Scanning Mars with radar from a space probe, researchers have detected a lake of liquid water under the ice that is more than 12 miles wide, according to a new study published Wednesday.
The discovery raises the tantalizing possibility that the water could be home to alien life, said the lead author, Roberto Orosei, a research scientist at Italy’s Institute of Radioastronomy of the National Institute of Astrophysics.
“We do not know the exact temperature, salinity, etc. of this body of water, but it is tempting to think that [it] may be similar to terrestrial environments in which life is able to thrive. This could be the first habitat discovered on Mars,” he said in an e-mail.
It is the first time there has been any detection of liquid water under the surface of Mars, he said.
The lake is approximately circular with a diameter of about 12 miles. It is about a mile below the surface. It has to be at least about 3 feet deep, or else it would not have been picked up by the radar scan, Orosei said.
The lake was found using the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on the Mars Express spacecraft, which was launched by the European Space Agency in June 2003 and arrived at Mars in December 2003, researchers said in a statement.
The researchers, whose work is being published Wednesday in the journal Science, found the lake while studying a region called Planum Australe in the southern ice cap of Mars, researchers said.
The radar results were similar to those for lakes of liquid water found under the Greenland and Antarctic ice sheets on Earth, researchers said.
Though the temperature on Mars may be too cold for pure water to remain liquid, Orosei and fellow researchers from a number of Italian institutions noted it was possible that the water was mixed with dissolved salts of magnesium, calcium, and sodium to form a brine, researchers said.
That could lower the freezing point for the water, along with pressure from the ice above, the researchers said.
The effect of the salts is the same as when you put salt on a road, said Kirsten Siebach, a planetary geologist at Rice University who wasn’t part of the study.
‘‘This water would be extremely cold, right at the point where it’s about to freeze. And it would be salty. Those are not ideal conditions for life to form,’’ Siebach said.
Still, she said, there are microbes on Earth that have been able to adapt to environments like that.
‘‘If these researchers are right, this is the first time we've found evidence of a large water body on Mars,’’ said Cassie Stuurman, a geophysicist at the University of Texas who found signs of an enormous Martian ice deposit in 2016.
Scott Hubbard, a professor of astronautics at Stanford University who served as NASA’s first Mars program director in 2000, called it ‘‘tremendously exciting.’’
‘‘Our mantra back then was ‘follow the water.’ That was the one phrase that captured everything,’’ Hubbard said. ‘‘So this discovery, if it stands, is just thrilling because it’s the culmination of that philosophy.’’
Material from The Associated Press was used in this report.