The origin of life on Earth is one of science’s biggest questions, and previous theories have suggested that lightning may have played a role.
While previous studies say volcanic or atmospheric lightning may have triggered chemical reactions that created organic molecules, a new study says that microlightning between oppositely-charged water droplets could have been the cause.
These imperceptible charges would overcome some of the original lightning theories’ limitations while providing a new avenue for exploration into life’s origins.
Why is there anything instead of nothing? The question is one of the greatest mysteries underpinning nearly every scientific field. Particle physicists ponder why matter exists, when the Big Bang should’ve produced self-annihilating antimatter in equal measure. Neuroscientists explore why animals exhibit forms of subjective consciousness rather than just a collection of electrical impulses. Biologists explore perhaps the most vital question of all: how did Earth give rise to life?
Of course, such a profound question is bound to inspire a plethora of possible theories—both scientific and otherwise. One of the leading theories, first proposed by American scientists Stanley Miller and Harold C. Urey back in 1953, suggests that atmospheric lightning may have kickstarted the production of amino acids by inducing chemical reactions on early Earth. This idea continues to hold sway today, as a Harvard University study last year supported the idea that cloud-to-ground lightning strikes (particularly ones produced by volcanic activity) could’ve provided life’s necessary ingredients, including molecules with carbon-nitrogen bonds.
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However, some critics suggest that such a genesis theory likely has a low probability, due to lightning’s infrequency and the dispersal of the ingredients required for this theory to take place. Now, a new study from Stanford University similarly explores the idea of life’s electrifying beginnings, but in another context—microlightning in water droplets. This new idea suggests that spray from waterfalls or breaking waves could have created its own electricity between oppositely charged water droplets. This could theoretically address one of the main concerns of the original theory, as the “lightning” is located among water droplets themselves. The results of the study were published in the journal Science Advances.
“We usually think of water as so benign, but when it’s divided in the form of little droplets, water is highly reactive […].On early Earth, there were water sprays all over the place—into crevices or against rocks, and they can accumulate and create this chemical reaction,” Richard Zare, senior author of the study from Stanford, said in a press statement. “I think this overcomes many of the problems people have with the Miller-Urey hypothesis.”
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In the study, Zare and his team used high-speed cameras to capture flashes of light called “microlightning” between large positively-charged water droplets and smaller negatively charged ones. They sent sprays of room temperature water into a chamber filled with nitrogen, methane, carbon dioxide, and ammonia gases—a.k.a. the atmosphere of early Earth. The team found that this reactive water created the molecules necessary for life with carbon-nitrogen bonds, including hydrogen cyanide, the amino acid glycine, and uracil.
“Microelectric discharges between oppositely charged water microdroplets make all the organic molecules observed previously in the Miller-Urey experiment, and we propose that this is a new mechanism for the prebiotic synthesis of molecules that constitute the building blocks of life,” Zare said in a press statement.
Both biologists and astrobiologists have thoroughly established the importance of water for habitable worlds, but if this new theory holds up to scrutiny, that importance has been drastically understated.
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Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.