Streaks of salty water flow down the mountains and canyons of Mars during summer seasons, raising the odds that life may one day be found on the Red Planet, Nasa scientists have announced. An analysis of the dark patches that ebb and flow on the slopes of Mars shows that they contain "hydrated" salt crystals containing molecules of water — the first time scientists have directly detected liquid water on Mars. Images taken from a spectroscopic instrument on board the Mars Reconnaissance Orbiter flying around the planet have confirmed the presence of briny water in the dark formations running periodically down the Martian slopes, which Nasa first detected in 2000. Last April, Nasa's Curiosity rover detected the presence of salts that could absorb water vapour in the Martian atmosphere, but now the Mars orbiter has found unambiguous signs that liquid water does indeed form around the salt crystals present in the dark streaks of the Martian hillsides.