Water is so essential for life on Earth that its presence is considered by scientists to be the most important indicator of potential habitability on alien worlds. For instance, Mars may have briefly had the right conditions to support life billions of years ago, when portions of its surface were awash in water, but it is unclear just how wet the red planet is today.
In 2018, scientists detected the possible presence of a salty water reservoir hidden about a kilometer under the icy Martian south pole. New observations now “strengthen the claim of the detection of a liquid water body” and “indicate the presence of other wet areas nearby,” according to a study published on Monday in Nature Astronomy.
While the new study is not definitive proof of subglacial lakes on Mars, it is tantalizing evidence that a few wet places may have survived on this planet, despite its overwhelmingly dry and irradiated surface.
Co-led by scientists Sebastian Emanuel Lauro and Elena Pettinelli from Roma Tre University in Italy, who were also co-authors on the 2018 study, the new research is an important development in the search for Martian life, if it exists.
“The possibility of extended hypersaline water bodies on Mars is particularly exciting because of the potential for the existence of microbial life,” said the team in the study. “Future missions to Mars should target this region to acquire experimental data in relation to the basal hydrologic system, its chemistry, and traces of astrobiological activity.”
The researchers studied Mars’ ice-covered south pole with the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS), an instrument onboard the European Space Agency’s Mars Express orbiter. MARSIS is similar to radar instruments on Earth that map out the topography of complex features, such as ice caps, by bouncing radio waves off them.
MARSIS picked up the outline of a possible lake, measuring some 19 miles (30 kilometers) in diameter, under the Ultimi Scopuli region of the Martian south pole, according to the 2018 study.
To get a more detailed read on the area, Lauro, Pettinelli, and their colleagues examined a much broader range of MARSIS observations, captured from 2010 to 2019. The results show that the central 30-kilometer lake might be flanked by at least three other smaller bodies of water.
The estimated temperature in this layer of ice is about minus 68°C (minus 90°F), well below the freezing point for water. If these signals truly are caused by deep, dark Martian lakes, they would likely have to be extremely salty in order to keep the water in a liquid state.
The properties of the speculative lakes are also crucial for assessing whether they could support life. Scientists have found microbes living in subglacial lakes in Antarctica, providing some hope for E.T. enthusiasts, but no doubt conditions under the Martian ice are even harsher than those on Earth.
In recent weeks, Venus has eclipsed Mars as the center of attention in the search for nearby aliens, thanks to an exciting study that detected a possible sign of life in the planet’s clouds.
Now, Mars has taken the spotlight back with new revelations about its potential water content.
Fortunately, the new studies leave scientists with all kinds of fascinating avenues to explore in the search for extraterrestrial life, right in our own solar backyard.