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Murchison - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Murchison_meteorite

From Wikipedia, the free encyclopedia Coordinates: 36°37′S 145°12′E

The is named after Murchison, Murchison Victoria, in Australia. It is one of the most studied due to its large mass (>100 kg), the fact that it was an observed fall, and it belongs to a group of meteorites rich in organic compounds.

1 History 2 Classification and composition 3 Organic matter 3.1 4 References 5 External links

A Murchison meteorite specimen at the National Museum of Natural History (Washington) Type On 28 September 1969 at about 10:58 AM, near the town of Murchison, Victoria in Australia, a bright fireball was Class observed to separate into three fragments before Group CM2 [1] disappearing, leaving a cloud of smoke. About 30 seconds Composition 22.13% total , 12% later, a tremor was heard. Many specimens were found over water an area larger than 13 km², with individual masses up to 7 Shock stage S1-2 kg; one, weighing 680 g, broke through a roof and fell in hay.[1] The total collected mass exceeds 100 kg. Country Australia Region Victoria Coordinates 36°37′S 145°12′E[1] Observed fall Yes The meteorite belongs to the CM group of carbonaceous Fall date 28 September 1969 (see ). Like most CM chondrites, Murchison is petrologic type 2, which means that 100 kg it experienced extensive alteration by water-rich fluids on its Pair of grains from the Murchison meteorite [2] before falling to Earth. CM chondrites, together with the CI group, are rich in and are among the most chemically primitive meteorites in our collections. Like other CM chondrites, Murchison contains abundant CAIs. Over 100 amino acids (some of the basic components of life) have been identified in the meteorite.

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Murchison contains common amino acids such as , and as well as unusual ones like isovaline and pseudoleucine.[3] The initial report stated that the amino acids were racemic (that is, the of their enantiomers are equally left- and right-handed), indicating that they are not present due to terrestrial contamination. A complex mixture of was isolated as well, similar to that found in the Miller-Urey experiment. and , usually considered to be earthly contaminants, were conspicuously Fragment of the Murchison meteorite (at absent in the samples. A specific family of amino acids called right) and isolated individual particles diamino acids was identified in the Murchison meteorite as (shown in the test tube). well.[4]

More research found that some amino acids were present in enantiomeric excess,[5] leading some to suspect terrestrial contamination, since it would be "unusual for an abiotic stereoselective decomposition or synthesis of amino acids to occur with amino acids but not with non-protein amino acids."[6] In 1997 research showed that individual amino-acid enantiomers from Murchison were enriched in the 15N relative to their terrestrial counterparts, which confirmed an extraterrestrial source for an L-enantiomer excess in the Solar System.[7] The list of organic materials identified in the meteorite was extended to polyols by 2001.[8]

Building on the idea that (existence of only left handed amino acids and right handed sugars) is triggered by deposition of chiral molecules on meteorites, research in 2005 demonstrated that an like L- is capable of catalyzing the formation of chiral sugars. The is non-linear, that is proline with an enantiomeric excess of 20% yields an allose with enantiomeric excess of 55% starting from a benzyloxy acetaldehyde in a sequential aldol type reaction in an organic solvent like DMF.[9] In other words a small enantiomeric excess of left-handed amino acids may explain terrestrial life's preference for right- handed sugars.

According to Engel, several lines of evidence indicate that the interior portions of well-preserved fragments Compound class[10] Concentration (ppm) from Murchison are pristine. Engel points to the array of Amino acids 17-60 amino acids Murchison contains and to isotope studies to bolster his position. A 2010 study by analytical chemist Aliphatic hydrocarbons >35 Philippe Schmitt-Kopplin and his colleagues using high Aromatic hydrocarbons 3319 resolution analytical tools including , Fullerenes >100 identified 14,000 unique molecular compounds including 70 amino acids in a sample of the meteorite.[11] [12] The Carboxylic acids >300 limited scope of the analysis by Hydrocarboxylic acids 15 undertaken by Schmitt-Kopplin's team provides for a and 1.3 potential 50,000 or more unique molecular compositions, with the team estimating the possibility of millions of Alcohols 11 distinct organic compounds in the meteorite. [13] Sulphonic acids 68 Phosphonic acids 2

Nucleobases

Measured and compounds are indigenous components of the Murchison meteorite. Carbon isotope ratios for and of 44.5‰ and +37.7‰, respectively, indicate a non-terrestrial origin for these compounds. These results demonstrate that many organic compounds which are components of life on Earth, were already present in the early solar system and may have played a key role in life's origin.[14]

