ESA’s Mars Express Finds Evidence of Underground Lake on Mars

Mars, as seen through the Hubble Space Telescope. Image credit:

Scientists have found possible evidence of an underground lake of liquid water on Mars, sparking interest from Mars watchers who are interested in the possibility of past or present Martian life. The discovery was made using data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding instrument (MARSIS) on the European Space Agency’s Mars Express.

The possible lake is located under the southern ice cap, an area known as Planum Australe. Between May 2012 and December 2015, MARSIS was used to observe this region by sending radar pulses through the surface and observing the pulses that came back. A sample of 29 radar pulses revealed a change in the signal that occurred about a mile beneath the surface in an area about 12.9 miles across. The reflection from this area was brighter than the radar that had been reflected in the surrounding area and matched similar radar readings coming from lakes that had been discovered under ice sheets in Antarctica and Greenland. Researchers were careful to rule out any other possibilities except for the chance that the bright zone simply consists of water-rich sediments

“We interpret this feature as a stable body of liquid water on Mars,” authors led by MARSIS chief investigator Roberto Orosei wrote in a paper for the journal Science.

Would it be a lake that’s suitable for life, as some have hinted? The water is actually below the temperature at which pure water would normally freeze, but is kept liquid by the presence of copious amounts of salts containing magnesium, calcium, and sodium. The water is likely much more briny than Earth’s oceans along with being seriously cold, which is not necessarily conducive for life.

The research team behind the discovery of the possible liquid lake plan to use the data to create a 3D image of what may be going on under the surface of Planum Australe. This may help to confirm that the liquid water lake exists and give a better idea of the exact dimensions of the lake.