Water’s role in Martian chemistry becoming clearer
As mission nears end, Phoenix Mars Lander finds chemical surprises
By Ron Cowen
Perched on a vast plain above the arctic circle of the Red Planet, NASA’s Phoenix Mars Lander has found new evidence that liquid water was once present in the north polar region and interacted with minerals there. Phoenix scientists reported the findings September 29 during a NASA press briefing.
Two Phoenix experiments identified calcium carbonates and clays in soil samples scooped up by the craft’s robotic arm. On Earth, both minerals are associated with the presence of liquid water.
Carbonates such as limestones form on Earth when carbon dioxide from the atmosphere dissolves in liquid water, making carbonic acid. The acid eats away at rocks, which eventually become carbonate deposits such as the White Cliffs of Dover.