
Left: original diagram of Stanley Miller's 1952 amino acid synthesis experiment. Right: a photo of Miller reconstructing his experiment.

In experiments, Miller-Urey experiment, or "Urey-Miller experiment", refers to the 1952 synthesis, by American bio-chemist (chnops-chemist) Stanley Miller, under the guidance of planetary chemist Harold Urey, of organic compounds (specifically the amino acids: glycine, α-alanine, β-alanine, and possibly aspartic acid and α-amino-n-butyric acid) from inorganic chemicals (specifically: methane CH4, ammonia NH3, water H20, and hydrogen H2) using an electrical discharge (see: lightning origin of life theory); thereby giving seeming experimental justification to the hypothesis of abiogenesis. [1]

The experiment was conducted in December 1952 and received in journal form submission to Science on 13 February 1953.

Synonyms include: Urey-Miller experiment or Miller experiment.

Preliminaries
The Miller-Urey experiment in some sense is a realization of English naturalist Charles Darwin’s 1871 warm pond model: [2]

“The original spark of life may have begun in a warm little pond, with all sorts of ammonia and phosphoric salts, lights, heat, electricity, etc., present, so that a protein compound was chemically formed ready to undergo still more complex changes.”

In 1924, Russian bio-chemist (chnops-chemist) Alexander Oparin published his The Origin of Life. Miller cites this as a preliminary in regards to his experiment.

In 1951, English molecular biologist (chnopsologist) John Bernal published his Physical Basis of Life (along with an earlier 1949 article published in the Proceedings of the Physical Society of London). Miller cites these as preliminaries to his experiment.

In 1952, planetary chemist Harold Urey, his The Planets: Their Origin and Development, speculated that the early terrestrial atmosphere was probably composed of ammonia, methane, and hydrogen. Urey a student of American physical chemist Gilbert Lewis and mentor to Stanley Miller. Urey gave Miller "many helpful suggestions and guidance in the course of [his] investigation". [1]

		d
Left: a labeled an annotated version of the Miller-Urey experiment. Right: a paper chromatogram showing the products of Miller's experiment, namely: the amino acids: glycine, α-alanine, β-alanine, and possibly aspartic acid and α-amino-n-butyric acid; where A and B were yet unidentified products. [1]

Discussion
The Miller-Urey experiment is frequently cited as scientific proof of synthesis of organic (or organic life) from inorganic (or inorganic life) or colloquially as the scientific proof of life from non-life.

References
1. Miller, Stanley L. (1953). “A Production of Amino Acids Under Possible Primitive Earth Conditions”, Science, 117:528-29.
2. Darwin, Charles. (1871). “Letter to Joseph Hooker”, in: The Life and Letters of Charles Darwin, Including an Autobiographical Chapter, Vol 3. (pg. 18). John Murray.

External links
● Miller-Urey experiment – Wikipedia.