Jeff/All,
Thanks for that link.  I was trying to add pressure to friction from an
earlier post, and your link is super...
Much appreciated,
Dave 

-----Original Message-----
From: Jeff Kuyken [mailto:i...@meteorites.com.au] 
Sent: Friday, March 20, 2009 2:11 AM
To: d...@fallingrocks.com; meteorite-list@meteoritecentral.com
Subject: Re: [meteorite-list] Carancas: Arsenic smell ?

Hi Dave,

> I believe fusion crust is created not only by the heat of atmospheric 
> friction but also by the heat generated through high pressures, the 
> latter generated by a column of molecules simply not having the time 
> to "get out of the way" being rapidly compressed rather than smoothly 
> displaced.

This was actually discussed several years ago here on the list. Space.com
also wrote about this in a "myths" article around the same time I think it
was.

http://www.meteorites.com.au/odds&ends/myths.html

Cheers,

Jeff



----- Original Message -----
From: "Dave Gheesling" <d...@fallingrocks.com>
To: <cyna...@charter.net>; <meteorite-list@meteoritecentral.com>
Sent: Friday, March 20, 2009 3:34 PM
Subject: Re: [meteorite-list] Carancas: Arsenic smell ?


> Darren/All,
>
> The thinner atmosphere on Mars -- and the lower minimum atmospheric entry
> velocity due to its gravity -- should only mean that the modeling to 
> produce
> surviving meteorites that look "just like they look on Earth" would be
> different for Mars re: entry velocities and angles, etc.  Presumably this
> data already exists, and if anyone has seen it please pass it along...
>
> I believe fusion crust is created not only by the heat of atmospheric
> friction but also by the heat generated through high pressures, the latter
> generated by a column of molecules simply not having the time to "get out 
> of
> the way" being rapidly compressed rather than smoothly displaced.
> Regardless, ablation is indeed a fact.  Meteorites don't enter our
> atmosphere attached to spheres, and presumably that artificial contraption
> may have made for a different-than-typical result.
>
> Think horse, not zebra, and think Occam's Razor.  There is no doubt much
> left to be learned, but extraordinary claims require extraordinary 
> evidence.
> An open mind is essential, but I'm not sure a predisposition to assume the
> utterly remarkable is called for here just yet.  I would also like to hear
> from potential resources who might be holding off on the publication of
> something fascinating; if memory serves, it was essentially the lack of
> agreement on the "impact structure" in Peru that led to the digging in of
> heels on opposing sides, but I was unaware that uncovered anomalies may 
> not
> yet have been published and would very much like to learn more...
>
> All best,
>
> Dave
> www.fallingrocks.com
> -----Original Message-----
> From: meteorite-list-boun...@meteoritecentral.com
> [mailto:meteorite-list-boun...@meteoritecentral.com] On Behalf Of Darren
> Garrison
> Sent: Friday, March 20, 2009 1:07 AM
> To: meteorite-list@meteoritecentral.com
> Subject: Re: [meteorite-list] Carancas: Arsenic smell ?
>
> Off-list argument relisted because-- well, the content has great potential
> for much wise input from other list members.
>
> On Thu, 19 Mar 2009 20:11:45 -0700, you wrote:
>
>>Lets back up a bit here. You know very well that my posts usually argue
>>against what we think we know. I think there is an over average amount
>>of guessing in meteoritics when compared to other Sciences.
>>There are a great deal of things that we simply have no way of knowing.
>>There is a well known photo of a meteorite sitting on Mars. We know
>>it's a meteorite because it looks just like they look on Earth. Why is
> that?
>>Do they Ablate the same while traveling through Mars' atmosphere?
>
> Answer-- no.  Mars has a much, much, much thinner atmosphere than Earth.
> There will be ablation, but not to the same degree.
>
>>this ablation question came up was to question whether or not we know
>>what meteorites look like prior to entry into Earths atmosphere.
>
> Many asteroids have been imaged while in space.  Some have been studied 
> from
> close-up.  Some small ones have been photographed very near earth.  We 
> know
> what THEY look like in space, and have no reason to assume that the ones
> that happen to intersect with Earth's orbit would look different from the
> others.  Moreover, none of the asteroids we photograph in space have
> anything resembling a fusion crust, nor do we know a mechanism by which an
> asteroid is space would require a fusion crust.  Moreover, even if a
> meteorite HAD a crust formed over it in space, the crust meteorites is
> composed of the same material of which the meteorite is composed (or an
> oxidized version of same) -- material with a melting point far below the
> temperature meteorites are known to experience as they pass through the
> atmosphere.  Therefore, any crust formed in space would burn off during
> atmospheric entry.
>
>>I mentioned this study to point out that not all material ablates to
>>form a fusion crust that would change it's appearance.
>
> That may be what you meant-- but it is NOT what you said.  You said that
> ablation did not take place, which is not true.  Not only were the samples
