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In this Friday, July 15, 2011 photo, scientists walk on the snow surrounding Summit Station, a small research facility situated 10,500 feet above sea level, on top of the Greenland ice sheet. Liz Morris, 64, of Cambridge University's Scott Polar Research Institute, left the station in July on a monthlong, 500-mile research trip on snowmobiles. Morris' research trip is funded by Britain's National Environmental Research Council and mounted with the U.S. National Science Foundation's cooperation. In 2003, Queen Elizabeth honored the intrepid Morris with a Polar Medal, given in recognition of distinguished service in Arctic and Antarctic exploration. Three years earlier the monarch inducted her into the Order of the British Empire. (AP Photo/Brennan Linsley)

Huge crack discovered in Antarctic glacier

A major glacier in Antarctica is melting unusually quickly because ocean currents are undermining it from below, researchers find. Scientists are gathering meaningful and accurate data of how ice sheets and glaciers are changing over time, and what this means for our planet.