Lightning strikes may have supplied primordial Earth with enough phosphorus to support the emergence of life, according to new research that offers an alternative explanation as to how living organisms were born.
Phosphorus is a vital building block of life as we know it, forming basic cell structures and the double helix shape of DNA and RNA.
Billions of years ago on early Earth, most of the available phosphorus was locked away in insoluble minerals. However one mineral, schreibersite, is highly reactive and produces phosphorus capable of forming organic molecules.
Since most schreibersite on Earth comes from meteorites, the emergence of life here has long been thought to be tied to the arrival of extraterrestrial rocks. But schreibersite is also contained within the glass-like rock formed by lightning strikes in some types of clay-rich soils.
Researchers in the US and Britain used state-of-the-art image techniques to analyze the amount of the phosphorus-giving mineral formed in each lightning strike. They then estimated how much schreibersite could have been produced over the eons before and around the time of the emergence of life on Earth, around 3.5 billion years ago.
“Lightning strikes on early Earth may have provided a significant amount of reduced phosphorus,” Benjamin Hess, lead study author from Yale’s Department of Earth and Planetary Sciences, says.