[meteorite-list] FW: Rocks from Space Picture of the Day -May 8, 2010

From: Galactic Stone & Ironworks <meteoritemike_at_meteoritecentral.com>
Date: Sun, 9 May 2010 09:55:25 -0400
Message-ID: <g2ie51421551005090655hbd2f5788jbc0ed7386bc54989_at_mail.gmail.com>

Hi Rob,

That's "rolly chair" talk....... ;) LOL

Best regards,

MikeG

PS - Sterling, you too!

On 5/9/10, Rob Matson <mojave_meteorites at cox.net> wrote:
> Hi All,
>
> Short opinion: manmade.
>
> Reasoning: the inability to produce such a form purely through
> atmospheric ablation. Just to remind everyone, all of the
> so-called Franconia irons are nothing more than chondritic
> iron that has separated from an H-chondrite fall -- either
> during flight, or by terrestrial weathering processes on the
> ground. Thus it has always bothered me that these irons were
> given a separate meteorite name from the ubiquitous H-chondrites
> at Franconia from which they derive. If my information is
> outdated on this subject, someone please let me know. But many
> (most?) of the people I know who have hunted Franconia and
> found these irons do not pretend that they are from a separate
> iron fall -- they all accept that the iron nuggets were
> spalled from an H-chondrite.
>
> So, getting back to Larry's unusual, tiny iron find. If this
> iron did not start at the top of the atmospere as a very tiny
> piece of iron, there would be no way to ablate it, let alone
> punch a hole through it. Since the Franconia irons were once
> part of a massive chondritic meteoroid, there was no opportunity
> for these irons to experience independent, high altitude, high
> velocity ablation. Their ablation history wouldn't have started
> until the main H-chondrite body had fragmented on a gigantic
> scale (e.g. terminal burst), which of course would have
> occurred at comparatively low altitude.
>
> On a final note, the H-chondrite fall at Franconia was not
> a recent one. While this part of NW Arizona receives little
> seasonal rainfall, I don't imagine that a 0.1-gram piece of
> iron could survive more than a century. But a manmade piece
> of iron, dropped there in the last 50 years, might possibly
> survive terrestrial weathering.
>
> I would love nothing more than for Larry's find to have an
> extraterrestrial origin; but the physics and history of finds
> at Franconia argue strongly against it.
>
> Best wishes,
> Rob
>
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-- 
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Mike Gilmer - Galactic Stone & Ironworks Meteorites
http://www.galactic-stone.com
http://www.facebook.com/galacticstone
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Received on Sun 09 May 2010 09:55:25 AM PDT