The building blocks for life on Earth may have arrived in meteorites


No one knows with absolute certainty how life originated on Earth. In its origins, about 4.5 billion years ago, the planet we live on was nothing more than a glowing ball floating in a convulsive universe. But at some point in its evolution, who knows how, in a hitherto inhospitable world, a series of ingredients that ended up giving rise to life as we know it. But how or where did these compounds arise? As argued A study published this Tuesday in the magazine ‘Nature’, everything indicates that the basic pieces to build life on Earth arrived after a meteor bombardment.

For understand this headlineand before jumping to somewhat risky conclusions about the extraterrestrial origins of life, it is worth taking a step back and talking about the find itself. The protagonists of the news of the day are three carbon rich meteorites (already known as Murchison, Murray and Tagish Lake). The analysis of these rocks has revealed that inside it hides several of the ‘building blocks’ that are needed to assemble the DNA and RNA chains and that, ultimately, ended up giving rise to life.

According to the scientific team responsible for this finding, the hokkaido japanese universityIt is the first time they meet pyrimidine nucleobases in meteorites (one of the two essential ingredients to forge life and that, until now, it was not clear how it had originated). Following this discovery, it is also the first time that we have the definitive confirmation that all ingredients necessary for life to sprout on earth can be traced in meteoroids (from the newly found pyrimidines to chemical compounds such as guanine, adenine and uracil). All the necessary pieces so that this journalist can be writing these lines and you reading them seem to have traveled through space and have fallen, by chance, on this planet.

It is the first time that it has been confirmed that all the basic elements for life can be traced back to meteorites.

The origin of everything

Does this mean that life on Earth has an extraterrestrial origin? Or that beyond this blue marble there are life forms traveling through space? astrobiologist Jesus Martinez Frias He answers with a resounding no. “Neither this nor any other study published to date proves that life comes from outside the Earth. Everything points to the chemical reactions that gave rise to these essential compounds were produced in outer space and then it was here, on Earth, where these ingredients came together and the combination that gave rise to life occurred“, explains the scientist, external to the just published study, in an interview with EL PERIÓDICO. “We are facing a very important scientific advance, but we cannot talk even remotely about the detection of extraterrestrial life“, ditch the expert.

To explain the formation (and origin) of these essential compounds for life, the scientific team lead by Yasuhiro Oba poses the following hypothesis. As collected by the analysis of ‘Nature’everything indicates that these chemical elements began to be forged even before the formation of the Solar System through an enigmatic sequence of photochemical reactionsThey settled on asteroids, traveled through the cosmos on the back of meteorites, and finally reached Earth. This hypothetical sequence, the experts put forward, was what “contributed to the appearance of genetic properties for the oldest life on Earth.

But beyond the meteor shower that brought these chemical compounds to the planet, Martínez Frías insists that the context was key for life to sprout. “If meteorites had fallen a few thousand years earlier, when the world was a glowing ball, we probably wouldn’t be talking right now. We were lucky that this ‘breeding ground’ coincided with a favorable geological timejust when the Earth cooled down and environments more suitable for this type of process began to prosper”, explains Martínez Frías, a researcher at the IGEO Institute of Geosciences (CSIC-UCM) and president of the Spanish Network of Planetology and Astrobiology. “The combination of all these factors was the ‘luck’ that allowed life to emerge,” adds the scientist.

“The combination of all these factors was the ‘luck’ that allowed life to arise”

Jesús Martínez Frías, astrobiologist

Extraterrestrial life?

Related news

Although the scientific news of the day has to do with the origins of all living things, the reality is that we are still not entirely clear on how life arose on the planet. That is, how these inorganic compounds Arriving from outer space, they ended up giving rise to something as organic as all the life forms that currently swarm the planet. This unknown, scientists argue, is not only key to understanding our origins, but could be decisive for seek life beyond our borders. “If life outside of Earth follows the same rules as here, looking for these essential pieces and studying how they have been combined could help us understand if there is life out there“, Explains the astrobiologist in statements to this newspaper.

Taking advantage of the occasion, how could it be otherwise, the astrobiologist also takes the opportunity to contribute his expert vision on the biggest of questions; if we are alone in the universe. “We have not yet found extraterrestrial life, but it is also true that we just got our heads off the planet. We haven’t even explored the worlds around us in depth so who knows what we may find in the future“, comments the scientist. Enthusiasm aside, Martínez Frías adds an essential nuance to talk about the search for extraterrestrial life: “We have to be especially rigorous when we talk about these issues because if every time we detect something we say that there are ‘signs of life ‘ on Venus, on Mars and on Pluto at the end It will seem that we have a zoo in the Solar System and it is not so“, jokes the expert.


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