Editing Miller–Urey experiment (section)

{{Short description|Experiment testing the origin of life}}
{{Use mdy dates|date=October 2024}}
[[File:Miller-Urey_experiment-en.svg|thumb|upright=1.6|The Miller–Urey experiment was a synthesis of small organic molecules in a mixture of simple gases in a thermal gradient created by heating (right) and cooling (left) the mixture at the same time, with electrical discharges.]]

The '''Miller–Urey experiment''',<ref>{{cite journal |vauthors=Hill HG, Nuth JA |year=2003 |title=The catalytic potential of cosmic dust: implications for prebiotic chemistry in the solar nebula and other protoplanetary systems |url=https://www.liebertpub.com/doi/10.1089/153110703769016389 |journal=[[Astrobiology (journal)|Astrobiology]] |volume=3 |issue=2 |pages=291–304 |bibcode=2003AsBio...3..291H |doi=10.1089/153110703769016389 |pmid=14577878|url-access=subscription }}</ref> or '''Miller experiment''',<ref>{{cite journal |author1=Balm SP |author2=Hare J.P. |author3=Kroto HW |year=1991 |title=The analysis of comet mass spectrometric data |journal=[[Space Science Reviews]] |volume=56 |issue=1–2 |pages=185–9 |bibcode=1991SSRv...56..185B |doi=10.1007/BF00178408 |s2cid=123124418}}</ref> was an experiment in [[chemical synthesis]] carried out in 1952 that simulated the conditions thought at the time to be present in the [[Prebiotic atmosphere|atmosphere of the early, prebiotic Earth]]. It is seen as one of the first successful experiments demonstrating the synthesis of [[organic compound]]s from [[inorganic compound|inorganic constituents]] in an [[Abiogenesis|origin of life]] scenario. The experiment used [[methane]] (CH<sub>4</sub>), [[ammonia]] (NH<sub>3</sub>), [[hydrogen]] (H<sub>2</sub>), in ratio 2:1:2, and water (H<sub>2</sub>O). Applying an electric arc (simulating lightning) resulted in the production of [[amino acid]]s.

It is regarded as a groundbreaking experiment, and the classic experiment investigating the origin of life ([[abiogenesis]]). It was performed in 1952 by [[Stanley Miller]], supervised by Nobel laureate [[Harold Urey]] at the [[University of Chicago]], and published the following year. At the time, it supported [[Alexander Oparin]]'s and [[J. B. S. Haldane]]'s hypothesis that the conditions on the primitive Earth favored chemical reactions that synthesized complex organic compounds from simpler inorganic precursors.<ref name="miller19532">{{cite journal |last=Miller |first=Stanley L. |year=1953 |title=Production of Amino Acids Under Possible Primitive Earth Conditions |url=http://www.abenteuer-universum.de/pdf/miller_1953.pdf |url-status=dead |journal=[[Science (journal)|Science]] |volume=117 |issue=3046 |pages=528–9 |bibcode=1953Sci...117..528M |doi=10.1126/science.117.3046.528 |pmid=13056598 |archive-url=https://web.archive.org/web/20120317062622/http://www.abenteuer-universum.de/pdf/miller_1953.pdf |archive-date=2012-03-17 |access-date=2011-01-17}}</ref><ref>{{cite journal |last=Miller |first=Stanley L. |author2=Harold C. Urey |year=1959 |title=Organic Compound Synthesis on the Primitive Earth |journal=[[Science (journal)|Science]] |volume=130 |issue=3370 |pages=245–51 |bibcode=1959Sci...130..245M |doi=10.1126/science.130.3370.245 |pmid=13668555}} Miller states that he made "A more complete analysis of the products" in the 1953 experiment, listing additional results.</ref><ref>{{cite journal |author1=A. Lazcano |author2=J. L. Bada |year=2004 |title=The 1953 Stanley L. Miller Experiment: Fifty Years of Prebiotic Organic Chemistry |journal=Origins of Life and Evolution of Biospheres |volume=33 |issue=3 |pages=235–242 |bibcode=2003OLEB...33..235L |doi=10.1023/A:1024807125069 |pmid=14515862 |s2cid=19515024}}</ref>

After Miller's death in 2007, scientists examining sealed vials preserved from the original experiments were able to show that more amino acids were produced in the original experiment than Miller was able to report with [[paper chromatography]].<ref name="BBC2">{{cite web |date=26 August 2009 |title=The Spark of Life |url=http://www.bbc.co.uk/programmes/b00mbvfh |url-status=live |archive-url=https://web.archive.org/web/20101113011054/http://www.bbc.co.uk/programmes/b00mbvfh |archive-date=2010-11-13 |website=BBC Four |postscript=. TV Documentary.}}</ref> While evidence suggests that Earth's [[prebiotic atmosphere]] might have typically had a composition different from the gas used in the Miller experiment, prebiotic experiments continue to produce [[racemic mixture]]s of simple-to-complex organic compounds, including amino acids, under varying conditions.<ref name="bada20132">{{cite journal<!-- Citation bot bypass--> |last1=Bada |first1=Jeffrey L. |year=2013 |title=New insights into prebiotic chemistry from Stanley Miller's spark discharge experiments |url=https://semanticscholar.org/paper/6f463e8a3611fa7f25c143991dfddac49c396b73 |journal=Chemical Society Reviews |volume=42 |issue=5 |pages=2186–96 |doi=10.1039/c3cs35433d |pmid=23340907 |s2cid=12230177}}</ref> Moreover, researchers have shown that transient, hydrogen-rich atmospheres – conducive to Miller-Urey synthesis – would have occurred after large [[asteroid]] [[impact event|impacts]] on early Earth.<ref name="Zahnle-2020">{{Cite journal |last1=Zahnle |first1=Kevin J. |last2=Lupu |first2=Roxana |last3=Catling |first3=David C. |last4=Wogan |first4=Nick |date=2020-05-01 |title=Creation and Evolution of Impact-generated Reduced Atmospheres of Early Earth |journal=The Planetary Science Journal |language=en |volume=1 |issue=1 |pages=11 |doi=10.3847/PSJ/ab7e2c |arxiv=2001.00095 |bibcode=2020PSJ.....1...11Z |issn=2632-3338 |doi-access=free }}</ref><ref name="Wogan-2023">{{Cite journal |last1=Wogan |first1=Nicholas F. |last2=Catling |first2=David C. |last3=Zahnle |first3=Kevin J. |last4=Lupu |first4=Roxana |date=2023-09-01 |title=Origin-of-life Molecules in the Atmosphere after Big Impacts on the Early Earth |journal=The Planetary Science Journal |volume=4 |issue=9 |pages=169 |doi=10.3847/psj/aced83 |arxiv=2307.09761 |bibcode=2023PSJ.....4..169W |issn=2632-3338 |doi-access=free }}</ref>