>
Date: Mon Jul 4 09:40:41 2005
Message-ID: <001e01c5809d$f54f4180$47578b90_at_mandin4f89ypwu>

This is such a fascinating subject for which many theories could hold merit
and it's very interesting to hear them all. One thing that would lead me to
believe meteorites are 'generally' not HOT is the function of ablation. My
rudimentary understanding is that it's not the meteorite itself that gets
hot, but rather the super heated/compressed air in front. This in turn heats
the surface of the stone which is then immediately ablated away. I would
assume that's why meteorite fusion crust is also comparatively so thin. It
seems ablation is a very efficient way of removing heat/energy and there
really might not be an appreciable rise in temperature throughout the
interior. Obviously this would depend a lot on the size of the stone too.
And the shape! I bet there would be a significant difference between highly
oriented meteorites and a "normal" shape.

Cheers,

Jeff

----- Original Message -----
From: E. L. Jones
To: Meteorite-list_at_meteoritecentral.com
Cc: AL Mitterling
Sent: Monday, July 04, 2005 9:42 AM
Subject: Re: [meteorite-list] Meteorites - warm or hot to the touch?


Hello Guys and Gals,

The Mohahans fall was reported by the young finders to be barely "hot
potato" holdable owing to the warmth. As to the Portales Valley and the
tarp, I believe there was a bit of debate as to whether or not the tarp
was melted or embedded. As an alumni of Ft Hood, Texas I remember
putting a black tie rod-end down on a boat cover where a couple of 120?+
days later the tie rod had melted the tarp enough for there to be a
bubble/smear of melted plastic under where the tie rod had lain. So I
remain slightly unconvinced as to whether the meteorite was "reentry
hot" enough to have done the melting or hot on subsequent days with high
"solar loading" hot!

One of the modern falls in Connecticut(Westfield?) was photographed ( if
I recall correctly) with a frost rind on the broken face of the stone
lying on the dinning room floor. Ms Hodge's account(Sylicaga , 1964?)
failed to mention if the stone was hot or cold.

I recall from previous discussions that when the Shuttle Orbiter
returns, there are some components that are dangerously hot while other
components rapidly frost up in the humid Florida air. Navigators know
never to touch the mast of the sextant after a reading for it can be
cold as -60?c especially over Greenland. Growing up on a TAC fighter
base the wings of an F-104 Starfighter were reputedly dangerously hot
upon a landing after a supersonic scramble. Over time, the leading edge
of the wing was so sharpened via ablation, they had to place rubber
strips on them for safety. I also recall that the cockpit temperature
of the SR-71 Blackbird could raise to over 400?f during the speed runs.
Even the waste/urine could boil and the cockpit was known for it's nasty
smell. Pilots of course wore an additional space-certified environmental
suit owing to the cockpit conditions mentioned above. All that said,
there is no dispute that meteorites (and aircraft) heat up in transit.
How specifically hot they are on the surface remains the unknown.

I personally believe the meteorite surface is very warm slightly hot on
most falls while the interior is very cold. That is what the physics
say should be. While metal/iron is a good heat conductor,
olivine/silicates is/are not, and it should take a longer time for the
two temperature extremes to neutralize in a stony fall. Ironically, an
iron might actually take longer to cool down than a stone becasue it
could theoretically store up more of the ablation heat internally than a
stony could.

IF I am ever at the moment of a fall, I've already rehearsed the
procedure. I intend to brand myself--hot and/or cold, and see if Al Lang
will send me around to shows with Michelle Knapp's Malibu.

Regards,
Elton

AL Mitterling wrote:

> I believe a tarp melted on the Portales Valley specimen provides
> un-refutable proof.

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Received on Mon 04 Jul 2005 09:40:32 AM PDT