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87-578: The Miller–Urey experiment , or Miller experiment , was an experiment in chemical synthesis carried out in 1952 that simulated the conditions thought at the time to be present in the atmosphere of the early, prebiotic Earth . It is seen as one of the first successful experiments demonstrating the synthesis of organic compounds from inorganic constituents in an origin of life scenario. The experiment used methane (CH 4 ), ammonia (NH 3 ), hydrogen (H 2 ), in ratio 2:2:1, and water (H 2 O). Applying an electric arc (simulating lightning) resulted in

174-420: A chemical reactor or a simple round-bottom flask . Many reactions require some form of processing (" work-up ") or purification procedure to isolate the final product. The amount produced by chemical synthesis is known as the reaction yield . Typically, yields are expressed as a mass in grams (in a laboratory setting) or as a percentage of the total theoretical quantity that could be produced based on

261-479: A chemically-reducing atmosphere on early Earth would have been conducive to organic synthesis in the presence of sunlight or lightning, gradually concentrating the ocean with random organic molecules until life emerged. In this way, frameworks for the origin of life were coming together, but at the mid-20th century, hypotheses lacked direct experimental evidence. At the time of the Miller–Urey experiment, Harold Urey

348-570: A chemist , Arrhenius was one of the founders of the science of physical chemistry . He received the Nobel Prize for Chemistry in 1903, becoming the first Swedish Nobel laureate. In 1905, he became the director of the Nobel Institute, where he remained until his death. Arrhenius was the first to use the principles of physical chemistry to estimate the extent to which increases in the atmospheric carbon dioxide are responsible for

435-493: A " post-impact " reducing atmosphere, a recent atmospheric modeling study has shown that an iron-rich impactor with a minimum mass around 4×10 – 5×10 kg would be enough to transiently reduce the entire prebiotic atmosphere, resulting in a Miller-Urey-esque H 2 -, CH 4 -, and NH 3 -dominated atmosphere that persists for millions of years. Previous work has estimated from the lunar cratering record and composition of Earth's mantle that between four and seven such impactors reached

522-461: A composition different from the gas used in the Miller experiment, prebiotic experiments continue to produce racemic mixtures of simple-to-complex organic compounds, including amino acids, under varying conditions. Moreover, researchers have shown that transient, hydrogen-rich atmospheres – conducive to Miller-Urey synthesis – would have occurred after large asteroid impacts on early Earth. Until

609-587: A flow system and did not note any significant reduction products. According to some, the reports of these experiments explain why Urey was rushing Miller's manuscript through Science and threatening to submit to the Journal of the American Chemical Society. By introducing an experimental framework to test prebiotic chemistry, the Miller–Urey experiment paved the way for future origin of life research. In 1961, Joan Oró produced milligrams of

696-556: A hydrogen atmospheric mixing ratio of at least 1% or higher at times during the Archean. Taken together, the view that early Earth's atmosphere was weakly reducing, with transient instances of highly-reducing compositions following large impacts is generally supported. 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

783-457: A large supply of complex organic molecules along with the water and other volatiles, however very low concentrations of biologically-relevant material combined with uncertainty surrounding the survival of organic matter upon impact make this difficult to determine. The Miller–Urey experiment was proof that the building blocks of life could be synthesized abiotically from gases, and introduced a new prebiotic chemistry framework through which to study

870-472: A more diverse suite of amino acids. Bada speculated that injecting the steam into the spark could have split water into H and OH radicals, leading to more hydroxylated amino acids during Strecker synthesis. In a separate set of experiments, Miller added hydrogen sulfide (H 2 S) to the reducing atmosphere, and Bada's analyses of the products suggested order-of-magnitude higher yields, including some amino acids with sulfur moieties . A 2021 work highlighted

957-445: A more-reducing atmosphere for the first few hundred million years. While the prebiotic atmosphere could have had a different redox condition than that of the Miller–Urey atmosphere, the modified Miller–Urey experiments described in the above section demonstrated that amino acids can still be abiotically produced in less-reducing atmospheres under specific geochemical conditions. Furthermore, harkening back to Urey's original hypothesis of

