Earth’s subglacial lakes are teeming with bacterial life, and similar life could survive in reservoirs of fluid on Mars, scientists have speculated.
“We’re much more confident now,” said Elena Pettinelli, professor of geophysics at Roma Tre University, Italy, who led the latest research and the earlier study. “We made a lot more observations and processed the data completely differently.”
Between 2012 and 2019, the planetary researcher and her team processed 134 observations of the region near the South Pole with ground penetrating radar from the Mars Express Orbiter ̵
They then applied a new technique to the observational data used to find lakes beneath the Antarctic ice sheet, as well as an older technique used in the 2018 study.
Both methods indicate that there is a “patchwork of buried fluid reservoirs” in the region, Pettinelli said – a large reservoir about 15 miles in diameter surrounded by several smaller fields up to 10 miles in diameter.
Researchers can’t tell how deep the reservoirs are, but they start about a mile below the surface, she said.
And while the radar won’t tell what they’re made of, they’re likely “hypersaline” solutions – water saturated with perchlorate salts of calcium, magnesium, sodium, and potassium – that keep them fluid at below minus 90 degrees Fahrenheit, said Pettinelli.
The new investigation into a potential subterranean niche for life on Mars comes just weeks after scientists reported they found potential signs of life in the clouds of the planet Venus.
If these are truly buried bodies of liquid water, they could be a prime place for microbial alien life to survive on the red planet – perhaps a remnant of life that would have existed billions of years ago if Mars had oceans of water upon itself would have had surface.
Liquid water is a key ingredient in life as we know it – although exotic chemicals based on hydrocarbons or carbon dioxide have also been suggested for life.
Mars is believed to be bone dry, but the moisture in its atmosphere freezes as water ice over the permanent carbon dioxide ice caps at the North and South Poles during the Martian winters.
If the discovery is confirmed, it will be the first time liquid water has been found on Mars and it will have a profound impact on the search for extraterrestrial life.
Steve Clifford of the Planetary Science Institute, a nonprofit based in Tucson, Arizona, agrees that an underground body of water is the most plausible explanation for Mars Express’s radar observations – but he argues that it may not be as cold or salty as that Suggest researchers.
Clifford, who worked on the Mars Express mission but was not involved in the new study, believes the subterranean fluid could be created by heat from the hot interior of the planet, which melts the icy sediments in the same way as Geothermal energy is the base melting the Antarctic ice sheet in some regions.
That would mean the underground reservoirs on Mars don’t have to be extremely salty to stay fluid, he said.
However, the new study does not convince everyone.
Planetary researcher Jack Holt of the University of Arizona’s Lunar and Planetary Laboratory at Tucson said in an email that Mars is likely far too cold for even hypersaline water to exist as a liquid – and if it did, it would be liquid Water also exist in regions where it looked the same on radar maps.
“If we use the same interpretation, feathers should flow out from the edge of the polar cap,” he said. “And that’s not the case.”
Holt works with radar on the Mars Reconnaissance Orbiter, which saw no signs of liquid water – although Mars Express researchers suspect he is using the wrong radar wavelengths to see them.
Holt also considers any description of buried “lakes” of water to be misleading: “At best, spotty wet sediment,” he said. “But that’s a stretch too.”