Living things leave behind tell-tale signs of their existence: fossilized bones, DNA, the chemical byproducts of metabolism. Living things on Earth, that is. There currently exists no predictive theory to completely guide astrobiologists searching for life beyond our planet, where the chemical signatures of life, and the geo- and atmospheric chemistries under which it evolved, might look quite different from Earth.
In early November, NASA’s Astrobiology Program launched the new Interdisciplinary Consortia for Astrobiology Research (ICAR), supporting eight teams focusing on specific outstanding questions in astrobiology. SFI External Professor Sara Walker (Arizona State University) is leading one of the teams, an interdisciplinary group of theorists and experimentalists whose expertise in geochemistry, microbiology, exoplanet atmospheres, network theory, and complex systems will help them explore the question: What detectable universal patterns distinguish living chemistries across diverse planetary environments?
Answering this question, Walker says, will help astrobiologists develop a theoretical framework to refine their search for extraterrestrial life, and to be able to recognize life as we don’t know it.
“So far, astrobiology has been really focused on the looking for chemistry of life as we know it — amino acids, metabolic bi-products like oxygen or methane,” says Walker. “What we’re trying to do is say that life is not a property of individual molecules; it’s a systems-level property that emerges from the interactions of many molecules and reactions. We want to understand and quantify the patterns in those molecules and reactions, then use those as new predictors of biosignatures.”
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