A vast underground lake has been discovered on Mars, a first in the study of the red planet! The lake was revealed in an article published in the scientific journal Science, published by Italian astrophysicists. Its existence had been suspected for a long time, but was not detected until now.
Water in solid form (ice) had already been discovered on Mars. However, never before has such a volume of liquid water been identified. This discovery could revive the hypothesis of a microbial life on Mars, liquid water being one of the prerequisites for the emergence of life as we know it on Earth.
To detect the underground lake, the researchers used a radar (MARSIS) present on the Mars Express, based on observations made between May 2012 and December 2015. The researchers’ attention was first attracted by unusually bright radar reflections from the martian underground. In other words, the characteristics of the environment observed on the radar suggested the existence of liquid water, explain the team of scientists, which also relied on permittivity calculations (response of a medium to an electric field) to prove that it is indeed water rather than just rock. Located beneath a layer of Martian ice at the South Pole of the planet, the lake would be about 20 km wide and suggests the presence of more water on the red planet.
“This is a staggering result that suggests that the presence of water on Mars is not just a temporary runoff revealed by previous discoveries, but a permanent body of water that creates the conditions for life over a period of time,” says Alan Duffy, an associate professor at Swinburne University, Australia, who did not participate in the study. The lake water that has been discovered may not be reachable, however. It is 1.5 km below the surface, in a harsh and icy environment.
The planet Mars is now cold, desert and arid, but could once have been hot and humid and shelter a large amount of liquid water and lakes several billion years ago, according to the study, which will have to be confirmed by the observation of liquid water elsewhere than under the icy pole of the planet. But the study does not reach consensus among the MARSIS team. “I would say that this is a plausible interpretation, but that it is not yet the master stroke,” said Jeffre Plaut, a researcher at NASA (not involved in the study), a journalist for Science.
On the same subject: Is there life on Mars?
The presence of a possible form of microbial life within the lake is, moreover, subject to debate. Some experts are skeptical about this, saying the lake would be too cold and brackish, and would contain a high dose of dissolved Martian salts and minerals. Its temperature is probably even below the freezing point of pure water, but the lake can remain in the liquid state due to the presence of magnesium, calcium and sodium. “We must remain cautious [on the hypothesis of life on Mars] because the concentration of salts needed to maintain water in the liquid state could be fatal to any microbial life similar to that of the Earth,” says Fred Watson, of the Australian Astronomical Observatory, not involved in the study.