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A huge 20-kilometer-wide liquid water lake lies beneath the southern ice cap of Mars, scientists have learned.
Dissolved salts are believed to maintain fluid water despite a temperature below the freezing point. 19659002] The discovery, which has major implications for the chances of survival of the red planet, was made by a European probe in orbit using a radar penetrating into the ground.
It is the first time that a large mbad of stable liquid water The lake, similar to those found under the ice sheets of Antarctica and Greenland, lies at about 1.5 km (0.9 miles) below the surface of an area called Planum Austral, near the south pole of Mars, and extending over 20 km
with such low surface temperatures that minus 68 degrees, it would not exist as a liquid under normal conditions.
But the dissolved salts of magnesium, calcium and sodium – known to be present in Martian Rocks – are thought to m aintain the brackish miniature sea by reducing the melting point of water to minus 74 degrees.
An Italian team of scientists detected the lake by conducting a radar survey using the Mars Express spacecraft.
Between 2012 and December 2015 the Planum The Southern Region was mapped by the Mars Advance radar for the Subsurface and Ionosphere (Marsis) survey instrument carried on the orbiter.
Radio waves emitted on the surface by Marsis penetrated through the ice and bounced toward the spacecraft. On the 29 radar samples, the scientists spotted a series of unusually strong reflections bearing a distinct electrical mark. They revealed the presence of liquid water.
Professor Roberto Orosei, of the University of Bologna, wrote in the journal Science : "Abnormally bright underground reflections are evident within a well-defined radius of 20 kilometers. .. which is surrounded by much less reflective zones.
"The quantitative badysis of radar signals shows that this luminous characteristic has a high relative dielectric permittivity (electrical polarization) which corresponds to that of aquiferous materials.
this characteristic as a stable body of liquid water on Mars. "
Extraterrestrial life
The lake can exist as a layer of clear water, or possibly be mixed with the ground to form a mud.
Anyway, the discovery greatly increases the chances of extraterrestrial life existing on Mars.
Liquid water is an essential requirement of life as we know it.
Billions of years ago, Mars would have had oceans and rivers The primitive life may have evolved on the planet, then disappeared when the world lost most of its atmosphere and became an arid icy desert.
If large expanses of liquid water are found under the Martian polar ice, they could theoretically live
High levels of salt in the water could make the environment difficult, but not impossible for life.
On Earth, a group of organisms known as n om of "halophiles" thrive in very salty conditions like those In an interview recorded by Science Professor Orosei revealed that his team spent years checking their results before being confident enough to announce Discovery. 19659002] "We found that any other explanation of these very strong echoes was not really tenable in light of the evidence we had available," he said. "We had to conclude that there is water on Mars today."
Radar data showed that the lake contained a large amount of salt, added Professor Orosei
"This is certainly not a very pleasant environment for life." He said.
But he pointed out that similar salty subglacial lakes in Antarctica had been found to support life.
"There are unicellular organisms that survive in such an environment with a metabolism that uses salt.", Said Professor
Marsis was not able to measure the depth of the lake, but scientists believe that it must be at least one meter thick.-PA
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