[meteorite-list] Suspected Meteorite GoesThroughWindowinIllinois

From: Chris Peterson <clp_at_meteoritecentral.com>
Date: Tue, 6 Mar 2007 18:22:40 -0700
Message-ID: <011601c76057$20523c30$2721500a_at_bellatrix>

>Are you saying
>that an infinitely dense object would be diverted 20 degrees by an 18
>mph
>wind (in the extreme)? If not, maybe you can help me understand better
>your
>assumption on how a chunk of metal like this floats or sails on the air
>currents?

Not exactly. An object in free fall is going to trend towards a
horizontal air speed of zero. In a steady 18 mph wind, that equates to a
horizontal ground speed of 18 mph. The heavier the object, the longer it
will take to reach that zero airspeed. So if this thing was falling
vertically, and then experienced a brief gust, it would hardly be
affected. On the other hand, if fell a mile in that wind, I'd expect its
ground speed to be close to the wind speed: it wouldn't be falling
vertically. This has little to do with aerodynamics. It is also why
there can be no apparent relationship between the orientation of a
strewn field and the path of the meteor that produced it.


>I've held plenty of irons that size and I don't think they would
>make good wings due to the weight to lift ratio. Not saying you are
>wrong -
>my intuition just seems to fail.

The object in question is quite small, and quite flat. It doesn't have
to be a very good wing to still generate some lift and produce an angled
descent (you'd probably use the term "crash" if an airplane landed at
the same angle as this chunk of metal). I've dropped similarly shaped
rocks off of cliffs, and watched them fall. They definitely don't drop
straight, but look a lot like falling leaves.


>What seems much more likely to me is that the object was hurled
>horizontally
>in which case it goes through the window and through the breaking glass
>is
>altered down at the desk which is plausible for an object hurled
>horizontally AFTER passing the maximum height (vertex) in its parabolic
>arc.

I would be more likely to believe this if it had just punctured the
cheap particle board desk. But the damage to the atlas is more
impressive. A stack of paper like that can absorb a lot of energy. It
looks to me like the object had considerably more velocity than I'd
expect from something tossed by hand. Maybe somebody a few blocks away
built a potato cannon?

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message -----
From: "MexicoDoug" <MexicoDoug at aim.com>
To: "Meteorite Mailing List" <meteorite-list at meteoritecentral.com>
Sent: Tuesday, March 06, 2007 5:33 PM
Subject: Re: [meteorite-list] Suspected Meteorite
GoesThroughWindowinIllinois


"If the object were falling at 50 m/s, an 18 mph wind would be
sufficient to
give it a 20? deviation"

The model of free fall would seem to differ greatly from an airplane in
dynamic equilibrium with the force of gravity, travelling horizontally
powered and depending on aerodynamically generated lift. Are you saying
that an infinitely dense object would be diverted 20 degrees by an 18
mph
wind (in the extreme)? If not, maybe you can help me understand better
your
assumption on how a chunk of metal like this floats or sails on the air
currents? I've held plenty of irons that size and I don't think they
would
make good wings due to the weight to lift ratio. Not saying you are
wrong -
my intuition just seems to fail.

Otherwise I have no problems with looking for the explanation,however
unlikely, can explain the observations. Well, it certainly doesn't
appear
to be thumbprinting nor fusion crust. Though the potential
thumbprinting
structure and irregularities certainly pours cold water on the airfoil
and
'lift' theory for me further. The professor in the video after a good
joke
and rather nice presentation says, if I can understand something to the
effect that "the fusion crust = the thumbprinting"., rather than what I
expected to hear, fusion crust and thumbprinting. Very minor
observation if
true and perhaps debatable as to whether thumprinting is fusion crust or
just a morphological characteristic caused by ablation as I would
describe
it. This is important tome as the difference between having true fusion
crust (as the professor seems to continue to say) or just some indented
chunk metal.

On the other hand, if it is so subject to the air currents due to its
light
weight, the apparent great energy that hole in the window and through
the
book and desk is unexplainable for me. So maybe intuition is dead
wrong.
What seems much more likely to me is that the object was hurled
horizontally
in which case it goes through the window and through the breaking glass
is
altered down at the desk which is plausible for an object hurled
horizontally AFTER passing the maximum height (vertex) in its parabolic
arc.
That would be my fraudless alternate explanation to explain the facts.

Best health,
Doug
Received on Tue 06 Mar 2007 08:22:40 PM PST