Mars' Dark Streaks May Be Caused by Dry Landslides, Not Water

Mars' intriguing dark streaks may not be evidence of liquid water after all. These long and narrow features, known as recurring slope lineae (RSL), darken some slopes near the Martian equator for weeks at a time during the warmest parts of the year. Some researchers posit that RSL are caused by transient flows of briny water, and therefore may be signs of a potentially habitable environment — an idea that was bolstered in 2015, when scientists announced that MRO had identified hydrated salts in the features.