Art and literature have often depicted the creation of life with big, dramatic moments — often involving electricity.
Mary Shelley’s Frankenstein got zapped into action. Michelangelo’s God (after six REALLY busy days) seemed to send an invisible but palpable spark into Adam’s extended finger, waking him into existence on the Sistine Chapel’s ceiling.
The same is true for one scientific theory of life’s creation on Earth.
Lightening and Life Creation
The theory states that a lightning bolt struck the ocean, triggering a chemical chain reaction that transformed inorganic compounds into organic ones. That scenario, called the Miller-Urey hypothesis, arose from a 1952 experiment showing that a mixture of water and inorganic molecules could produce organic ones after electricity was applied to the mix.
Now, a new experiment demonstrates that life could have formed through much smaller and less dramatic electrochemical interactions, according to a paper in Science Advances.
Read More: Minerals Reveal a New Understanding of Original Life on Earth
Tiny Volts of Microlightning
Stanford University researchers sprayed water into a mixture of gases thought to have existed in Earth’s early atmosphere. That spray, by itself, produces small electrical charges. Then, the tiny volts — which the researchers call “microlightning” — coax inorganic molecules to transform into organic ones, including uracil. That molecule, with its carbon-nitrogen bonds, is a key component of both DNA and RNA.
“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,” Richard Zare, a Stanford chemistry professor and an author of the paper, said in a press release.
Scientists believe that Earth’s “chemistry set” had plenty of chemicals swirling about its first few billion years of existence. However, the theory is that there were few, if any, organic compounds in the mix — especially ones with that essential carbon-nitrogen bond.
The Miller-Urey experiment provided one possible explanation for how gases like methane, ammonia, and hydrogen could create these organic molecules via lightning strikes. However, the theory’s critics say lightning is too infrequent and the chemicals in the ocean too spread about for this to be a workable scenario.
Small but Mighty
Zare and his team first experimented with how water droplets developed electrical charges when split by a spray or splash. They observed that larger droplets often carried positive charges, while smaller ones were negative. Sometimes, when two oppositely charged droplets got close to each other, sparks jumped between. The process resembles how energy is built up in clouds and then released as lightning.
Since these mini bolts are so hard to see, the researchers captured them with high-speed cameras. Despite its small size, microlightning still carries a good bit of energy.
Molecular Life Source
Next, the researchers sent sprays of room temperature water into a gas mixture including nitrogen, methane, carbon dioxide, and ammonia gases, all of which are thought to have been around on early Earth. This interaction created organic molecules with carbon-nitrogen bonds.
Besides being chemically viable, the researchers argue that this scenario for jump-starting life is much more statistically probable.
“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,” Zare said. “I think this overcomes many of the problems people have with the Miller-Urey hypothesis.”
Read More: Planetary Evolution May be the Reason for Human Life, and Life Elsewhere
Article Sources
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Before joining Discover Magazine, Paul Smaglik spent over 20 years as a science journalist, specializing in U.S. life science policy and global scientific career issues. He began his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.
