Mathilde Fontez, editor-in-chief of the scientific magazine Epsiloon : the big question of life on Mars, occupies the researchers of the whole world. The red planet would once have been conducive to life…
franceinfo: Researchers say today that life could have developed on Mars. And even that it is this life that would have made the planet unlivable?
Mathilde Fontez: This is of course an assumption. But solidly supported. It has just been launched by researchers from the Observatoire de la Côte d’Azur and the University of Arizona who have modeled all the geophysics and geochemistry of the Martian crust – the upper part of the planet’s soil. And this, more than 3.7 billion years ago – shortly after the formation of the planet, to see if it could develop populations of primitive life. Cells like those that formed on Earth at the same time…
Because then, Mars was more hospitable than today?
Yes, astrophysicists are convinced of that: at the time there was water, a denser atmosphere than today, milder temperatures. Hence the idea that there could have been life. Hence the research currently being carried out by space probes and rovers roaming the planet. This is what NASA’s Perseverance robot does, for example: it collects samples from the soil of Mars in the hope of finding clues to a past life.
And the researchers’ response? A life is possible?
They answer yes: all the conditions were well and truly met for the development of ecosystems. But there is a catch: their model concludes that these micro-organisms would have, while developing, completely changed the climate of the planet: they would have consumed the dihydrogen from the atmosphere, and released large quantities of methane.
With a dramatic impact: that’s how Mars would have cooled, that it would have lost a large part of its atmosphere. It would even have completely covered itself with ice, depriving the micro-organisms of breathing gases. And they would eventually die out, except maybe a few pockets of underground life that might have been preserved.
It’s a bit of an apocalypse scenario…
Yes, that obviously resonates with our own impact on our planet: what if all life was ultimately a bit parasitic for the body that shelters it? What if all life had a planetary impact, not necessarily very positive? This questions the likelihood of finding life forms elsewhere.