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

[Meteorites USA]

Did I miss the answers to these questions? Sorry if it's already been 
answered. ;)



On 12/30/2010 1:59 PM, Meteorites USA wrote:
> 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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