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1044-469: A place at the core of modern climate science. Arrhenius, in this work, built upon the prior work of other famous scientists, including Joseph Fourier , John Tyndall , and Claude Pouillet . Arrhenius wanted to determine whether greenhouse gases could contribute to the explanation of the temperature variation between glacial and inter-glacial periods. Arrhenius used infrared observations of the moon – by Frank Washington Very and Samuel Pierpont Langley at

1131-492: A series of individual chemical reactions, each with its own work-up. For example, a laboratory synthesis of paracetamol can consist of three sequential parts. For cascade reactions , multiple chemical transformations occur within a single reactant, for multi-component reactions as many as 11 different reactants form a single reaction product and for a " telescopic synthesis " one reactant experiences multiple transformations without isolation of intermediates. Organic synthesis

1218-436: A supervisory position. At the age of three, Arrhenius taught himself to read without the encouragement of his parents and, by watching his father's addition of numbers in his account books, became an arithmetical prodigy . In later life, Arrhenius was profoundly passionate about mathematical concepts, data analysis and discovering their relationships and laws. At age eight, he entered the local cathedral school , starting in

1305-517: A theory to explain the ice ages , Arrhenius, in 1896, was the first to use basic principles of physical chemistry to calculate estimates of the extent to which increases in atmospheric carbon dioxide (CO 2 ) will increase Earth's surface temperature through the greenhouse effect . These calculations led him to conclude that human-caused CO 2 emissions, from fossil-fuel burning and other combustion processes, are large enough to cause global warming. This conclusion has been extensively tested, winning

1392-416: A while (his father was very ill and would die in 1885) and had received an appointment at Uppsala. In an extension of his ionic theory Arrhenius proposed definitions for acids and bases , in 1884. He believed that acids were substances that produce hydrogen ions in solution and that bases were substances that produce hydroxide ions in solution. In 1885, Arrhenius next received a travel grant from

1479-449: Is 5.35 (± 10%) W/m for Earth's atmosphere. Based on information from his colleague Arvid Högbom , Arrhenius was the first person to predict that emissions of carbon dioxide from the burning of fossil fuels and other combustion processes were large enough to cause global warming. In his calculation Arrhenius included the feedback from changes in water vapor as well as latitudinal effects, but he omitted clouds, convection of heat upward in

1566-421: Is a lack of geochemical observations to constrain the exact composition of the prebiotic atmosphere, recent models point to an early "weakly reducing" atmosphere; that is, early Earth's atmosphere was likely dominated by CO 2 and N 2 and not CH 4 and NH 3 as used in the original Miller–Urey experiment. This is explained, in part, by the chemical composition of volcanic outgassing. Geologist William Rubey

1653-469: Is a set photochemical reactions of species in the Miller-Urey atmosphere that can result in formaldehyde: A photochemical path to HCN from NH 3 and CH 4 is: Other active intermediate compounds ( acetylene , cyanoacetylene , etc.) have been detected in the aqueous solution of Miller–Urey-type experiments, but the immediate HCN and aldehyde production, the production of amino acids accompanying

1740-583: Is a special type of chemical synthesis dealing with the synthesis of organic compounds . For the total synthesis of a complex product, multiple procedures in sequence may be required to synthesize the product of interest, needing a lot of time. A purely synthetic chemical synthesis begins with basic lab compounds. A semisynthetic process starts with natural products from plants or animals and then modifies them into new compounds. Inorganic synthesis and organometallic synthesis are used to prepare compounds with significant non-organic content. An illustrative example

1827-504: Is an active area of research in prebiotic chemistry. Below is a table of amino acids produced and identified in the "classic" 1952 experiment, as analyzed by Miller in 1952 and more recently by Bada and collaborators with modern mass spectrometry, the 2008 re-analysis of vials from the volcanic spark discharge experiment, and the 2010 re-analysis of vials from the H 2 S-rich spark discharge experiment. While not all proteinogenic amino acids have been produced in spark discharge experiments, it

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1914-421: Is generally accepted that early life used a simpler set of prebiotically-available amino acids. Chemical synthesis A chemical synthesis involves one or more compounds (known as reagents or reactants ) that will experience a transformation under certain conditions. Various reaction types can be applied to formulate a desired product. This requires mixing the compounds in a reaction vessel, such as

