I can imagine if light from a star travels for billions of years, that not only the rapid removal of the star but also the distance (including the attenuation of the light) can have an influence on the redshift.
Asker: Pros, age 62
Answer
What we measure as redshift is the displacement of spectral lines. These correspond to absorptions by atoms, and the wavelengths are fixed by constants of nature. The fact that the light travels a long way does not change that: in an old photo a baby has not become an old man or woman. The distance effect does attenuate the light, but the contrast of the absorption remains the same.
Answered by
Prof. dr. Christopher Waelkens
Astronomy
Catholic University of Leuven
Old Market 13 3000 Leuven
https://www.kuleuven.be/
Old Market 13 3000 Leuven
https://www.kuleuven.be/
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