[meteorite-list] Suspected Meteorite GoesThroughWindowinIllinois

From: MexicoDoug <MexicoDoug_at_meteoritecentral.com>
Date: Tue, 6 Mar 2007 18:33:52 -0600
Message-ID: <005001c76050$4a0a7d00$64cc5ec8_at_0019110394>

"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


----- Original Message -----
From: "Chris Peterson" <clp at alumni.caltech.edu>
To: "Meteorite Mailing List" <meteorite-list at meteoritecentral.com>
Sent: Tuesday, March 06, 2007 5:43 PM
Subject: Re: [meteorite-list] Suspected Meteorite
GoesThroughWindowinIllinois


> But Chris, if you are that generous with the benefit of doubt...

I'm just seeking an explanation. If we discount outright fraud, the fact
remains that a chunk of metal came through a window and hit a desk with
enough speed to knock a hole in it. That's fairly difficult to do via
any prosaic mechanisms that come to mind. I think it's a reasonable
assumption that this was a falling object, and if so, its path deviated
rather substantially from the vertical. So how can that be explained?
Well, there could have been a stiff wind that day. If the object were
falling at 50 m/s, an 18 mph wind would be sufficient to give it a 20?
deviation. Or, as I suggested before, an object with a high surface area
to mass ratio could experience significant aerodynamic effects. Neither
of these explanations seem to be stretching things too far.

> what general effect would the lift, drag, and related
> turbulence, have caused on this fragile lightweight during the final
> part
> of ablating 'flight' - as there are no signs of orientation and
> density
> could have reached up to 10% sea level :-)

Who can say? Certainly these effects _do_ influence the flight of
meteoroids while they are still in their ablative flight. Drag is
usually approximated based on a spherical body, and lift and turbulence
largely ignored. But not all meteoroids are spherical, and the existence
of oriented meteorites is evidence of the influence of aerodynamics.
While the little photographic evidence I've seen doesn't really suggest
a meteorite (I'd guess something like a chunk of runway debris that fell
off an airplane tire when the gear went down), if it actually is a
meteorite I'd guess its history is similar to this one:
http://www.cloudbait.com/misc/cp.jpg (recognize it?), which rather
obviously was shaped, distorted, and generally ripped apart _after_
ablation stopped. That is, a piece of shrapnel ripped off at the very
end, and which had no time to experience significant surface melting.
I'd assume it was part of a much larger object until that point- an
object not as sensitive to aerodynamics.

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 3:08 PM
Subject: Re: [meteorite-list] Suspected Meteorite Goes
ThroughWindowinIllinois


> Hi Chris, Rob, List,
>
> Meteorite goes through the window ... or science thrown out the
> window?
>
> But Chris, if you are that generous with the benefit of doubt, to be
> consistent, what general effect would the lift, drag, and related
> turbulence, have caused on this fragile lightweight during the final
> part
> of ablating 'flight' - as there are no signs of orientation and
> density
> could have reached up to 10% sea level :-)
>
> Quick someone better classify that airfoil integrity for the DoD :-)
>
> Did the (dust) devil done it? Chicago is the 'Windy' City, though
> this
> historically refers to all the 'hot air'.
>
> Best wishes,
> Doug

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Received on Tue 06 Mar 2007 07:33:52 PM PST