Since the discovery of dark streaks on the slopes of Mars in 2011, astronomers have been excited about potential evidence of water beneath the surface of the red planet.
원문출처 : http://www.cnn.com/2017/11/21/world/mars-water-sand-rsl-study/index.html
원문출처 : http://www.cnn.com/2017/11/21/world/mars-water-sand-rsl-study/index.html