An underground salt-laden lake has been found on Mars, according to Italian researchers.
The team used a radar instrument on an orbiting spacecraft to detect the body of water underneath Mars's polar ice cap. The lake could be a possible habitat for life, the report said.
The reservoir — which is approximately 20 kms in diameter and is shaped like a rounded triangle — is the first stable body of liquid water ever found on Mars.
Researchers said the lake looked similar to the ones found beneath the Antartic and Greenland.
"This is the place on Mars where you have something that most resembles a habitat, a place where life could subsist," said planetary scientist Roberto Orosei of Istituto Nazionale di Astrofisica in Italy, who led the research published in the journal Science.
Data was collected for roughly three years using an instrument aboard the European Space Agency’s Mars Express spacecraft that penetrated the Martian ice caps and sent back radar pulses to the Express.
"This took us long years of data analysis and struggles to find a good method to be sure that what we were observing was unambiguously liquid water," said study co-author Enrico Flamini, chief scientist at the Italian Space Agency.
Orosei said the lake's water was below freezing point but remained liquid thanks to a sizeable amount of salt.
Researchers are still waiting to see if any more bodies of water are found on the Red planet or if this was a one-off discovery.
If other reservoirs are detected and a network of glacial lakes is uncovered — like on Earth — then it could indicate that water has persisted on Mars for millions of years, said Orosei.
The question then would be if any life forms could have developed and if they've been able to survive until now, he added.
Whatever the outcome, the researchers say it would take years to verify whether something is living in the reservoir. They would have to drill through the ice first to sample the water below.
In the past, Mars had already been home to bodies of water as evidenced by dry bed lakes and river valleys on its surface.