Yes, but it wouldn’t be locally measurable, as as the article notes mass is dimensional, meaning from your reference frame you’d notice no change. As to lookin

Yes, but it wouldn’t be locally measurable, as as the article notes mass is dimensional, meaning from your reference frame you’d notice no change. As to looking at older galaxies - maybe - but if the relativistic mass of photons is also changing due to the same phenomenon, there would be no difference in observations.