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Churchman, James
(2004).
DOI: https://doi.org/10.21954/ou.ro.0000f58c
Abstract
We take a new look at an old concept. Textbook descriptions of cosmological redshift are examined. In particular, explanations that treat cosmological redshift as a continual loss of energy as the radiation propagates are found to be hard to reconcile with Quantum Theory. A new treatment of the subject is presented that compares cosmological redshift with gravitational redshift as demonstrated by the “classic” Pound Rebka experiment. Cosmological redshift in a spatially flat universe, is presented as being due to a rising “global” gravitational potential. The evidence for the Universe being essentially spatially flat is reviewed and found to be compelling. The relationship between the scale factor of the universe and the potential is found and a modifled version of the Robertson Walker metric is derived with the components of the metric tensor being expressed in terms of the global potential. A simple treatment of the quantum electromagnetic field is shown to be compatible with the notion of cosmological redshift, if the time coordinate of the background space-time in which the theory is expressed, is that of the new modifled Robertson Walker metric. Finally the possibihty of building an apparatus that would directly detect the rising potential is examined. For such an apparatus it is shown that in a non-accelerating universe the effects of the rising potential are unobservable in local experiments, but that there may be observable effects if the universe is accelerating.