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Re: (meteorobs) FWD from Keith Evanson
Keith>>George, without having any real meteor experience I can still comment
based
on some fundamentals of physical science. We all know that NASA reentry of
various vehicles including the space shuttle is only possible because of
highly insulating refractories (ceramics) that are adhered to the vehicle
surface. The heat transfer coefficients of metals are far too great and
without the refractory tiles, the contents of the vehicle (including
people) would become extremely hot...<<
Keith, If the heated up surfaces of a meteoroid didn't slough off...which they
do, I suppose the heat would transfer to the meteor's innards. But the
meteoroid continuously heats the surface, sloughs off and re-exposes fresh
parts that gets heated up in turn. This process continues throughout the
meteroids incandescent descent. When the meteoroid finally reaches a slower
velocity that no longer produces the friction to melt the outer surfaces,
There probably is not much additional heat transfer to the interior to
appreciably change it's contents. When the meteoroid finally hits the ground,
it is said that the meteorite is warm at best to the touch. Probably from the
extreme interior cold influencing the surface temperature?
Whereas in the space shuttle, it is designed so that none of it's exterior
will appreciably slough off and heat up the interior. The shuttle doesn't
have the same kind of luxury of giving off it's outer layers, carrying away
the accumulated heat in the process. If it did, I guess very little of it
would be left? Which is the case for an incoming meteoroid. The meteorites
that reaches the ground, start out quite a bit bigger when it first entered
the atmosphere than it does when it drops to the ground.
George Zay