AFP – Lightning may have supplied the primordial Earth with enough phosphorus to support the emergence of life, according to new research on Tuesday that offered an alternative explanation for how living organisms were born.
Phosphorus is a vital component of life as we know it, forming basic cellular structures and the double helix form of DNA and RNA.
Billions of years ago on early Earth, most of the available phosphorus was locked up in insoluble minerals.
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However, one mineral, schreibersite, is highly reactive and produces phosphorous capable of forming organic molecules.
Since most of the schreibersite on Earth comes from meteorites, it was long thought that the appearance of life here was linked 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 from the US and Britain used state-of-the-art imaging techniques to analyze the amount of phosphorous-providing mineral that is formed in each ray.
They then estimated how much schreibersite might have been produced over the eons before and around the time life emerged on Earth, about 3.5 billion years ago.
“Lightning on early Earth may have provided a significant amount of reduced phosphorus,” Benjamin Hess, lead author of the study from Yale’s Department of Earth and Planetary Sciences, told AFP.
“And by synthesizing the best of our knowledge about conditions on the early Earth, I think our results confirm this hypothesis.”
Writing in the journal Nature Communications, Hess and his colleagues estimated that the lightning could have produced between 110 and 11,000 kilograms of phosphorus a year.
Using weather simulations on early Earth, they said that while meteorite impacts began to wane after the Moon formed 4.5 billion years ago, lightning surpassed space rocks in phosphorus production about 3.5 billion years ago. years.
That moment coincides with the origin of life.
Hess said the research did not completely rule out meteorites as another life-giving source of phosphorus.
“Meteorite impacts at the time of the emergence of life are much smaller than was thought a decade ago,” he said.
“But I don’t see our work as a competition against meteorites as a source of phosphorus. The more fonts the better. “
He said he wanted to find out if the lightning produces trace amounts of phosphorus on other planets where meteorite impacts are rare.
“Meteorite impacts diminish over time, while lightning strikes, at least on Earth, are relatively constant over time,” Hess added.