Liquid water ‘lake’ revealed on Mars

Researchers have found evidence of an existing body of liquid water on Mars, reports BBC. What they believe to be a lake sits beneath the Red Planet's south polar ice cap, and is about 20km across.

Previous research found possible signs of intermittent liquid water flowing on the martian surface, but this is the first sign of a persistent body of water on the planet in the present day.

Lake beds like those explored by Nasa's Curiosity rover show water was present on the surface of Mars in the past. However, the planet's climate has since cooled due to its thin atmosphere, leaving most of its water locked up in ice.

The discovery was made using Marsis, a radar instrument on board the Mars Express orbiter. "It's probably not a very large lake," says Prof Roberto Orosei from the Italian National Institute for Astrophysics, who led the study.

Marsis wasn't able to determine how deep the layer of water might be, but the research team estimate that it is a minimum of one metre.

“This really qualifies this as a body of water. A lake, not some kind of meltwater filling some space between rock and ice, as happens in certain glaciers on Earth,” Prof Orosei added.

Radar instruments like Marsis examine the surface and immediate subsurface of the planet by sending out a signal and examining what is bounced back. The continuous white line at the top of the radar results above marks the beginning of the South Polar Layered Deposit; a filo pastry-like accumulation of water ice and dust.

Beneath this, researchers spotted something unusual. “In light blue you can see where the reflections from the bottom are stronger than surface reflection. This is something that is to us the tell tale sign of the presence of water,” says Prof Orosei.

Dr Manish Patel from the Open University explains: “We have long since known that the surface of Mars is inhospitable to life as we know it, so the search for life on Mars is now in the subsurface. “This is where we get sufficient protection from harmful radiation, and the pressure and temperature rise to more favourable levels. Most importantly, this allows liquid water, essential for life.” This principle of following the water is key to astrobiology - the study of potential life beyond Earth.

So while the findings suggest water is present, they don’t confirm anything further. “We are not closer to actually detecting life,” Dr Patel told BBC News, “but what this finding does is give us the location of where to look on Mars. It is like a treasure map - except in this case, there will be lots of ‘X’s marking the spots.”

The water’s temperature and chemistry could also pose a problem for any potential martian organisms. In order to remain liquid in such cold conditions (the research team estimate between -10 and -30 Celsius where it meets the ice above), the water likely has a great many salts dissolved in it.

Liquid water lake revealed on Mars

Researchers have found evidence of an existing body of liquid water on Mars, reports BBC. What they believe to be a lake sits beneath the Red Planets south polar ice cap, and is about 20km across. Previous research found possible signs of intermittent liquid water flowing on the martian surface, but this is the first sign of a persistent body of water on the planet in the present day. Lake beds like those explored by Nasas Curiosity rover show water was present on the surface of Mars in the past. However, the planets climate has since cooled due to its thin atmosphere, leaving most of its water locked up in ice. The discovery was made using Marsis, a radar instrument on board the Mars Express orbiter. Its probably not a very large lake, says Prof Roberto Orosei from the Italian National Institute for Astrophysics, who led the study. Marsis wasnt able to determine how deep the layer of water might be, but the research team estimate that it is a minimum of one metre. This really qualifies this as a body of water. A lake, not some kind of meltwater filling some space between rock and ice, as happens in certain glaciers on Earth, Prof Orosei added. Radar instruments like Marsis examine the surface and immediate subsurface of the planet by sending out a signal and examining what is bounced back. The continuous white line at the top of the radar results above marks the beginning of the South Polar Layered Deposit; a filo pastry-like accumulation of water ice and dust. Beneath this, researchers spotted something unusual. In light blue you can see where the reflections from the bottom are stronger than surface reflection. This is something that is to us the tell tale sign of the presence of water, says Prof Orosei. Dr Manish Patel from the Open University explains: We have long since known that the surface of Mars is inhospitable to life as we know it, so the search for life on Mars is now in the subsurface. This is where we get sufficient protection from harmful radiation, and the pressure and temperature rise to more favourable levels. Most importantly, this allows liquid water, essential for life. This principle of following the water is key to astrobiology - the study of potential life beyond Earth. So while the findings suggest water is present, they dont confirm anything further. We are not closer to actually detecting life, Dr Patel told BBC News, but what this finding does is give us the location of where to look on Mars. It is like a treasure map - except in this case, there will be lots of Xs marking the spots. The waters temperature and chemistry could also pose a problem for any potential martian organisms. In order to remain liquid in such cold conditions (the research team estimate between -10 and -30 Celsius where it meets the ice above), the water likely has a great many salts dissolved in it.