A gargantuan iceberg weighing more than one trillion tons has broken away from western Antarctica. Scientists had been monitoring a break in the Larsen C ice shelf following the collapse of the Larsen A ice shelf in 1995 and had observed significant advances in the rift over the past 12 months. Experts said a 5,800-square-kilometer section of Larsen C was confirmed to have broken away between Monday and Wednesday by NASA's Aqua MODIS satellite.