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1. ^ a b c Meteoritical Bulletin Database: Murchison meteorites as a source of sugar-related organic (http://tin.er.usgs.gov/meteor compounds for the early Earth". Nature 414: /metbull.php?code=16875) 879–883. doi:10.1038/414879a (http://dx.doi.org 2. ^ S. A. Airieau, J. Farquhar, M. H. Thiemens, L. /10.1038%2F414879a) . A. Leshin, H. Bao, E. Young. Planetesimal sulfate 9. ^ Córdova, Armando; Engqvist, Magnus; Ibrahem, and aqueous alteration in CM and CI Ismail; Casas, Jesús; Sundén, Henrik (2005). carbonaceous chondrites (http://www.lpi.usra.edu "Plausible origins of homochirality in the amino /meetings/lpsc2007/pdf/1230.pdf) . Geochimica et acid catalyzed neogenesis of carbohydrates". Cosmochimica Acta, Volume 69, Issue 16, p. Chem. Commun.: 2047–2049. 4167-4172. doi:10.1039/b500589b (http://dx.doi.org 3. ^ Kvenvolden, Keith A.; Lawless, James; Pering, /10.1039%2Fb500589b) . Katherine; Peterson, Etta; Flores, Jose; 10. ^ Machalek, Pavel (February 17 2007). "Organic Ponnamperuma, Cyril, Kaplan, Isaac R.; Moore, Molecules in and Meteorites and life on Carleton (1970). "Evidence for extraterrestrial Earth" (http://www.pha.jhu.edu/~pmachal2 amino-acids and hydrocarbons in the Murchison /ism_review_redone_feb07.pdf) (PDF). meteorite" (http://chemport.cas.org/cgi-bin Department of Physics and Astronomy, Johns /sdcgi?APP=ftslink&action=reflink&origin=npg& Hopkins University. http://www.pha.jhu.edu version=1.0&coi=1:CAS:528:DyaE3MXisVCnsg /~pmachal2/ism_review_redone_feb07.pdf. %3D%3D&pissn=0028-0836&pyear=1983& Retrieved 2008-10-07. md5=cb8b015f54156458fa2be8cdca44789f) . 11. ^ "Space rock contains organic molecular feast" Nature 228 (5275): 923–926. (http://news.bbc.co.uk/2/hi/science/nature doi:10.1038/228923a0 (http://dx.doi.org /8516319.stm) . BBC News. 15 February 2010. /10.1038%2F228923a0) . http://chemport.cas.org http://news.bbc.co.uk/2/hi/science/nature /cgi-bin/sdcgi?APP=ftslink&action=reflink& /8516319.stm. Retrieved 2010-02-15. origin=npg&version=1.0& 12. ^ Schmitt-Kopplin, Philippe; Zelimir Gabelica, coi=1:CAS:528:DyaE3MXisVCnsg%3D%3D& Régis D. Gougeon, Agnes Fekete, Basem pissn=0028-0836&pyear=1983& Kanawati, Mourad Harir, Istvan Gebefuegi, md5=cb8b015f54156458fa2be8cdca44789f. Gerhard Eckel, and Norbert Hertkorn. (Published 4. ^ Meierhenrich, Uwe J.; al. (2004). "Identification online before print February 16, 2010). "High of diamino acids in the Murchison meteorite". molecular diversity of extraterrestrial organic PNAS 101: 9182–9186. matter in Murchison meteorite revealed 40 years doi:10.1073/pnas.0403043101 (http://dx.doi.org after its fall" (http://www.pnas.org/content/early /10.1073%2Fpnas.0403043101) . /2010/02/12/0912157107.full.pdf+html) (PDF). 5. ^ Engel, Michael H.; Nagy, Bartholomew (April PNAS 107: 2763-2768. http://www.pnas.org 29, 1982). "Distribution and enantiomeric /content/early/2010/02 composition of amino acids in the Murchison /12/0912157107.full.pdf+html. Retrieved meteorite". Nature 296: 837–840. 2010-02-16. doi:10.1038/296837a0 (http://dx.doi.org 13. ^ [|Matson, John /10.1038%2F296837a0) . (http://www.scientificamerican.com 6. ^ Bada, Jeffrey L.; Cronin, John R.; Ho, /author.cfm?id=1237) ] (15 February 2010). Ming-Shan, Kvenvolden, Keith A.; Lawless, James "Meteorite That Fell in 1969 Still Revealing G.; Miller, Stanley L.; Oro, J.; Steinberg, Spencer Secrets of the Early Solar System" (February 10, 1983). "On the reported optical (http://www.scientificamerican.com activity of amino acids in the Murchison /article.cfm?id=murchison-meteorite) . Scientific meteorite". Nature 301: 494–496. American. http://www.scientificamerican.com doi:10.1038/301494a0 (http://dx.doi.org /article.cfm?id=murchison-meteorite. Retrieved /10.1038%2F301494a0) . 2010-02-15. 7. ^ Engel, Michael H.; Macko, S. A. (September 1, 14. ^ Martins, Zita; Oliver Botta, Marilyn L. Fogel 1997). "Isotopic evidence for extraterrestrial Mark A. Sephton, Daniel P. Glavin, Jonathan S. non-racemic amino acids in the Murchison Watson, Jason P. Dworkin, Alan W. Schwartz, meteorite". Nature 389: 265–268. Pascale Ehrenfreund. (Available online 20 March doi:10.1038/38460 (http://dx.doi.org 2008). "Extraterrestrial nucleobases in the /10.1038%2F38460) . Murchison meteorite" 8. ^ Cooper, George; Kimmich, Novelle; Belisle, (http://astrobiology.gsfc.nasa.gov/analytical Warren; Sarinana, Josh; Brabham, Katrina; Garrel, /PDF/Martinsetal2008.pdf) (PDF). Earth and Laurence (December 20, 2001). "Carbonaceous Planetary Science Letters.

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http://astrobiology.gsfc.nasa.gov/analytical /PDF/Martinsetal2008.pdf. Retrieved 2008-10-07.

Rosenthal, Anne M. (2003-02-12). "Murchison's Amino Acids: Tainted Evidence?" (http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=375) . Astrobiology Magazine. http://www.astrobio.net/news/modules.php?op=modload&name=News& file=article&sid=375. Retrieved from "http://en.wikipedia.org/wiki/Murchison_meteorite" Categories: Chondrite meteorites | Origin of life | Astrobiology | Geology of Australia | 1969 in Australia | 1969 in science

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