As photon travels, pair particles of dipole photon shows relaxation which we call dopler red shift. so, red shift is merely related with the travel distance of photon.
However, It is not sufficient to explain why Bing Bang is importantly cited in the society. CBB is developed for the unsatisfied people for dipole photon model.
Atomic nucleus decays in two ways. alpha and beta decays are names for the escape of electron and helium from nucleus. In analogy, star might have decayed resulting in a new planet birth which is CBB.