Murchison meteorite

On 28 September 1969 at approximately 10:58 a.m. local time, near Murchison, Victoria, in Australia, a bright fireball was observed to separate into three fragments before disappearing, leaving a cloud of smoke. About 30 seconds later, a tremor was heard. Many fragments were found scattered over an area larger than {{convert|13|km2}}, with individual mass up to {{convert|7|kg}}; one, weighing {{convert|680|g|lb|1}}, broke through a roof and fell in hay. The total collected mass of the meteorite exceeds {{convert|100|kg|-1}}.Pepper, F. [https://www.abc.net.au/news/science/2019-10-02/murchison-meteorite-50th-anniversary-1969-science-geology/11528644 When a space visitor came to country Victoria] {{Webarchive|url=https://web.archive.org/web/20191001225750/https://www.abc.net.au/news/science/2019-10-02/murchison-meteorite-50th-anniversary-1969-science-geology/11528644 |date=1 October 2019 }} ABC News, 2 October 2019. Retrieved 2 October 2019.

The meteorite belongs to the CM group of carbonaceous chondrites. Like most CM chondrites, Murchison is petrologic type 2, which means that it experienced extensive alteration by water-rich fluids on its parent body{{cite journal |last1=Airieau |first1=S. A. |last2=Farquhar |first2=J. |last3=Thiemens |first3=M. H. |last4=Leshin |first4=L. A. |last5=Bao |first5=H. |last6=Young |first6=E. |doi=10.1016/j.gca.2005.01.029 |title=Planetesimal sulfate and aqueous alteration in CM and CI carbonaceous chondrites |journal=Geochimica et Cosmochimica Acta |volume=69 |issue=16 |pages=4167–4172 |date=2005 |bibcode=2005GeCoA..69.4167A |citeseerx=10.1.1.424.6561 }}

before falling to Earth. CM chondrites, together with the CI group, are rich in carbon and are among the most chemically primitive meteorites.{{cite web |url=http://www.psrd.hawaii.edu/PSRDglossary.html |title=Planetary Science Research Discoveries: Glossary |access-date=24 January 2012 |archive-url=https://web.archive.org/web/20120124211721/http://www.psrd.hawaii.edu/PSRDglossary.html |archive-date=24 January 2012 |url-status=live }} Like other CM chondrites, Murchison contains abundant calcium-aluminium-rich inclusions. More than 15 amino acids, some of the basic components of life, have been identified during multiple studies of this meteorite.{{cite journal |title=Nonprotein Amino Acids from Spark Discharges and Their Comparison with the Murchison Meteorite Amino Acids |last1=Wolman |first1=Yecheskel |last2=Haverland |first2=William J. |last3=Miller |first3=Stanley L. |journal=Proceedings of the National Academy of Sciences|volume=69 |issue=4 |pages=809–811 |date=April 1972 |pmc=426569 |pmid=16591973 |doi=10.1073/pnas.69.4.809|bibcode = 1972PNAS...69..809W |doi-access=free }}

In January 2020, astronomers reported that silicon carbide grains from the Murchison meteorite had been determined to be presolar material. The oldest of these grains was found to be 3 ± 2 billion years older than the 4.54 billion years age of the Earth and Solar System, making it the oldest material found on Earth to date.{{cite news |last=Weisberger |first=Mindy |title=7 Billion-Year-Old Stardust Is Oldest Material Found on Earth - Some of these ancient grains are billions of years older than our sun. |url=https://www.livescience.com/oldest-material-on-earth.html |date=13 January 2020 |work=Live Science |access-date=13 January 2020 |archive-url=https://web.archive.org/web/20200114030808/https://www.livescience.com/oldest-material-on-earth.html |archive-date=14 January 2020 |url-status=live }}

File:Murchison-meteorite-ANL.jpg

Murchison contains common amino acids such as glycine, alanine, and glutamic acid as well as unusual ones such as isovaline and pseudoleucine.{{cite journal |title=Evidence for extraterrestrial amino-acids and hydrocarbons in the Murchison meteorite |last1=Keith Kvenvolden |display-authors=etal |journal=Nature |volume=228 |issue=5275 |pages=923–926 |date=1970 |url=http://chemport.cas.org/cgi-bin/sdcgi?APP=ftslink&action=reflink&origin=npg&version=1.0&coi=1:CAS:528:DyaE3MXisVCnsg%3D%3D&pissn=0028-0836&pyear=1983&md5=cb8b015f54156458fa2be8cdca44789f |doi=10.1038/228923a0 |pmid=5482102 |bibcode=1970Natur.228..923K |s2cid=4147981 |url-access=subscription }} A complex mixture of alkanes was isolated as well, similar to that found in the Miller–Urey experiment. Serine and threonine, usually considered to be earthly contaminants, were conspicuously absent in the samples. A specific family of amino acids called diamino acids was identified in the Murchison meteorite as well.{{cite journal |title=Identification of diamino acids in the Murchison meteorite |last1=Meierhenrich |first1=Uwe J. |journal=PNAS |volume=101 |pages=9182–9186 |date=2004 |doi=10.1073/pnas.0403043101 |pmid=15194825 |issue=25 |pmc=438950 |bibcode=2004PNAS..101.9182M |last2=Muñoz Caro |first2=Guillermo M. |last3=Bredehöft |first3=Jan Hendrik |last4=Jessberger |first4=Elmar K. |last5=Thiemann |first5=Wolfram H.-P. |doi-access=free }}

