Illustration of NASA's InSight Lander on the Martian surface by the artist. InSight started on November 26, 2018 to investigate the internal structure and composition of Mars.
Photo credits: NASA / JPL-Caltech
Usually, Mars missions are aimed at Looking for signs of life, on the surface of the planet, in places where signs of old water can be seen (a reliable indication of where life is on Earth). But while life has not yet surfaced on the surface of Mars, there could be a plethora of microbial Martians gathering in the underground. This is the result of a study presented at the Annual Meeting of the American Geophysical Union (AGU) on December 11th.
In recent decades, underground exploration has revealed the so-called "deep biosphere" – an underground environment dominated by microorganisms. And scientists suspect that a similar biologically rich zone can thrive under the Martian surface as well. [Mars-like Places on Earth]
In fact, perhaps there was no evolutionary urge to populate the surface of Mars, said Joseph Michalski, associate professor at the Department of Earth Sciences, University of Hong Kong, in the presentation. The expectation that life has developed on the surface of Mars may reflect an inclination that has been set by what we know about life on our home planet, Michalski said.
Billions of years ago, when the planets in our solar system were young, the surface of Mars was probably quite similar to Earth's rocky neighbor. That changed when Mars lost its magnetic field, causing it to be bombarded with fierce radiation that would have made survival extremely difficult above ground, Michalski told Live Science.
It is possible, however, that life on Mars has already "cooked" before this happened. Scientists believe that life first appeared on Earth about 3.8 to 3.9 billion years ago, when conditions in some places probably resembled today's hydrothermal environments – much like Mars did. Maybe life on Mars was born at the same time as it took shape on earth, but adapted exclusively to underground life, Michalski said.
"In these hydrothermal environments, life could have come and survived underground for a long time," he said.
And if the Earth's deep biosphere is an indication, the subterranean Martian microbial communities could be exceedingly rich and diverse. The deep biosphere of the Earth was discovered only about 30 years ago, and estimates since then have suggested that these deep-living microorganisms make up nearly half of all life on earth, Michalski told Live Science.
Microbes in Earth's Deep Biosphere Play A Role A role in burying carbon, which could otherwise become a greenhouse gas, is related to deep energy resources "and is important to understand the origins and evolution of life" Michalski said.
"What the" deep biosphere "really means on Earth and how it relates to exoplanets and other planets in our solar system," he said. "It's a window into our own origins."
Mars is a particularly promising place to search for alien microbes because it is "even more habitable" for microorganisms than the Earth's deep biosphere. Mars 'subsurface rock is more porous than it is on Earth – it creates pockets for nutrients and gas exchange – and Mars' cooler core (though still molten) provides a more hospitable temperature for rock-borne microbes, added Michalski.
"We might have unicellular organisms that could be inactive for a long time but could survive by metabolizing hydrogen, methane and possibly sulfur," Michalski told Live Science. "Without being too specific, we believe that there are many possibilities."
Original article about Live Science .