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{{short description|Chemical experiment that simulated conditions on the early Earth and tested the origin of life}}

{{short description|Chemical experiment that simulated conditions on the early Earth and tested the origin of life}}

The Miller–Urey experiment (or Miller experiment) was a chemical experiment that simulated the conditions thought at the time (1952) to be present on the early Earth and tested the chemical origin of life under those conditions. The experiment at the time supported Alexander Oparin's and J. B. S. Haldane's hypothesis that putative conditions on the primitive Earth favoured chemical reactions that synthesized more complex organic compounds from simpler inorganic precursors. Considered to be the classic experiment investigating abiogenesis, it was performed in 1952 by Stanley Miller, supervised by Harold Urey at the University of Chicago, and published the following year.

The Miller–Urey experiment (or Miller experiment) was a chemical experiment that simulated the conditions thought at the time (1952) to be present on the early Earth and tested the chemical origin of life under those conditions. The experiment at the time supported Alexander Oparin's and J. B. S. Haldane's hypothesis that putative conditions on the primitive Earth favoured chemical reactions that synthesized more complex organic compounds from simpler inorganic precursors. Considered to be the classic experiment investigating abiogenesis, it was performed in 1952 by Stanley Miller, supervised by Harold Urey at the University of Chicago, and published the following year.

Miller-Urey 实验(或称 Miller 实验)是一个化学实验，模拟当时(1952年)认为存在于早期地球上的条件，并在这些条件下测试生命的化学起源。当时的实验支持亚历山大·伊万诺维奇·奥巴林和 j。霍尔丹的假说认为，原始地球上的假定条件有利于从简单的无机前体合成更复杂的有机化合物的化学反应。1952年，斯坦利 · 米勒在芝加哥大学哈罗德 · 尤里的指导下完成了这项研究，并于次年发表。

<font color="#ff8000"> 米勒尤里实验 Miller–Urey experiment</font>(或称 Miller 实验)是一个化学实验，模拟了当时（1952年）认为存在于早期地球上的条件，并在这些条件下测试了生命的化学起源。当时的实验支持了亚历山大·奥帕林和J·B·s·霍尔丹的假设，即原始地球上假定的条件有利于化学反应，即从简单的无机前体合成更复杂的有机化合物。它被认为是研究自然发生的经典实验，1952年由斯坦利·米勒完成，由芝加哥大学的哈罗德·尤里监督，并于次年出版。

== Experiment ==

== Experiment实验 ==

[[File:Miller-Urey experiment - Work by the C3BC consortium, licensed under CC-BY-3.0.webm|thumb|Descriptive video of the experiment]]

[[File:Miller-Urey experiment - Work by the C3BC consortium, licensed under CC-BY-3.0.webm|thumb|Descriptive video of the experiment]]

The experiment used water (H₂O), methane (CH₄), ammonia (NH₃), and hydrogen (H₂). The chemicals were all sealed inside a sterile 5-liter glass flask connected to a 500 ml flask half-full of  water. The  water in the smaller flask was heated to induce evaporation, and the water vapour was allowed to enter the larger flask. Continuous electrical sparks were fired between the electrodes to simulate lightning in the water vapour and gaseous mixture, and then the simulated atmosphere was cooled again so that the water condensed and trickled into a U-shaped trap at the bottom of the apparatus.

The experiment used water (H₂O), methane (CH₄), ammonia (NH₃), and hydrogen (H₂). The chemicals were all sealed inside a sterile 5-liter glass flask connected to a 500 ml flask half-full of  water. The  water in the smaller flask was heated to induce evaporation, and the water vapour was allowed to enter the larger flask. Continuous electrical sparks were fired between the electrodes to simulate lightning in the water vapour and gaseous mixture, and then the simulated atmosphere was cooled again so that the water condensed and trickled into a U-shaped trap at the bottom of the apparatus.

实验用水(h < sub > 2 </sub > o)、甲烷(CH < sub > 4 </sub >)、氨(NH < sub > 3 </sub >)和氢(h < sub > 2 </sub >)。这些化学物质全部密封在一个5升的无菌玻璃瓶里，瓶子连接着一个500毫升的半满水的瓶子。将小瓶中的水加热以使其蒸发，然后允许水蒸气进入大瓶。电极之间连续发射电火花来模拟水蒸气和气体混合物中的闪电，然后再次冷却模拟大气，使水冷凝并在仪器底部滴入 u 形陷阱。

实验用水(H2O)、甲烷(CH4)、氨(NH3)和氢(H 2)。所有的化学物质都被密封在一个5升的无菌玻璃瓶里，这个玻璃瓶连接着一个500毫升的半满水的烧瓶。将小烧瓶中的水加热以诱导蒸发，使水蒸气进入大烧瓶。在电极之间连续地点燃电火花，以模拟水蒸气和气体混合物中的闪电，然后再次冷却模拟的大气，使水凝结并滴入装置底部的U形阱中。

After a day, the solution collected at the trap had turned pink in colour, and after a week of continuous operation the solution was deep red and turbid.

After a day, the solution collected at the trap had turned pink in colour, and after a week of continuous operation the solution was deep red and turbid.

The original experiment remained in 2017 under the care of Miller and Urey's former student Jeffrey Bada, a professor at the UCSD, Scripps Institution of Oceanography.  , the apparatus used to conduct the experiment was on display at the Denver Museum of Nature and Science.

The original experiment remained in 2017 under the care of Miller and Urey's former student Jeffrey Bada, a professor at the UCSD, Scripps Institution of Oceanography.  , the apparatus used to conduct the experiment was on display at the Denver Museum of Nature and Science.

最初的实验在2017年由 Miller 和 Urey 以前的学生 Jeffrey Bada 负责，他是加州大学圣地亚哥分校斯克里普斯海洋研究所的教授。实验仪器在丹佛自然科学博物馆展出。

最初的实验在2017年由 Miller 和 Urey以前的学生 Jeffrey Bada 负责，他是加州大学圣地亚哥分校斯克里普斯海洋研究所的教授。实验仪器在丹佛自然科学博物馆展出。

One-step reactions among the mixture components can produce hydrogen cyanide (HCN), formaldehyde (CH₂O), and other active intermediate compounds (acetylene, cyanoacetylene, etc.):

One-step reactions among the mixture components can produce hydrogen cyanide (HCN), formaldehyde (CH₂O), and other active intermediate compounds (acetylene, cyanoacetylene, etc.):

混合组分之间的一步反应可以生成氰化氢、甲醛和其他活性中间体化合物(乙炔、氰乙炔等)。):

混合组分之间的一步反应可以生成氰化氢、甲醛和其他活性中间体化合物(乙炔、氰乙炔等):

==Chemistry of experiment==

==Chemistry of experiment实验化学==

One-step reactions among the mixture components can produce [[hydrogen cyanide]] (HCN), [[formaldehyde]] (CH₂O),<ref>https://www.webcitation.org/query?url=http://www.geocities.com/capecanaveral/lab/2948/orgel.html&date=2009-10-25+16:53:26 Origin of Life on Earth by Leslie E. Orgel</ref><ref>{{Cite book |url=http://books.nap.edu/openbook.php?record_id=11860&page=85 |title=Read "Exploring Organic Environments in the Solar System" at NAP.edu |accessdate=2008-10-25 |url-status=live |archiveurl=https://web.archive.org/web/20090621053626/http://books.nap.edu/openbook.php?record_id=11860&page=85 |archivedate=2009-06-21 |doi=10.17226/11860 |year=2007 |isbn=978-0-309-10235-3 |last1=Council |first1=National Research |last2=Studies |first2=Division on Earth Life |last3=Technology |first3=Board on Chemical Sciences and |last4=Sciences |first4=Division on Engineering Physical |last5=Board |first5=Space Studies |last6=System |first6=Task Group on Organic Environments in the Solar }} Exploring Organic Environments in the Solar System (2007)</ref> and other active intermediate compounds ([[acetylene]], [[cyanoacetylene]], etc.):{{Citation needed|date=June 2016}}