2001-444: Is introduced, homochirality can then propagate through biological systems in various ways. In this way, enantioselective synthesis is not required of Miller-Urey reactions if other geochemical processes in the environment are introducing homochirality. Finally, Miller-Urey and similar experiments primarily deal with the synthesis of monomers ; polymerization of these building blocks to form peptides and other more complex structures

2088-448: Is the next step of prebiotic chemistry schemes. Polymerization requires condensation reactions , which are thermodynamically unfavored in aqueous solutions because they expel water molecules. Scientists as far back as John Desmond Bernal in the late 1940s thus speculated that clay surfaces would play a large role in abiogenesis, as they might concentrate monomers. Several such models for mineral-mediated polymerization have emerged, such as

2175-428: Is the preparation of the anti-cancer drug cisplatin from potassium tetrachloroplatinate . Svante Arrhenius Svante August Arrhenius ForMemRS ( / ə ˈ r iː n i ə s , ə ˈ r eɪ n i ə s / ə- REE -nee-əs, -⁠ RAY - , Swedish: [ˈsvânːtɛ aˈrěːnɪɵs] ; 19 February 1859 – 2 October 1927) was a Swedish scientist . Originally a physicist , but often referred to as

2262-414: Is true that Miller-Urey setups produce racemic mixtures, the origin of homochirality is a separate area in origin of life research. Recent work demonstrates that magnetic mineral surfaces like magnetite can be templates for the enantioselective crystallization of chiral molecules, including RNA precursors , due to the chiral-induced spin selectivity (CISS) effect. Once an enantioselective bias

2349-678: Is used); C {\displaystyle C} is the CO 2 concentration at end of the period being studied; ln is the natural logarithm (= log base e ( log e )); and Δ F {\displaystyle \Delta F} is the augmentation of the temperature, in other words the change in the rate of heating Earth's surface ( radiative forcing ), which is measured in Watts per square meter . Derivations from atmospheric radiative transfer models have found that α {\displaystyle \alpha } (alpha) for CO 2

2436-483: The 1903 Nobel Prize in Chemistry . Arrhenius put forth 56 theses in his 1884 dissertation, most of which would still be accepted today unchanged or with minor modifications. The most important idea in the dissertation was his explanation of the fact that solid crystalline salts disassociate into paired charged particles when dissolved, for which he would win the 1903 Nobel Prize in Chemistry. Arrhenius's explanation

2523-656: The Allegheny Observatory in Pittsburgh – to calculate how much of infrared (heat) radiation is captured by CO 2 and water (H 2 O) vapour in Earth's atmosphere. Using 'Stefan's law' (better known as the Stefan–Boltzmann law ), he formulated what he referred to as a 'rule'. In its original form, Arrhenius's rule reads as follows: Here, Arrhenius refers to CO 2 as carbonic acid (which refers only to

2610-737: The Nobel Prizes . He was elected a member of the Royal Swedish Academy of Sciences in 1901. For the rest of his life, he would be a member of the Nobel Committee on Physics and a de facto member of the Nobel Committee on Chemistry. He used his positions to arrange prizes for his friends ( Jacobus van 't Hoff , Wilhelm Ostwald , Theodore Richards ) and to attempt to deny them to his enemies ( Paul Ehrlich , Walther Nernst , Dmitri Mendeleev ). In 1901 Arrhenius

2697-554: The Royal Netherlands Academy of Arts and Sciences . Eventually, Arrhenius's theories became generally accepted and he turned to other scientific topics. In 1902, he began to investigate physiological problems in terms of chemical theory. He determined that reactions in living organisms and in the test tube followed the same laws. In 1904, he delivered at the University of California a course of lectures,

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2784-411: The limiting reagent . A side reaction is an unwanted chemical reaction that can reduce the desired yield. The word synthesis was used first in a chemical context by the chemist Hermann Kolbe . Many strategies exist in chemical synthesis that are more complicated than simply converting a reactant A to a reaction product B directly. For multistep synthesis , a chemical compound is synthesized by

2871-421: The nucleobase adenine from a concentrated solution of HCN and NH 3 in water. Oró found that several amino acids were also formed from HCN and ammonia under those conditions. Experiments conducted later showed that the other RNA and DNA nucleobases could be obtained through simulated prebiotic chemistry with a reducing atmosphere . Other researchers also began using UV - photolysis in prebiotic schemes, as

