- The possible salty discharge as seen by NASA's Mars Reconnaissance Orbiter. Image has been color-enhanced and reprojected. (NASA/JPL-Caltech/Univ. of Arizona)
After peering at images taken by NASA's Mars Reconnaissance Orbiter season after season, scientists have grown to believe that there is water flowing on Mars.
However, if it exists, the water's not likely to be the kind of abundant, thirst-slaking enjoyment that is agua on Earth. Rather, a thirsty Mars cosmonaut would have to suck it out of rusty red sands, and the taste would be salty, perhaps like seawater or pickle juice.
Alfred McEwen of the University of Arizona, Tucson, explained the water theory in a paper published last Thursday in the journal Science. McEwen's the guy in charge of the spacecraft's High Resolution Imaging Science Experiment, which since its kick-off has documented the Red Planet's various wrinkles and scars in fine detail. Now the scientist and his team believe they've come across suggestive photographic evidence that Mars cries briny tears during its warm seasons.
Deep rivets and gullies on Mars indicate that water flowed quite powerfully over the surface at one time, and perhaps even supported life. But few traces of liquid are evident today, with the popular thought being that any water on Mars is frozen beneath the ground. But repeated imaging of the Newton Crater by McEwen's crew reveal that dark somethings move across the planet's surface as the days tick by.
These so-called "recurring slope lineae" are up to five yards wide and grow from bedrock on the crater's southern hemisphere. As the surface heats up during the Martian spring and summer, approaching a sultry 80 degrees Fahrenheit, new lines appear and lengthen.
You can see this strange process occur in the below video narrated by McEwen. Says NASA: "Liquid brines near the surface might explain this activity, but the exact mechanism and source of the water are not understood." (More photos of the possible water over here.)