spacetoday.net: Scientists link linear features on Mars to water

Posted: Wed, Feb 12, 2014, 6:27 AM ET (1127 GMT)
Recurring slope lineae features on Mars (Ga. Tech)

Planetary scientists analyzing data from a NASA spacecraft believe flowing water is the most likely explanation for a series of linear features seen on crater walls on Mars, but say that they do not have conclusive evidence water caused the features. Scientists examined features called recurring slope lineae (RSL), dark streaks often seen on steep slopes like crater walls that appear every Martian year. Spectral analysis of the features by NASA's Mars Reconnaissance Orbiter turned up no evidence of water or salts in the RSL features studied, but they did find "distinct and consistent" signatures for ferric and ferrous minerals different from the rest fo the landscape. Scientists writing in a paper in Nature Geoscience acknowledge that they don't have a "smoking gun" for water, but that they cannot identify a mechanism for creating the RSL features that doesn't involve water.