One-step reactions among the mixture components can produce [[hydrogen cyanide]] (HCN), [[formaldehyde]] (CH₂O),<ref>https://www.webcitation.org/query?url=http://www.geocities.com/capecanaveral/lab/2948/orgel.html&date=2009-10-25+16:53:26 Origin of Life on Earth by Leslie E. Orgel</ref><ref>{{Cite book |url=http://books.nap.edu/openbook.php?record_id=11860&page=85 |title=Read "Exploring Organic Environments in the Solar System" at NAP.edu |accessdate=2008-10-25 |url-status=live |archiveurl=https://web.archive.org/web/20090621053626/http://books.nap.edu/openbook.php?record_id=11860&page=85 |archivedate=2009-06-21 |doi=10.17226/11860 |year=2007 |isbn=978-0-309-10235-3 |last1=Council |first1=National Research |last2=Studies |first2=Division on Earth Life |last3=Technology |first3=Board on Chemical Sciences and |last4=Sciences |first4=Division on Engineering Physical |last5=Board |first5=Space Studies |last6=System |first6=Task Group on Organic Environments in the Solar }} Exploring Organic Environments in the Solar System (2007)</ref> and other active intermediate compounds ([[acetylene]], [[cyanoacetylene]], etc.):{{Citation needed|date=June 2016}}

The formaldehyde, ammonia, and HCN then react by Strecker synthesis to form amino acids and other biomolecules:

The formaldehyde, ammonia, and HCN then react by Strecker synthesis to form amino acids and other biomolecules:

然后，甲醛、氨和 HCN 通过 Strecker 合成反应生成氨基酸和其他生物分子:

然后，甲醛、氨和 HCN 通过 Strecker合成反应生成氨基酸和其他生物分子:

The experiments showed that simple organic compounds of building blocks of proteins and other macromolecules can be formed from gases with the addition of energy.

The experiments showed that simple organic compounds of building blocks of proteins and other macromolecules can be formed from gases with the addition of energy.

This experiment inspired many others. In 1961, Joan Oró found that the nucleotide base adenine could be made from hydrogen cyanide (HCN) and ammonia in a water solution. His experiment produced a large amount of adenine, the molecules of which were formed from 5 molecules of HCN.  

This experiment inspired many others. In 1961, Joan Oró found that the nucleotide base adenine could be made from hydrogen cyanide (HCN) and ammonia in a water solution. His experiment produced a large amount of adenine, the molecules of which were formed from 5 molecules of HCN.  

这个实验启发了许多其他人。1961年，Joan oró 发现，在水溶液中，由氰化氢和氨制成的核苷酸碱基腺嘌呤。他的实验产生了大量的腺嘌呤，其分子由5个 HCN 分子组成。

这个实验启发了许多其他人。1961年，Joan oró 发现，在水溶液中，由氰化氢和氨制成的核苷酸碱基腺嘌呤。他的实验产生了大量的腺嘌呤，其分子由5个HCN分子组成。

==Other experiments==

==Other experiments其他实验==

Also, many amino acids are formed from HCN and ammonia under these conditions.  

Also, many amino acids are formed from HCN and ammonia under these conditions.  

This experiment inspired many others. In 1961, [[Joan Oró]] found that the [[nucleotide]] base [[adenine]] could be made from [[hydrogen cyanide]] (HCN) and [[ammonia]] in a water solution. His experiment produced a large amount of adenine, the molecules of which were formed from 5 molecules of HCN.<ref>{{cite journal |vauthors=Oró J, Kimball AP |title=Synthesis of purines under possible primitive earth conditions. I. Adenine from hydrogen cyanide |journal=Archives of Biochemistry and Biophysics |volume=94|issue=2 |pages=217–27 |date=August 1961 |pmid=13731263 |doi=10.1016/0003-9861(61)90033-9}}</ref>  

This experiment inspired many others. In 1961, [[Joan Oró]] found that the [[nucleotide]] base [[adenine]] could be made from [[hydrogen cyanide]] (HCN) and [[ammonia]] in a water solution. His experiment produced a large amount of adenine, the molecules of which were formed from 5 molecules of HCN.<ref>{{cite journal |vauthors=Oró J, Kimball AP |title=Synthesis of purines under possible primitive earth conditions. I. Adenine from hydrogen cyanide |journal=Archives of Biochemistry and Biophysics |volume=94|issue=2 |pages=217–27 |date=August 1961 |pmid=13731263 |doi=10.1016/0003-9861(61)90033-9}}</ref>  

Experiments conducted later showed that the other RNA and DNA nucleobases could be obtained through simulated prebiotic chemistry with a reducing atmosphere.

Experiments conducted later showed that the other RNA and DNA nucleobases could be obtained through simulated prebiotic chemistry with a reducing atmosphere.

Also, many amino acids are formed from HCN and ammonia under these conditions.<ref>{{cite journal |vauthors=Oró J, Kamat SS |title=Amino-acid synthesis from hydrogen cyanide under possible primitive earth conditions |journal=Nature |volume=190 |issue= 4774|pages=442–3 |date=April 1961 |pmid=13731262 |doi=10.1038/190442a0|bibcode = 1961Natur.190..442O |url=https://www.semanticscholar.org/paper/1aea2775f328d439e5bb65e61fdf3b988d829052 }}</ref>  

Also, many amino acids are formed from HCN and ammonia under these conditions.<ref>{{cite journal |vauthors=Oró J, Kamat SS |title=Amino-acid synthesis from hydrogen cyanide under possible primitive earth conditions |journal=Nature |volume=190 |issue= 4774|pages=442–3 |date=April 1961 |pmid=13731262 |doi=10.1038/190442a0|bibcode = 1961Natur.190..442O |url=https://www.semanticscholar.org/paper/1aea2775f328d439e5bb65e61fdf3b988d829052 }}</ref>  

 

Experiments conducted later showed that the other [[Nucleobase|RNA and DNA nucleobases]] could be obtained through simulated prebiotic chemistry with a [[reducing atmosphere]].<ref>{{cite book | title=Origins of Prebiological Systems and of Their Molecular Matrices| editor= Fox SW| author=Oró J| year=1967| pages=137| publisher=New York Academic Press}}</ref>

Experiments conducted later showed that the other [[Nucleobase|RNA and DNA nucleobases]] could be obtained through simulated prebiotic chemistry with a [[reducing atmosphere]].<ref>{{cite book | title=Origins of Prebiological Systems and of Their Molecular Matrices| editor= Fox SW| author=Oró J| year=1967| pages=137| publisher=New York Academic Press}}</ref>

 

There also had been similar electric discharge experiments related to the origin of life contemporaneous with Miller–Urey. An article in The New York Times (March 8, 1953:E9), titled "Looking Back Two Billion Years" describes the work of Wollman (William) M. MacNevin at The Ohio State University, before the Miller Science paper was published in May 1953. MacNevin was passing 100,000 volt sparks through methane and water vapor and produced "resinous solids" that were "too complex for analysis."  The article describes other early earth experiments being done by MacNevin.  It is not clear if he ever published any of these results in the primary scientific literature.<!--is it not clear because academics have researched this and somehow can't tell, or is it just not clear to the Wikipedia contributor from reading only the NYT article?-->

