Editing Miller–Urey experiment (section)

== Extraterrestrial sources of amino acids ==
[[File:Murchison crop.jpg|thumb|A sample of the Murchison meteorite on display at the [[National Museum of Natural History]], Washington, D.C.]]
Conditions similar to those of the Miller–Urey experiments are present in other regions of the [[Solar System]], often substituting [[ultraviolet]] light for lightning as the energy source for chemical reactions.<ref>{{cite journal |last1=Nunn |first1=JF |year=1998 |title=Evolution of the atmosphere |journal=Proceedings of the Geologists' Association. Geologists' Association |volume=109 |issue=1 |pages=1–13 |doi=10.1016/s0016-7878(98)80001-1 |pmid=11543127|bibcode=1998PrGA..109....1N }}</ref><ref>{{cite journal |last1=Raulin |first1=F |last2=Bossard |first2=A |year=1984 |title=Organic syntheses in gas phase and chemical evolution in planetary atmospheres. |journal=Advances in Space Research |volume=4 |issue=12 |pages=75–82 |bibcode=1984AdSpR...4l..75R |doi=10.1016/0273-1177(84)90547-7 |pmid=11537798}}</ref><ref>{{cite journal |last1=Raulin |first1=François |last2=Brassé |first2=Coralie |last3=Poch |first3=Olivier |last4=Coll |first4=Patrice |year=2012 |title=Prebiotic-like chemistry on Titan |journal=Chemical Society Reviews |volume=41 |issue=16 |pages=5380–93 |doi=10.1039/c2cs35014a |pmid=22481630}}</ref> The [[Murchison meteorite]] that fell near [[Murchison, Victoria]], Australia in 1969 was found to contain an amino acid distribution remarkably similar to Miller-Urey discharge products.<ref name="Dreifus-2010" /> Analysis of the organic fraction of the Murchison meteorite with [[Fourier-transform ion cyclotron resonance]] mass spectrometry detected over 10,000 unique compounds,<ref>{{Cite journal |last1=Schmitt-Kopplin |first1=Philippe |last2=Gabelica |first2=Zelimir |last3=Gougeon |first3=Régis D. |last4=Fekete |first4=Agnes |last5=Kanawati |first5=Basem |last6=Harir |first6=Mourad |last7=Gebefuegi |first7=Istvan |last8=Eckel |first8=Gerhard |last9=Hertkorn |first9=Norbert |date=2010-02-16 |title=High molecular diversity of extraterrestrial organic matter in Murchison meteorite revealed 40 years after its fall |journal=Proceedings of the National Academy of Sciences |language=en |volume=107 |issue=7 |pages=2763–2768 |doi=10.1073/pnas.0912157107 |issn=0027-8424 |pmc=2840304 |pmid=20160129 |bibcode=2010PNAS..107.2763S |doi-access=free }}</ref> albeit at very low ([[Parts per billion|ppb]]–[[Parts per million|ppm]]) concentrations.<ref>{{Cite journal |last1=Shock |first1=Everett L. |last2=Schulte |first2=Mitchell D. |date=1990-11-01 |title=Summary and implications of reported amino acid concentrations in the Murchison meteorite |url=https://dx.doi.org/10.1016/0016-7037%2890%2990131-4 |journal=Geochimica et Cosmochimica Acta |volume=54 |issue=11 |pages=3159–3173 |doi=10.1016/0016-7037(90)90131-4 |pmid=11541223 |bibcode=1990GeCoA..54.3159S |issn=0016-7037}}</ref><ref>{{Cite journal |last1=Koga |first1=Toshiki |last2=Naraoka |first2=Hiroshi |date=2017-04-04 |title=A new family of extraterrestrial amino acids in the Murchison meteorite |journal=Scientific Reports |language=en |volume=7 |issue=1 |pages=636 |doi=10.1038/s41598-017-00693-9 |bibcode=2017NatSR...7..636K |issn=2045-2322|doi-access=free |pmid=28377577 |pmc=5428853 }}</ref> In this way, the organic composition of the Murchison meteorite is seen as evidence of Miller-Urey synthesis outside Earth.

[[Comet]]s and other [[Trans-Neptunian object|icy outer-solar-system bodies]] are thought to contain large amounts of complex carbon compounds (such as tholins) formed by processes akin to Miller-Urey setups, darkening surfaces of these bodies.<ref name="Sagan-1979" /><ref>{{cite journal |vauthors=Thompson WR, Murray BG, Khare BN, Sagan C |date=December 1987 |title=Coloration and darkening of methane clathrate and other ices by charged particle irradiation: applications to the outer solar system |journal=Journal of Geophysical Research |volume=92 |issue=A13 |pages=14933–47 |bibcode=1987JGR....9214933T |doi=10.1029/JA092iA13p14933 |pmid=11542127 |title-link=methane clathrate}}</ref> Some argue that comets bombarding the early Earth could have provided a large supply of complex organic molecules along with the water and other volatiles,<ref>{{cite journal |last=PIERAZZO |first=E. |author2=CHYBA C.F. |year=2010 |title=Amino acid survival in large cometary impacts |journal=Meteoritics & Planetary Science |volume=34 |issue=6 |pages=909–918 |bibcode=1999M&PS...34..909P |doi=10.1111/j.1945-5100.1999.tb01409.x |s2cid=97334519|doi-access=free }}</ref><ref>{{Cite journal |last1=Chyba |first1=Christopher |last2=Sagan |first2=Carl |date=1992 |title=Endogenous production, exogenous delivery and impact-shock synthesis of organic molecules: an inventory for the origins of life |url=https://www.nature.com/articles/355125a0 |journal=Nature |language=en |volume=355 |issue=6356 |pages=125–132 |doi=10.1038/355125a0 |pmid=11538392 |bibcode=1992Natur.355..125C |s2cid=4346044 |issn=1476-4687}}</ref> however very low concentrations of biologically-relevant material combined with uncertainty surrounding the survival of organic matter upon impact make this difficult to determine.<ref name="Miller" />