SALTWATER LAKE FOUND IN THE RED PLANET'S SOUTH POLE
European researchers announce that they have finally obtained evidence of the presence of water in a liquid state on Mars. Thanks to the radar system installed in the Mars Express probe of the European Space Agency (ESA), it seems that underneath a layer of ice, this body of water may be saline.
This unusual discovery, completed by a team of Italian researchers, came to pass given the similarity between data obtained in the Planum Australe region of Mars, located in its south pole, and data from large liquid lakes found under Antarctica and Greenland.
The research, published in the magazine Science, has been hailed by President of the Italian Space Agency Roberto Battiston as "the most important in recent years."
These results were obtained through a study of 29 radar sample sets, which mapped an area at the planet's south pole and showed a very pronounced change 1.5 kilometers below the surface, which is made of many layers of ice and dust. Specifically, the radar identified a particularly bright reflection beneath the layered deposits within a 20 kilometer wide area.
Roberto Orosei, scientific head of the MARSIS radar installed on the Mars Express probe, has explained that "we found that the echoes coming from below this area were stronger than the surface echoes. That only occurs when observing sub-glacial water, such as in Antarctica."
By analyzing the properties of reflected radar signals and considering the composition of stratified deposits and the expected temperature profile below the surface, scientists interpret the reflection as an interface between ice and a stable body of liquid water, which can be loaded with salt, saturated sediment. "This subsurface anomaly on Mars has radar properties that match water or water-rich sediments," says Roberto Orosei.
Orosei has explained in statements to Efe that they have needed a few years in order to arrive at these conclusions. All other possible explanations were eliminated one by one until they reached the conclusion that it had to be water.
But in addition, the study asserts that it is salt water. The pressure of the ice sheet and also the temperature of the underground lake, which remains between minus 30 and 70 degrees Celsius, are two factors that only could occur with salt water. The same is true on Earth.
The existence of a biological deposit has not been ruled out. To do this, he took the example of Lake Vostok, the largest of some nearly 400 sub-glacial lakes known in Antarctica, and whose water remains liquid due to the heavy weight of the ice sheet.
Scientists do not rule out the possibility of finding a "biological deposit," since it has been proven that some bacteria can survive at very low temperatures, especially in saline substances. However, adds Orosei, being able to find evidence will be difficult and could take years since the ice would have to be drilled. For Orosei, it is a great start to continue analyzing the red planet thanks to the Mars Express probe, launched in 2003 for the purpose of studying the Martian atmosphere, its geology and to search for traces of water.
NASA already confirmed the existence of liquid salt water on Mars in September 2015, a finding that opened up the possibility of finding some form of life on the planet in the Solar System closest to Earth.