2958-453: The panspermia hypothesis. In the 1920s, Leonard Troland wrote about a primordial enzyme that could have formed by chance in the primitive ocean and catalyzed reactions, and Hermann J. Muller suggested that the formation of a gene with catalytic and autoreplicative properties could have set evolution in motion. Around the same time, Alexander Oparin's and J. B. S. Haldane's " Primordial soup " ideas were emerging, which hypothesized that

3045-533: The solar corona , the aurora borealis , and zodiacal light . He thought life might have been carried from planet to planet by the transport of spores , the theory now known as panspermia . He thought of the idea of a universal language , proposing a modification of the English language . He was a board member for the Swedish Society for Racial Hygiene (founded 1909), which endorsed mendelism at

3132-422: The 1950s toward understanding how Miller-Urey chemistry behaves in various environmental settings. In 1983, testing different atmospheric compositions, Miller and another researcher repeated experiments with varying proportions of H 2 , H 2 O, N 2 , CO 2 or CH 4 , and sometimes NH 3 . They found that the presence or absence of NH 3 in the mixture did not significantly impact amino acid yield, as NH 3

3219-497: The 19th century, there was considerable acceptance of the theory of spontaneous generation , the idea that "lower" animals, such as insects or rodents, arose from decaying matter. However, several experiments in the 19th century – particularly Louis Pasteur 's swan neck flask experiment in 1859 — disproved the theory that life arose from decaying matter. Charles Darwin published On the Origin of Species that same year, describing

3306-483: The Earth's increasing surface temperature. His work played an important role in the emergence of modern climate science . In the 1960s, Charles David Keeling reliably measured the level of carbon dioxide present in the air showing it was increasing and that, according to the greenhouse hypothesis, it was sufficient to cause significant global warming . The Arrhenius equation , Arrhenius acid , Arrhenius base, lunar crater Arrhenius , Martian crater Arrhenius ,

3393-499: The Hadean Earth. A large factor controlling the redox budget of early Earth's atmosphere is the rate of atmospheric escape of H 2 after Earth's formation. Atmospheric escape – common to young, rocky planets — occurs when gases in the atmosphere have sufficient kinetic energy to overcome gravitational energy . It is generally accepted that the timescale of hydrogen escape is short enough such that H 2 made up < 1% of

3480-533: The Making [1908]) directed at a general audience, where he suggested that the human emission of CO 2 would be strong enough to prevent the world from entering a new ice age, and that a warmer earth would be needed to feed the rapidly increasing population: At this time, the accepted consensus explanation is that, historically, orbital forcing has set the timing for ice ages, with CO 2 acting as an essential amplifying feedback . However, CO 2 releases since

3567-835: The Swedish Academy of Sciences, which enabled him to study with Ostwald in Riga (now in Latvia ), with Friedrich Kohlrausch in Würzburg , Germany , with Ludwig Boltzmann in Graz, Austria , and with Jacobus Henricus van 't Hoff in Amsterdam . In 1889, Arrhenius explained the fact that most reactions require added heat energy to proceed by formulating the concept of activation energy , an energy barrier that must be overcome before two molecules will react. The Arrhenius equation gives

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3654-491: The UV flux would have been much higher on early Earth. For example, UV-photolysis of water vapor with carbon monoxide was found to yield various alcohols , aldehydes, and organic acids . In the 1970s, Carl Sagan used Miller-Urey-type reactions to synthesize and experiment with complex organic particles dubbed " tholins ", which likely resemble particles formed in hazy atmospheres like that of Titan . Much work has been done since

3741-824: The United States National Academy of Sciences in 1908. He was elected an Honorary Member of the Netherlands Chemical Society in 1909. He became a Foreign Member of the Royal Society (ForMemRS) in 1910. He was elected an International Member of the American Philosophical Society in 1911. In 1912, he was elected a Foreign Honorary Member of the American Academy of Arts and Sciences In 1919, he became foreign member of

3828-566: The apparatus used to conduct the experiment was on display at the Denver Museum of Nature and Science . In 1957 Miller published research describing the chemical processes occurring inside his experiment. Hydrogen cyanide (HCN) and aldehydes (e.g., formaldehyde) were demonstrated to form as intermediates early on in the experiment due to the electric discharge. This agrees with current understanding of atmospheric chemistry , as HCN can generally be produced from reactive radical species in

