A new study suggests that dark streaks on Mars are signs of flowing sand — not water. Monday's news throws cold water on 2015 research that indicated these recurring slope lines were signs of water currently on Mars. Instead, Arizona scientists said these lines — called "recurrent slope lineae" (RSL) — appear more like dry, steep flows of sand, rather than water trickling downhill, at or near the surface. The scientists say if water is present, it's likely a small amount — and not conducive to life. The space agency's top Mars scientist, Michael Meyer, says the latest study does not rule out the presence of water.

Source: CBC News November 20, 2017 22:18 UTC