Earth’s core is far away from a quiet place. The planet roars with action deep below our ground actions, from plate tectonics to convection currents that scatter through the hot magmatic fluids far below the crust.
Now scientists researching satellite data of Earth have observed something inside Earth we’ve never noticed before. A new type of magnetic surge stretches around the surface of our planet’s nucleus every seven years.
This discovery could explain how Earth’s magnetic field is developed and indicate our planet’s thermal history and evolution, that is, the incremental cooling of the planetary nucleus.
“Measurements of the magnetic field from instruments based on the surface of Earth suggested that there was some kind of wave action, but we needed the global coverage offered by measurements from space to reveal what is actually going on.”
“We combined satellite measurements from Swarm, and also from the earlier German Champ mission and Danish Ørsted mission, with a computer model of the geodynamo to explain what the ground-based data had thrown up – and this led to our discovery.”
“Magnetic waves are likely to be triggered by disturbances deep within the Earth’s fluid core, possibly related to buoyancy plumes,” Gillet says.