Italian scientists have discovered on one of the poles of Mars a system of four lakes with liquid water, which are located under the surface of the planet. They cover an area equal to the territory of the Czech Republic. The same group of scientists first reported finding a lake under the surface of Mars in July 2018. This discovery was made based on the analysis of data obtained from the Mars radiosonde by the MARSIS spacecraft installed on the Mars Express Orbiter.
Those data were based on just 29 observations made from 2012 to 2015, and many scientists said that a broader set of data was needed to confirm conclusions about the lake’s existence. In the new work, the researchers used MARSIS data from 2010 to 2019; a total of 134 observations. They were able to confirm the presence of the lake discovered in 2018, as well as find three more. All lakes, as scientists have found out, make up a single system.
The total area under the surface occupied by the lakes is 75 thousand square kilometers. The largest of the four lakes is located in the center of the system and is 30 kilometers wide. It is surrounded by three smaller lakes several kilometers wide each.
As noted by one of the authors of the study, geophysicist Elena Pettinelli, if the existence of a single subglacial lake could be caused by some unique conditions, the existence of a whole system of lakes suggests that the process of their formation is probably relatively simple and ordinary, so there may be more such lakes.
The water in the discovered reservoirs, scientists believe, is very salty — taking into account the pressure and temperatures, otherwise it could not exist in liquid form and would turn into ice. Exactly how much salt is contained in the water is still unclear — radiosonding itself does not allow us to determine this. This question is of key importance for the possibility of life in Martian reservoirs — if the salt concentration is too high, living organisms will not be able to exist in such water.
Before the discovery of reservoirs, the existence of liquid water reserves on Mars was not known. On the surface of the planet there are sufficient reserves of water in the form of ice and most of it is concentrated near the poles.
