does dark mass/energy change cosmic red shift Virtually all cosmology is based on the observation that galactic light is red-shifted.  The Hubble Law defines that the red-shift is proportional to distance photons traveled.  Further, this observation is specifically explained by the general relativistic expansion of space-time.  No other explanation is accepted of any alternate or additional reason(s) that might reduce the energy (red-shift) of galactic photons observe.  Can other factors describe the decrease in the frequency of these ancient photons?
It appears that universe contains a large amount of dark matter and dark energy - which is rather difficult to define its relationship with known mass/energy through current general relativity and quantum mechanics.   What of these concepts PREVENT a photon’s energy from being reduced by incremental interaction with dark matter/energy – that occurred over immense distances and vast eons?   Can other additional (hidden) variables influence the interpretation that expansion of space-time is the singular explanation of the galactic red-shifting?  Obviously, any additional factor would require revision of certain aspects of the accepted cosmology paradigm. 
 A: Dark energy is said to be speeding up the expansion of the universe. The faster the expansion the greater the redshift. Dark matter, on the other hand, forms an integral part of galactic mass and always has done. This galactic mass forms a large part of the mass of the universe, and until the advent of dark energy it was believed that the mass of the universe would eventually slow the expansion to a standstill, at which point it would collapse on itself and transform the redshift into a blueshift. We would thus have a Big Bang - Big Crunch universe. followed, many believed, by a Big Bounce,so the universe would oscillate between the two states for ever. So will matter and dark matter, which are trying to slow the expansion down, eventually triumph, or will dark energy increase the rate of expansion and prevent this from happening? At present dark energy seems to be winning, but we can't be sure. New data or a new interpretation of old data may find we are slowing down after all. For this reason the Big Bang - Big Crunch model hasn't been entirely abandoned by some cosmologists, but their faith is wavering. Other factors which are at present hidden variables may be influencing the redshift that we observe, so we await further developments in this field.      
