On another thread, users have asked for an explanation of the "red shift" of photons (the apparent loss of energy of photons due to the expansion of the universe.) All they ever got was a GENERAL RELATIVITY explanation.
So, I'll rephrase the question: if a so-called "photon" represents a discrete QUANTUM of energy exchanged between two or more atoms as a result of the the electron shell of one atom changing its energy level, then what happens to the energy of those photons that "arrive" at a lower energy level (lower "frequency") as a result of red shift?
Let me try and clarify my question based on my understanding of how "photons" work. Let say atom A releases a quantum of electromagnetic energy equal to 3 units. One atom B absorbs 1 of those energy units, and atom C absorbs 2 units. We could then say that atom A emitted two "photons." If, however, atom D absorbed all 3 energy units, then we would have to say that Atom A emitted one "photon." I think this I where people get confused--photons aren't "real" PARTICLES you can count like sheep. They're just a mathematical description of chunks of energy that get "exchanged" AS THOUGH that energy were being delivered as chunks.
So, back to my question: if the energy of EACH "photon" being received is less than it was when it was "emitted," where does that energy go? Does it become "more" photons? I know, I know, in RELATIVITY the work of bending space time robs the "photons" of some of their energy (precisely the way the bending of leaf springs in a dragster robs the axle of some of the energy directed toward the wheels.) BUT our question is: What is the QUANTUM explanation? And please, don't just point the relativistic answer we already got.
If you don't HAVE a quantum explanation, just say so.