Schumann resonances
= Schumann resonances
{wiki=Schumann_resonances}
Schumann resonances are a set of fundamental electromagnetic resonances that occur in the Earth-ionosphere cavity. These resonances are named after physicist Winfried Otto Schumann, who predicted their existence in 1952. Here's how they work: 1. **Cavity Structure**: The Earth and the ionosphere act like a gigantic waveguide.