Exponential cosmological redshift in a linearly expanding universe

Abstract

The first principles analysis of the radiation by an arbitrary source in a flat Friedmann-Robertson-Walker space-time is presented. The obtained analytical solution explicitly shows that the cosmological redshift is not of kinematic origin and that the source and the observer may be regarded as being at rest with respect to eachother at all times. At the same time the effect of the time-variation of the metric on the propagation of light appears to be underestimated in the standard cosmology. The cosmological redshift caused by the linear time-variation of the metric turns out to be an exponential rather than linear function of the well-defined spatial distance and the apparent brightness of the source contains an even stronger exponential decay factor.