"Sun->Earth or Sun->Jupiter is a small beer"? How do you mean? This is a real physical example with real physical consequences for example for how much dimmer t

"Sun->Earth or Sun->Jupiter is a small beer"? How do you mean? This is a real physical example with real physical consequences for example for how much dimmer the light is per area (by 1/r^2) and by how much redder it is (by 1/r). What are the real physical consequences of thinking that the photon is "emitted and absorbed at the same instant"?