Pretty big news from NASA today getting lost amid the financial panic: observations made by the Mars Reconnaissance Orbiter have revealed possible flowing water during the warmest months on the Red Planet.
Dark, finger-like features appear and extend down some Martian slopes during late spring through summer, fade in winter, and return during the next spring. Repeated observations have tracked the seasonal changes in these recurring features on several steep slopes in the middle latitudes of Mars’ southern hemisphere.
“The best explanation for these observations so far is the flow of briny water,” said Alfred McEwen of the University of Arizona, Tucson. McEwen is the principal investigator for the orbiter’s High Resolution Imaging Science Experiment (HiRISE) and lead author of a report about the recurring flows published in Thursday’s edition of the journal Science.
Some aspects of the observations still puzzle researchers, but flows of liquid brine fit the features’ characteristics better than alternate hypotheses. Saltiness lowers the freezing temperature of water. Sites with active flows get warm enough, even in the shallow subsurface, to sustain liquid water that is about as salty as Earth’s oceans, while pure water would freeze at the observed temperatures.
Why is this important? We already knew that Mars has water: ice has already been detected near the surface in many regions. But with liquid water comes a much higher possibility of life – and the knock-on effect from that is perhaps more chance of future missions to the Red Planet. According to NASA Administrator Charles Bolden, the MRO observations bring 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.”