Located under a layer of Martian ice, the lake is about 12 miles (20 kilometers) wide, said the report led by Italian researchers in the US journal Science. Robert Orosei, who led the new research which has shown that liquid water still exists on Mars in the form of a subglacial lake, noted that studielectric permittivity allowed scientists to locate this body of water. “This is just one small study area; it is an exciting prospect to think there could be more of these underground pockets of water elsewhere, yet to be discovered,” he said. As Imperial College London geophysicist Martin Siegert enthusiastically explained, “It will open up a very interesting area of science on Mars.”

It is believed that billions of years ago there may have been a plentiful supply of water on Mars, back when its atmosphere was much different than it is today, and old lake beds, river channels and floodplains are still fully visible on the planet’s surface. Liquid water would have major implications for life on Mars and future human settlements

Orosei told New Scientist that a combination of calcium, magnesium, and sodium salts on Mars can lower water’s freezing point, which might explain the possibility of a liquid lake. The device that can be credited for the new discovery of the liquid lake on the Red Planet is called the Mars Advanced Radar for Subsurface and Ionosphere Sounding instrument (MARSIS), and was held on the orbiter known as the Mars Express, which was deployed by the European Space Agency. But after reprogramming the radar tool on the Mars Express satellite – called the Mars Advanced Radar for Subsurface and Ionosphere Sounding, or MARSIS – radar pulses were able to penetrate the surface of the ice caps. These reflections “provide scientists with information about what lies beneath the surface.”

A team of researchers led by Roberto Orosei of the National Institute for Astrophysics in Bologna, Italy, surveyed a region called Planum Australe, located in the southern ice cap of Mars, from May 2012 until December 2015. The subglacial lake on Mars was found by the European Space Agency's Mars Express and measures 12.4 miles in length

Scientists have just published a new study which has confirmed that the first known liquid water has been found on Mars, with a lake lurking 0.93 miles beneath the ice cap at the Red Planet’s south pole and extending 12.4 miles in length

As Science Magazine report, the lake on Mars is believed to be very similar to pools of water that can also be found beneath the ice of Antarctica and Greenland.
Scientists at INAF announce the discovery of a liquid water lake beneath a polar ice cap on Mars. The discovery was made using MARSIS, a radar instrument on board the European Space Agency's Mars Express orbiter.