Overview

Our planetary neighbor looks like a desert world — cold, arid, and devoid of any form of life. It may be now, but it wasn’t always that way. The fields of astrochemistry, astrobiology, astrogeology, and astronautics are poring over each region of the Red Planet, searching for clues that will help them understand its past and future, as one day Mars could become our home.

Now, a study published in Nature Astronomy indicates that Mars may have presented optimal biospheric conditions for the development of microbial life 4 billion years ago, just when life was beginning to emerge on Earth. But on Mars, the scene would not be a gigantic ocean, but rather a thin layer of regolith — a type of rock.

The science and other stuff to know

The team of researchers who carried out the study modeled different scenarios and found that the possibility that life arose on Mars sheltered under a rocky mantle is high. In this way, the microbes would be protecting themselves from the devastating radiation of the Sun that the thin atmosphere of the planet could not absorb.

The researchers hypothesize that these life forms could have consumed hydrogen (the most abundant element in the early martian atmosphere) and produced methane as waste. Over a considerable period, excess methane in the thin atmosphere could have produced a global drop in temperature, forcing life forms deeper below the surface. Without enough greenhouse gases to keep the surface warm, an Ice Age would have started on Mars that eventually wiped out microbes.

This approach is a bit scary from a philosophical point of view. At least that’s what Boris Sauterey, lead author of the article, suggests: “[life] could actually cause its own demise.”

So what?

Other investigations have tried to reconstruct the geological and climatological past of Mars in order to understand its evolution. Kaveh Pahlevan — lead author of a recently published paper on Mars’ atmosphere — and his team found evidence of a glaciation period on the Red Planet and suggested that Sauterey and colleagues’ research should be considered in future studies of the field since if life did exist on Mars, it completely conditioned and modified its entire climatology.

What’s next?

It is expected that, in the next decade, we will have samples of Martian soil brought back by rovers that travel the planet. These should shed light on the past cycles of Mars and the presence of living organisms. Meanwhile, space agencies continue to design and send robots in search of long-awaited proof of alien life. Sauterey and his colleagues consider the most conducive places for life to be Hellas Planitia and the Jezero crater. Although Sauterey intends to investigate the sub-martian depths in search not only of fossils but of living organisms.