The results of a recent study lend further credence to previous research that suggested the presence of a large salt water lake beneath the Martian surface.
The findings and the presence of other wetlands and basins or "bodies of water" on Mars could be crucial in the search for alien life on the planet.
Water on Mars may also be the key to "planetary protection" work. The work required to ensure that humanity does not contaminate other planets with life from Earth during missions to explore them.
It appears clear, after this umpteenth signal, that even more extensive work is needed. We need to take a closer look at Mars and its chemistry: there may be traces of what they call "astrobiological activity" or alien life.
Water basins on Mars, the importance of MARSIS
The discovery was made using MARSIS, or Mars Advanced Radar for Subsurface and Ionosphere Sounding, which is on board the Mars Express probe sent by the European Space Agency in orbit around Mars.
The instrument sends out radar pulses that can penetrate the surface and polar caps of Mars. They can then be measured as they bounce off the spacecraft, allowing researchers to delve into the planet without touching it.
In 2018, researchers using that tool announced that they had found a vast lake beneath the surface of Mars. The discovery was hailed as a major step forward in the search for alien life on the planet.
At the time, the study was also questioned by experts who wondered whether scientists had gathered enough details about the nature of the body. There were doubts, in essence, that they were liquid water basins.
The Italian discovery
In the new study, the researchers led by Elena Pettinelli Roma Tre University used techniques borrowed from terrestrial satellites to study lakes under Antarctic glaciers.
In this way, they were able to analyze the data from MARSIS which examined a huge mass around the body found on Mars. This allowed them to confirm that it was liquid.
Water on Mars? Super saline
The team was also able to find a number of other bodies of water on Mars, separated from the main body, which appear to form a mosaic of various salt lakes.
The data seem to indicate that the bodies are "hypersaline solutions". A real brine in which high concentrations of salt dissolve in the water.
This is perhaps the reason why these pools of water are able to remain liquid despite the very cold conditions of the south pole of Mars.