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On July 25, 2018, a new study published in Science by researchers from the Italian Space Agency announced that radar detected a potentially life-harboring, liquid, salty water lake below the southern polar ice cap of Mars.
If confirmed, this will be the first time a large body of water has been found on the Red Planet, settling a debate that has occupied scientists for decades.
We already knew that Mars once harbored vast bodies of water because of the dried up river valleys and lake beds they left behind, but this is the first stable body of water found to currently exist on the planet.
The lake, which measures around 12 miles across and over three feet deep, lies roughly a mile beneath the surface. The water is expected to be below freezing, but salts already found on the planet may lower the melting point and allow it to remain a liquid.
MARSIS, the Mars Advanced Radar for Subsurface and Ionosphere Sounding instrument on the Mars Express spacecraft collected evidence between May 2012 and December 2015. The instrument works by penetrating the surface of the ice caps with radar pulses. The radio waves bounce off the terrain back to the spacecraft, giving scientists clues about the composition of the subsurface. Water, which is more reflective of radar than rocks and sediment, reflects stronger radar waves.
When bright reflections in the radio signals appeared, scientists immediately took note. But before drawing any conclusions, all of the other possible explanations for the anomaly had to be ruled out.
Luckily, after two years of evaluating the data, researchers have determined that the reflections can only be attributed to liquid water. Similar lakes under ice sheets in Antarctica and Greenland were also detected using radar. A microbial life that lives in those extreme Earthly environments may also exist on Mars, scientists say.
For scientists, the next step will not only be to collect further evidence of this lake, but also seeking others like it hiding below the surface.