There also had been similar electric discharge experiments related to the origin of life contemporaneous with Miller–Urey. An article in The New York Times (March 8, 1953:E9), titled "Looking Back Two Billion Years" describes the work of Wollman (William) M. MacNevin at The Ohio State University, before the Miller Science paper was published in May 1953. MacNevin was passing 100,000 volt sparks through methane and water vapor and produced "resinous solids" that were "too complex for analysis."  The article describes other early earth experiments being done by MacNevin.  It is not clear if he ever published any of these results in the primary scientific literature.<!--is it not clear because academics have researched this and somehow can't tell, or is it just not clear to the Wikipedia contributor from reading only the NYT article?-->

与米勒-尤雷同时期也有过类似的与生命起源有关的放电实验。《纽约时报》(The New York Times，1953年3月8日: E9)的一篇题为《回顾20亿年》(Looking Back Two Billion Years)的文章，描述了1953年5月《米勒科学》(Miller Science)论文发表之前，沃尔曼(William) m. MacNevin 在俄亥俄州立大学(Ohio State University)的工作。麦克尼文将10万伏特的火花通过甲烷和水蒸气，产生“树脂状固体” ，“太复杂，无法分析”这篇文章描述了麦克尼文正在进行的其他早期地球实验。目前尚不清楚他是否在主要科学文献中发表过这些结果。< ! ——是因为学者们已经研究过这个问题，但不知怎么搞的，还是因为维基百科的撰稿人只读了《纽约时报》的文章就不清楚? <

与米勒-尤里同时期也有过类似的与生命起源有关的放电实验。《纽约时报》（1953年3月8日：E9）上的一篇题为“回顾20亿年”的文章描述了1953年5月米勒科学论文发表之前，俄亥俄州立大学的沃尔曼（William）M.MacNevin的工作。麦克尼文通过甲烷和水蒸气产生10万伏特的火花，产生“树脂固体”，这些“树脂固体”过于复杂，无法分析。目前还不清楚他是否曾在原始科学文献中发表过这些结果。（不清楚是因为学者们已经对此进行了研究，不知何故无法判断，还是仅仅因为阅读了《纽约时报》的文章，维基百科的撰稿人就不清楚了？）

K. A. Wilde submitted a paper to Science on December 15, 1952, before Miller submitted his paper to the same journal on February 10, 1953. Wilde's paper was published on July 10, 1953.  Wilde used voltages up to only 600 V on a binary mixture of carbon dioxide (CO₂) and water in a flow system.  He observed only small amounts of carbon dioxide reduction to carbon monoxide, and no other significant reduction products or newly formed carbon compounds.

K. A. Wilde submitted a paper to Science on December 15, 1952, before Miller submitted his paper to the same journal on February 10, 1953. Wilde's paper was published on July 10, 1953.  Wilde used voltages up to only 600 V on a binary mixture of carbon dioxide (CO₂) and water in a flow system.  He observed only small amounts of carbon dioxide reduction to carbon monoxide, and no other significant reduction products or newly formed carbon compounds.

1952年12月15日，k · a · 王尔德向《科学》杂志提交了一篇论文，之后米勒又于1953年2月10日向同一杂志提交了他的论文。王尔德的论文发表于1953年7月10日。王尔德使用的电压只有600v 对二氧化碳(CO < sub > 2 </sub >)和流动系统中的水的二元混合物。他观察到只有少量的二氧化碳减少为一氧化碳，没有其他重要的还原产物或新形成的碳化合物。

1952年12月15日，K·A· 王尔德向《科学》杂志提交了一篇论文，之后米勒又于1953年2月10日向同一杂志提交了他的论文。王尔德的论文发表于1953年7月10日。王尔德使用的电压只有600v 对二氧化碳(CO2)和流动系统中的水的二元混合物。他观察到只有少量的二氧化碳减少为一氧化碳，没有其他重要的还原产物或新形成的碳化合物。

Other researchers were studying [[Ultraviolet|UV]]-[[photolysis]] of water vapor with [[carbon monoxide]]. They have found that various alcohols, aldehydes and organic acids were synthesized in reaction mixture.<ref>[https://doi.org/10.1007%2FBF00931407 Synthesis of organic compounds from carbon monoxide and water by UV photolysis] ''Origins of Life''. December 1978, Volume 9, Issue 2, pp 93-101

Other researchers were studying [[Ultraviolet|UV]]-[[photolysis]] of water vapor with [[carbon monoxide]]. They have found that various alcohols, aldehydes and organic acids were synthesized in reaction mixture.<ref>[https://doi.org/10.1007%2FBF00931407 Synthesis of organic compounds from carbon monoxide and water by UV photolysis] ''Origins of Life''. December 1978, Volume 9, Issue 2, pp 93-101

 

More recent experiments by chemists Jeffrey Bada, one of Miller's graduate students, and Jim Cleaves at Scripps Institution of Oceanography of the University of California, San Diego were similar to those performed by Miller.  However, Bada noted that in current models of early Earth conditions, carbon dioxide and nitrogen (N₂) create nitrites, which destroy amino acids as fast as they form. <!--However, the early Earth may have had significant amounts of iron and carbonate minerals able to neutralize the effects of the nitrites. --> <!-- Please find a scientific paper that makes this statement before removing the tag -- and then the remark may be visible again --> When Bada performed the Miller-type experiment with the addition of iron and carbonate minerals, the products were rich in amino acids. This suggests the origin of significant amounts of amino acids may have occurred on Earth even with an atmosphere containing carbon dioxide and nitrogen.

More recent experiments by chemists Jeffrey Bada, one of Miller's graduate students, and Jim Cleaves at Scripps Institution of Oceanography of the University of California, San Diego were similar to those performed by Miller.  However, Bada noted that in current models of early Earth conditions, carbon dioxide and nitrogen (N₂) create nitrites, which destroy amino acids as fast as they form. <!--However, the early Earth may have had significant amounts of iron and carbonate minerals able to neutralize the effects of the nitrites. --> <!-- Please find a scientific paper that makes this statement before removing the tag -- and then the remark may be visible again --> When Bada performed the Miller-type experiment with the addition of iron and carbonate minerals, the products were rich in amino acids. This suggests the origin of significant amounts of amino acids may have occurred on Earth even with an atmosphere containing carbon dioxide and nitrogen.

