hi, so i have just finished reading my first ever book on quantum electro-dynamics (the feynmann lectures). i am in year 13 of school, or High school some might call it. he draws a diagram in the book (a space time diagram) to represent an electron absorbing a photon and then re-emitting the photon, this is what i understand as scattering. however he also draws diagrams that show the electron emitting a photon before it has even absorbed the photon in question! my understanding is that an electron is a fundamental particle, so it shouldn't really contain a photon to emit, unless it had already absorbed one.... (i know that the photon is essentially just energy inside the electron). so does the electron actually have to travel backwards through time after absorbing the photon (as the diagram suggests) to re emit it or is there some other mechanism that goes on here? i'm just confused as to whether this electron has physically travelled backwards in time, or whether it is just how the mathematics is arranged... please let me know what you think :) lntz.