At a Glance
- Finding clues of water on other celestial bodies is of prime importance since it points at the increased possibilities of life.
- The latest study used a large data set from 134 observations conducted between 2012 to 2019.
- The study claims that these lakes are salty due to the lack of atmosphere in the planet.
Back in 2018, researchers had discovered the presence of the first large lake under the ice at Mars’s south pole. However, due to lack of data, the discovery raised a lot of scepticism, mainly owing to the unlikely scenario of unfrozen water at such a cold region of the red planet.
Now, after two years, scientists have confirmed the validity of this breakthrough discovery and have explained the possible reason for its presence. In doing so, the Italian researchers have also found fresh evidence of three small ponds of salt water around the large lake, under the ice-covered South Polar Region of Mars.
“Our results strengthen the claim of the detection of a liquid water body at Ultimi Scopuli and indicate the presence of other wet areas nearby,” read the research paper. Finding clues of water on other celestial bodies is of prime importance since it points at the increased possibilities of life. Now, these confirmations using the latest set of data have opened all new possibilities for studying the south polar region of the planet.
Hunt for the lakes
The presence of such subglacial lakes in Mars was first detected by Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) at the base of the south polar layered deposits named Ultimi Scopuli. The latest study used a large data set from 134 observations conducted between 2012 to 2019. The earlier findings had analysed only 29 observations collected between 2012 and 2015, which led to scepticism about the presence of a large lake on Mars.
The instrument onboard Mars Express used radar detection techniques to find clues of liquid water beneath the Martian surface. The possible identification of subsurface liquid water was one of the main goals of MARSIS, which was part of the Mars Express mission launched in 2003 by the European Space Agency.
The presence of different types of material beneath a surface is interpreted using the signals reflected back to the instrument. This helps to detect the kind of material—rock, ice or water—beneath any surface. Moreover, the method is also used to find subsurface glacial lakes on Earth in regions like Antarctica, Canada, and Greenland.
Three new salty lakes
The researchers state that the lakes are found in a liquid state, although there's not enough heat beneath Mars to melt the ice. The possible reason behind this existence is Mars inhabitable atmosphere. The study claims that these lakes are salty due to the lack of atmosphere in the planet and this, in turn, keeps the water in a liquid state and lowers its freezing point.
Moreover, the salty nature of the lakes could downplay the possibilities of life on Mars. The research paper states that the discovery has reinvigorated the debate about the origin and stability of liquid water under present-day Martian conditions. However, some planetary scientists have raised scepticism even about the new confirmations, saying the heat flow below the ice cap is not enough to support even a brine solution, reports Nature.
As per the study, the lakes are spread over an area of about 75,000 square kilometres. The largest lake in the centre measures about 30 kilometres across, and in its vicinity holds three smaller lakes—each known to be a few kilometres wide.
The Martian atmosphere has always intrigued scientists as ancient Mars once harboured oceans which may have supported life forms on the red planet. The clues of water can be seen in the form of carved river valleys all over the surface. However, it underwent dramatic changes over the billion years which changed its geology and left the remnants of seas and oceans buried in the planet’s ancient history.
The study was published in the journal Nature Astronomy earlier this week and can be accessed here.