The initial report in 1970 stated that the amino acids were racemic and therefore formed in an abiotic manner, because amino acids of terrestrial proteins are all of the L-configuration of chirality. Later, in 1982, it was reported that the amino acid alanine had an excess of the L-configuration,{{cite journal |title=Distribution and enantiomeric composition of amino acids in the Murchison meteorite |last1=Engel |first1=Michael H. |last2=Nagy |first2=Bartholomew |journal=Nature |volume=296 |pages=837–840 |date=29 April 1982 |doi=10.1038/296837a0 |issue=5860 |bibcode=1982Natur.296..837E |s2cid=4341990 }} but this is a protein amino acid which led several scientists to suspect terrestrial contamination according to the argument that it would be "unusual for an abiotic stereoselective decomposition or synthesis of amino acids to occur with protein amino acids but not with non-protein amino acids".{{cite journal |title=On the reported optical activity of amino acids in the Murchison meteorite |last1=Bada |first1=Jeffrey L. |last2=Cronin |first2=John R. |last3=Ho |first3=Ming-Shan |last4=Kvenvolden |first4=Keith A. |last5=Lawless |first5=James G. |last6=Miller |first6=Stanley L. |last7=Oro |first7=J. |last8=Steinberg |first8=Spencer |journal=Nature |volume=301 |pages=494–496 |date=10 February 1983 |doi=10.1038/301494a0 |issue=5900 |bibcode=1983Natur.301..494B |s2cid=4338550 }} But in 1997, L-excesses were also reported for several non-protein amino acids,{{cite journal |last1=Cronin |first1=John R. |last2=Pizzarello |first2=S. |title=Enantiomeric excesses in meteoritic amino acids |journal=Science |date=1997 |volume=275 |pages=951–955 |doi=10.1126/science.275.5302.951 |pmid=9020072 |issue=5302|bibcode = 1997Sci...275..951C |s2cid=10979716 }} suggesting an extraterrestrial source for molecular asymmetry in the Solar System. Some amino acids were found to be racemic (equal quantities of right-handed and left-handed). Around the same time, an enrichment in the isotope ¹⁵N was reported,{{cite journal |title=Isotopic evidence for extraterrestrial non-racemic amino acids in the Murchison meteorite |last1=Engel |first1=Michael H. |last2=Macko |first2=S. A. |journal=Nature |volume=389 |pages=265–268 |date=1 September 1997 |doi=10.1038/38460 |pmid=9305838 |issue=6648 |bibcode=1997Natur.389..265E |s2cid=4411982 }} however this result and the non-racemicity of alanine (but not of the others) were explained as possibly due to analysis error.{{cite journal |last1=Pizzarello |first1=Sandra |last2=Cronin |first2=J. R. |title=Alanine enantiomers in the Murchison meteorite |journal=Nature |date=1998 |volume=394 |page=236 |doi=10.1038/28306 |pmid=9685155 |issue=6690|bibcode = 1998Natur.394..236P |s2cid=4424928 |doi-access=free }}

By 2001, the list of organic materials identified in the meteorite was extended to polyols.{{cite journal |title=Carbonaceous meteorites as a source of sugar-related organic compounds for the early Earth |last1=Cooper |first1=George |last2=Kimmich |first2=Novelle |last3=Belisle |first3=Warren |last4=Sarinana |first4=Josh |last5=Brabham |first5=Katrina |last6=Garrel |first6=Laurence |journal=Nature |volume=414 |pages=879–883 |date=20 December 2001 |doi=10.1038/414879a |pmid=11780054 |issue=6866 |bibcode=2001Natur.414..879C |s2cid=199294 |url=https://zenodo.org/record/1233202 |access-date=2 July 2019 |archive-url=https://web.archive.org/web/20200116010831/https://zenodo.org/record/1233202 |archive-date=16 January 2020 |url-status=live |doi-access=free }}

