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Liquid water on Mars? New research points to buried “lakes”

Earth’s subglacial lakes teem with bacterial life, and such life could survive in liquid reservoirs on Mars, the scientists speculated.

“We are much more confident now,” said Elena Pettinelli, professor of geophysics at Roma Tre University, who led the latest research and the previous study. “We made many other observations and processed the data completely differently.”

The planetary scientist and her team compiled 134 observations of the region near the south pole with ground-penetrating radar from the Mars Express Orbiter between 2012 and 201

9 – more than four times more than before and covering a period of time more than double. long.

They then applied a new technique to the observation data that was used to find lakes beneath the Antarctic ice sheet, as well as an older technique used in the 2018 study.

Both methods indicate there is a “mosaic” of buried reservoirs of liquids in the region, Pettinelli said – a large reservoir about 15 miles in diameter surrounded by several smaller spots up to 6 miles in diameter.

Researchers can’t tell how deep the reservoirs are, but they start about a mile below the surface, he said.

The stratified ice deposits at the Martian South Pole, revealed by the Mars Express radar.NASA

And while the radar doesn’t show what they’re made of, they’re likely “hypersaline” solutions – water saturated with perchlorate salts of calcium, magnesium, sodium, and potassium – that keep them liquid at minus 90 degrees Fahrenheit, Pettinelli said.

The new study of a potential underground niche for life on Mars comes just weeks after scientists reported finding potential signs of life in the clouds of the planet Venus.

If these are indeed buried bodies of liquid water, they could be a prime spot where alien microbial life could survive on the red planet – perhaps a remnant of life that could have existed there billions of years ago if Mars had seas of water on the red planet. its surface.

Liquid water is a key ingredient for life as we know it, although exotic chemicals for life based on hydrocarbons or carbon dioxide have also been proposed.

Mars is thought to be dry by now, but the moisture in its atmosphere freezes during Martian winters in the form of water ice above the permanent carbon dioxide ice caps at the north and south poles.

If the discovery is verified, this is the first time liquid water has been found on Mars and will have a profound impact on the search for extraterrestrial life.

Steve Clifford of the Planetary Science Institute, a non-profit organization based in Tucson, Arizona, said he agrees that a body of groundwater is the most plausible explanation for the Mars Express radar observations, but argues that it could don’t be as cold or salty as the researchers suggest.

Clifford, who worked on the Mars Express mission but was not involved in the new study, said he thinks underground liquid could be created by the heat of the planet’s warm interior by melting icy sediments in the same way that geothermal heat does. melts the base of the Antarctic ice sheet in some regions.

A radar map of the region near the south pole of Mars where hypersaline water is thought to exist below the surface, shown here in shades of blue.Nature Astronomy and Lauro et al

That would mean that underground reservoirs on Mars don’t have to be extremely salty to remain liquid, he said.

However, not everyone is convinced by the new study.

Planetary scientist Jack Holt of the University of Arizona’s Lunar and Planetary Laboratory in Tucson said in an email that Mars was probably too cold for even hypersaline water to exist as a liquid – and if so, then the liquid water would also exist in regions that looked the same on radar maps.

“If we apply the same interpretation, there should be springs sticking out along the edge of the polar cap,” he said. “And that’s not it.”

Holt works with radar on the Mars Reconnaissance Orbiter, which has seen no signs of liquid water, although Mars Express researchers suggest that he is using the wrong radar wavelengths to see them.

Holt also thinks that any description of buried water “lakes” is misleading: “At best, mottled wet sediment,” he said. “But this too is a stretch.”

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