Orbiting the red planet NASA's Mars Reconnaissance Orbiter (MRO) has discovered evidence that warm, salty water may flow across Mars during its warmest months.
The discovery was made when the MRO recorded images and video footage of "finger-like" formations and features running down a number of Martian peaks.
After examining the images with those previously taken of the planet, researchers discovered that the features followed a seasonal pattern, appearing in the planet's spring period, staying through summer before disappearing in winter.
Richard Zurek of NASA's Jet Propulsion Laboratory in Pasadena, Calif. and MRO project scientist commented on the features: "These dark lineations are different from other types of features on Martian slopes... Repeated observations show they extend ever farther downhill with time during the warm season."
The features were recorded on the steep slopes housed in the middle latitudes of Mars' southern hemisphere. NASA scientists have estimated that the features are around 0.5 to five meters wide. The images showed each feature varying in length with the longest extending hundreds of yards across the martian landscape.
The water is thought to be contain salt as the images taken show the flows extend and darken on formations facing the planet's equator. This would mean that the areas captured showing the features would be too warm for carbon-dioxide frost and too cold for pure water.
The researchers have since speculated that the water is briny in character, citing Mars abundant salt deposits and the fact that brine has a lower freezing point as evidence.
Alfred McEwen of the University of Arizona, Tucson and principal investigator for the orbiter's High Resolution Imaging Science Experiment (HiRISE) commented on the discovery: "The best explanation for these observations so far is the flow of briny water."
The Search For Life
Since the features were discovered NASA was quick to highlight that the water's presence could indicate the existence of life on Mars.
NASA Administrator Charles Bolden commented on the question of potential Martian life: "NASA's Mars Exploration Program keeps bringing us closer to determining whether the Red Planet could harbor life in some form... and it reaffirms Mars as an important future destination for human exploration."
Since the discovery several scientists have downplayed the significance of the features, highlighting that NASA are yet to actually see water flowing on the Martian surface.
When NASA scientists checked the images, the features didn't actually contain any water. The researchers have since speculated that this may be because the water flows and disappears rapidly, or because it flows beneath the Martian surface. Neither explanation has been taken to completely explain the dark colouration of the features.
Speaking about the features mysterious colouration McEwen clarified: "The flows are not dark because of being wet... They are dark for some other reason.
"It's a mystery now, but I think it's a solvable mystery with further observations and laboratory experiments."