Talk:Murchison meteorite

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Amino Acid List[edit]

I just removed the following list of amino acids found in the meteorite from the Amino acid page:

Such detailed info about one specific specimen seems inappropriate for the general amino acid page, and someone reading about the meteorite itself would likely not see it there either. Someone who is interested should consider adding it here, formatting it as a wiki list (or list of sublists, or whatever), adding italics, greek letters, caps/lowercase and other standard chemical typographic conventions, etc. DMacks 18:06, 5 June 2006 (UTC)

Non-linear catalysis[edit]

is this paragraph a joke? i hope so: "The catalysis is non-linear, that is proline with an enantiomeric excess of 20% yields a allose with enantiomeric excess of 55% starting from a benzyloxy acetaldehyde in a sequential aldol type reaction in an organic solvent like DMF [5]. In other words a small amount of chiral amino acids may explain the evolution of right-handedness of sugars." —The preceding unsigned comment was added by 143.252.80.100 (talkcontribs) 13:31, 27 July 2006 (UTC).

Are you questioning the science of the amplification (20% leads to 55%), something else about the science, the relevance to the meteorite, or something else? DMacks 14:51, 27 July 2006 (UTC)

I had the exact same reaction when I read that paragraph. Perhaps it makes sense to people in the appropriate field, but even though I come from a field rich in jargon (computer engineering) I think that paragraph needs some serious work. Unfortunately I don't even know where to start. Is it suggesting that some of the unusual "left-handed"(?) amino acids could be creating "right-handed" sugars? If so, maybe just say that?76.126.58.246 (talk) 21:09, 12 August 2010 (UTC)

Trying to clean up the text. It looks too much like a ransom note just now. Kortoso (talk) 21:21, 11 September 2013 (UTC)

See if the new paragraph makes sense. Kortoso (talk) 21:58, 11 December 2013 (UTC)

Question[edit]

I am seeing a fair number of sources that say that as many as 50 of the Murchison amino acids are not found on Earth. What gives? New chemicals suddenly discovered? Or science writers abbreviating things again? http://www.astrobio.net/exclusive/375/murchisons-amino-acids-tainted-evidence Kortoso (talk) 21:41, 11 September 2013 (UTC)

I am seeing too many assumptions that Murchison and other meteorites are "the source" of these compounds, rather than the more conservative conclusion that it is representative of another celestial body in which organic compounds were evolved. http://www.scientificamerican.com/article.cfm?id=murchison-meteoriteKortoso (talk) 21:51, 11 September 2013 (UTC)

Fossils[edit]

http://science.jrank.org/pages/4501/Murchison-Meteorite.html "In 1997, NASA scientists announced evidence that the Murchison meteorite contained microfossils that resemble microorganisms." I can't seem to find a primary source for this however. Kortoso (talk) 19:50, 11 December 2013 (UTC)

Ah, here: http://www.panspermia.org/hoover.htm
Discredited, BTW. Kortoso (talk) 21:01, 11 December 2013 (UTC)
See this on its publisher, the Journal of Cosmology. -BatteryIncluded (talk)

Isotopic pairing?[edit]

"At the same time, L-excesses of alanine were again found in Murchison but now with enrichment in the isotope 15N,[1] however, the isotopic pairing was later contested on analytical grounds.[2]"

  1. ^ Engel, Michael H.; Macko, S. A. (September 1, 1997). "Isotopic evidence for extraterrestrial non-racemic amino acids in the Murchison meteorite". Nature 389 (6648): 265–268. Bibcode:1997Natur.389..265E. doi:10.1038/38460. PMID 9305838. 
  2. ^ Pizzarello, Sandra; Cronin, JR (1998). "Alanine enantiomers in the Murchison meteorite". Nature 394: 236. doi:10.1038/28306. 

- this is an abstract from the article. The second part of the sentence says, "the isotopic pairing was later contested on analytical grounds." - was it? In the reference given after the statement I found only that they reported very similar δ15nitrogen values for L-alanine and D-alanine; these values are quite high in comparison with those of terrestrial amino acids. On this basis, they argued that contamination of the meteorite by terrestrial L-alanine can be ruled out because, if it contributed to the L-enantiomer excess, the lower 15N content of terrestrial L-alanine would significantly lower the δ15N value that they observed for L-alanine. So, not the isotopic pairing, but terrestrial origin of this pairing was contested. Or the terrestrial origin of l-alanine excess itself. Or have I misunderstood anything?-- Pyramid ion  14:03, 19 April 2014 (UTC)