Charges cause water droplets in an early-Earth atmosphere to build up pre-life chemicals.
We know Earth formed roughly 4.54 billion years ago and that the first single cell lifeforms were present roughly 1 billion years after that. What we don’t know is what triggered the process that turned our planet from a barren ball of rock into a world hosting amazing abundance of lifeforms. “We’re trying to understand how do you go from non-life to life. Now I think we have made a real contribution to solving this mystery,” says Richard Zare, a Stanford University chemistry professor. Zare is the senior author of the recent study into a previously unknown electrochemical process that might have helped supply the raw materials needed for life.
Zare’s team demonstrated the existence of micro-lightning, very small electricity discharges that occur between tiny droplets of water spray. When triggered in a mixture of gases made to replicate the atmosphere on early Earth, these micro-lightnings produced chemical compounds used by present-day life, like glycine, uracil, and urea, along with chemical precursors like cyanoacetylene, and hydrogen cyanide. “I’m not saying it’s the only way this could happen—I wasn’t there,” Zare acknowledged. “But it’s a new plausible mechanism that gives us building blocks of life.”
Lightning in the bulb
Scientific research into the beginnings of life on Earth started in the 1920s with Aleksander Oparin and J.B.S. Haldane, scientists who independently proposed that life on Earth could have arisen through a process of gradual chemical evolution. In their view, inorganic molecules might have reacted due to energy from the Sun or lightning strikes to form life’s building blocks, like amino acids. Those building blocks, Oparin and Haldane argued, could have accumulated in the oceans, making a “primordial soup.”