Mars is the planet most studied, not only because it is our neighbor in the solar system, but also because of its characteristics: today Mars is a giant fossil , with some traces of internal activity, but incapable of renewing soil materials or maintaining liquid water. on its surface, as it does on Earth, to host life. Instead, the more we learn about Mars, the more it may reflect a snapshot of Earth’s future; which also means that Mars could have been a planet teeming with life in the past.
Studying the surface of Mars, there is a mystery that has been intoxicating scientists for years: a series of ancient flows, similar to those on Earth due to the lava that runs down the slopes, and that leaves its deep footprints in the rock. . Now, a team of scientists claims to have unraveled the mystery: they have discovered that some of these flows would not be caused by lava, but by mud.
Landforms on the Martian surface number in the tens of thousands; they often form massive channels, probably the product of ancient fluids that flowed downstream. These extremely long channels stretch for many hundreds of kilometers. They are believed to be the result of massive floods, comparable to the largest floods ever to occur on Earth . Finally, when the water seeps underground, it can emerge again as mud. These movements of mud would be responsible for the mysterious flows observed on the surface, as published in the journal Nature Geoscience .
Scientists have been observing flow lines on Mars in spacecraft images for years, but they have not yet been visited by any of the rovers exploring its surface, and there was some ambiguity about whether they are lava flows or mud.
To verify the nature of these flows, the scientists recreated the Martian environment through experiments at low pressure and extremely cold temperatures (-20 ° C).
They found that free-flowing mud under Martian conditions behaves differently than on Earth, due to rapid freezing and the formation of an icy crust. This is because the water is not stable and begins to boil and evaporate. Evaporation removes latent heat from the mud, eventually causing it to freeze.
Under Martian conditions, these experimental mudflows created shapes similar to the ‘pahoehoe’ lava that occurs frequently in Hawaii or Iceland, where the lava cools to form ripples on smooth surfaces. However, these same shapes are not reproducible on Earth: under Earth’s atmospheric pressure, the experimental mud flows did not expand and had no icy crust, even in very cold conditions, as is proposed for Mars.
This ‘sedimentary volcanism’ has also been proposed for the dwarf planet Ceres , which lies in the asteroid belt between Mars and Jupiter, and could possess an ocean of water beneath its icy crust. Therefore, both Mars and Ceres would present this same type of volcanism, according to the scientists’ explanation, under their particular atmospheric conditions.
