Water on Mars: Underground system of lakes with liquid water discovered

Two years ago, researchers reported the discoveryGreat Salt Lake under the ice at the South Pole of Mars. This discovery, however, was met with excitement and some skepticism. Now scientists have confirmed the presence of a lake on the Red Planet and, moreover, have found three more. A new study published in the journal Nature Astronomy indicates that there is indeed a buried reservoir of super-saline liquid water near the South Pole. The authors of the scientific work believe that such a lake significantly increases the likelihood of its own microscopic life on the Red Planet. The results of the study showed that an underground "lake" of liquid water has accumulated under frozen layers of sedimentary rocks - akin to the subglacial lakes found under the Antarctic and Greenland ice sheets here on Earth. Since the terrestrial subglacial lakes are teeming with bacterial life, scientists seriously believe that such a life could survive in liquid reservoirs of water on Mars.

Mars may have microbial life of its own

Water on Mars

At one of the poles of the Red Planet, Italian researchers found a system of four lakes with liquid water, which are under the surface of Mars. A new study on the presence of liquid water on the Red Planet near the South Pole comes just weeks after scientists reported finding potential signs of life in the clouds of Venus. Read more about whether microorganisms can exist in the atmosphere of the hottest planet in the solar system in our material.

Mars is believed to be a completely dry planet, butmoisture in its atmosphere freezes during Martian winters in the form of ice, forming the very ice caps at the North and South poles of the planet. If the findings of the new study are confirmed and liquid water is discovered on Mars for the first time, this will have a huge impact on the search for extraterrestrial life.

This is what the Korolyov crater looks like near the North Pole of Mars.

Liquid water is a key ingredient for life as we know it, although exotic chemicals based on hydrocarbons or carbon dioxide cannot be ruled out.

Salt lakes on Mars

As you know, on the surface of Mars lowpressure that arises due to the absence of a dense atmosphere on the planet. This fact makes the existence of liquid water on the surface of the Red Planet impossible. But scientists have long believed that there may be water under the surface of Mars - perhaps billions of years ago there were lakes and seas on the Red Planet. If such reservoirs exist, then they could become a potential habitat for Martian life. On Earth, life is able to survive in sub-ice lakes in places like Antarctica.

To determine if Mars is reallythere is an underground system of lakes, the researchers used a radar device on the Mars Express apparatus called Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) to probe the south polar region of the planet. MARSIS sends out radio waves that bounce off layers of material on and below the planet's surface. How the signal is reflected indicates the kind of material that is present in a particular location - rock, ice, or water, for example. A similar method is used to identify subsurface glacial lakes on Earth.

Layered ice deposits at the South Pole of Mars, detected by radar from Mars-Express

During the work, the researchers applied a newtechniques to the observational data that were used to find lakes under the Antarctic ice sheet, as well as technologies used in the 2018 study. According to Nature, both methods indicate that there is "Patchwork" of buried fluid reservoirs - large reservoir about 24 kilometersdiameter, surrounded by several smaller (up to 9 km) areas. At the moment, scientists cannot say with certainty how deep the discovered reservoirs are, but their approximate beginning can be found about one and a half meters below the surface.

And although the radar does not show what they are made ofdiscovered lakes, they are probably "hypersaline" solutions - water saturated with perchlorate salts of calcium, magnesium, sodium and potassium - that keep them liquid at temperatures of minus 90 degrees Fahrenheit and below.

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Hot debates

but the existence of the Martian lakes themselves is still debated. After the 2018 discovery, researchers are discussingproblems such as not having a sufficient heat source to turn ice into water. And while the latest discovery confirms the 2018 observations and includes much more data, not everyone is convinced that the identified regions are liquid water.

So, planetary scientist Jack Holt from ArizonaThe university believes that Mars is probably too cold for even hypersaline water to exist there as a liquid, and that if that were the case, then liquid water would also exist in regions that would look the same on radar maps. Holt works with radar on the Mars Reconnaissance Orbiter, which did not find any signs of liquid water and believes that "there is not enough heat flow on Mars to maintain brine, even under the ice cap."

Image: radar map of Mars.
A radar map of an area near Mars' south pole where hypersaline water is believed to exist beneath the surface is shown here in shades of blue. Nature Astronomy and Lauro et al.

Do you think Mars really has liquid water? We will wait for the answer in the comments to this article as well as in our Telegram chat

Steve Clifford of the Institute of Planetary Science, whichdid not participate in the study, agrees that an underground body of water is the most plausible explanation for the radar observations of the Mars Express spacecraft, but claims that the water may not be so cold or salty as the researchers suggest. Clifford believes that the underground fluid could have come from the heat coming from the hot interior of the planet, melting ice deposits in the same way that geothermal heat melts the base of the Antarctic ice sheet in some regions of our planet.

Accurate answers to a huge number of questions aboutthe Martian system of underground lakes may be able to find a Chinese mission, which is already on its way to the Red Planet. Recall that the Tianwen-1 mission will enter orbit in February 2021 and in addition to deploying the rover on the surface, the orbiter will be equipped with a set of scientific instruments. These include radar equipment that can be used to conduct similar observations. Well, let's wait!