[meteorite-list] Meteorite Questions

[Mark Abbott]

My understanding is that the geology of that area is karst (i.e. 
limestone) , which forms in rectangular blocks. The transfer of the 
energy of the explosion was enhanced in some direction and not in 
others... resulting in the squarish shape.

Mark Abbott

Walter Branch wrote:
> Hello Everyone,
>
> I have had plenty of time recently to ponder things such as 
> meteorites.  I am also alone at home at present and am bored.  Would 
> some kind, more-knowledgeable-than-me soul help me with some 
> meteoritical questions.
>
> For example, why does the rim of meteor crater appear "squared" in 
> some photos, while in others it appears very round?  Perspective?  
> Lighting? Extremely highly localized tectonic shifting (back and forth)?
>
> Also, why is Tatahouine so green? Olivine? Krylon?
>
> I am looking at a slice of NWA 4664 right now (thank you Eric Olson) 
> and I don't see any much green.  Maybe that one is a bad example 
> because NWA 4664 doesn't even look like at Diogenite!
>
> Also, I have read that some meteoroids travel through space in streams 
> and impact the Earth simultaneously (i.e., they have already broken up 
> before they hit the Earth's atmosphere).  How can this be?  I would 
> think that once a meteoroid has broken in space (most likely due to 
> impact), minute deviations of the individual pieces in the initial 
> trajectory would translate into ever increasing deviations in the 
> individual piece's trajectory, over time.  Unless two pieces were 
> traveling in EXACTLY parallel lines, over time the pieces would be 
> widely dispersed in space.
>
> Remember comet Shoemaker-Levy 9?  It was broken apart by gravitational 
> forces from Jupiter only a year prior to impact, yet by the time it 
> had encountered the Jovian atmosphere the separation between the 
> pieces was wider than the diameter of the Earth!  After only a year.
>
> Traveling over eons to make it to the inner solar system, how can a 
> meteoroid stream stay intact enough to cause a tiny strewnfield on the 
> Earth? I would not think that the Earth's gravitational field would be 
> strong enough to do what Jupiter did.
>
> Also, I know I have asked this before but I still don't understand how 
> researchers can determine cosmic ray exposure ages for a meteorite 
> which ablated a significant portion of the material that absorbed most 
> of the cosmic rays and which may have fragmented in flight through the 
> Earth's atmosphere.
>
> Anyone?
>
> -Walter Branch
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