[meteorite-list] Friable meteorites

From: MexicoDoug <mexicodoug_at_meteoritecentral.com>
Date: Tue, 25 Oct 2011 00:12:25 -0400 (EDT)
Message-ID: <8CE60E36FA8A1BC-1028-682E8_at_Webmail-d109.sysops.aol.com>

Hi John ---

Yup something like that!

But if yo9u want to be more mundane, a meteor seems to me to be just a
trail of plasma, same as lightning except for the seed (the meteoroid
itself). Lucky for us it is, because if it weren't, there would be
nothing to see. Or, at minimum, there would be no trail. The reason
for the delay and sight of the streak of light (persistent train) must
be because the air-particle mixture involved in the wake has been
turned into a plasma by the passing of the object. Once the energy
source passes, the electrons recombine with their nuclei and the plasma
is convertted into regular gas again.

So, just to be clear: You are not seeing the plasma (the actual shield)
when you see the meteor. What you are seeing is the energy (in the
form of light) that these free roaming electrons lose as soon as they
are recaptured by the nearest electron-stripped nuclei.

That's an interesting concept actually, because it is simply a decay -
so it has a bulk half life. What makes it interesting in this moment
is that the brightest point on the trail may or may not be right around
the "head" if the half life is sufficiently long since there is a
temperature dependence in order for the nuclei to capture the electrons
again, which will be different for each different mass and shape of
meteormass and atmospheric densit, in addition to the composition.

So it would be possibly observable if you could record an extremely
fast image, to see a snapshot in time of the light energy density and
how far back, or, generally speaking the energy density gradient
(=brightness).

That, to me brings up a whole world of possibilities of analysis.
Probably someone is studying this somewhere or maybe it is old hat, but
I don't have a clue. In effect what I'm saying is taking super short
exposures (time interval TBD) of meteors with determined locations one
could actually calculate how big the mass is. If a standard is needed,
an experiment could be designed to fire particles toward earth from a
low orbiting satellite.

Ah, if only I were in school again, I'd be a perpetual project hopping
student ;-)

Kindest wishes
Doug

PS, I love the "shields" abnalogy, but I want to correct my
"form-in-place" idea ... it was a sloppy way to say it because I also
got carried away with the beam-me-up stuff. Reading the above, it's
clwear the shield is not a form in place one, but rather a disposible
tunnel one. Well, at least the Enterprise can use its sensors to find
the residual. In order to make sense of when the Romulans sent each of
the meteoroid sized invaders to hide in Earth and track them down,
though, the main ship's computer will need to reference our paper on
half life relationship to be studied above...


-----Original Message-----
From: John.L.Cabassi <John at Cabassi.net>
To: 'MexicoDoug' <mexicodoug at aim.com>; gmhupe <gmhupe at centurylink.net>;
mikestang <mikestang at gmail.com>
Cc: meteorite-list <meteorite-list at meteoritecentral.com>
Sent: Mon, Oct 24, 2011 10:55 pm
Subject: RE: [meteorite-list] Friable meteorites


G'Day Master Doug
Very interesting. Maybe you've stumbled upon force field. Could I be
referring to "shields up"?? Plasma is fascinating, not as fascinating as
Carancas, friable, fast and low and behold a crater. Will we ever solve
this dilemma? Fraid knot. Sorry, that was a personal joke. ;-)

Cheers
John Cabassi
IMCA 2125



-----Original Message-----
From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of
MexicoDoug
Sent: Sunday, October 23, 2011 11:03 PM
To: gmhupe at centurylink.net; mikestang at gmail.com
Cc: meteorite-list at meteoritecentral.com
Subject: Re: [meteorite-list] Friable meteorites


Pete wrote:

"My question is how do they survive to the ground, to be found not as a
dust, but in large pieces?"

Pete you're in the good company of David Rittenhouse who asked the same
question in 1780.

It's related to the other conundrum - How do they stay relatively cool
inside while the surface becomes fused? That seemingly goes against
common sense. And with Irons it is even better because at much lower
temperatures, the Widmanstatten pattern would become annealled and
lost. Yet there is a fusion region on irons that can be measured in
fractions of a millimeter in some cases, and never much more.

Somehow, and I'm winging it though I should know, the process of
ablation is so darn efficient at removing the heat generated, much like
we sweat, that the ablating surface provides a natural air conditioner
for what's inside, just like a swamp cooler but absorbing even by an
electric excitation mechanism which discharges the energy by
transforming from electrical into light energy, hece the brightness
observed/

But that still doesn't explain why going into a headwind of 10 miles
per second everything doesn't rip apart. That must, and please correct
me if I am wrong, be due to two or three factors working in concert on
the forward face of the mass:
1. heat is wicked off immediately by the sublimation described above
2,3. the ablated material leaving the surface creates a plasma which
either has a much lower frictional coefficient or creates a static
layer of plasma travelling with the object which essential operates as
a battering ram forming its own sacrificial layer, or both.

Thus, the rock from space is like an insulated kernal traveling in its
own form in place shields.

When it finishes its high energy velocities it goes into free fall
which reaches a maximum speed of under 400 mph in most cases much less
which upon hitting a soft surface can survive. But if it hits a rock,
you probably will be out of luck

Carancas was different because it never reached free fall, and the
impact was like whipping a piece of cement to belly flop against a hard
wall of something. Even then, a portion of material in the aft section
can survive. Try whipping pieces of chalk against a wall and you'll
demonstrate a similar effect and perhaps get some cone of material
stuck to the wall and a few crumbs falling back, along with a lot of
dust. If it is large enough, and traveling in a herd of rocks which is
also likely since they can become insultaed in their form in place
sublimation shield, the first stones will be sacrificial but some in
the back may survive. A possible explanation for Carancas. Or, just
that their were some laggers that fell behind the main bolus and their
higher surface area slowed them much more to better withsatand an
impact.

Kindest wishes
Douig

PS nice domain, Pete
PPS another way to produce some friable meteorites is let them fall in
water and see what happens and recover them later. After they dry out
enough material may be leached (since they are porous) that they become
much more friable. Care to give an example?



-----Original Message-----
From: Greg Hupe <gmhupe at centurylink.net>
To: Michael Mulgrew <mikestang at gmail.com>
Cc: The List <meteorite-list at meteoritecentral.com>
Sent: Mon, Oct 24, 2011 12:57 am
Subject: Re: [meteorite-list] Friable meteorites


Hey All,
I would have to suggest Nakhlites are one of the most friable
meteorites.

Best Regards,
Greg Hupe

On Oct 23, 2011, at 9:50 PM, Michael Mulgrew <mikestang at gmail.com>
wrote:

> Pete,
>
> If you want to talk friable meteorites, take a look at Tagish Lake. It

> is one of my most favorite meteorites, it is the least dense meteorite

> known to man. Fascinating!
>
> -Michael in so. Cal.
>
> On Sun, Oct 23, 2011 at 9:06 PM,
<pshugar at messengersfromthecosmos.com> wrote:
>>
>> In a conversation with someone today, it was mentioned that Kilabo
>> was extremely friable. Another really friable meteorite was Caracas,
>> Peru. My question is how do they survive to the ground, to be found
>> not as a dust, but in large pieces? How did they make a crator?
>> Have the scientists figured out how the Caracas meteorite made
>> such a large crator?
>> Many questions and so little time to figure out what happened.
>> Pete
>>
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Received on Tue 25 Oct 2011 12:12:25 AM PDT