Images and data from the Mars Express probe show that in the distant past, all of Mars was surrounded by a network of large bodies of water and underground reservoirs of moisture, whose traces were preserved at the bottom of the largest craters and crevasses of the planet. Evidence of its existence has been presented in the journal JGR: Planets.
In recent years, scientists have found many hints that rivers, lakes and entire oceans of water existed on the surface of Mars in ancient times, containing almost as much liquid as our Arctic Ocean.
On the other hand, some planetary scientists believe that even in ancient times, Mars could be too cold for the permanent existence of the oceans, and its water could be in a liquid state only during volcanic eruptions.
Recently, these notions have been shaken. Planetologists have found in photographs of some of the Martian craters at the equator of the red planet, such as Istok and Yesero, and in the northern polar latitudes, such as Lyo, traces of water flows. More recently, in geological terms, a few tens or hundreds of millions of years ago, they moved along the surface of Mars.
This discovery has left many scientists wondering how liquid water could have entered the surface of Mars and survived long enough to form a network of deep and very long and branched channels in the rocks near the slopes of these craters.
Francesco Salese of Gabriel D'Annunzio University (Italy) and his colleagues discovered a possible source of this moisture and found traces of a giant network of surface lakes and groundwater bodies by studying the structure of two dozen of the deepest hollows and craters on the surface of Mars.
Many of them, as scientists today assume, represent part of the bottom of the oceans of Mars or dry ancient lakes, which in the past were fed by the waters of rivers. European planetary scientists have checked whether this is really so by analyzing how and where the water in their vicinity could flow.
This analysis revealed unexpectedly many features of these bodies of water, which could not be explained by the fact that water flowed along the slopes of craters and depressions from top to bottom, moving only under the influence of gravity.
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The mechanism of formation of “ reverse ” aquatic landforms on Mars.
All such anomalies, as scientists note, were located at the same "height above sea level" and arose under the influence of water rising up. This made them look like landslides, mud avalanches and sand emissions on the shores of the Earth's seas, generated by the rise in level or the movement of groundwater.
After analyzing the location of such groundwater reservoirs, Salese and his team concluded that they were all combined into a giant network of underground moisture reservoirs. It periodically rose to the surface of Mars and formed temporary or even permanent lakes in those craters where topography and soil structure contributed to this.
How much water was contained there in the past and whether it is hiding there now, scientists cannot yet say. Titov hopes that further observations of these deep craters will help provide similar estimates and understand whether traces of ancient life or even existing Martian microbes may be hidden there.