3915-564: The apparatus, which was sampled. After a day, the solution that had collected at the trap was pink, and after a week of continuous operation the solution was deep red and turbid , which Miller attributed to organic matter adsorbed onto colloidal silica . The boiling flask was then removed, and mercuric chloride (a poison) was added to prevent microbial contamination. The reaction was stopped by adding barium hydroxide and sulfuric acid , and evaporated to remove impurities. Using paper chromatography , Miller identified five amino acids present in

4002-489: The aqueous form H 2 CO 3 in modern usage). The following formulation of Arrhenius's rule is still in use today: where C 0 {\displaystyle C_{0}} is the concentration of CO 2 at the beginning (time-zero) of the period being studied (if the same concentration unit is used for both C {\displaystyle C} and C 0 {\displaystyle C_{0}} , then it doesn't matter which concentration unit

4089-403: The aqueous solution and ascorbic acid to inhibit oxidation, yields of amino acids greatly increased, demonstrating that amino acids can still be formed in more neutral atmospheres under the right geochemical conditions. In a prebiotic context, they argued that seawater would likely still be buffered and ferrous iron could inhibit oxidation. In 1999, after Miller suffered a stroke, he donated

4176-674: The atmosphere of prebiotic Earth, but, in 2005, a hydrodynamic model of hydrogen escape predicted escape rates two orders of magnitude lower than previously thought, maintaining a hydrogen mixing ratio of 30%. A hydrogen-rich prebiotic atmosphere would have large implications for Miller-Urey synthesis in the Hadean and Archean , but later work suggests solutions in that model might have violated conservation of mass and energy. That said, during hydrodynamic escape, lighter molecules like hydrogen can "drag" heavier molecules with them through collisions, and recent modeling of xenon escape has pointed to

4263-486: The atmosphere that arise when CH 4 and nitrogen break apart under ultraviolet (UV) light . Similarly, aldehydes can be generated in the atmosphere from radicals resulting from CH 4 and H 2 O decomposition and other intermediates like methanol . Several energy sources in planetary atmospheres can induce these dissociation reactions and subsequent hydrogen cyanide or aldehyde formation, including lightning, ultraviolet light, and galactic cosmic rays . For example, here

4350-550: The atmosphere, and other essential factors. His work is currently seen less as an accurate quantification of global warming than as the first demonstration that increases in atmospheric CO 2 will cause global warming, everything else being equal. Arrhenius's absorption values for CO 2 and his conclusions met criticism by Knut Ångström in 1900, who published the first modern infrared absorption spectrum of CO 2 with two absorption bands, and published experimental results that seemed to show that absorption of infrared radiation by

4437-453: The building blocks of life from simpler molecules, but these were not intended to simulate any prebiotic scheme or even considered relevant to origin of life questions. But the scientific literature of the early 20th century contained speculations on the origin of life. In 1903, physicist Svante Arrhenius hypothesized that the first microscopic forms of life, driven by the radiation pressure of stars, could have arrived on Earth from space in

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4524-538: The building blocks of proteins and other macromolecules, can abiotically be formed from gases with the addition of energy. There were a few similar spark discharge experiments contemporaneous with Miller-Urey. An article in The New York Times (March 8, 1953) titled "Looking Back Two Billion Years" describes the work of Wollman M. MacNevin at Ohio State University , before the Miller Science paper

4611-474: The conditions on the primitive Earth favored chemical reactions that synthesized complex organic compounds from simpler inorganic precursors. 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 . While evidence suggests that Earth's prebiotic atmosphere might have typically had

4698-485: The contents of his laboratory to Bada. In an old cardboard box, Bada discovered unanalyzed samples from modified experiments that Miller had conducted in the 1950s. In a " volcanic " apparatus, Miller had amended an aspirating nozzle to shoot a jet of steam into the reaction chamber. Using high-performance liquid chromatography and mass spectrometry , Bada's lab analyzed old samples from a set of experiments Miller conducted with this apparatus and found some higher yields and

