Some cliff faces on Mars feature dark streaks that appear during the warm months, then disappear when weather turns colder. Writing in the journal Science, some researchers say that the streaks could be signs of briny water on the Martian surface. Planetary scientist Alfred McEwen discusses the findings, and what they might mean for future studies of the red planet.
Below: Time-lapse video over several seasons taken by the HIRISE imaging system on the Mars Reconnaissance Orbiter. NASA video.
Produced by Charles Bergquist, Director and Contributing Producer