Minerals that were transferred to Earth in meteorites more than 4 billion years ago have long been considered vital ingredients for life to thrive on our planet.
Illustration of lightning hitting Earth 4 billion years ago.
However, according to geologists, lightning strikes are just as important as meteorites to create perfect conditions for life on Earth.
Scientists believe that the minimum amount of minerals present on early Earth was caused by billions of lightning strikes.
Detect important minerals
A study published in Nature Communications led by scientist Benjamin Hess of the School of Earth and Environment, at the University of Leeds (UK) looked at the possibility that lightning could contribute to life.
The scientists found that life could develop on Earth-like planets through the same mechanism at any time if the atmospheric conditions were right.
Hess et al. Studied an exceptionally large and primitive fulgurite sample. This is a rock created when lightning strikes the ground. This model was formed when lightning struck a house in Glen Ellyn, Illinois (USA) in 2016 and donated to the Geology department at the nearby Wheaton College.
The Leeds researchers were initially interested in how fulgurite was formed, but were later intrigued when they discovered that there was an unusual amount of a phosphorus mineral called schreibersite in the sample at Glen Ellyn.
Phosphorus is essential for life and plays an important role in all life processes from movement to growth and reproduction. Phosphorus has been present on Earth since infancy and is in minerals that cannot be dissolved in water, however, schreibersite can.
Mr. Hess is a graduate student at Yale University, Connecticut (USA), said, “Many people believe that life on Earth originates from shallow surface waters according to the famous” small warm pond “concept of the house. Darwin Science ”.
“Most models of how life might form on the Earth’s surface show that meteors carry small amounts of schreibersite.
Our research found a relatively large amount of shreibersite in fulgurite “- he said -” Lightning hits the Earth regularly, which proves that phosphorus is necessary for the origin of life on the Earth’s surface not only. rely on asteroid collisions.
Perhaps more importantly, this also means that the formation of life on another Earth could still take place long after meteoric collisions became rare.
The phosphorus minerals produced by the lightning bolts exceeded those from meteorites when Earth was about 3.5 billion years old (the age of the earliest known microscopic fossils), the team estimated. That underscores the importance of lightning to life on Earth.
Furthermore, lightning bolts are much less destructive than meteorite collisions, meaning they are less likely to interfere with fragile evolutionary paths in which life can
develope.
The fulgurite was excavated in Glen Ellyn, Illinois (USA).
The role of lightning quantity
Lightning is also a topic of interest to scientists when thinking about life on Earth in the early days because it leads to the production of gases like nitrous oxide that played a role in the origin of life. .
Hess and his other researchers used this existing research to investigate and review the rate of lightning strikes on early Earth. Today, we have 560 million lightning strikes a year.
Meanwhile, early Earth, this number was from 1 to 5 billion per year, of which 100 million to 1 billion lightning strikes the ground. Over a billion years, lightning strikes can reach 1 trillion and generate a lot of phosphorus.
In the early days, lightning struck more on Earth because there was more carbon dioxide in the atmosphere. Carbon dioxide contributes to global temperatures and the higher the temperature, the more intense and frequent the storms are, Hess said.
“Carbon dioxide levels soared on Earth early after a Mars-sized object crashed into Earth and created the Moon 4.5 billion years ago. This also releases a lot of gas from inside the Earth, like carbon dioxide, which then gets trapped in the Earth’s atmosphere and leads to more lightning, ”explained Hess.
The fulgurite fragment is found in Glen Ellyn, Illinois (USA).
Expert review
Dr., Associate Professor of Geochemistry Jason Harvey and Professor of Geology and Structural Construction Sandra Piazolo at Leeds University’s School of Earth and Environment advised Mr. Hess on the above research project.
“The initial meteor bombardment was a one-time event in the Solar System,” said Dr. Harvey. When the planets reach their mass, the additional distribution of phosphorus from the meteorites becomes negligible.
On the other hand, lightning is not a one-off event, the elements necessary for the formation of life can thus be transferred to the surface of a planet. This means that life can appear on Earth-like planets at any given time.
Meanwhile, Professor Piazolo said: “The above interesting research opens the door to some future paths when searching for and analyzing in depth new fulgurite in the early Earth-like environment, analyzing The effect of heating on other minerals is to realize similar characteristics.
There is also a further analysis of this particularly well preserved fulgurite to determine the extent of the physical and chemical processes within it ”.
“All these studies will help to improve our understanding of the importance of fulgurite in changing the chemical environment of the Earth over time” – Professor Piazolo added.
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