4785-510: The energy source for chemical reactions. 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. Analysis of the organic fraction of the Murchison meteorite with Fourier-transform ion cyclotron resonance mass spectrometry detected over 10,000 unique compounds, albeit at very low ( ppb – ppm ) concentrations. In this way,

4872-480: The experiment and so encouraged Miller to take full credit for the work. Despite this the set-up is still most commonly referred to including both their names. After not hearing from Science for a few weeks, a furious Urey wrote to the editorial board demanding an answer, stating, "If Science does not wish to publish this promptly we will send it to the Journal of the American Chemical Society ." Miller's manuscript

4959-449: The fact that Miller–Urey experiments have not generated all 22 genetically-encoded amino acids , this does not actually conflict with the evolutionary perspective on the origin of life. Another common criticism is that the racemic (containing both L and D enantiomers ) mixture of amino acids produced in a Miller–Urey experiment is not exemplary of abiogenesis theories, as life on Earth today uses almost exclusively L-amino acids. While it

5046-601: The fifth grade, distinguishing himself in physics and mathematics , and graduating as the youngest and most able student in 1876. At the University of Uppsala, he was dissatisfied with the chief instructor of physics and the only faculty member who could have supervised him in chemistry, Per Teodor Cleve , so he left to study at the Physical Institute of the Swedish Academy of Sciences in Stockholm under

5133-400: The gas in the atmosphere was already "saturated" so that adding more could make no difference. Arrhenius replied strongly in 1901 ( Annalen der Physik ), dismissing the critique altogether. He touched on the subject briefly in a technical book titled Lehrbuch der kosmischen Physik (1903). He later wrote Världarnas utveckling (1906) (German: Das Werden der Welten [1907], English: Worlds in

5220-567: The importance of the high-energy free electrons present in the experiment. It is these electrons that produce ions and radicals, and represent an aspect of the experiment that needs to be better understood. After comparing Miller–Urey experiments conducted in borosilicate glassware with those conducted in Teflon apparatuses, a 2021 paper suggests that the glass reaction vessel acts as a mineral catalyst , implicating silicate rocks as important surfaces in prebiotic Miller-Urey reactions. While there

5307-507: The industrial revolution have increased CO 2 to a level not found since 10 to 15 million years ago, when the global average surface temperature was up to 6 °C (11 °F) warmer than now and almost all ice had melted, raising world sea-levels to about 100 feet (30 m.) higher than today's. Arrhenius estimated based on the CO 2 levels at his time, that reducing levels by 0.62–0.55 would decrease temperatures by 4–5 °C (Celsius) and an increase of 2.5 to 3 times of CO 2 would cause

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5394-400: The interlayers of layered double hydroxides like green rust over wet-dry cycles. Some scenarios for peptide formation have been proposed that are even compatible with aqueous solutions, such as the hydrophobic air-water interface and a novel " sulfide -mediated α-aminonitrile ligation" scheme, where amino acid precursors come together to form peptides. Polymerization of life's building blocks

5481-463: The mechanism of biological evolution . While Darwin never publicly wrote about the first organism in his theory of evolution, in a letter to Joseph Dalton Hooker , he speculated: But if (and oh what a big if) we could conceive in some warm little pond with all sorts of ammonia and phosphoric salts, light, heat, electricity etcetera present, that a protein compound was chemically formed, ready to undergo still more complex changes [...]" At this point, it

5568-477: The mountain of Arrheniusfjellet , and the Arrhenius Labs at Stockholm University were so named to commemorate his contributions to science. Arrhenius was born on 19 February 1859 at Vik (also spelled Wik or Wijk), near Uppsala , Kingdom of Sweden , the son of Svante Gustav and Carolina Thunberg Arrhenius, who were Lutheran. His father had been a land surveyor for Uppsala University , moving up to

5655-480: The object of which was to illustrate the application of the methods of physical chemistry to the study of the theory of toxins and antitoxins , and which were published in 1907 under the title Immunochemistry . He also turned his attention to geology (the origin of ice ages ), astronomy , physical cosmology , and astrophysics , accounting for the birth of the Solar System by interstellar collision. He considered radiation pressure as accounting for comets ,

5742-400: The organic composition of the Murchison meteorite is seen as evidence of Miller-Urey synthesis outside Earth. Comets and other 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. Some argue that comets bombarding the early Earth could have provided

