Life on Earth may not have begun with a big lightning strike in the ocean, as scientists once thought.
Instead, tiny electric sparks from crashing waves and waterfalls—called “microlightning”—might have played a key role in creating the first building blocks of life.
A new study from Stanford University shows that when water droplets are sprayed into gases that were likely present on early Earth, they can form organic molecules.
These include carbon-nitrogen compounds, which are essential for DNA, RNA, and proteins.
The research, published in Science Advances, offers a fresh take on the well-known Miller-Urey experiment.
A new twist on an old theory
The Miller-Urey experiment, conducted in 1952, showed that organic molecules could form when electricity (like lightning) was applied to a mix of water and gases such as methane, ammonia, and hydrogen.
This led to the idea that life may have started from a lightning strike.
However, critics argue that lightning was too rare and the ocean too vast for this to be the main source of life’s ingredients.
Now, Stanford researchers propose an alternative: small water droplets producing tiny sparks could have done the same job—without needing lightning.
How water creates tiny sparks
In their study, the researchers found that when water droplets are divided—like in a spray or splash—they develop different electrical charges. Larger droplets tend to have a positive charge, while smaller ones are negative.
When they come close together, tiny sparks of electricity jump between them, similar to how lightning forms in clouds.
This process, called “microlightning,” happens frequently in nature—whenever waves crash, waterfalls spray, or raindrops splash. Though these flashes are too small to see, they carry enough energy to trigger important chemical reactions.
Life’s building blocks from water sprays
To test this idea, the research team sprayed room-temperature water into a gas mixture similar to early Earth’s atmosphere. This mixture included nitrogen, methane, carbon dioxide, and ammonia. The result? The tiny sparks helped create key organic molecules, such as hydrogen cyanide, the amino acid glycine, and uracil, a component of RNA.
These findings suggest that instead of rare lightning strikes, countless tiny water droplets hitting rocks or crashing against shorelines might have sparked the first steps toward life.
“Early Earth had water splashing everywhere—waves, waterfalls, and raindrops,” said senior author Richard Zare. “This could explain how life’s essential molecules formed in a way that makes more sense than the lightning theory.”
Zare’s team has been studying how tiny water droplets behave. They have found that these droplets can also help produce ammonia, a key ingredient in fertilizer, and hydrogen peroxide, a powerful disinfectant.
“We usually think of water as harmless, but in tiny droplets, it’s surprisingly reactive,” Zare said. This discovery could change how we understand both the origins of life and water’s hidden power in everyday chemistry.
