[meteorite-list] Meteorites - warm or hot to the touch?
From: E. L. Jones <jonee_at_meteoritecentral.com>
Date: Sun Jul 3 19:42:44 2005 Message-ID: <42C877E3.4070005_at_epix.net> 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. Received on Sun 03 Jul 2005 07:42:27 PM PDT |
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