米勒的一个研究生，化学家 Jeffrey Bada 和斯克里普斯海洋研究所的 Jim Cleaves 最近做的实验与 Miller 的相似。然而，Bada 指出，在目前的早期地球环境模型中，二氧化碳和氮(n < sub > 2 </sub >)会产生亚硝酸盐，这些亚硝酸盐会在形成时迅速破坏氨基酸。<！-- 然而，早期地球可能含有大量的铁和碳酸盐矿物质，能够中和亚硝酸盐的作用。在去掉标签之前，请找一篇科学论文阐述这一观点——然后可能会再次看到这一评论——当八达进行了加入铁和碳酸盐矿物质的米勒式实验时，其产物富含氨基酸。这表明，即使在含有二氧化碳和氮的大气层中，大量氨基酸的起源也可能发生在地球上。

米勒的研究生之一、化学家杰弗里·巴达和加州大学圣地亚哥斯克里普斯海洋学研究所的吉姆·克里夫斯最近的实验与米勒的实验相似。然而，Bada指出，在目前的早期地球条件模型中，二氧化碳和氮（N2）会产生亚硝酸盐，亚硝酸盐在氨基酸形成的同时也会被破坏。<!--然而，早期地球可能有大量的铁和碳酸盐矿物能够中和亚硝酸盐的影响。--> <!--在去掉标签之前，请先找到一篇科学论文来说明这一点——然后这句话可能会再次显现出来——当Bada进行米勒式实验，添加铁和碳酸盐矿物时，产品富含氨基酸。这表明，即使在含有二氧化碳和氮气的大气中，也可能有大量氨基酸的起源。

Akiva Bar-nun, Hyman Hartman.</ref>

Akiva Bar-nun, Hyman Hartman.</ref>

Some evidence suggests that Earth's original atmosphere might have contained fewer of the reducing molecules than was thought at the time of the Miller–Urey experiment. There is abundant evidence of major volcanic eruptions 4 billion years ago, which would have released carbon dioxide, nitrogen, hydrogen sulfide (H₂S), and sulfur dioxide (SO₂) into the atmosphere. Experiments using these gases in addition to the ones in the original Miller–Urey experiment have produced more diverse molecules. The experiment created a mixture that was racemic (containing both L and D enantiomers) and experiments since have shown that "in the lab the two versions are equally likely to appear"; however, in nature, L amino acids dominate. Later experiments have confirmed disproportionate amounts of L or D oriented enantiomers are possible.

Some evidence suggests that Earth's original atmosphere might have contained fewer of the reducing molecules than was thought at the time of the Miller–Urey experiment. There is abundant evidence of major volcanic eruptions 4 billion years ago, which would have released carbon dioxide, nitrogen, hydrogen sulfide (H₂S), and sulfur dioxide (SO₂) into the atmosphere. Experiments using these gases in addition to the ones in the original Miller–Urey experiment have produced more diverse molecules. The experiment created a mixture that was racemic (containing both L and D enantiomers) and experiments since have shown that "in the lab the two versions are equally likely to appear"; however, in nature, L amino acids dominate. Later experiments have confirmed disproportionate amounts of L or D oriented enantiomers are possible.

一些证据表明，地球原始大气层中还原分子的含量可能比 Miller-Urey 实验时所认为的要少。有大量的证据表明，40亿年前的大型火山爆发会向大气中释放二氧化碳、氮、硫化氢(h < sub > 2 </sub > s)和二氧化硫(SO < sub > 2 </sub >)。除了最初的 Miller-Urey 实验中使用的气体之外，使用这些气体的实验已经产生了更多样化的分子。该实验创造了一种外消旋体(包含 l 和 d 对映体)的混合物，此后的实验表明，“在实验室中，这两种化合物出现的可能性相等” ; 然而，在自然界中，l 氨基酸占主导地位。后来的实验证实了不成比例的 l 或 d 取向对映异构体是可能的。

一些证据表明，地球原始大气层中还原分子的含量可能比 Miller-Urey 实验时所认为的要少。有大量的证据表明，40亿年前的大型火山爆发会向大气中释放二氧化碳、氮、硫化氢(H2S)和二氧化硫(SO2)。除了最初的 Miller-Urey 实验中使用的气体之外，使用这些气体的实验已经产生了更多样化的分子。该实验创造了一种外消旋体(包含L和D对映体)的混合物，此后的实验表明，“在实验室中，这两种化合物出现的可能性相等” ; 然而，在自然界中，l 氨基酸占主导地位。后来的实验证实了不成比例的L或D取向对映异构体是可能的。

==Earth's early atmosphere==

==Earth's early atmosphere地球最早的大气层==

Originally it was thought that the primitive secondary atmosphere contained mostly ammonia and methane. However, it is likely that most of the atmospheric carbon was CO₂ with perhaps some CO and the nitrogen mostly N₂.  In practice gas mixtures containing CO, CO₂, N₂, etc. give much the same products as those containing CH₄ and NH₃ so long as there is no O₂. The hydrogen atoms come mostly from water vapor. In fact, in order to generate aromatic amino acids under primitive earth conditions it is necessary to use less hydrogen-rich gaseous mixtures. Most of the natural amino acids, hydroxyacids, purines, pyrimidines, and sugars have been made in variants of the Miller experiment.

Originally it was thought that the primitive secondary atmosphere contained mostly ammonia and methane. However, it is likely that most of the atmospheric carbon was CO₂ with perhaps some CO and the nitrogen mostly N₂.  In practice gas mixtures containing CO, CO₂, N₂, etc. give much the same products as those containing CH₄ and NH₃ so long as there is no O₂. The hydrogen atoms come mostly from water vapor. In fact, in order to generate aromatic amino acids under primitive earth conditions it is necessary to use less hydrogen-rich gaseous mixtures. Most of the natural amino acids, hydroxyacids, purines, pyrimidines, and sugars have been made in variants of the Miller experiment.

起初人们认为原始的二次大气主要含有氨和甲烷。但是，大气中的大部分碳可能是 CO < sub > 2 </sub > ，也可能是一些 CO 和氮大部分是 n < sub > 2 </sub > 。在实际应用中，含有 CO、 CO < sub > 2 </sub > 、 n < sub > 2 </sub > 等的混合气体。只要没有 o < sub > 2 </sub > ，就可以给出与含 CH < sub > 4 </sub > 和 NH < sub > 3 </sub > 相同的产品。氢原子主要来自水蒸气。事实上，为了在原始土壤条件下生成芳香族氨基酸，必须使用较少的富氢气体混合物。大多数天然氨基酸、羟基酸、嘌呤、嘧啶和糖都是米勒实验的变体。

起初人们认为原始的二次大气主要含有氨和甲烷。但是，大气中的大部分碳可能是 CO2 ，也可能是一些 CO 和氮大部分是N2 。在实际应用中，含有 CO、 CO2 、 N2 等的混合气体。只要没有O 2 ，就可以给出与含 CH4和 NH3  相同的产品。氢原子主要来自水蒸气。事实上，为了在原始土壤条件下生成芳香族氨基酸，必须使用较少的富氢气体混合物。大多数天然氨基酸、羟基酸、嘌呤、嘧啶和糖都是米勒实验的变体。

Some evidence suggests that Earth's original atmosphere might have contained fewer of the reducing molecules than was thought at the time of the Miller–Urey experiment. There is abundant evidence of major volcanic eruptions 4 billion years ago, which would have released carbon dioxide, nitrogen, [[hydrogen sulfide]] (H₂S), and [[sulfur dioxide]] (SO₂) into the atmosphere.<ref name=Green>{{Cite journal|last=Green|first=Jack|title=Academic Aspects of Lunar Water Resources and Their Relevance to Lunar Protolife|journal=International Journal of Molecular Sciences|year=2011|volume=12|issue=9|pages=6051–6076|doi=10.3390/ijms12096051|pmid=22016644|pmc=3189768|ref=harv}}</ref> Experiments using these gases in addition to the ones in the original Miller–Urey experiment have produced more diverse molecules. The experiment created a mixture that was racemic (containing both L and D [[enantiomer]]s) and experiments since have shown that "in the lab the two versions are equally likely to appear";<ref name="NS">{{Cite news |date=2006-06-02 |title=Right-handed amino acids were left behind |periodical=[[New Scientist]] |publisher=Reed Business Information Ltd |issue=2554 |pages=18 |url=https://www.newscientist.com/channel/life/mg19025545.200-righthanded-amino-acids-were-left-behind.html |accessdate=2008-07-09 |url-status=live |archiveurl=https://web.archive.org/web/20081024211531/http://www.newscientist.com/channel/life/mg19025545.200-righthanded-amino-acids-were-left-behind.html |archivedate=2008-10-24 }}</ref> however, in nature, L amino acids dominate. Later experiments have confirmed disproportionate amounts of L or D oriented enantiomers are possible.<ref>{{cite journal |last=Kojo |first=Shosuke |first2=Hiromi |last2=Uchino |first3=Mayu |last3=Yoshimura |first4=Kyoko |last4=Tanaka |date=October 2004 |title=Racemic D,L-asparagine causes enantiomeric excess of other coexisting racemic D,L-amino acids during recrystallization: a hypothesis accounting for the origin of L-amino acids in the biosphere |journal=Chemical Communications |volume= |issue=19 |pages=2146–2147 |pmid=15467844 |doi=10.1039/b409941a}}</ref>

