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Re: (meteorobs) Meteor Collisions
Just a short note: Meteor "collisions" actually occur all the time. Each time
you walk down a long street, you are probably picking up a fragment of a tiny
bit of interplanetary dust known as a "micrometeorite".
As this example illustrates, almost NO meteorite strikes earth with anything
like celestial velocity! Unless an object is large enough to cause an AMAZING
fireball (which would likely be visible and reported for thousands of miles),
it'll strike the ground with no more force than a rock dropped from a plane.
By the same token, all credible reports of smaller meteorites describe them
as already cool to the touch, by the time they've fallen all the way from a
"burn-out" point above 30 km in altitude, down to the ground... So an object
of sufficient size might crunch a car trunk, or open a hole in an old house's
leaky roof, but is very, very, very unlikely to destroy an airliner!
This cold, free-fall stretch of a meteor trajectory is called "dark fall".
For those of us "more informed" meteor watchers who inhabit this list, it is
vital to keep these simple physical facts in mind! That way, when a witness
comes to you with a report of a falling meteorite poking a glowing hole in
their car, or catching their house on fire, you can patiently explain... :)
Clear skies!
Lew Gramer
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