> ablated, but they were improperly placed on the heat shield so as to not 
> be
> at the maximum heat point where they were supposed to be-- ablation would
> have been even higher (possibly complete) if the samples had been properly
> placed.  AND at least one of the samples weren't properly assembled so as 
> to
> protect the bacterial samples on the bottom (and who knows what happened 
> to
> material lost
> completely):
>
> http://www.cosis.net/abstracts/EPSC2008/00407/EPSC2008-A-00407-1.pdf
>
>
>>at some point in their journey. And by the way the wind pressure while
>>traveling out to space could have done this damage to the rocks.
>
> No.
>
>>We cannot assume the ablation was caused by reentry at all.
>
> Yes, we can.
>
>>In fact because no black crust appeared we can say that this experiment
>>proved nothing about the actual cause of black crust at all.
>
> We know what causes the black crust-- melting of the meteorite's surface 
> due
> to the heat of atmospheric friction.
>
>>Maybe if they had fusion crust prior to reentry they would have ablated
> less?
>
> No.  Because the fusion crust is made of the exact same material as the 
> rest
> of the meteorite, with the same melting point.  If anything, it would have
> began ablation MORE QUICKLY because the black crust would absorb more 
> heat.
> Basic physics.
>
>>looked like prior to entry. I went on to point out that we have all
>>seem pictures of meteors fly across the sky only to re-exit our 
>>atmosphere.
>
> Okay, I'll give you that one.  One of the rare meteoroids that enters the
> atmosphere deep enough to start ablating but then skips back into space
> likely has a fusion crust.  A fusion crust formed by Earth's atmosphere,
> like other fusion crusts.
>
>>survive while others don't. Maybe something else gives them this tough
>>surface we call fusion crust? This is one of the questions I have .
>
> The fusion crust isn't tough-- it is a very thin, very fragile thing that
> weathers away very quickly if the meteorite isn't found and "rescued" from
> the weather.
>
>>Another is why have we not figured out an easy way to authenticate
>>whether a rock is even from space.
>
> And there never will be a easy way-- if it looks like a meteorite to 
> someone
> who knows meteorites, well, then it can be tested.  But any meteorite that
> looks just like an ordinary rock, in an area where you would expect to 
> find
> ordinary rocks, will sit there forever without being tested.
>
>>Moon rocks the only way to tell them apart is by chemical analysis.
>>So, you find a rock from the moon with no crust all scientist assume it
>>is from Earth.
>
> Not always true.  As Randy Korotev himself pointed out once on the list 
> when
> discussing possible lunar breccias, a lunar breccia will have random sized
> pieces (some very small, some very large) that are not rounded--  
> terrestrial
> sedementary breccias will usually have all the pieces of a similar size,
> with rounded surfaces.  Look at photos of lunar breccias on google and
> you'll see those features.
>
>>coating. If there were an easier way to tell them apart we would find 
>>them.
>
>>I have rocks that look just like the collections of Moon rocks but
>>unless you can find a scientist to study it , it will never be discovered.
>
> There is an old saying-- "if you see hoof prints, think horse, not zebra."
> (Of course, that wouldn't apply in Africa.)  You must look at mundane
> explainations for something before you start looking at exotic ones.
>
>>I am not trying to disprove any science I just want to wake up a few
>>scientists to realize that we don't know everything yet.
>
> Yes, there are countless things that are not known to science.  The
> temperature at which a given mineral melts and the temperature that a
> meteoroid is subjected to as it passes through the atmosphere are not 
> among
> those unknowns, however.
> If you have an ice cube, and you put it in a room where the temperature is
> 80 degrees F, that ice cube is going to melt.  If you take a rock with a
> melting point of 1,000 degrees F and subject it to frictional temperatures
> of 3,000 degrees F, that rock is going to melt just as surely as that ice
> cube in a room.
> There is no "ablation theory of fusion crusts" any more than there is a
> "melting theory of why my ice cube is a puddle"-- it is a simple fact 
> based
> on knowledge of the materials that compose a meteorite and knowledge of 
> how
> much frictional heating a meteoroid entering the atmosphere would be
> subjected to.
>
>>You have a way of pushing buttons but of coarse that is what you live for.
>
> For some, "pushing buttons" seems to mean "disagreeing with what you say,
> and saying so."
>
>>you live for. Isn't it? The stuff I said about Cosmo chemistry is true
>>but as soon as a scientist publishes it the community will be up in arms.
>
> Again, "if you see hoof prints, think horse, not zebra"-- the chances of
> making a monumental new discovery are much lower than the chances of 
> having
> just another H4-5.  If anyone involved in studying Carancas who has found
> "inexplicable cosmochemistry" in it that they are "unwilling to publish", 
> is
> reading this, can't you at least mention it here?
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