The European Space Agency's (ESA) Mars Express orbiter has confirmed the existence of four underground lakes in the planet's south polar region. The largest lake, buried 1.5kms beneath deposits of ice and dust, was discovered by radar between 2012 and 2015. More radar data collected by Mars Express has confirmed that finding and also identified 3 smaller lakes nearby.
[image] Scientists think the lakes contain a high degree of disolved salts which prevent the liquid water from freezing. Some hypersaline lakes on Earth reach 40% concentrations; how saline the Mars brine is remains unknown for now. Research has shown that water with dissolved salts of magnesium and calcium perchlorate can remain liquid at -123C.
Whether life could exist in the lakes is another unknown. Only a few types of microbes can exist in Earth's highly saline lakes. Studies show that when temperatures are warm, halophiles can withstand higher salinity levels than when the environment is cold. Mars polar region is cold and the lake water probably close to saturation. The latest findings are published in Nature Astronomy.
