Editing Miller–Urey experiment (section)

== Experiment ==
[[File:Miller-Urey experiment - Work by the C3BC consortium, licensed under CC-BY-3.0.webm|thumb|Descriptive video of the experiment]]
In the original 1952 experiment, methane (CH<sub>4</sub>), ammonia (NH<sub>3</sub>), and hydrogen (H<sub>2</sub>) were all sealed together in a 2:2:1 ratio (1 part H<sub>2</sub>) inside a sterile 5-L glass flask connected to a 500-mL flask half-full of water (H<sub>2</sub>O). The gas chamber was intended to represent [[Prebiotic atmosphere|Earth's prebiotic atmosphere]], while the water simulated an ocean. The water in 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 (laboratory)|condenser]] below the gas chamber allowed [[aqueous solution]] to accumulate into a U-shaped trap at the bottom of 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]].<ref name="miller19532" /> The boiling flask was then removed, and [[Mercury(II) chloride|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 the solution: [[glycine]], [[Alanine|α-alanine]] and [[Beta-Alanine|β-alanine]] were positively identified, while [[aspartic acid]] and [[Alpha-Aminobutyric acid|α-aminobutyric acid]] (AABA) were less certain, due to the spots being faint.<ref name="miller19532" />

Materials and samples from the original experiments remained in 2017 under the care of Miller's former student, [[Jeffrey Bada]], a professor at the [[University of California, San Diego|UCSD]], [[Scripps Institution of Oceanography]] who also conducts origin of life research.<ref name="Dreifus-2010">{{cite news |last=Dreifus |first=Claudia |author-link=Claudia Dreifus |date=2010-05-17 |title=A Conversation With Jeffrey L. Bada: A Marine Chemist Studies How Life Began |newspaper=nytimes.com |url=https://www.nytimes.com/2010/05/18/science/18conv.html |url-status=live |archive-url=https://web.archive.org/web/20170118034218/http://www.nytimes.com/2010/05/18/science/18conv.html |archive-date=2017-01-18}}</ref> {{as of|2013}}, the apparatus used to conduct the experiment was on display at the [[Denver Museum of Nature and Science]].<ref>{{cite news |title=Astrobiology Collection: Miller-Urey Apparatus |publisher=Denver Museum of Nature & Science |url=http://www.dmns.org/science/museum-scientists/david-grinspoon/funky-science-wonder-lab/research-updates/astrobiology-collection-miller-urey-apparatus |archive-url=https://web.archive.org/web/20130524090309/http://www.dmns.org/science/museum-scientists/david-grinspoon/funky-science-wonder-lab/research-updates/astrobiology-collection-miller-urey-apparatus/ |archive-date=2013-05-24}}</ref>