Seeing radio [Reflections]

AS AN ENGINEER, I FOUND THE CURRENT BEST-SELLING novel All the Light We Cannot See nostalgic and thought provoking. The story is about a young German boy, Werner, and a blind French girl, Marie-Laure, during the German occupation of France in 1939. · Before I read the book I assumed that the title had to do with the blindness of Marie-Laure, but instead the title refers to radio waves, as illustrated by this passage from the book: "What do we call visible light? We call it color. But the electromagnetic spectrum runs to zero in one direction and infinity in the other, so really, children, all of light is invisible." · The author, Anthony Doerr, has said that his original motivation was to "conjure up a time when hearing the voice of a stranger in your home was a miracle." The story portrays an era when families clustered around radios made by companies such as Philco and Grundig, when propaganda dominated broadcasts and radios were critical to both armies and resistance cells, when people twiddled the dials of shortwave receivers to search for voices from faraway cities, and when the music on the airwaves was Mozart and Bach. · The characterization of radio waves as invisible light interests me. Somehow I associate photons with visible light but not with radio waves. The very word "photons" seems to connote visible light. In most of classical electrical studies we deal instead with electrons–charged particles that have associated fields and, when they move, create waves.