Today I did the usual thinking, watched some courses online etc. and found out(or rather reminded myself) that the EM waves can be produced only when a charge oscillates.(or thats what the professor at Yale said) But then I remembered LED diodes, and their ability to emit light. Electron goes from higher energy to lower energy state and produces a photon in process. Not until today I gave this a thought. How come it emits a photon? Photon is a EM wave, it oscillates. So in order to emit a photon, it had to oscillate in the process? Is this one of those answers "it just does that", "its the way it works" or is there more to it? Because all textbooks are going as deep as: change of energy: emit a photon.