NASA’s Mars Reconnaissance Orbiter (MRO) has spotted slopes carved into the martian surface that scientists say appear most likely to have been created by the seasonal flow of salty water.

The imagery, which NASA released during an Aug. 4 press conference, depict dark, finger-like features that appear and extend down some martian slopes during late spring through summer, fade in winter and return the next spring.

“The best explanation for these observations so far is the flow of briny water,” said the University of Arizona’s Alfred McEwen, the principal investigator for MRO’s High Resolution Imaging Science Experiment camera and lead author of the report about the recurring flows.

NASA said the recurring features have been spotted on several steep slopes in the middle latitudes of Mars’ southern hemisphere.

McEwen and his fellow researchers believe the water is salty because pure water would freeze at the observed temperatures.

While frozen water has been detected near the surface in many of Mars’ middle to high-latitude regions, NASA said the results unveiled Aug. 4 are the closest scientists have come to finding evidence of liquid water on the planet’s surface.

NASA launched the Lockheed Martin-built MRO spacecraft in August 2005 aboard an Atlas 5 rocket.



Trapped Mars Rover Found Signs of Subsurface Water