Scientists recently presented a study (published in Nature Astronomy) suggesting that ancient Mars may have hosted a world teeming with microscopic organisms.
There are a few places in our solar system where life as we know it likely developed in addition to Earth. While our planet is the only place where life evolved into intelligent life, it is likely that more places than one either hosted life at one point in their history or continue to do so to this day. Among the best candidates are some of the moons of Jupiter, like Europa, for example. The Juno mission recently visited this alien world. The spacecraft managed to take some of the closest images of the alien world in two decades. But there are other worlds, like Enceladus, for example, a moon of Saturn, where life could exist.
Recently, Chinese scientists found the essential elements for life on the distant moon. But we do not have to travel out so far into the outer solar system to look for life or traces of life. Mars is the most likely place for us to look for possible evidence of alien life. Based on what we know so far, billions of years ago, the red planet was wet. Mars was a humid place with an atmosphere that was capable of hosting life.
It is nearly impossible for life to exist on the surface of Mars. This is based on the idea that life as we know it must also exist elsewhere, needing the same elements. However, beneath Mars, deep within the red planet, life could have flourished even when Mars became the arid desert we see today.
Ancient microorganisms on Mars
French scientists recently presented a study (published in Nature Astronomy) suggesting that ancient Mars may have hosted a world teeming with microscopic organisms. However, the researchers concluded that if these simple life forms had existed, they would have caused a Martian Ice Age and wiped themselves out.
Findings like these show how poorly we understand the cosmos since even simple microbes, those invisible to the naked eye, might exist and even cause their own demise. The lead author, Boris Sauterey, a postdoctoral researcher at the Sorbonne University, and his colleagues wrote in Nature Astronomy that they evaluated the Martian crust’s habitability 4 billion years ago when it was thought to be more humid and hospitable than today. They used climate and terrain models to estimate the habitability of the crust.
Back then, several inches of dirt protected hydrogen-gobbling, methane-producing microbes from harsh incoming radiation, which might have flourished just beneath the surface. According to Sauterey, Mars could have been teeming with these organisms anywhere there was no ice. Sauterey said that early Mars’s thin, carbon dioxide-rich atmosphere would have sucked so much hydrogen from it. This would have jeopardized its moist, warm climate. To survive, organisms at or near the surface may have buried deeper within the plane. Temperatures plunged by nearly minus 400 degrees Fahrenheit (minus 200 degrees Celsius). Given the nitrogen-dominated atmosphere of Earth, microbes may have contributed to maintaining temperate conditions.
Climate is Key
Kaveh Pahlevan of the SETI Institute says future climate models for Mars should take into account French research, as per phys.org. An earlier study by Pahlevan suggested that Mars’s oceans were warm and wet when Mars first formed. However, he and his team concluded that the atmosphere was dense and mostly hydrogen at the time. This acted as a heat-trapping greenhouse gas that eventually drifted to higher altitudes and was lost to space. In the French study, microbes were investigated in an atmosphere dominated by carbon dioxide, so it does not apply to earlier times on Mars, Pahlevan said. The unexplored Hellas Planitia is among the best places to look for alien life. Jezero Crater, too, where NASA’s Perseverance rover is currently collecting rocks that will be returned to Earth in a decade.