Some evidence suggests that Earth's original atmosphere might have contained fewer of the reducing molecules than was thought at the time of the Miller–Urey experiment. There is abundant evidence of major volcanic eruptions 4 billion years ago, which would have released carbon dioxide, nitrogen, [[hydrogen sulfide]] (H₂S), and [[sulfur dioxide]] (SO₂) into the atmosphere.<ref name=Green>{{Cite journal|last=Green|first=Jack|title=Academic Aspects of Lunar Water Resources and Their Relevance to Lunar Protolife|journal=International Journal of Molecular Sciences|year=2011|volume=12|issue=9|pages=6051–6076|doi=10.3390/ijms12096051|pmid=22016644|pmc=3189768|ref=harv}}</ref> Experiments using these gases in addition to the ones in the original Miller–Urey experiment have produced more diverse molecules. The experiment created a mixture that was racemic (containing both L and D [[enantiomer]]s) and experiments since have shown that "in the lab the two versions are equally likely to appear";<ref name="NS">{{Cite news |date=2006-06-02 |title=Right-handed amino acids were left behind |periodical=[[New Scientist]] |publisher=Reed Business Information Ltd |issue=2554 |pages=18 |url=https://www.newscientist.com/channel/life/mg19025545.200-righthanded-amino-acids-were-left-behind.html |accessdate=2008-07-09 |url-status=live |archiveurl=https://web.archive.org/web/20081024211531/http://www.newscientist.com/channel/life/mg19025545.200-righthanded-amino-acids-were-left-behind.html |archivedate=2008-10-24 }}</ref> however, in nature, L amino acids dominate. Later experiments have confirmed disproportionate amounts of L or D oriented enantiomers are possible.<ref>{{cite journal |last=Kojo |first=Shosuke |first2=Hiromi |last2=Uchino |first3=Mayu |last3=Yoshimura |first4=Kyoko |last4=Tanaka |date=October 2004 |title=Racemic D,L-asparagine causes enantiomeric excess of other coexisting racemic D,L-amino acids during recrystallization: a hypothesis accounting for the origin of L-amino acids in the biosphere |journal=Chemical Communications |volume= |issue=19 |pages=2146–2147 |pmid=15467844 |doi=10.1039/b409941a}}</ref>

More recent results may question these conclusions. The University of Waterloo and University of Colorado conducted simulations in 2005 that indicated that the early atmosphere of Earth could have contained up to 40 percent hydrogen—implying a much more hospitable environment for the formation of prebiotic organic molecules. The escape of hydrogen from Earth's atmosphere into space may have occurred at only one percent of the rate previously believed based on revised estimates of the upper atmosphere's temperature. One of the authors, Owen Toon notes: "In this new scenario, organics can be produced efficiently in the early atmosphere, leading us back to the organic-rich soup-in-the-ocean concept... I think this study makes the experiments by Miller and others relevant again." Outgassing calculations using a chondritic model for the early earth complement the Waterloo/Colorado results in re-establishing the importance of the Miller–Urey experiment.

More recent results may question these conclusions. The University of Waterloo and University of Colorado conducted simulations in 2005 that indicated that the early atmosphere of Earth could have contained up to 40 percent hydrogen—implying a much more hospitable environment for the formation of prebiotic organic molecules. The escape of hydrogen from Earth's atmosphere into space may have occurred at only one percent of the rate previously believed based on revised estimates of the upper atmosphere's temperature. One of the authors, Owen Toon notes: "In this new scenario, organics can be produced efficiently in the early atmosphere, leading us back to the organic-rich soup-in-the-ocean concept... I think this study makes the experiments by Miller and others relevant again." Outgassing calculations using a chondritic model for the early earth complement the Waterloo/Colorado results in re-establishing the importance of the Miller–Urey experiment.

最近的研究结果可能会质疑这些结论。滑铁卢大学和科罗拉多大学博尔德分校在2005年进行的模拟表明，地球早期的大气可能含有高达40% 的氢，这意味着一个更适宜生命起源前有机分子形成的环境。氢气从地球大气层逃逸到太空的速度可能只有先前根据对高层大气温度的修正估计所认为的速度的百分之一。其中一位作者欧文 · 图恩(Owen Toon)指出: “在这种新的情况下，有机物可以在早期大气中高效生产，这将我们带回到富含有机物的海洋汤的概念... ..。我认为，这项研究使米勒和其他人的实验再次具有相关性。”使用早期地球的线粒体模型进行排气计算补充滑铁卢/科罗拉多实验的结果，重新建立了米勒-尤雷实验的重要性。

最近的研究结果可能会质疑这些结论。滑铁卢大学和科罗拉多大学在2005年进行了模拟，结果表明地球早期大气中可能含有高达40%的氢，这意味着有利于形成益生元有机分子的环境更加有利。氢从地球大气层逃逸到太空的速度可能只有先前根据对高层大气温度的修正估计所相信的速率的百分之一。作者之一欧文·图恩指出：“在这个新的场景中，有机物可以在早期大气中高效地产生，这让我们回到海洋中富含有机物的汤的概念。。。我认为这项研究使米勒和其他人的实验再次具有相关性。“利用早期地球的球粒陨石模型进行放气计算，补充了滑铁卢/科罗拉多的结果，重新确立了米勒-乌雷实验的重要性

 

Originally it was thought that the primitive [[secondary atmosphere]] contained mostly ammonia and methane. However, it is likely that most of the atmospheric carbon was CO₂ with perhaps some CO and the nitrogen mostly N₂.  In practice gas mixtures containing CO, CO₂, N₂, etc. give much the same products as those containing CH₄ and NH₃ so long as there is no O₂. The hydrogen atoms come mostly from water vapor. In fact, in order to generate aromatic amino acids under primitive earth conditions it is necessary to use less hydrogen-rich gaseous mixtures. Most of the natural amino acids, [[hydroxy acid|hydroxyacids]], purines, pyrimidines, and sugars have been made in variants of the Miller experiment.<ref name=bada2013/><ref>{{cite journal|last1=Ruiz-Mirazo|first1=Kepa|last2=Briones|first2=Carlos|last3=de la Escosura|first3=Andrés|title=Prebiotic Systems Chemistry: New Perspectives for the Origins of Life|journal=Chemical Reviews|year=2014|volume=114|issue=1|pages=285–366|doi=10.1021/cr2004844|pmid=24171674}}</ref>

