[meteorite-list] NASA finds extra-terrestrial amino-acids in Sudan meteorites

[Meteorites USA]

This raises some very interesting question. If the interior (core) of 
the smaller stones from smaller meteorite falls such as Murchison, 
Tagish Lake, Allende, Ash Creek, Mifflin, or any meteorite fall for that 
matter, are still frozen during entry and upon impact, then would it be 
a stretch of logic to assume a larger iron mass, such as Canyon Diablo, 
which was estimated to be 50 meters wide, would also still have a frozen 
core upon impact?

After all it did hold probably most of it's cosmic velocity, meaning it 
was incandescent for just a few seconds at most, right? Even when you 
consider iron conducts heat much faster and more efficiently than stone, 
could such a large mass heat all the way to the core in just a couple 
few seconds?

Regards,
Eric



On 12/30/2010 1:41 PM, Matson, Robert D. wrote:
> Hi Mike and List,
>
> Have been meaning to post a reply about the article link Mike posted:
>
>    
>> http://www.digitaljournal.com/article/301636
>>      
>    
>> I assume they are talking about Almahata Sitta. I had not heard this
>> before.
>>      
> Yes, Almahata Sitta is right. As we all know, ET amino acids have been
> found in plenty of carbonaceous meteorites, perhaps most famously
> within Murchison. So I was curious to find out what was so special
> about finding them in carbon-rich 2008 TC3 (Almahata Sitta). A quote
> from the article:
>
> "Amino-acids have been found in carbon-rich meteorites before but this
> is the first time the acid substances have been found in a meteorite
> as hot as 2,000 Fahrenheit (1,100c). This naturally heated hot rock
> should have obliterated any form of organic material, reports National
> Geographic.
>
> Daniel Glavin, an astro-biologist at NASA's Goddard Space Flight
> Centre in Maryland said, "Previously, we thought the simplest way to
> make amino acids in an asteroid was at cooler temperatures in the
> presence of liquid water, this meteorite suggests there's another way
> involving reactions in gases as a very hot asteroid cools down."
>
> So the obvious question to ask is why anyone thinks that the interior
> of 2008 TC3 was ever heated up to 1100 C? Sure, the *surface* of the
> asteroid got very hot when it entered earth's atmosphere, but how is
> that different from Murchison or any other meteorite-generating fall?
> The interior of 2008 TC3 should never have been above freezing.
>
> So something must be missing from the article to explain why they
> believe Almahata Sitta's interior got so hot. About all I can come
> up with is that they assumed 2008 TC3 was a rubble pile (almost
> certainly true given the range of petrology), and that it fragmented
> into tiny pieces very high in the atmosphere while still moving at
> cosmic velocity. Instead of heat from ablation only affecting the
> outer centimeter or so of the surface of a 4-meter monolithic rock,
> all the individual fragments got the blast treatment. I still don't
> buy it, though. Small fragments decelerate so rapidly that there
> wouldn't be time to heat up the interior of even a 1" diameter rock.
>
> So the question is, am I missing something?  --Rob
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