Three underground lakes have been found near the South Pole of Mars.
Scientists also confirmed the existence of a fourth lake – the presence of which was indicated in 2018.
Liquid water is important for biology, so that discovery will be of interest to researchers studying other possibilities of life in the solar system.
But lakes are also thought to be very salty, making it difficult for any microbes to live in them.
The thin atmosphere of Mars is such that the presence of liquid water on the surface is an impossibility. But water can remain liquid under the ground.
The latest discovery was made using data from radar instruments on the European Space Agency’s (ESA) Mars Express spacecraft, which has been orbiting the Red Planet since December 2003.
In 2018, researchers used data from Mercedes radar to report signs of a 20 km-wide subsurface lake located 1.5 km under the south polar layer deposits of Mars, composed of thick polar caps, ice and dust layers.
However, that finding was based on 29 observations collected by Marsis between 2012 and 2015. Now, the team, including many similar scientists from the 2018 study, has analyzed many large datasets of 134 radar profiles collected between 2010 and 2019.
“Our 2018 study has not only confirmed the position, extent and power of the reflector, but we have found three new bright fields,” said Elena Patinelli, co-author of the University of Roma Tray in Italy.
“The main lake is surrounded by a small body of liquid water, but due to the technical characteristics of the radar, and its distance from the Martian surface, we cannot determine for sure whether they are connected to each other.”
The team borrowed a technique commonly used in radar sounder investigations of sub-glacial lakes in Antarctica, Canada and Greenland, adapting the method of analyzing data from Mars recesses.
Sebastian Lauro, co-author of Roma Tray University, said: “The best-fitting interpretation of the available evidence is that high-intensity reflections (from Mars) are coming from expanded pools of liquid water,” said Sebastian Lauro, co-author of Roma Tray University. Was.
These depots do not have enough heat to melt ice, so scientists believe that there should be a high concentration of salt dissolved in liquid water. These chemical salts (unlike the material we spray on our chips) can significantly reduce the freezing point of water.
In fact, recent experiments show that water with dissolved salts of magnesium and calcium perchlorate (a chemical compound containing chlorine bound to four oxygenates) can remain liquid at a temperature of -123C.
“These experiments have shown that temperatures in the Mauritanian polar regions (even at temperatures below the cooling temperature of pure water) can continue to brinens for a geographically significant period of time,” said Grazella Cara Pareli, co-author of the University of Southern Queensland. , .Australia.
“So we think that in any process of formation and continuity of sub-ice water beneath the ice polar caps the liquid needs more salinity.”
Whether life will survive in such conditions depends on how salty this Martin bridge is. On Earth, only the most specialized type of microorganisms, known as halophils, can survive in water-soluble substances.
Roberto Rossi, chief scientist of the Mars Experiment, said: “While the existence of a single sub-glacial lake is due to extraordinary conditions such as the presence of volcanoes under a sheet of ice, the discovery of a whole system of lakes suggests that their formation process is relatively simple and common. Most of Mars exists for history.
“For this reason, they were still able to retain traces of any life that could have evolved when Mars had a ga of atmosphere, a mild climate, and the presence of Earth-like liquid water in the beginning.”