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Re: (meteorobs) Meteorites and Terminal velocity
If a falling body happens to travel at low speeds like 700 mph (1126
km/hr) in the thin atmosphere, then they sould be cooling, but at speeds of
2100 mph (3379 km/hr) then heating will occur as the SR-71
demonstrates.
I believe that sonic booms associatied with meteors indicates a
possibility of high rates of speed in the lower atmosphere where heating
can occur, however, it does not reveal how fast a meteor is traveling only
that it's traveling faster than sound. The meteor would have to be traveling
several times the speed of sound to generate heating so sonic booms may be
only an indication that a hot meteorite may strike the ground. Most of the
time they should be cool or cold for several reasons. Small meteorites of
several ounces should be cold, they can't resist cooling during freefall.
Stony meteorites should be cool or cold, they transfer heat very slowly,
but some iron meteorites of several pounds may be hot or cold, depending
on their individual experiance with the dynamics of speed in the
atmosphere, length of their freefall (angle of attack) and if some
componets of the meteorite contributes to heating through ignition (Nick,
that's for you). In working with iron the red heat of a metal will reappear
after sudden cooling if the interior is red heat hot or more, so exterior
cooling during freefall may not last long enough to cool the interior of the
meteorite if it is hot from solar heating (prior to entering the shadow of
the Earth), heated in the upper atmosphere while approaching the state of
ablation, and heated during the period of 3X supersonic flight if any speed
occurred.
Dave English
Oceanside, California
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