[meteorite-list] Re: Flaming Meteors
From: E.L. Jones <jonee_at_meteoritecentral.com>
Date: Thu Apr 22 09:43:35 2004
Lew likes these questions diverted to the Meteorite list but I'll
answer you here for the time being. If anyone wants to discuss it more I
suggest we take it up there.
I am still looking for the specific answer to your question, but for
now I believe that a meteoroid of over 1 meter retains some cosmic
energy and it goes up exponentially. I recall that a 10 meter object
loses virtually no cosmic energy so somewhere in between 1 meter and 10
meters. We need someone to help us out with the speed of
retardation--the velocity at which below, the meteor no longer
incandesces and dark flight begins and work backwards
If I recall correctly , Norton County, an aubrite achondrite with less
density than an iron, falling in 1948, had a 1 ton stone buried up in a
crater in a Kansas corn or wheat field to a depth of 12 ft, and the
crater was around 30 ft in diameter. The location was discovered when
the farmer's tractor fell into the crater. For some reason the crater
was obscured-- having fallen in February it wasn't found until sometime
in the spring. Hoba, a 60 ton Iron, is embedded in bedrock in Africa to
a depth of 8 ft or so.
Of note to your question about the retention of heat, Stony meteorites
have a very low efficiency of heat transfer. The short duration of
flight and the evaporative cooling effect which allows the melted
material to conduct heat away may leave the outer area warm, so far as
we know, but internally it remains near absolute zero or the temperature
it had in orbit. The jury is still out as to the possibility of hot
freshly fallen meteorites, evidence is doubtful.
At what point (range of masses) does a meteor (let's say a stony iron)
have sufficient mass to retain most of its hypersonic velocity and heat
to the earth's surface.
Received on Fri 27 Jul 2001 01:37:16 AM PDT