Mashable reports on astrobiology research that may have found a simpler (and, importantly, more portable) way to detect traces of life on alien planets … by measuring up amounts of chemicals rather than identifying specific life-related molecules:
It turns out a strong statistical divide exists between biological and nonbiological samples, according to a new study. The results are published in Nature Astronomy. Though looking for molecular diversity in a sample is not a silver bullet for detecting aliens, it could offer one more strong piece of evidence to weigh in the balance.
“Astrobiology is fundamentally a forensic science,” said Gideon Yoffe, lead author of the paper and a researcher at the Weizmann Institute of Science in Israel, in a statement. “We’re trying to infer processes from incomplete clues, often with very limited data collected by missions that are extraordinarily expensive and infrequent.”
In the study, amino acids from biological samples usually contained a wider and more balanced and organized mix of compounds because cells actively make many compounds for specific jobs. Abiotic samples — specimens formed without life — tended to look sparse, with a few simple amino acids dominating the mixture. Some contaminated meteorites shifted closer to the biological group, indicating that biology changes chemical patterns in recognizable ways.
The researchers also found samples that leaned in the other direction. Biological samples that had suffered heavy damage from heat, radiation, or age started to resemble nonliving chemistry because they lost molecular diversity over time. Ancient rocks, fluids from hydrothermal vents, and some fossils all showed signs of this deterioration.
Scientists wondered whether radiation could erase the biological signal. They simulated conditions in the icy surface layers of Europa, one of Jupiter’s moons, and found that the diversity pattern often survived, even after substantial chemical damage.
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Curiosity or Perseverance could potentially do this kind of statistical test if ever the rovers were to detect a broad suite of related organic compounds and measure the reliable relative amounts of those different molecules, said Fabian Klenner, a UC Riverside assistant professor of planetary sciences and coauthor on the paper. The current limitation isn’t that the rovers are incapable of analyzing molecular diversity, but that they need a sample rich and varied enough in organic data.
The technique might be especially useful for NASA’s eight-rotor Dragonfly aircraft, which is expected to explore Titan, an icy moon of Saturn, in the mid-2030s. The aircraft will have a mass spectrometer device designed to analyze and characterize organic molecules.
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You can read more of Klenner’s research here, at Nature Astronomy.