Fluctuations in Earth's magnetic field that repeat every seven years can be used to probe the inner workings of our planet
Diagram showing wave-like flow at the surface of Earth's outer core and background magnetic field lines Felix Gerick Small magnetic waves discovered in Earth's core could help illuminate what is going on deep inside our planet. Earth's core has a solid inner layer and an outer layer made of liquid metal. The difference in temperature between the hot centre and cooler exterior layer drives convection currents in the liquid, and the movement of charged particles in the metal creates the planet's magnetic field. The motion is turbulent and chaotic, and therefore the magnetic field varies over time. Nicolas Gillet at Grenoble Alpes University and his colleagues observed Earth's geomagnetic field between 1999 and 2021 using data from satellites as well as observatories on the…