Our planet's liquid iron outer core is slowly giving up its secrets to a trio of satellites launched by ESA in 2013. Called Swarm, the three probes have been studying Earth's magnetic field at the source. In the process, they've revealed startling changes in a molten layer region 2,200 kilometers beneath the Pacific Ocean. In 2010, material in that area of Earth's outer core changed direction. Insteading of moving slowly westward, it's now headed east and picking up speed. Scientists are working to figure out why by using the European Space Agency's (ESA) Swarm data and additional information from ESA's CryoSat mission and ground-based instruments.