Phoenix finds evidence of past liquid water on Mars

Phoenix has found minerals on Mars that suggest the craft's bone-dry landing site may once have been quite wet, researchers announced on Monday. The lander has also spotted the first hints of snowfall, in clouds high above the ground.

Since the 1970s, spacecraft have beamed back images of deep channels and canyons that suggest water once flowed across the Red Planet. More recently, both orbiting spacecraft and NASA's rovers have also found mineralogical evidence of liquid water on the planet's surface.

But the history of liquid water has been less clear at higher Martian latitudes, where water did not etch dramatic features such as gullies into the planet's surface. Now, Phoenix has found evidence of past liquid water – thought to be a crucial requirement for life – on the planet's northern plains.