I mean there is this division between virtual (in static situations) and real photons as the quanta of the EM field, but aren't all photons essentially "virtual" in the sense that they are purely made up by us in order to explain why we see discrete impacts of specific energy for a given EM field on a given target etc? What I want to ask by this is that for the elementary particles like electrons and protons/neutrons we can "see" them in more ways (cloud chambers etc) than we can see photons and for photons I assume we really don't have any real mechanism to "see" their existence at all apart from noticing the changes that happen when certain energy/frequency EM field is present within an area? PS. I do realize virtual photons are just an expression to describe situation of a static EM field versus normal photons that describe a dynamic EM field which can transfer energy. Would it be fair to say that excluding the fact that it is all around us and we have learned the working principle of the EM field, it's basics or whatever makes it up in the first place is just as much of a mystery to us as dark matter or dark energy? Yet we don't say "dark EM field" but we say dark matter, but we do know some things about dark matter don't we? So in a sense we also know some things about the EM field and some others we simply can't know, where is the line between calling something solved and calling something "dark" given the fact that in physics many times certain aspects work the way they do without us having a real physical way of understanding the reasons behind that?