With more than two years of measurements by ESA’s Swarm satellite trio, changes in the strength of Earth's magnetic field are being mapped in detail. Launched at the end of 2013, Swarm is measuring and untangling the different magnetic signals from Earth’s core, mantle, crust, oceans, ionosphere and magnetosphere – an undertaking that will take several years to complete. ESA-SWARM http://www.esa.int/Our_Activities/Observing_the_Earth/Swarm/Earth_s_magnetic_heartbeat
