The European Space Agency's (Esa) Mars Express spacecraft has spotted what appears to be an active Glacier on the Martian surface, located in the Deuteronilus Mensae region between Mars' rugged southern highlands and the flat northern lowlands. While Glaciers have been identified before on Mars, previous sightings have been of very old formations (in the region of millions of years old.) This newly identified Glacier may only be several thousand years old. Distinctive glacial ridges have been spotted with white tips that can only be freshly exposed ice. This is an extremely rare occurrence, since as soon as water is exposed to the Martian atmosphere, it sublimates (turns from a solid state directly into gas). More detail can be found at the BBC News website.