Why Water?

Following water has guided exploration over time. Water carried explorers and dropped them in new lands. It often marked sites for settlement. Fresh liquid water was and still is vital for life.

Following water continues to guide exploration as we explore space. Find water, and you might find a friendly place for life as we understand it. Find water, and you might find life itself.

The Phoenix Lander continues seeking the Martian Holy Grail: water and possible life-supporting conditions.

Mars is a cold desert with no liquid water on its surface. While there may be no liquid water, water as a gas or solid can be found on Mars. Based upon the discoveries of the Mars Odyssey Orbiter in 2002, large amounts of water ice have been found on and just below the surface of Mars in the northern arctic plain. Water, as water vapor, is vital to the weather and climate of Mars. Phoenix will be the first mission to collect meteorological data from the Martian arctic. Once Phoenix visits Mars, scientists may be able to create models of Mars' past climate and predict future weather processes.

Did liquid water ever exist on the surface of Mars? Evidence from Mars Global Surveyor, Odyssey and Exploration Rover missions suggest that billions of years ago, water once flowed in canyons and pooled in shallow lakes. Digging with its robotic arm into the circumpolar region of Mars, the Phoenix lander may uncover new information about water ice and the soil. Perhaps, through scientific analysis, closed doors to the past will be opened as scientists gain a clearer understanding of the history of liquid water on Mars. Some believe that liquid water may have been found in the arctic as recently as 100,000 years ago.

What could evidence of past liquid water mean?

Life, as we understand it, requires liquid water.

Liquid water is an amazing chemical. Water, in a liquid form, helps chemicals move into and out of cells. Water vapor and water ice can't do this. Liquid water also helps proteins do their jobs.

Water can do some things that other liquids can't. It stays a liquid within a wide temperature range and has the ability to "hold" energy. This helps prevent temperature swings that could affect life. Climate and weather changes are softened by the presence of liquid water.

Unlike most molecules, water floats when it freezes. A frozen layer of water - ice - helps insulate the water below. This protects the liquid environment and any life in it.

Water molecules are "polar" or have a slightly negative side and a slightly positive side. Each end of the water molecule attracts other charged particles. This helps materials dissolve more easily in water.

The Phoenix Lander will be hunting for precious water and clues to Mars' past, present and future. While doing this, it may find evidence of life on Mars.

Following water continues to guide exploration.

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