Originally it was thought that the primitive [[secondary atmosphere]] contained mostly ammonia and methane. However, it is likely that most of the atmospheric carbon was CO₂ with perhaps some CO and the nitrogen mostly N₂.  In practice gas mixtures containing CO, CO₂, N₂, etc. give much the same products as those containing CH₄ and NH₃ so long as there is no O₂. The hydrogen atoms come mostly from water vapor. In fact, in order to generate aromatic amino acids under primitive earth conditions it is necessary to use less hydrogen-rich gaseous mixtures. Most of the natural amino acids, [[hydroxy acid|hydroxyacids]], purines, pyrimidines, and sugars have been made in variants of the Miller experiment.<ref name=bada2013/><ref>{{cite journal|last1=Ruiz-Mirazo|first1=Kepa|last2=Briones|first2=Carlos|last3=de la Escosura|first3=Andrés|title=Prebiotic Systems Chemistry: New Perspectives for the Origins of Life|journal=Chemical Reviews|year=2014|volume=114|issue=1|pages=285–366|doi=10.1021/cr2004844|pmid=24171674}}</ref>

==Extraterrestrial sources==

==Extraterrestrial sources外星源==

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|title=Evolution of the atmosphere|journal=Proceedings of the Geologists' Association. Geologists' Association|year=1998|volume=109|issue=1|pages=1–13|pmid=11543127|doi=10.1016/s0016-7878(98)80001-1}}</ref><ref>{{cite journal|last1=Raulin|first1=F|last2=Bossard|first2=A|title=Organic syntheses in gas phase and chemical evolution in planetary atmospheres.|journal=Advances in Space Research|year=1984|volume=4|issue=12|pages=75–82|pmid=11537798|doi=10.1016/0273-1177(84)90547-7|bibcode=1984AdSpR...4...75R}}</ref><ref>{{cite journal|last1=Raulin|first1=François|last2=Brassé|first2=Coralie|last3=Poch|first3=Olivier|last4=Coll|first4=Patrice|title=Prebiotic-like chemistry on Titan|journal= Chemical Society Reviews|year=2012|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 over 90 different amino acids, nineteen of which are found in Earth life. [[Comet]]s and other [[Trans-Neptunian object|icy outer-solar-system bodies]] are thought to contain large amounts of complex carbon compounds (such as [[tholin]]s) formed by these processes, darkening surfaces of these bodies.<ref>{{cite journal |vauthors=Thompson WR, Murray BG, Khare BN, Sagan C |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 |date=December 1987 |pmid=11542127 |doi=10.1029/JA092iA13p14933 |bibcode=1987JGR....9214933T|title-link=methane clathrate }}</ref> The early Earth was bombarded heavily by comets, possibly providing a large supply of complex organic molecules along with the water and other volatiles they contributed.<ref>{{cite journal|last=PIERAZZO|first=E.|author2=CHYBA C.F.|title=Amino acid survival in large cometary impacts|journal=Meteoritics & Planetary Science|year=2010|volume=34|issue=6|pages=909–918|doi=10.1111/j.1945-5100.1999.tb01409.x|bibcode=1999M&PS...34..909P}}</ref>  This has been used to infer an origin of life outside of Earth: the [[panspermia]] hypothesis.

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|title=Evolution of the atmosphere|journal=Proceedings of the Geologists' Association. Geologists' Association|year=1998|volume=109|issue=1|pages=1–13|pmid=11543127|doi=10.1016/s0016-7878(98)80001-1}}</ref><ref>{{cite journal|last1=Raulin|first1=F|last2=Bossard|first2=A|title=Organic syntheses in gas phase and chemical evolution in planetary atmospheres.|journal=Advances in Space Research|year=1984|volume=4|issue=12|pages=75–82|pmid=11537798|doi=10.1016/0273-1177(84)90547-7|bibcode=1984AdSpR...4...75R}}</ref><ref>{{cite journal|last1=Raulin|first1=François|last2=Brassé|first2=Coralie|last3=Poch|first3=Olivier|last4=Coll|first4=Patrice|title=Prebiotic-like chemistry on Titan|journal= Chemical Society Reviews|year=2012|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 over 90 different amino acids, nineteen of which are found in Earth life. [[Comet]]s and other [[Trans-Neptunian object|icy outer-solar-system bodies]] are thought to contain large amounts of complex carbon compounds (such as [[tholin]]s) formed by these processes, darkening surfaces of these bodies.<ref>{{cite journal |vauthors=Thompson WR, Murray BG, Khare BN, Sagan C |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 |date=December 1987 |pmid=11542127 |doi=10.1029/JA092iA13p14933 |bibcode=1987JGR....9214933T|title-link=methane clathrate }}</ref> The early Earth was bombarded heavily by comets, possibly providing a large supply of complex organic molecules along with the water and other volatiles they contributed.<ref>{{cite journal|last=PIERAZZO|first=E.|author2=CHYBA C.F.|title=Amino acid survival in large cometary impacts|journal=Meteoritics & Planetary Science|year=2010|volume=34|issue=6|pages=909–918|doi=10.1111/j.1945-5100.1999.tb01409.x|bibcode=1999M&PS...34..909P}}</ref>  This has been used to infer an origin of life outside of Earth: the [[panspermia]] hypothesis.

In recent years, studies have been made of the amino acid composition of the products of "old" areas in "old" genes, defined as those that are found to be common to organisms from several widely separated species, assumed to share only the last universal ancestor (LUA) of all extant species. These studies found that the products of these areas are enriched in those amino acids that are also most readily produced in the Miller–Urey experiment. This suggests that the original genetic code was based on a smaller number of amino acids – only those available in prebiotic nature – than the current one.

In recent years, studies have been made of the amino acid composition of the products of "old" areas in "old" genes, defined as those that are found to be common to organisms from several widely separated species, assumed to share only the last universal ancestor (LUA) of all extant species. These studies found that the products of these areas are enriched in those amino acids that are also most readily produced in the Miller–Urey experiment. This suggests that the original genetic code was based on a smaller number of amino acids – only those available in prebiotic nature – than the current one.

近年来，人们对“老”基因中“老”区域的产物的氨基酸组成进行了研究，“老”基因被定义为来自几个相距甚远的物种的生物体所共有的氨基酸组成，这些物种被认为在所有现存物种中只共享最后共同祖先。这些研究发现，这些区域的产物富含那些在 Miller-Urey 实验中也最容易产生的氨基酸。这表明，最初的遗传密码是基于较少数量的氨基酸-只有那些在生命起源之前的性质-比现在的。

近年来，人们对“老”基因中“老”区域的产物的氨基酸组成进行了研究，“老”基因被定义为来自几个相距甚远的物种的生物体所共有的氨基酸组成，这些物种被认为在所有现存物种中只共享最后共同祖先。这些研究发现，这些区域的产物富含那些在 Miller-Urey 实验中也最容易产生的氨基酸。这表明，最初的遗传密码是基于比现在更少的氨基酸-只有那些在益生元性质-比目前的。

 

==Recent related studies近年相关研究==

==Recent related studies==

Jeffrey Bada, himself Miller's student, inherited the original equipment from the experiment when Miller died in 2007. Based on sealed vials from the original experiment, scientists have been able to show that although successful, Miller was never able to find out, with the equipment available to him, the full extent of the experiment's success. Later researchers have been able to isolate even more different amino acids, 25 altogether. Bada has estimated that more accurate measurements could easily bring out 30 or 40 more amino acids in very low concentrations, but the researchers have since discontinued the testing. Miller's experiment was therefore a remarkable success at synthesizing complex organic molecules from simpler chemicals, considering that all known life uses just 20 different amino acids.

