I was recently told by a friend who teaches college physics that "in reality radio waves are only generated when an electric current is made to move violently through a conductor". He went on to elaborate how this works with normal radio antennas, WiFi, etc. but honestly it went over my head.
One thing that stood out was that, he explained, early radio transmission (and even some modern) works through "spark gaps" and how antennas are just refined or less visibly "sparky" versions of these.
It was super interesting to me, but I'm not finding details that (to my lay-woman mind) line up with what he explained in terms of something that I could see as "violent". Could someone please explain this to me through a model or visualization and maybe share some key terms that I can use to research this more?