[meteorite-list] Temperature of meteorites

[almitt2 at localnet.com]

Greetings listees,

ahhh the hot/cold debate rears it's head again. I appreciate Bernd's 
list of falls that seem to indicate warm more so than cold but there 
are many factors to consider when compiling data. In Bernd's list, how 
many of these warm specimens were observed by laymen?? Often there are 
other factors to consider and layman's observations can be often wrong. 
If a black specimen sits for very long in the sunlight it will absorb 
warmth and appear warm or hot.

Things to consider, Fall dynamics. The space shuttles build up a lot of 
high heat during decent through the atmosphere. Shuttles have to cool 
for a while after landing. Meteoroids, depending on their fall speed, 
only pass through the atmosphere for a short period of time (seconds 
before dark flight) and don't have suffiecent time to build up heat. 
The ablating process often removes the molten material as the object 
falls keeping the specimen more or less at cold space temperature.

Catching up or head on collision with Earth effects speed and 
temperature and fall dynamics. Spinning or stable flight (possible 
oriented specimen) affects temperature. Size of specimen and retention 
of cold from space.

One thing for certain when thinking about the hot/cold debate. If 
meteoroids are heated up molten when they fall, then the chemistry 
would be altered and isotopes reset. Most meteorites don't have high 
heat alteration from falls or our ability to study them would be 
impossible. The age would be reset from the heating. The study of 
meteorites is the study of un-altered specimens from our solar systems 
past!!

I tend to be a cold when they land believer but think a few can come 
down oriented and there is time for them to absorb some heat from the 
fall. Nininger investigated several falls seen by laymen that were 
frosted over but he was efficient at determaining facts based on the 
story tellers.

There are a lot more considerations and facts about falls that are 
probably still not understood at this time. Fall dynamics are difficult 
to study unless you have an expert with equipment the second the fall 
occurs at the site when it happens.

My hot and cold worth.

--AL Mitterling
Mitterling Meteorites