Tiny ‘microlightning' flashes inside water droplets may have sparked life on Earth

Independent

14-03-2025

Life may have first emerged on Earth after crashing waterfalls or breaking waves sparked tiny 'microlightning' discharges in water droplets, according to a new study.
The research, published in the journal Science Advances, demonstrates that water sprayed into a mixture of gases present in the early atmosphere can lead to the formation of organic chemical compounds such as uracil, one of the molecules in RNA.
It reveals that tiny electric discharges between oppositely charged water droplets can make the building block molecules of life.
'We propose that this is a new mechanism for the prebiotic synthesis of molecules that constitute the building blocks of life,' study author Richard Zare from Stanford University said.
For nearly two billion years after it formed, the Earth contained a swirl of chemicals, but organic molecules needed for making proteins, enzymes, nucleic acids, and other compounds essential for life had not emerged.
Precisely how these biological components came about is a mystery.
One famous experiment conducted in 1952 by American chemists Stanley Miller and Harold Urey provided a possible explanation: lightning striking the oceans and interacting with early atmospheric gases such as methane, ammonia and hydrogen could have created life-building organic molecules.
However, critics pointed out that lightning flashes were too infrequent and the oceans too large and dispersed for this scenario.
Now, Dr Zare and his team have an alternate hypothesis that doesn't require infrequent lightning for the emergence of the early organic molecules.
Their study shows that larger water droplets often carry positive charges and smaller ones negative. When such oppositely charged droplets come close to each other, sparks jump between them. This is what they call 'microlightning'.
The researchers sent sprays of room-temperature water through an Early-earth gas mixture containing nitrogen, methane, carbon dioxide, and ammonia, and used high-speed cameras to document the tiny flashes of light.
The result was the formation of organic molecules with carbon-nitrogen bonds like hydrogen cyanide, the amino acid glycine, and the RNA chemical uracil.
Based on this result, the study claims that lightning strikes are not necessary, and tiny sparks from crashing waves or waterfalls may have jump-started life on the planet.
'On early Earth, there were water sprays all over the place, in crevices or against rocks, and they can accumulate and create this chemical reaction,' Dr Zare said.
'I think this overcomes many of the problems people have with the Miller-Urey hypothesis.'