5829-468: The origin of life. Simulations of protein sequences present in the last universal common ancestor (LUCA), or the last shared ancestor of all extant species today, show an enrichment in simple amino acids that were available in the prebiotic environment according to Miller-Urey chemistry. This suggests that the genetic code from which all life evolved was rooted in a smaller suite of amino acids than those used today. Thus, while creationist arguments focus on

5916-428: The physicist Erik Edlund in 1881. His work focused on the conductivities of electrolytes . In 1884, based on this work, he submitted a 150-page dissertation on electrolytic conductivity to Uppsala for the doctorate . It did not impress the professors, who included Cleve, and he received a fourth-class degree, but upon his defense it was reclassified as third-class. Later, extensions of this very work would earn him

6003-599: The plateau in HCN and aldehyde concentrations, and slowing of amino acid production rate during HCN and aldehyde depletion provided strong evidence that Strecker amino acid synthesis was occurring in the aqueous solution. Strecker synthesis describes the reaction of an aldehyde, ammonia, and HCN to a simple amino acid through an aminoacetonitrile intermediate: Furthermore, water and formaldehyde can react via Butlerov's reaction to produce various sugars like ribose . The experiments showed that simple organic compounds, including

6090-413: The possibility of a prebiotic synthesis experiment. While Urey initially discouraged Miller, he agreed to allow Miller to try for a year. By February 1953, Miller had mailed a manuscript as sole author reporting the results of his experiment to Science . Urey refused to be listed on the manuscript because he believed his status would cause others to underappreciate Miller's role in designing and conducting

6177-399: The production of amino acids . 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

6264-589: The professors at Uppsala, but Arrhenius sent it to a number of scientists in Europe who were developing the new science of physical chemistry , such as Rudolf Clausius , Wilhelm Ostwald , and Jacobus Henricus van 't Hoff . They were far more impressed, and Ostwald even came to Uppsala to persuade Arrhenius to join his research team in Riga. Arrhenius declined, however, as he preferred to stay in Sweden-Norway for

6351-558: The quantitative basis of the relationship between the activation energy and the rate at which a reaction proceeds. In 1891, he became a lecturer at the Stockholm University College ( Stockholms Högskola , now Stockholm University ), being promoted to professor of physics (with much opposition) in 1895, and rector in 1896. About 1900, Arrhenius became involved in setting up the Nobel Institutes and

6438-403: The ratio of reducing and oxidizing gases. More recently, Jeffrey Bada and H. James Cleaves, graduate students of Miller, hypothesized that the production of nitrites, which destroy amino acids, in CO 2 and N 2 -rich atmospheres may explain low amino acids yields. In a Miller-Urey setup with a less-reducing (CO 2 + N 2 + H 2 O) atmosphere, when they added calcium carbonate to buffer

6525-721: The reducing environment necessary for the Oparin-Haldane "primordial soup" scenario. Stanley Miller arrived at the University of Chicago in 1951 to pursue a PhD under nuclear physicist Edward Teller , another prominent figure in the Manhattan Project. Miller began to work on how different chemical elements were formed in the early universe, but, after a year of minimal progress, Teller was to leave for California to establish Lawrence Livermore National Laboratory and further nuclear weapons research. Miller, having seen Urey lecture on his 1952 paper, approached him about

6612-402: The smaller flask was boiled such that water vapor entered the gas chamber and mixed with the "atmosphere". A continuous electrical spark was discharged between a pair of electrodes in the larger flask. The spark passed through the mixture of gases and water vapor, simulating lightning. A condenser below the gas chamber allowed aqueous solution to accumulate into a U-shaped trap at the bottom of

6699-484: The solution: glycine , α-alanine and β-alanine were positively identified, while aspartic acid and α-aminobutyric acid (AABA) were less certain, due to the spots being faint. Materials and samples from the original experiments remained in 2017 under the care of Miller's former student, Jeffrey Bada , a professor at the UCSD , Scripps Institution of Oceanography who also conducts origin of life research. As of 2013,

