Mars: A vast expanse of liquid water may have been discovered beneath the surface
Thanks to radar analyzes, scientists have just revealed the presence, under the ice of the South Pole of Mars, of a large pocket of liquid water. An incredible discovery that remains to be confirmed with certainty but which is already reviving the debate on the possible existence of Martian life forms.
After the revelation last June of the presence of organic molecules on Mars, it is an even more incredible news that scientists have just unveiled. In an article published in the journal Science, a team of Italian researchers announces indeed have found, on the red planet, nothing more than ... a vast expanse of liquid water! An additional argument - and not least - in favor of the existence of Martian life forms.
This stretch of water would be far from being a mere puddle. Buried one kilometer and a half under the ice cap that covers the South Pole of Mars, this precious liquid - essential to life - would form a huge underground reservoir almost 20 kilometers wide. "There is water there, there is no doubt about it," said one of the co-authors of the study, Enrico Flamini, Italian head of the Mars Express mission, at a press conference.
It is indeed the radar which is equipped with this probe launched in 2003 by the European Space Agency which made it possible to make the extraordinary discovery. For twelve years, Mars Advanced Radar for Subsurface and Ionosphere Sounding, or MARSIS, has been scanning the surface of the red planet for signs of liquid water.
Focused research on a restricted area
Between May 2012 and December 2015, the researchers focused their efforts on a specific area 200 kilometers wide of the polar plain located south of Mars, the "Planum Austral". Scientists recorded no less than 29 radar profiles in the region by bombarding it with radio waves.
After having reached the surface of the planet, these waves penetrate in depth, before being reflected. It is therefore this signal sent back by the Martian subsoil that Italian researchers have studied. The presence of water modifies the nature of reflected waves, which appear more strongly on radar images. A characteristic image that scientists have had the surprise to observe at the level of Planum Austral.
After verification, the researchers assure it, it is indeed liquid water and not the frozen form of the liquid, or even dry ice. Ex post facto simulations attest to this. There remains a major problem that scientists have not yet solved: that of temperature that could theoretically prevent the maintenance of water in liquid form.
At the depth of a kilometer and a half at which the body of water has been detected, a temperature of about -68 ° C prevails. Well below the -13 ° C hypersaline waters of Antarctica, liquids too. But on Mars, salts abound: sodium, magnesium, or calcium; as many ions that could be dissolved in Martian water, thus considerably lowering its solidification point.
In addition to its chemistry, it is also the pressure on the water that could help keep it liquid. The ice mass that surmounts it could, according to researchers' calculations, allow it to freeze only below the temperature threshold of -74 ° C, well below -68 ° C estimated at this depth.
Everything leads to believe that the water detected under the South Pole of Mars is indeed liquid, despite the doubts issued by some specialists. Quoted by New Scientist, Jeffery Plaut of NASA's Jet Propulsion Laboratory described the results as promising, but said they need to be confirmed by further studies. According to this specialist, radar images could also be explained by a particular arrangement of ice.
A step closer to the discovery of life on Mars
One thing is certain: this fantastic breakthrough once again nourishes the hopes of discovering Martian life ... "There is evidence on Earth of an important microbial life in the waters under the poles, and even microbes that can survive in ice veins, "says astrobiologist Brendan Burns of the University of New South Wales, Australia, who was not involved in the study.
"The existence of similar scenarios on Mars remains to be proven experimentally, but this discovery of the potential presence of liquid water beneath the surface of Mars opens the way to fascinating areas of space exploration," says the scientist. As exciting as it is, this discovery of liquid water under the Martian surface raises hopes still uncertain ...
The high concentrations of salts of water, m