An international research team has found a way to quantify the structures of complex molecules that could help identify the unique chemical signatures of life forms on other planets or possibly new life forms created in the laboratory.
âOur system is the first falsifiable hypothesis for the detection of life. It is based on the idea that only living systems can produce complex molecules that cannot randomly form in any amount. â- Professor Lee Cronin.
Scientists from the University of Glasgow under the direction of Professor Lee Cronin, as well as staff from NASA and Arizona State University, used “assembly theory” sites. This decomposition provides a measure of complexity, the so-called molecular arrangement number, which differs from all other measures of complexity because it is both calculable and directly observable. Molecular assembly theory can also be used to explain that the greater the number of steps it takes to break down a given complex molecule, the less likely the molecule was created without life.
Identification of chemical signatures
One of the greatest challenges in finding extraterrestrial life was identifying life’s unique chemical signatures, which led to several ultimately unproven claims about the discovery of extraterrestrial life. The metabolic experiments of NASA’s Mars lander Viking, for example, discovered only simple molecules whose existence alongside living processes could be explained by natural, non-living processes.
Professor Cronin, Regius Professor of Chemistry at the University of Glasgow, said: âOur system is the first falsifiable hypothesis to detect life. It is based on the idea that only living systems can produce complex molecules that cannot randomly form in any quantity. With this we avoid the problem of the definition of life – instead we concentrate on the complexity of chemistry. “
A life detection tool based on this method could be used on missions to extraterrestrial locations to detect biosignatures or even detect the emergence of new forms of artificial life in the laboratory.
Professor Cronin added, âThis is important because developing an approach that cannot produce false positives is critical to supporting the first discovery of off-earth life, an event that happened only once in human history will happen.”
‘Identifying molecules as biosignatures using assembly theory and mass spectrometry’, is published in Nature Communications. The research was supported by funding from the Engineering and Physical Sciences Research Council (EPSRC), the John Templeton Foundation, the European Research Council (ERC), and the Defense Advanced Research Projects Agency (DARPA).
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