Water on Mars

(Reuters) - The Mars Phoenix Lander has found ice on the surface of the Red Planet, triumphant NASA scientists said on Thursday, a key discovery for the spacecraft as it searches for water and signs of life on Earth's closet planetary neighbor

The proof came in a series of pictures sent back by Phoenix of a trench it dug with its robotic arm at the arctic circle of Mars, showing dice-sized chunks of white material that are seen to melt away over the course of several days.
"It is with great pride and a lot of joy today that I announce we've found the proof we've been seeking that this really is water ice and not some other material," mission principal investigator Peter Smith, of the University of Arizona, said at a press conference.
The presence of water on Mars is crucial because it is a key to the question of whether life, even in the form of mere microbes, exists or has ever existed on Mars. On Earth, water is a necessary ingredient for life.
Scientists first discovered what they believed was a vast sheet of ice under the barren surface of the Martian north pole in 2002, when the Mars Odyssey Orbiter detected it through a hydrogen analysis while circling the planet.