In 1952, German physicist and professor W.O. Schumann hypothesized there were measurable electromagnetic waves in the atmosphere that existed in the cavity (or space) between the surface of the earth and the ionosphere. According to NASA, the ionosphere is an abundant layer of electrons, ionized atoms, and molecules that stretches from approximately 30 miles above the surface of the earth to the edge of space, at about 600 miles. This dynamic region grows and shrinks (and further divides into sub-regions) based on solar conditions and is a critical link in the chain of Sun-Earth interactions. It’s this “celestial power station” that makes radio communications possible.