Nasa: Mars has flowing water
Flowing liquid water is almost certainly responsible for mysterious features on Mars that change with the seasons, scientists believe.
Satellite images have identified narrow streaks, typically less than five metres wide, that appear on slopes during warm seasons, lengthen, and then fade when conditions become cooler.
Experts have speculated that water might be involved in the formation of the gully-like features, known as recurring slope lineae (RSL), but only now has evidence supporting the theory come to light.
