A Quintillion Lightning Strikes May Have Kick-Started Life on Earth

Understanding lightning strikes' role could have implications in the search for life beyond our planet.
Derya Ozdemir
A sample of fulgurite being analyzed.Benjamin Hess

Scientists are step by step unraveling the cornerstones of life by tracing back what could have taken place on Earth millions of years ago. Now, a new study by researchers at Yale and the University of Leeds suggests that lightning strikes may have provided the spark of life by unlocking the needed phosphorus for the creation of biomolecules that would be the basis of life on Earth, according to a press release by the university.

While science has a vague understanding of how life came to be on our planet, some things don't add up due to our lack of knowledge, and how life got started on Earth is still one of science's most profound mysteries. For example, we know that the earliest undisputed signs of life showed up 3.5 billion years ago, but there is a problem with that since life didn't have the right ingredients to came to be yet.

In order to achieve life on Earth, a precise cocktail of critical ingredients is needed, and one of those ingredients is phosphorus, which plays a key role in all life processes from movement to reproduction. However, during those times, phosphorus was trapped inside minerals on early Earth.

Releasing usable phosphorous

The team of researchers questioned how Earth's phosphorus get into a usable form to help create biomolecules crucial to life. As described in the study published in Nature Communications, flashes of lightning could have freed phosphorus, leading to the creation of the stuff needed for life.

Since meteorites contain phosphorus mineral schreibersite, the researchers first examined them. If meteorites struck the Earth's surface with enough frequency, this could explain a lot. However, it was seen that frequency of impacts during the early days of Earth was estimated to be too low.

However, that wasn't the only place schreibersite was present, as diverted by a separate team of researchers in 2009. Schreibersite can be found in fulgurites -- glassy veins of melted sand, soil, or rock that form when lightning strikes the ground. 

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In order to test this idea, the team led by Benjamin Hess, a graduate student in Yale’s Department of Earth & Planetary Sciences, used computer modeling. They estimated that the early Earth experienced far more lightning than we do now. While today we see about 560 million flashes of lightning per year, the ancient Earth would see 1–5 billion flashes. Out of those, between 100 million and 1 billion would strike the ground.

The researchers state that, over a period of a billion years, a quintillion lightnings could have potentially struck the ground and helped release usable phosphorous.

"Unlike meteorite impacts, which are extremely destructive, lightning strikes would provide a relatively non-destructive, continual source of reactive phosphorus species that would not interfere with the delicate evolutionary steps required for complex prebiotic synthesis," the authors wrote.

Understanding how life came to be on Earth and the role of lightning strikes as a way of releasing usable phosphorous could have immense implications 

"Our findings are likely applicable to any planet which has an atmosphere that generates lightning. So long as a planet has a significant amount of lightning, it would have a source of phosphorus needed for the emergence of life," Hess explained.