The Red Planet has just gotten a bit bluer as scientists announce the discovery of a lake that they believe is about 12 miles wide and is less than a mile (1.6 kilometers) in ice at the south pole of Mars ,
Scientists have so far offered much weaker evidence of such reservoirs as well as strong evidence of smaller amounts of water on the planet. But the new findings still make a splash
"It's always exciting to talk about liquid water on today's Mars," said Ashwin Vasavada, project scientist at NASA for the Curiosity mission, told Space.com. However, he declined to say how confident he is in the statements of the study because he is not an expert in the kind of radar image the team used. "It's exciting because of possible implications for the habitability of Mars." [Geometry Helps Solve the Mystery of Mars̵
And it is too early to say what exactly these implications might be. Scientists still need to confirm the discovery itself and understand exactly what properties water can have, which will require missions that are yet to be developed, let alone started.
Water under the ice?
The new research builds on more than three decades of theorization of scientists about the chances that water under Mars lurks polar maps, just like here on Earth.
This idea was first proposed by Steve Clifford, who is now a planetary scientist on Mars at the Planetary Science Institute in Arizona, and was not involved in the new research. He was inspired by studies of scientists on lakes below the Antarctic and Greenland ice sheets here on Earth, he told Space.com. These lakes arise when the heat from inside the planet melts the glaciers. He thought a similar scenario might be taking place under the ice caps on Mars – we just had no way to look under the ice.
The new research tried to do just that with the help of radar data captured by an instrument called MARSIS. The radar pulses are used to study the ionosphere and the internal structure of the planet. Since 2003, it has orbited the planet aboard Mars Express, a European spaceship.
The radar signals MARSIS produces depend on the material they meet, in different ways back to Mars Express. And the team behind the new research said that the signals that MARSIS recorded above the south pole of Mars can only be explained by a large underground pool of liquid water.
"We spotted water on Mars," lead author Roberto Orosei, co-investor at MARSIS and a scientist at the National Institute of Astrophysics in Italy, said in a video released with the paper. "MARSIS was able to detect echoes under the southern polar cap of Mars that were stronger than surface echoes, and this condition on Earth only happens when you observe sub-glacial water like in Antarctica over places like Lake Wostok." And while the team has only evidence of one location, they suspect it is not the only one of these subglacial lakes (the Antarctic hides about 400 such features).
According to the Radarechos, the lake is no more than 12.5 miles (20 km) across and is buried about a mile below the surface of the ice cap. The scientists can not figure out exactly how deep the lake is, but they have confirmed that it is at least 1 meter deep. It must be quite salty, because the ice above it is quite clear and therefore quite cold – if there were pure water under this type of ice, it would be frozen, the researchers said.
The team used data on three and a to ensure that their analysis included multiple passes across the same region. They also considered a few other scenarios that might have explained the data they saw, including a layer of carbon dioxide ice that hid under the water ice. But the researchers said they were dissatisfied with these explanations.
Other scientists may not agree. "I think it's a very, very convincing argument, but it's not a conclusive or definitive argument," Clifford said. "There is always the possibility that conditions that we did not foresee exist at the base of the cap and are responsible for this bright reflection."
The research is described in an article published in the journal Science on July 25.
Life means water, but water does not mean life
If future studies confirm that the mysterious layer under the ice is actually water, scientists will have a lot of other issues with that Reservoir before they can make predictions about what discovery means for the possibility of life on Mars. [Curiosity Rover Finds Ancient ‘Building Blocks for Life’ on Mars]
"If you have liquid water and you consider its relevance to life, then you must go beyond the fact that it is fluid and ask the temperature if it is in life," said Vasavada any liquid water is the same in life's ability to use it. "In particular, he pointed out the high salt content that would be required to keep water liquid at such low temperatures, which could overwhelm even the most salt-loving life forms he suggested.
Scientists on Earth have drilled through glaciers to study the underlying water and found microbial life, so if there ever was any life on Mars, this life could theoretically have survived, hidden in it or similar lakes, Clifford suggested.
"There is no reason to expect that it would not continue to this day," he said of ir there is an old microbial life on Mars. "The subsoil is a very, very stable environment compared to the surface of a planet, protected from impact and protected from climate change."