Miller–Urey experiment facts for kids
The idea was to simulate hypothetical conditions thought to be present on the early Earth (Hadean or early Archaean). It was a test of the chemical origins of life. Specifically, the experiment tested Alexander Oparin's and J.B.S. Haldane's hypothesis that conditions on the primitive Earth favored chemical reactions that synthesized organic compounds from inorganic precursors. Considered to be the classic experiment on the origin of life, it was conducted in 1952 and published in 1953 by Stanley Miller and Harold Urey at the University of Chicago.
After Miller's death in 2007, scientists examined sealed vials preserved from the original experiments. They were able to show that there were well over 20 different amino acids produced in Miller's original experiments. That is considerably more than those Miller originally reported, and more than the 20 that naturally occur in life.
Moreover, some evidence suggests that Earth's original atmosphere might have had a different composition than the gas used in 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.
Note that organic compounds, including amino acids, are present in the meteorite dust which rains down on Earth. Therefore, interest in abiogenesis and the origin of life has shifted to the question of how cells and large macromolecules formed.
Miller–Urey experiment Facts for Kids. Kiddle Encyclopedia.