The European Space Agency's Mars Express orbiter has sent back images that show there is plenty of icy water at the red planet's southern pole. The finding confirms previous scientific studies suggesting the presence of icy water in the far reaches of earth's closest neighbor.
Since the late 1960s, scientists have used earthbound observations to try to determine whether Mars' polar caps are covered with icy water similar to the condition of earth's polar climates.
But astronomers have lacked a close-up view of the red planet's southern pole, until now. The Mars Express orbiter, which arrived in December, has given scientists that view. It has found three structures that contain icy water, according to Timothy Titus, a space scientist with the U.S. Geological Survey in Arizona.
The largest of the structures is a bright, perennial ice cap about 400 meters in length.
A team of French astronomers, who made the discovery of icy water in Mars' south pole, describe their work in the journal Nature.
Mr. Titus says the European orbiter's finding of frozen water in Mars' southernmost region is not related to geological signs of water discovered recently by Opportunity, one of two U.S. rovers scouring the surface of the red planet's equator for evidence that water once flowed on Mars.
Scientists believe where there is water there may have once been life. Mr. Titus says life might exist in the Martian poles, but the extreme climate would make it difficult to look. "If you look on earth in the extreme environments where you actually find life, the rovers would have a hard time getting to [those areas]," he said. "But that doesn't mean we should stop looking."
Meanwhile, the U.S. Mars rover Opportunity has acquired more evidence that water once surged through the area of the red planet it is inspecting. The rover's instruments confirm that little beads spread throughout a rock formation contain an iron compound that can form in water.
Harvard University geologist Andrew Knoll says the small beads contain large amounts of hematite, an iron compound known to form in water on Earth. "So the story of hematite at this outcrop is a story of rock-water interactions, of diffusion of chemicals through water," he explains.
U.S. satellite observations have shown large deposits of hematite in this region of Mars, but this is the first confirmation it is in the beads - double evidence of the existence of water on the planet.