Hydrated salts are evidence for flowing water on Mars
Scientists at NASA have discovered evidence for flowing water on the surface of Mars. Spectral data recorded by the imaging spectrometer of the Mars Reconnaissance Orbiter indicates the presence of hydrated salts in recurring slope lineae at four different locations on the planet. These narrow streaks of low reflectance on the surface of Mars grow in the downslope direction during warm seasons when temperatures reach 250 K – 300 K and fade away during cold seasons. The hydrated salts most likely represent a mixture of magnesium perchlorate (Mg(ClO4)2.H2O), magnesium chlorate (Mg(ClO3)2.H2O) and sodium perchlorate (NaClO4.H2O), and appear to be most abundant when the recurring slope lineae are most extensive. This suggests that these structures are formed as a result of water flowing at the surface or in the shallow subsurface of Mars. The discovery of liquid water is a major step in the search for extant life on Mars.
Journal reference: Ojha, L., Wilhelm, M. B., Murchie, S. L., McEwen, A. S., Wray, J. J., Hanley, J., … & Chojnacki, M. (2015). Spectral evidence for hydrated salts in recurring slope lineae on Mars. Nature Geoscience.
Image: Recurring slope lineae in the Garni Crater on Mars as seen from the Mars Reconnaissance Orbiter. Source: NASA/Jet Propulsion Laboratory-Caltech/University of Arizona.