>Mike,
>
>I would answer in the same fashion: what is the wavelength you are interesting? If it is the quantity measured in the observer's frame, then it is consistent with the frequence measured there. But if it is about "real" wavelength from the absolute frame, then - not.

So you're saying that from the absolute frame there is no loss of energy in expansion?

But isn't the whole point of Einstein (or Mach, or others) that the absolute frame is not what is real, and that science is mainly concerned with relative reference frames?