Water ice has been discovered on the surface of Mars near the fringes of the southern polar cap, extending the detection of frozen water to three regions of the Red Planet. Researchers had previously found frozen water beneath Martian soil in the southern hemisphere and at the surface of the northern cap. They had been puzzled over the lack of a similar finding in the icy southern cap. Only frozen carbon dioxide, commonly called dry ice, had been found there. Other researchers have suggested in previous studies that the dry ice makes up but a thin layer that hides a deep water ice cap. The new discovery, made with NASA’s orbiting Odyssey spacecraft and announced today, could support this idea, said study leader Timothy Titus of the U.S. Geological Survey.