Veritable shields against high-energy particles, planets’ magnetic fields are produced by iron moving in their liquid core. Yet the dominant model for explaining this system does not fit the smallest celestial bodies. Researchers at the Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE, CNRS/Aix Marseille Université/Centrale Marseille) and the University of Leeds have proposed a new model suggesting that turbulence in the liquid cores is due to tides produced by gravitational interactions between celestial bodies. The model infers that instead of being due to large, turbulent molten iron vortices far from the surface, movements in the core are due to the superposition of many wave-type motions. This work was published in Physical Review Letters on July 21, 2017.