6786-525: The time, and contributed to the topic of contraceptives around 1910. However, until 1938 information and sale of contraceptives was prohibited in the Kingdom of Sweden. Gordon Stein wrote that Svante Arrhenius was an atheist. In his last years he wrote both textbooks and popular books, trying to emphasize the need for further work on the topics he discussed. In September 1927, he came down with an attack of acute intestinal catarrh and died on 2 October. He

6873-625: Was a Professor of Chemistry at the University of Chicago who had a well-renowned career, including receiving the Nobel Prize in Chemistry in 1934 for his isolation of deuterium and leading efforts to use gaseous diffusion for uranium isotope enrichment in support of the Manhattan Project . In 1952, Urey postulated that the high temperatures and energies associated with large impacts in Earth's early history would have provided an atmosphere of methane (CH 4 ), water (H 2 O), ammonia (NH 3 ), and hydrogen (H 2 ), creating

6960-503: Was buried in Uppsala. He was married twice, first to his former pupil Sofia Rudbeck (1894–1896), with whom he had one son, Olof Arrhenius  [ sv ; fr ] , and then to Maria Johansson (1905–1927), with whom he had two daughters and a son. Arrhenius was the grandfather of bacteriologist Agnes Wold , chemist Svante Wold , and ocean biogeochemist Gustaf Arrhenius  [ sv ; fr ; ru ; zh ] . In developing

7047-436: Was elected to the Swedish Academy of Sciences, against strong opposition. In 1903 he became the first Swede to be awarded the Nobel Prize in Chemistry . In 1905, upon the founding of the Nobel Institute for Physical Research at Stockholm, he was appointed rector of the institute, the position where he remained until retirement in 1927. In 1911, he won the first Willard Gibbs Award. He was elected an International Member of

7134-520: Was eventually published in Science in May 1953. In the original 1952 experiment, methane (CH 4 ), ammonia (NH 3 ), and hydrogen (H 2 ) were all sealed together in a 2:2:1 ratio (1 part H 2 ) inside a sterile 5-L glass flask connected to a 500-mL flask half-full of water (H 2 O). The gas chamber was intended to represent Earth's prebiotic atmosphere , while the water simulated an ocean. The water in

7221-445: Was generated from N 2 during the spark discharge. Additionally, CH 4 proved to be one of the most important atmospheric ingredients for high yields, likely due to its role in HCN formation. Much lower yields were obtained with more oxidized carbon species in place of CH 4 , but similar yields could be reached with a high H 2 /CO 2 ratio. Thus, Miller-Urey reactions work in atmospheres of other compositions as well, depending on

7308-595: Was known that organic molecules could be formed from inorganic starting materials, as Friedrich Wöhler had described Wöhler synthesis of urea from ammonium cyanate in 1828. Several other early seminal works in the field of organic synthesis followed, including Alexander Butlerov 's synthesis of sugars from formaldehyde and Adolph Strecker 's synthesis of the amino acid alanine from acetaldehyde , ammonia , and hydrogen cyanide . In 1913, Walther Löb synthesized amino acids by exposing formamide to silent electric discharge , so scientists were beginning to produce

7395-453: Was one of the first to compile data on gases emitted from modern volcanoes and concluded that they are rich in CO 2 , H 2 O, and likely N 2 , with varying amounts of H 2 , sulfur dioxide (SO 2 ), and H 2 S. Therefore, if the redox state of Earth's mantle — which dictates the composition of outgassing – has been constant since formation , then the atmosphere of early Earth was likely weakly reducing, but there are some arguments for

7482-512: Was published in May 1953. MacNevin was passing 100,000V sparks through methane and water vapor and produced " resinous solids" that were "too complex for analysis." Furthermore, K. A. Wilde submitted a manuscript to Science on December 15, 1952, before Miller submitted his paper to the same journal in February 1953. Wilde's work, published on July 10, 1953, used voltages up to only 600V on a binary mixture of carbon dioxide (CO 2 ) and water in

7569-552: Was that in forming a solution , the salt disassociates into charged particles that Michael Faraday had given the name ions many years earlier. Faraday's belief had been that ions were produced in the process of electrolysis , that is, an external direct current source of electricity was necessary to form ions. Arrhenius proposed that, even in the absence of an electric current, aqueous solutions of salts contained ions. He thus proposed that chemical reactions in solution were reactions between ions. The dissertation did not impress

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