Liquid Water Exists Below Freezing Point on Mars, NASA Curiosity Rover Finds

NASA's curiosity has found evidence for liquid water existing below Martian surface trapped in salts.

Experiments conducted by various equipment onboard Curiosity found that calcium perchlorates allow liquid water to exist even at -70 degree Celsius, a temperature usually too low for water to exist as liquid on earth. The salts lower the freezing point of water, allowing it stay in liquid form up to 15 cm below surface.

Researchers involved with the Curiosity mission explained that brine formation happens during winter nights when temperatures are low but evaporation ensues when temperatures rise during the day, constituting the Mars water cycle. Experiments were conducted close to Martian equator where Curiosity landed. Researchers believe that the brine could be more persistent and resist evaporation at higher latitudes where temperatures would be lower and humidity higher.

"What we see are the conditions for the formation of brines on the surface. These perchlorate salts have a property called deliquescence. They take the water vapor from the atmosphere and absorb it to produce the brines. We see a daily water cycle - which is very important. This cycle is maintained by the brine. On Earth we have an exchange between the atmosphere and the ground through rain. But we don't have this on Mars," co-investigator of the Curiosity Mission Javier Martin-Torres told BBC.

The existence of known microbial life at freezing temperatures is being doubted but researchers have not ruled out such life below surface or at different locations on the planet.