Originally Posted By: Bill
The red-shift of light due to the expansion of the universe is not due to the doppler effect caused by the speed of the source. The shift is due to the expansion of the universe. Therefore the light is not red-shifted to a 0 frequency, or at least not at the Hubble Radius.


This gives me the opportunity to the accuracy of a small extract from my past notes.

"Having used the Doppler Effect, with its resultant red shift, to establish that the Universe is expanding, it has to be said that this cosmological redshift which I used as “proof” is not, strictly, an example of the Doppler effect at all. Although the galaxy groups are separating, they are not moving through space; space itself is expanding and carrying the material of the Universe with it. Therefore the stretching of the waves does not occur only at the source, as is the case with the sound waves from a receding car; it happens over the whole distance because it is spacetime that is expanding while the light waves are passing through it. Waves are stretched throughout their journey – the further they travel the more they are red shifted."

Does that sound right?

There never was nothing.