My question is a little more broad than I could make clear in the title but here goes. First of all, to be clear, am I correct in understanding that light behaves in precisely the same way as an electron in the sense that there exists a wave function which evolves according the Schrodinger equation and which is "collapsed" upon some kind of observation to produce measurable properties? Secondly, suppose we have an electron oscillating in a vacuum. This will create an electromagnetic wave correct? Now my first question is this, is there any directional bias in that wave as a result of the direction in which the electron oscillates? So if the electron is oscillating back and forth along some arbitrary x-axis, does the conservation of momentum play any part in fixing the direction of travel of the electromagnetic wave from the start? Of course, there has to be something else involved to make the electron oscillate... So suppose we had two electrons attached by a spring and we offset the system such that it would oscillate back and forth as a closed system. The totally energy and momentum are conserved, so does this mean that there is no need for any emitted photons to assume a particular direction right from the start? And presumably this hypothetical system would gradually lose energy and come to rest as a result of this emission? (This is starting to sound like the old classical issue with the electrons spiralling into the nucleus) More generally, does an EM wave actually have a direction of travel? Or is it more correct to think of it like a ripple on a pond spreading out in all directions from the source, and the apparent direction of travel is merely something which is inferred from the place in which it is later detected? After all, we never truly observe a photon. We can observe that electron A at position, x and time, t has lost a certain amount of energy, and we can observe that electron B at position, (x + dx) and time, (t + dt) has gained an equal amount of energy and so we say that "a photon has travelled in a straight line from electron A to electron B". But in reality, all we have are two electrons exchanging energy at a distance over an amount of time which is related to that distance by the so called "speed of light". Does a photon really need to exist to explain this or have we merely inferred the existence of a photon to explain the way that the energy moves from one place to another? Apologies for squeezing 4 or 5 questions into one post but I believe this is really one general discussion/question about the nature of light.