The meteorite contained a mixture of left-handed and right-handed amino acids; most amino acids used by living organisms are left-handed in chirality, and most sugars used are right-handed. A team of chemists in Sweden demonstrated in 2005 that this homochirality could have been triggered or catalyzed by the action of a left-handed amino acid such as proline.{{cite journal |title=Plausible origins of homochirality in the amino acid catalyzed neogenesis of carbohydrates |last1=Córdova |first1=Armando |last2=Engqvist |first2=Magnus |last3=Ibrahem |first3=Ismail |last4=Casas |first4=Jesús |last5=Sundén |first5=Henrik |journal=Chemical Communications |pages=2047–2049 |date=2005 |doi=10.1039/b500589b |pmid=15834501 |issue=15 }}

Several lines of evidence indicate that the interior portions of well-preserved fragments from Murchison are pristine. A 2010 study using high resolution analytical tools including spectroscopy, identified 14,000 molecular compounds, including 70 amino acids, in a sample of the meteorite.{{cite news |first=Doreen |last=Walton |title=Space rock contains organic molecular feast |date=15 February 2010 |url=http://news.bbc.co.uk/2/hi/science/nature/8516319.stm |work=BBC News |access-date=15 February 2010 |archive-url=https://web.archive.org/web/20100216052616/http://news.bbc.co.uk/2/hi/science/nature/8516319.stm |archive-date=16 February 2010 |url-status=live }}{{cite journal |title=High molecular diversity of extraterrestrial organic matter in Murchison meteorite revealed 40 years after its fall |journal=PNAS |volume=107 |pages=2763–2768 |date=16 February 2010 |first1=Philippe |last1=Schmitt-Kopplin |first2=Zelimir |last2=Gabelica |first3=Régis D. |last3=Gougeon |first4=Agnes |last4=Fekete |first5=Basem |last5=Kanawati |first6=Mourad |last6=Harir |first7=Istvan |last7=Gebefuegi |first8=Gerhard |last8=Eckel |first9=Norbert |last9=Hertkorn |url=http://www.pnas.org/content/early/2010/02/12/0912157107.full.pdf+html |format=PDF |doi=10.1073/pnas.0912157107 |pmid=20160129 |issue=7 |pmc=2840304 |bibcode=2010PNAS..107.2763S |access-date=16 February 2010 |archive-url=https://web.archive.org/web/20121202013703/http://www.pnas.org/content/early/2010/02/12/0912157107.full.pdf+html |archive-date=2 December 2012 |url-status=live |doi-access=free }} The limited scope of the analysis by mass spectrometry provides for a potential 50,000 or more unique molecular compositions, with the team estimating the possibility of millions of distinct organic compounds in the meteorite.{{cite magazine |first=John |last=Matson |title=Meteorite That Fell in 1969 Still Revealing Secrets of the Early Solar System |date=15 February 2010 |magazine=Scientific American |url=http://www.scientificamerican.com/article.cfm?id=murchison-meteorite |access-date=15 February 2010 |archive-url=https://web.archive.org/web/20110319025453/http://www.scientificamerican.com/article.cfm?id=murchison-meteorite |archive-date=19 March 2011 |url-status=live }}

In November 2019, along with the Northwest Africa 801 meteorite it was the first to provide evidence of pentoses (including ribose) in space, using Gas chromatography–mass spectrometry. All the straight-chain five-carbon aldoses were found but tetroses, sugar alcohols, sugar acids, and deoxyribose were not detected.{{Cite web|url=https://www.newsweek.com/sugar-detected-inside-meteorites-first-time-ever-1472986|title=Sugar has been detected inside meteorites for the first time ever|last=McCall|first=Rosie|date=2019-11-20|website=Newsweek|language=en|archive-url=|archive-date=|access-date=2019-11-26}}{{cite web |last1=Steigerwald |first1=William |title=First Detection of Sugars in Meteorites Gives Clues to Origin of Life |url=https://www.nasa.gov/news-release/first-detection-of-sugars-in-meteorites-gives-clues-to-origin-of-life/ |publisher=NASA |access-date=6 March 2025}}{{cite journal |last1=Furukawa |first1=Yoshihiro |last2=Chikaraishi |first2=Yoshito |last3=Ohkouchi |first3=Naohiko |last4=Ogawa |first4=Nanako O. |last5=Glavin |first5=Daniel P. |last6=Dworkin |first6=Jason P. |last7=Abe |first7=Chiaki |last8=Nakamura |first8=Tomoki |title=Extraterrestrial ribose and other sugars in primitive meteorites |journal=PNAS |date=2019 |volume=116 |issue=49 |pages=24440-24445 |doi=10.1073/pnas.1907169116 |url=https://www.pnas.org/doi/pdf/10.1073/pnas.1907169116 |access-date=5 March 2025|pmc=6900709 }}

