You might already have seen this image in a newspaper or magazine. It illustrated NASA’s announcement on 28 September of liquid-water flows on Mars. The evidence comes from dark, narrow streaks on slopes appearing in the Martian summer season, before they fade away during the winter. These "recurring slope lineae" are seen here at the Hale crater as the dark features some 100 m long. The detection of hydrated salts on these slopes corroborates the idea that the streaks are indeed formed by liquid water. The unreal look of the picture betrays a particular processing. Indeed, the image was produced by draping a false colour image – combining infrared, red, and blue/green channels – onto a digital-terrain model of the same site with vertical exaggeration by a factor of 1.5. It is based on observations by the High Resolution Imaging Science Experiment (HiRES) camera on the Mars Reconnaissance Orbiter (Picture of the month, CERN Courier November 2013 p11, March 2010 p9, December 2009 p11).

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• https://www.nasa.gov/press-release/nasa-confirms-evidence-that-liquid-water-flows-on-today-s-mars