Quote:
Originally Posted by modest
My understanding is that you can model redshift as recession with one coordinate choice or you can model it with expanding space with another coordinate choice. Essentially: either galaxies are redshifted because they have a recession velocity or they are redshifted because space between them expands. I don't see how you could apply both.
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Hi
,
That appears to be 2 ways of looking at the same thing: the recession velocity of distant galaxies is due to the expansion of space between them (they are directly related values).
To be clear (and this is not directed at anyone's comments, but rather to draw attention back to the main topic), the decrease in wavelength to space ratio is still present whether or not there is a redshift (or blueshift) due to an observer's velocity.
As space is increasing size (metric expansion of space) and the wavelength of light emitted does not change in transit, the ratio of the wavelength of light to the size of space is getting smaller as the size of space increases.
