Associated Press: A chunk of ice spreading across 7 square miles (18 square kilometers) has broken off a Canadian ice shelf in the Arctic, scientists say. The sheet broke away last week from the Ward Hunt Ice Shelf off the north coast of Ellesmere Island in Canada’s far north. (See map.) Large ice segments–including this 1.5-square-mile (4-square-kilometer) chunk, above–were seen drifting near the ice shelf. Derek Mueller, a researcher at Trent University in Ontario, was careful not to …