Recent studies have reported the discovery of subterranean lakes of liquid water below the polar ice caps of Mars. However, other studies claim that it could be a mirage and that there is no lake. Now, two new studies arrive that feed this debate reaching opposite conclusions.
The red planet has been under study by scientists for years. The space race to reach Mars is open and meanwhile, some studies debate the existence of underground lakes in the polar ice caps of Mars . For the moment we have to settle for discovering Mars from Earth through science fiction series, movies, documentaries and the great research work carried out by scientists from all over the world.
Evidence in 2018 and 2020
In 2018, a group of Italian researchers reported in the journal Science that the radar of the Mars Express spacecraft of the European Space Agency (ESA) had detected a reflecting surface with an extension of 20 km long at a depth of one and a half kilometers. at the south pole of Mars.
These researchers believed that it was the sign of a huge reservoir of liquid water with a certain resemblance to the subglacial lakes that planet Earth has in the Greenland and Antarctic ice sheets. A story that soon appeared in all the media. The water, they claimed, remained in a liquid state despite the low temperatures, about -68 degrees Celsius, usual on Mars. In turn, another study suggested that the water could be being heated by an underground magma chamber. Two years later, based on data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding ( MARSIS ) radar instrument, researchers found three new underground lakes.
Scientists disagree
However, not all scientists agree with this evidence about the possibility of underground lakes on Mars. One researcher discovered that reflections picked up by radar were common in that region of Mars . Conclusion to which was added the idea that deposits of mineral clays containing metals and saline ice could generate similar signals. Add to this that the clay hypothesis was also tested in the laboratory by checking radar reflections from frozen clay samples. In this case, the conclusions pointed to a close match with the signals from Mars Express.
As if that were not enough, recently two studies have joined the debate. The first, published in the journal Earth and Planetary Sciences Letters , focused on examining salts thought to keep water from freezing and studied how they respond to radar. The team of researchers created perchlorate and chloride brines by subjecting them to a chamber that simulated the pressure and temperature of Mars.
The conclusions of this study showed that these brines produce the same signal detected by the radar. “They may not be deep lakes, the researchers said, but the brines could be saturated between grains of ice or soil.”
On the other hand, a study conducted from the University of Texas at Austin published in the journal Geophysical Research Letters states that “the liquid water detected under the southern polar cap of Mars by the Mar Express mission’s radar is more likely to be volcanic rock buried under the ice .”
“For water to stay so close to the surface, you need both a very salty environment and a strong locally generated heat source, but that doesn’t match what we know of that region,” he argues. Cyril Grima, a planetary scientist at the University of Texas Institute for Geophysics. In short, scientists will have to continue investigating to find out if there really are underground lakes on Mars.