[meteorite-list] Meteoroids Before Meteorites
From: Mr EMan <mstreman53_at_meteoritecentral.com>
Date: Sat, 14 Mar 2009 06:26:56 -0700 (PDT)
Let me discuss this another way. Carl I believe that you really didn't mean to say that the color of a space weathered meteoroid's surface is the reason it is black when it reaches the ground. Ordinary chondrites arrive mostly blackish/charcoal-gray because of a melted film of magnetite and high iron silicates which forms black glass--Not because of their pre-entry colors which are moot once ablation begins.
External color before entry has practically nothing per se to do with color after entry. Color before entry was what was being discussed and the reasoning behind that has already been posted. Fusion crust has to do with composition which is why the link you provided leads to a false impression about normal fusion crust colors and how they relate to matrix colors.
The "fusion" crust of a sandstone meteorite would hardly be typical. Seems to me that you are mixing up fusion crust color and meteoroid matrix colors. If not please explain how West was black already and now is white inside???? If you really believe the crust in space is the same crust after entry then I encourage you to do some more reading about how much of a meteoroid is lost due to ablation.
--- On Fri, 3/13/09, cdtucson at cox.net <cdtucson at cox.net> wrote:
> From: cdtucson at cox.net <cdtucson at cox.net>
> Subject: Re: [meteorite-list] Meteoroids Before Meteorites
> To: meteorite-list at meteoritecentral.com, "Eric Wichman" <eric at meteoritewatch.com>
> Date: Friday, March 13, 2009, 3:40 PM
> This is a very interesting question to me because ; How do
> we know what color these west rocks were prior to entering
> our Atmosphere?Maybe we don't? As seen in the video of
> the fall it looks to me that something came apart in
> mid-air. But maybe those are represented by only the broken
> ones found on the ground. What if the complete stones
> actually came in black? It is not a stretch to imagine that
> because we simply do not know the answer. There is no way we
> could know. Before you think I'm crazy consider the only
> bit of information we know for a fact was done by the
> Europeans called "stone6".
> In this experiment none of the rocks turned black. Some of
> the rocks in fact did not change colors at all. and the ones
> that did, changed to a creamy white crust.
> So, who is to say these rocks are not already black while
> traveling through space. The evidence here actually leans in
> that direction. Maybe these rocks were already coated with
> black crust and that is what protects them from evaporation
> when they travel through our atmosphere.
> Again, this may sound silly but if you look at the evidence
> from this study and you acknowledge the fact that the things
> we do see in space are in fact already dark it does make you
> wonder. Maybe our atmosphere is not the reason they are
> black after all? Something else comes to mind, We have all
> seen pictures of meteors traveling through our atmosphere
> and then back out again. Wouldn't those accumulate crust
> and then continue on there journey? ???.
> Carl Esparza
> IMCA 5829
Received on Sat 14 Mar 2009 09:26:56 AM PDT