Jeffrey Bada, himself Miller's student, inherited the original equipment from the experiment when Miller died in 2007. Based on sealed vials from the original experiment, scientists have been able to show that although successful, Miller was never able to find out, with the equipment available to him, the full extent of the experiment's success. Later researchers have been able to isolate even more different amino acids, 25 altogether. Bada has estimated that more accurate measurements could easily bring out 30 or 40 more amino acids in very low concentrations, but the researchers have since discontinued the testing. Miller's experiment was therefore a remarkable success at synthesizing complex organic molecules from simpler chemicals, considering that all known life uses just 20 different amino acids.

In recent years, studies have been made of the [[amino acid]] composition of the products of "old" areas in "old" genes, defined as those that are found to be common to organisms from several widely separated [[species]], assumed to share only the [[last universal ancestor]] (LUA) of all extant species. These studies found that the products of these areas are enriched in those amino acids that are also most readily produced in the Miller–Urey experiment. This suggests that the original genetic code was based on a smaller number of amino acids – only those available in prebiotic nature – than the current one.<ref>{{cite journal |author1=Brooks D.J. |author2=Fresco J.R. |author3=Lesk A.M. |author4=Singh M. |url=http://mbe.oupjournals.org/cgi/content/full/19/10/1645 |title=Evolution of amino acid frequencies in proteins over deep time: inferred order of introduction of amino acids into the genetic code |journal=Molecular Biology and Evolution |date=October 1, 2002 |volume=19 |pages=1645–55 |pmid=12270892 |issue=10 |doi=10.1093/oxfordjournals.molbev.a003988 |url-status=dead |archiveurl=https://web.archive.org/web/20041213094516/http://mbe.oupjournals.org/cgi/content/full/19/10/1645 |archivedate=December 13, 2004 |doi-access=free }}</ref>

In recent years, studies have been made of the [[amino acid]] composition of the products of "old" areas in "old" genes, defined as those that are found to be common to organisms from several widely separated [[species]], assumed to share only the [[last universal ancestor]] (LUA) of all extant species. These studies found that the products of these areas are enriched in those amino acids that are also most readily produced in the Miller–Urey experiment. This suggests that the original genetic code was based on a smaller number of amino acids – only those available in prebiotic nature – than the current one.<ref>{{cite journal |author1=Brooks D.J. |author2=Fresco J.R. |author3=Lesk A.M. |author4=Singh M. |url=http://mbe.oupjournals.org/cgi/content/full/19/10/1645 |title=Evolution of amino acid frequencies in proteins over deep time: inferred order of introduction of amino acids into the genetic code |journal=Molecular Biology and Evolution |date=October 1, 2002 |volume=19 |pages=1645–55 |pmid=12270892 |issue=10 |doi=10.1093/oxfordjournals.molbev.a003988 |url-status=dead |archiveurl=https://web.archive.org/web/20041213094516/http://mbe.oupjournals.org/cgi/content/full/19/10/1645 |archivedate=December 13, 2004 |doi-access=free }}</ref>

In 2008, a group of scientists examined 11 vials left over from Miller's experiments of the early 1950s. In addition to the classic experiment, reminiscent of Charles Darwin's envisioned "warm little pond", Miller had also performed more experiments, including one with conditions similar to those of volcanic eruptions. This experiment had a nozzle spraying a jet of steam at the spark discharge. By using high-performance liquid chromatography and mass spectrometry, the group found more organic molecules than Miller had. They found that the volcano-like experiment had produced the most organic molecules, 22 amino acids, 5 amines and many hydroxylated molecules, which could have been formed by hydroxyl radicals produced by the electrified steam. The group suggested that volcanic island systems became rich in organic molecules in this way, and that the presence of carbonyl sulfide there could have helped these molecules form peptides.

In 2008, a group of scientists examined 11 vials left over from Miller's experiments of the early 1950s. In addition to the classic experiment, reminiscent of Charles Darwin's envisioned "warm little pond", Miller had also performed more experiments, including one with conditions similar to those of volcanic eruptions. This experiment had a nozzle spraying a jet of steam at the spark discharge. By using high-performance liquid chromatography and mass spectrometry, the group found more organic molecules than Miller had. They found that the volcano-like experiment had produced the most organic molecules, 22 amino acids, 5 amines and many hydroxylated molecules, which could have been formed by hydroxyl radicals produced by the electrified steam. The group suggested that volcanic island systems became rich in organic molecules in this way, and that the presence of carbonyl sulfide there could have helped these molecules form peptides.

 

[[Jeffrey Bada]], himself Miller's student, inherited the original equipment from the experiment when Miller died in 2007. Based on sealed vials from the original experiment, scientists have been able to show that although successful, Miller was never able to find out, with the equipment available to him, the full extent of the experiment's success. Later researchers have been able to isolate even more different amino acids, 25 altogether. Bada has estimated that more accurate measurements could easily bring out 30 or 40 more amino acids in very low concentrations, but the researchers have since discontinued the testing. Miller's experiment was therefore a remarkable success at synthesizing complex organic molecules from simpler chemicals, considering that all known life uses just 20 different amino acids.<ref name="BBC">{{cite web |website=BBC Four |url=http://www.bbc.co.uk/programmes/b00mbvfh |title=The Spark of Life |url-status=live |archive-url=https://web.archive.org/web/20101113011054/http://www.bbc.co.uk/programmes/b00mbvfh |archive-date=2010-11-13 |postscript=. TV Documentary. |date=26 August 2009}}</ref>

[[Jeffrey Bada]], himself Miller's student, inherited the original equipment from the experiment when Miller died in 2007. Based on sealed vials from the original experiment, scientists have been able to show that although successful, Miller was never able to find out, with the equipment available to him, the full extent of the experiment's success. Later researchers have been able to isolate even more different amino acids, 25 altogether. Bada has estimated that more accurate measurements could easily bring out 30 or 40 more amino acids in very low concentrations, but the researchers have since discontinued the testing. Miller's experiment was therefore a remarkable success at synthesizing complex organic molecules from simpler chemicals, considering that all known life uses just 20 different amino acids.<ref name="BBC">{{cite web |website=BBC Four |url=http://www.bbc.co.uk/programmes/b00mbvfh |title=The Spark of Life |url-status=live |archive-url=https://web.archive.org/web/20101113011054/http://www.bbc.co.uk/programmes/b00mbvfh |archive-date=2010-11-13 |postscript=. TV Documentary. |date=26 August 2009}}</ref>

The main problem of theories based around amino acids is the difficulty in obtaining spontaneous formation of peptides. Since John Desmond Bernal's suggestion that clay surfaces could have played a role in abiogenesis, scientific efforts have been dedicated to investigating clay-mediated peptide bond formation, with limited success. Peptides formed remained over-protected and shown no evidence of inheritance or metabolism. In December 2017 a theoretical model developed by Erastova and collaborators  suggested that peptides could form at the interlayers of layered double hydroxides such as green rust in early earth conditions. According to the model, drying of the intercalated layered material should provide energy and co-alignment required for peptide bond formation in a ribosome-like fashion, while re-wetting should allow mobilising the newly formed peptides and repopulate the interlayer with new amino acids. This mechanism is expected to lead to the formation of 12+ amino acid-long peptides within 15-20 washes. Researches also observed slightly different adsorption preferences for different amino acids, and postulated that, if coupled to a diluted solution of mixed amino acids, such preferences could lead to sequencing.

