Mars could be the next galactic frontier, but before humans go we’ll have to figure out how they will get water. In a study published today in Nature Geoscience, scientists report they have found evidence to support a saline solution: it may be possible to collect water from the brine that exists in fiery planet’s soil.
Contrary to some reports, this isn’t the first evidence of liquid water on Mars. The Mars Phoenix lander reportedly photographed water droplets forming on its leg in 2009 (and also found the presence of perchlorates in the soil). But it's always exciting find any hint of possibility of water on another planet—water! on Mars!—and this new evidence makes it that much easier to indulge in dreams of off-Earth living.
Here's what's new: After analyzing the temperature and humidity data that NASA’s Curiosity rover collected during its first year roaming Mars’ equator, the researchers believe Martian winters provide the right conditions for liquid to form, even in the face of the planet’s icy cold environment (with temperatures sometimes dipping below 225 degrees Fahrenheit). That’s because soil on Mars contains perchlorate salts, which drastically lower the freezing point of water.
The team found that during Martian winter, conditions throughout the cold but humid nights would allow liquid water to be stable in the first five centimeters of the surface. Shorter periods of stability would also be possible in other seasons.
They suggest that calcium perchlorate in the ground absorbs water from the atmosphere until it dissolves into a salty solution, or brine. This process is called deliquescence. When the sun comes up and the temperature rises, the water evaporates and returns to the atmosphere, starting the cycle anew.
This finding does not necessarily support evidence for life on Mars (because temperatures are still far to cold for any known organisms), but it could help us one day inhabit the place ourselves. “It’s a proof of a concept of an instrument that will take water out of the atmosphere to produce liquid water for astronauts,” study author Javier Martin-Torres tells New Scientist. Who’s ready to go exploring? Who knows — a new expedition might even find the newest "first evidence" that there's water on the red planet.