A Powerful New Tool to Find Alien Life
Fatty acids on Mars! Amino acids on asteroids! Complex carbon chains in interstellar clouds!
There have been many exciting headlines about the discovery of organic molecules in space, but so far, no life. Indeed, several non-living processes, such as fusion within stars, are capable of producing these molecules. This raises an important question: if we detect organic compounds from extraterrestrial life, how will we know? New research published in Natural astronomy adds a powerful new tool to our toolbox.
According to planetary scientists at the University of California, Riverside, the key to distinguishing biotic from abiotic organic compounds lies in their organization. “We show that life does not just produce molecules,” study author Fabian Klenner explained in a statement. “Life also produces an organizing principle that can be seen by applying statistics. »
Read more: “Will we know about extraterrestrial life when we see it? »
The researchers applied a statistical framework used in ecology to describe different ecosystems by quantifying their richness (how many species live there) and evenness (how evenly distributed they are). After examining 100 different datasets of organic compounds found in microbes, fossils, meteorites and more, the researchers were able to determine the unique characteristics that distinguish biotic compounds from abiotic compounds.
Amino acids produced by life are more evenly distributed than abiotic amino acids, which tend to be shorter, simpler chains. Abiotic fatty acids, on the other hand, have a more uniform distribution than those present in living cells (and mainly constitute cell membranes). Surprisingly, this simple test is sensitive enough to detect the biological origins of a compound when the sample has been significantly degraded. Researchers were able to distinguish the statistical signals of life from fossilized dinosaur eggshells.
However, the researchers emphasize that this new test cannot be used alone to definitively “prove” the existence of extraterrestrial life. Instead, it’s another arrow in our biosignature detection quiver. “Our approach is an additional way to assess whether life could have been there,” Klenner said. “And if different techniques all point in the same direction, then it becomes very powerful.”
The next headline you read about the search for organic compounds in space might include a few more exclamation points.
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Main image: NASA
