New evidence suggests there is flowing water on Mars

The mysterious streaks on the side of some Martian slopes have intrigued scientists ever since they were first spotted three years ago. Now they have just got more intriguing: it seems they get longer when it is hotter. And the best explanation Nasa can think of is they contain liquid water. Known as recurring slope lineae (RSL), these striations were identified in 2011 by scientists looking at pictures sent back by the Mars Orbiter. With the goal of much Mars exploration to identify surface water, considered by some a prerequisite for life, the RSL seemed sufficiently interesting to merit further