In 2020, NASA announced that hexamethylenetetramine had been found in the Murchison, Murray and Tagish Lake meteorites.{{cite web |last1=Steigerwald |first1=William |title=Key Building Block for Organic Molecules Discovered in Meteorites |url=https://www.nasa.gov/solar-system/key-building-block-for-organic-molecules-discovered-in-meteorites/ |website=NASA |access-date=31 March 2025}}{{cite journal |last1=Oba |first1=Yasuhiro |last2=Takano |first2=Yoshinori |last3=Naraoka |first3=Hiroshi |last4=Furukawa |first4=Yoshihiro |last5=Glavin |first5=Daniel P. |last6=Dworkin |first6=Jason P. |last7=Tachibana |first7=Shogo |title=Extraterrestrial hexamethylenetetramine in meteorites—a precursor of prebiotic chemistry in the inner solar system |journal=Nature Communications |date=2020 |volume=11 |page=6243 |doi=10.1038/s41467-020-20038-x |url=https://www.nature.com/articles/s41467-020-20038-x |access-date=3 April 2025|pmc=7721876 }}

{{Further|Nucleobase}}

Measured purine and pyrimidine compounds were found in the Murchison meteorite. Carbon isotope ratios for uracil and xanthine of δ¹³C = +44.5‰ and +37.7‰, respectively, indicate a non-terrestrial origin for these compounds. This specimen demonstrates that many organic compounds could have been delivered by early Solar System bodies and may have played a key role in life's origin.{{cite journal |title=Extraterrestrial nucleobases in the Murchison meteorite |journal=Earth and Planetary Science Letters |date=20 March 2008 |first1=Zita |last1=Martins |author-link1=Zita Martins |first2=Oliver |last2=Botta |first3=Marilyn L. |last3=Fogel |author-link3=Marilyn Fogel |first4=Mark A. |last4=Sephton |first5=Daniel P. |last5=Glavin |first6=Jonathan S. |last6=Watson |first7=Jason P. |last7=Dworkin |first8=Alan W. |last8=Schwartz |first9=Pascale |last9=Ehrenfreund|author-link9=Pascale Ehrenfreund |volume=270 |issue=1–2 |pages=130–136 |url=http://astrobiology.gsfc.nasa.gov/analytical/PDF/Martinsetal2008.pdf |access-date=7 October 2008 |doi=10.1016/j.epsl.2008.03.026 |bibcode=2008E&PSL.270..130M |arxiv=0806.2286 |s2cid=14309508 |archive-url=https://web.archive.org/web/20110810095031/http://astrobiology.gsfc.nasa.gov/analytical/PDF/Martinsetal2008.pdf |archive-date=10 August 2011 |url-status=dead}}{{Cite news |date=2022-04-27 |title=Australian meteorite one of three with key building blocks for life's 'prebiotic soup' |language=en-AU |work=ABC News |url=https://www.abc.net.au/news/2022-04-27/australian-meteorite-one-of-three-with-key-dna-building-blocks/101018500 |access-date=2022-04-27}}{{cite journal |last1=Oba |first1=Yasuhiro |last2=Takano |first2=Yoshinori |last3=Furukawa |first3=Yoshihiro |last4=Koga |first4=Toshiki |last5=Glavin |first5=Daniel P. |last6=Dworkin |first6=Jason P. |last7=Naraoka |first7=Hiroshi |title=Identifying the wide diversity of extraterrestrial purine and pyrimidine nucleobases in carbonaceous meteorites |journal=Nature Communications |date=2022 |volume=13 |pages=2008 |doi=10.1038/s41467-022-29612-x |url=https://www.nature.com/articles/s41467-022-29612-x |access-date=4 April 2025|pmc=9042847 }}

• Cosmochemistry
• Glossary of meteoritics
• Panspermia

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{{Reflist|30em}}

{{Commons category|Murchison meteorite}}

• {{cite web |url=http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=375 |title=Murchison's Amino Acids: Tainted Evidence? |first=Anne M. |last=Rosenthal |date=12 February 2003 |work=Astrobiology Magazine |archive-url=https://web.archive.org/web/20040830180317/http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=375 |archive-date=2004-08-30 |url-status=usurped}}
• {{cite web |url=http://www.scientificamerican.com/article.cfm?id=murchison-meteorite |title=Meteorite That Fell in 1969 Still Revealing Secrets of the Early Solar System |first=John |last=Matson |date=15 February 2010 |publisher=Scientific American}}

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