Between 3,500 and 4,500 million years ago, about a trillion rays fell on our planet , at which time the first living organisms emerged, according to a new research led by scientists from the universities of Yale and Leeds and collected by the magazine Nature.
The mystery of life’s recipe
One of the most relevant mysteries for science is how life began on Earth and if it also appeared on other planets. This study puts on the table that this massive shower of electrical discharges would have contributed a key ingredient for life: phosphorus.
Phosphorus is one of the six elements crucial for life (always as we know it, of course), necessary for the creation of biomolecules as the basis of life, and although it is common on modern Earth, it may not always have been So. In fact, billions of years ago, it was not easy to find it. In the distant past, any amount of phosphorus was enclosed within insoluble minerals, inaccessible for the awakening of life.
So how did phosphorus get to our planet?
The emergence of life on Earth depended on a very specific cocktail of critical ingredients , one of which we have already said is reactive phosphorus. Scientists first examined meteorites – chunks of space rocks like asteroids and comets that fall to Earth’s surface. Meteorites containing the water-soluble phosphorus mineral schreibersite would have crashed to Earth’s surface often enough to create the conditions necessary for biological life. But…
There is a problem with this approach.
It would have taken far more space rocks crashing into Earth than is thought to have fallen on our planet, because at the time life is believed to have awakened, between 3,500 and 4,500 million years ago, the frequency of the Meteorite collisions on Earth plummeted as most of the planets and moons in our solar system had begun to take shape.
What brought the phosphorus, then?
Precisely another important source of phosphorus is schreibersite, which we can also find in fulgurites , which are formed when lightning strikes the ground. Lightning can heat surfaces to nearly 2,760 degrees Celsius , forging new minerals that weren’t there before. To test this hypothesis, the researchers created a computer simulation to find out how many lightning strikes struck Earth at the time when life began to appear, when Earth’s atmosphere was significantly richer in CO2 (and therefore warmer). and prone to storms). It was from 1 to 5 billion lightning bolts every year.
Thus, over a billion years, up to a quintillion of rays would have struck the surface of our young planet, individually releasing some usable phosphorus. According to his calculations, the lightning would have left between 110 and 11,000 kg of phosphorus a year, something that could have made a difference for the emergence of life. For although the range is wide, even the lowest extreme would have been enough to feed the first life forms.
This work helps us understand how life may have formed on Earth and how it could still be forming on other Earth-like planets, “explains Benjamin Hess, lead author of the study.
The spark of life, more than ever .
Referencia: Lightning strikes as a major facilitator of prebiotic phosphorus reduction on early Earth, Nature Communications (2021). DOI: 10.1038/s41467-021-21849-2 , dx.doi.org/10.1038/s41467-021-21849-2
