"Red Shift" caused by space itself ?? Perhaps the distant objects are not receding at all. If "space" is not empty, but rather is a complex structure, probably containing energy which can be released (wouldn't we just love to know how), then as light "waves" - I prefer to call them emanations - proceed through vast tracts of structured "empty" space, perhaps the light is "tugged" by the structure. This tugging would affect the red end of the spectrum more than the UV end... thus causing a red shift. N'est-ce pas ? This structure of "empty" space can be shown capable of producing opposite particles under stress. That is... apply force to the structure and out pop particles- albeit ones which "cancel" each other out, it is true. If space can be distorted (by massive objects) then it must have some kind of structure. If there was literally nothing there, it could not be "bent" (as in Einstein's "rubber sheet" example of orbits. N'est-ce pas ? Ergo, light passes through a structure that could impede its progress or distort its progress.