Marcelo bellucci
08/12/2020 - 13:11
- Clarín.com
- Society
One of the great questions of humanity is how life originated on Earth . The fossil footprints found in the rocks indicate that it all began about 3.8 billion years ago, only 700 million years after the formation of our planet. But the evidence for the transition between chemistry and biology is still blank. For some experts, such as astrobiologist Nathalie Cabrol , the answer to this puzzle could lie on Mars .
This researcher, considered one of the most outstanding in this field, is also the director of the SETI Institute Carl Sagan for studies of life in the universe. Of French origin, Nathalie obtained her doctorate from the Sorbonne University. In 1986, she became the first person to study Gusev Crater on the planet Mars. Together with her husband, Edmond Grin, she directed a geological survey at the Sorbonne until 1994, when she moved to the United States to work at NASA, where she currently works.
“If we find biosignatures on Mars, this finding will confirm that there are now two planets in this Solar System where life could develop. This will show that what happened on Earth was not a coincidence and also, the chances of it being repeated in other regions increase. Because all the planets that make up this neighborhood come from the same chemistry and the same physics . This implies that we share a family tree and as each place is unique, the way of life that we find will also be, ”Cabrol said yesterday in a videoconference at Fundación Puerto de Ideas, from Chile.
Scientist Nathalie Cabrol, searching for the origins of life
Mars is considered to be a first cousin of Earth , as it shares many similarities. In addition to being very close, the length of the day is almost the same, it has seasons, atmosphere, clouds, large masses of icy water at the poles, mountains, river canyons and valleys.
“The red planet is our direct window into the past , with large swaths of its surface dating back more than 3.5 billion years. This corresponds to the early days of life on Earth, when colonies of microbes thrived and evolved, setting the stage for the more complex ecosystems that were yet to come. We still don't know if something similar happened in parallel on Mars, when this planet was relatively hospitable compared to the frozen and almost airless desert that it has become, ”Cabrol synthesizes.
The most consensual definition of what “life” means was coined by the North American biochemist Gerald F. Joyce (1956) and was adopted by the NASA Astrobiology Institute: "A self-sustaining chemical system with the capacity to carry out a Darwinian evolution ".
Scientist Nathalie Cabrol, analyzing samples of Extremophiles.
“In nature there are many elements that are related to the origin of life and perhaps the definitive answer is not where we are looking for it. And while biology may be the beginning or the tip of that matrix, there are other branches such as quantum physics or neuroscience that begin to question our sense of reality and put the true meaning of life in check . Because if they tell me that the Universe is life and consciousness, then I no longer have to look for life because it is everywhere. However, I can direct my search towards the manifestation of diversity and complexity. That is why it is so difficult to begin to define what life means, because everything is life and you cannot conceptualize everything. Instead we can take a specific part to try to find a more concrete answer and thus move on to the next point ”, he warns.
In 1976, NASA landed the Viking 1 and 2 probes on Mars, which managed to transmit photos of the surface from the plains of Chryse and Utopia. These two missions conducted experiments to detect life on the Martian surface and their results were more controversial than conclusive.
Considered one of the most outstanding astrobiologists, Nathalie Cabrol is also the director of the SETI Institute Carl Sagan.
“Before Perseverance, only one mission set out to search for life on Mars, but you had no idea what kind of environment or conditions it was facing. It was truly a blind trip. It was the first mission to land and the images used as a guide had been obtained by Mariner 6 and 7. Some of the biologists who participated in the mission found very ambiguous results. They even claimed that there was life on Mars because they detected chemical reactions. But when we improved the analytical techniques, we saw that the reaction was a product of the oxidative environment of the planet ”, says the expert.
Since then, NASA began to develop an integrated exploration program that included analyzing the environment, atmosphere, and planetary geology, ultimately leading to life.
"The previous step was Curiosity, which allowed us to characterize habitability. We now know that we are not going to find much biomass that has developed on the surface. Biosignatures correspond to an extreme environment, like those of an isolated oasis. We are focusing on small areas and the challenge is to find those micro habitats to investigate. In this race that we started five years ago, we ask ourselves what a microbe needs to survive there and what is the best place on the planet where it could survive ”.
“Since then we have found many organic elements on Mars, but organic molecules are not life , they are just the building blocks of life. These organic molecules can be compared to the pieces of a layman. If they are stored in the box they are only pieces, but when they are combined, you can build whatever you want. The same thing happens with organic molecules, some are left on the planet wandering around, looking for other elements with which to associate. We still do not know if they will be able to form something more complex. Many of the missions that started this year will seek the same answer ”.
At least three missions to Mars before Perseverance had microphones as part of their design and all have failed. The first one to fly to Mars in 1999 aboard NASA's Mars Polar Lander crashed to the surface. So far, no country has successfully shipped a microphone, so the surface sounds are not officially known .
“We all hope that this mission fulfills a long-awaited dream: listening to the wind on another planet , the sound of sand passing through the rover, and imagining what human life would sound like up there. This instrument, by capturing a sound that we already know, will affectively allow us to be closer. When InSight recorded earthquakes on Mars last year and the information received was translated into sound, it was incredible. But it is not the same as listening directly to it. Also, we will be able to hear the rover at work, the movements of the robotic arm as it scrapes the ground. And while for some this is insignificant, I think that the eyes are not the only sense that can tell us if something is right or not. Listening to the drill, how the camera unfolds can provide us with a lot of extra information about what is happening on the planet ”, concludes Cabrol.
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