The main problem of theories based around amino acids is the difficulty in obtaining spontaneous formation of peptides. Since John Desmond Bernal's suggestion that clay surfaces could have played a role in abiogenesis, scientific efforts have been dedicated to investigating clay-mediated peptide bond formation, with limited success. Peptides formed remained over-protected and shown no evidence of inheritance or metabolism. In December 2017 a theoretical model developed by Erastova and collaborators  suggested that peptides could form at the interlayers of layered double hydroxides such as green rust in early earth conditions. According to the model, drying of the intercalated layered material should provide energy and co-alignment required for peptide bond formation in a ribosome-like fashion, while re-wetting should allow mobilising the newly formed peptides and repopulate the interlayer with new amino acids. This mechanism is expected to lead to the formation of 12+ amino acid-long peptides within 15-20 washes. Researches also observed slightly different adsorption preferences for different amino acids, and postulated that, if coupled to a diluted solution of mixed amino acids, such preferences could lead to sequencing.

以氨基酸为基础的理论的主要问题是很难获得肽的自发形成。自从约翰·德斯蒙德·伯纳尔提出粘土表面可能在自然发生中起作用以来，科学家致力于研究粘土介导的肽键的形成，但成效有限。形成的肽保护过度，没有遗传或新陈代谢的证据。2017年12月，Erastova 和他的合作者开发的一个理论模型表明，在早期的地球条件下，多肽可以在层状双氢氧化物的中间层形成，例如绿锈。根据该模型，插层材料的干燥应提供能量和以核糖体样的方式形成肽键所需的共排列，而再湿润应允许活化新形成的肽和重新填充层与新的氨基酸。这一机制有望在15-20次洗涤过程中形成12 + 氨基酸长肽。研究人员还观察到对不同氨基酸的吸附偏好略有不同，并假定，如果与混合氨基酸的稀释溶液相结合，这种偏好可能导致排序。

以氨基酸为基础的理论的主要问题是很难获得肽的自发形成。自从约翰·德斯蒙德·伯纳尔提出粘土表面可能在自然发生中起作用以来，科学家致力于研究粘土介导的肽键的形成，但成效有限。形成的肽保护过度，没有遗传或新陈代谢的证据。2017年12月，Erastova和他的合作者开发的一个理论模型表明，在早期的地球条件下，多肽可以在层状双氢氧化物的中间层形成，例如绿锈。根据该模型，插层材料的干燥应提供能量和以核糖体样的方式形成肽键所需的共排列，而再湿润应允许活化新形成的肽和重新填充层与新的氨基酸。这一机制有望在15-20次洗涤过程中形成12 + 氨基酸长肽。研究人员还观察到对不同氨基酸的吸附偏好略有不同，并假定，如果与混合氨基酸的稀释溶液相结合，这种偏好可能导致排序。

In 2008, a group of scientists examined 11 vials left over from Miller's experiments of the early 1950s. In addition to the classic experiment, reminiscent of [[Charles Darwin]]'s envisioned "warm little pond", Miller had also performed more experiments, including one with conditions similar to those of [[volcano|volcanic]] eruptions. This experiment had a nozzle spraying a jet of steam at the spark discharge. By using [[high-performance liquid chromatography]] and [[mass spectrometry]], the group found more organic molecules than Miller had. They found that the volcano-like experiment had produced the most organic molecules, 22 amino acids, 5 [[amine]]s and many [[hydroxylate]]d molecules, which could have been formed by [[hydroxyl radical]]s produced by the electrified steam. The group suggested that volcanic island systems became rich in organic molecules in this way, and that the presence of [[carbonyl sulfide]] there could have helped these molecules form [[peptide]]s.<ref name=Johnson2008>{{cite journal |vauthors=Johnson AP, Cleaves HJ, Dworkin JP, Glavin DP, Lazcano A, Bada JL |title=The Miller volcanic spark discharge experiment |journal=Science |volume=322 |issue=5900 |pages=404 |date=October 2008 |pmid=18927386 |doi=10.1126/science.1161527|bibcode = 2008Sci...322..404J }}</ref><ref>{{cite web | title='Lost' Miller–Urey Experiment Created More Of Life's Building Blocks | date=October 17, 2008 | website=Science Daily | url=https://www.sciencedaily.com/releases/2008/10/081016141411.htm | accessdate=2008-10-18 | url-status=live | archiveurl=https://web.archive.org/web/20081019111114/http://www.sciencedaily.com/releases/2008/10/081016141411.htm | archivedate=October 19, 2008 }}</ref>

In 2008, a group of scientists examined 11 vials left over from Miller's experiments of the early 1950s. In addition to the classic experiment, reminiscent of [[Charles Darwin]]'s envisioned "warm little pond", Miller had also performed more experiments, including one with conditions similar to those of [[volcano|volcanic]] eruptions. This experiment had a nozzle spraying a jet of steam at the spark discharge. By using [[high-performance liquid chromatography]] and [[mass spectrometry]], the group found more organic molecules than Miller had. They found that the volcano-like experiment had produced the most organic molecules, 22 amino acids, 5 [[amine]]s and many [[hydroxylate]]d molecules, which could have been formed by [[hydroxyl radical]]s produced by the electrified steam. The group suggested that volcanic island systems became rich in organic molecules in this way, and that the presence of [[carbonyl sulfide]] there could have helped these molecules form [[peptide]]s.<ref name=Johnson2008>{{cite journal |vauthors=Johnson AP, Cleaves HJ, Dworkin JP, Glavin DP, Lazcano A, Bada JL |title=The Miller volcanic spark discharge experiment |journal=Science |volume=322 |issue=5900 |pages=404 |date=October 2008 |pmid=18927386 |doi=10.1126/science.1161527|bibcode = 2008Sci...322..404J }}</ref><ref>{{cite web | title='Lost' Miller–Urey Experiment Created More Of Life's Building Blocks | date=October 17, 2008 | website=Science Daily | url=https://www.sciencedaily.com/releases/2008/10/081016141411.htm | accessdate=2008-10-18 | url-status=live | archiveurl=https://web.archive.org/web/20081019111114/http://www.sciencedaily.com/releases/2008/10/081016141411.htm | archivedate=October 19, 2008 }}</ref>

==Amino acids identified==

==Amino acids identified氨基酸鉴定 ==

Below is a table of amino acids produced and identified in the "classic" 1952 experiment, as published by Miller in 1953, and the 2010 re-analysis of vials from the H₂S-rich spark discharge experiment.

Below is a table of amino acids produced and identified in the "classic" 1952 experiment, as published by Miller in 1953, and the 2010 re-analysis of vials from the H₂S-rich spark discharge experiment.

下面是由 Miller 在1953年发表的1952年“经典”实验中产生和鉴定的氨基酸表，以及2010年对 h < sub > 2 </sub > s 高密度火花放电实验中小瓶的重新分析。

下面是由 Miller 在1953年发表的1952年“经典”实验中产生和鉴定的氨基酸表，以及2010年对H2S高密度火花放电实验中小瓶的重新分析。

{{Category see also|Chemical synthesis of amino acids}}

{{Category see also|Chemical synthesis of amino acids}}

==References==

==References参考==

{{Reflist|30em}}

{{Reflist|30em}}

==External links==

==External links外部链接==

*[http://millerureyexperiment.com A simulation of the Miller–Urey Experiment along with a video Interview with Stanley Miller] by Scott Ellis from CalSpace (UCSD)

*[http://millerureyexperiment.com A simulation of the Miller–Urey Experiment along with a video Interview with Stanley Miller] by Scott Ellis from CalSpace (UCSD)