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Radar Shows Evidence of a Subterranean Lake on Mars

An Italian team of scientists has found radar evidence of a lake just a mile below the surface of Mars.

The body of water, roughly 12 miles across, is located below the southern polar ice cap of the Red Planet, much like the lakes below Antarctica on Earth, according to a new study published in Science.

The discovery was made using MARSIS, a ground-penetrating radar tool aboard the European Space Agency’s Mars Express spacecraft orbiting Mars.

“Ground-penetrating radars use radio signals that are capable of penetrating into the ground and then get reflections from the material under the surface,” Roberto Orosei, principal investigator on MARSIS and a planetary scientist at the Italian National Institute for Astrophysics, told NPR. Water is especially reflective of radar, making the tool useful in the search for the life-sustaining liquid.

Between May 2012 and December 2015, MARSIS mapped the area around the southern ice cap of Mars. When they found evidence of the subterranean lake, they were careful not to jump to conclusions, the scientists told NPR. Evidence of past bodies of water and periodic flowing water have been discovered, but this is the first time a present body of water has been found on Mars.

“After years, literally a couple of years of … discussion, debate and let’s say general head-scratching,” Orosei told NPR, “we really felt confident that any other explanation would fail.”

Assured of their discovery, they published their findings in Science on Wednesday.

The scientists expect the water is very salty, otherwise it would freeze. Still, this doesn’t mean life couldn’t exist within the lake. Dr. Manish Patel from the Open University told BBC that scientists have long known the surface of Mars is uninhabitable, but life could exists below the surface.

“This is where we get sufficient protection from harmful radiation, and the pressure and temperature rise to more favourable levels. Most importantly, this allows liquid water, essential for life,” said Patel. “We are not closer to actually detecting life, but what this finding does is give us the location of where to look on Mars.”

The European Space Agency already has a Mars rover in the works, set to land on our neighboring planet in 2021. The rover will be able to drill 2 meters below the surface, searching for signs of life.