For example, the further a galaxy is from us, the more red it is.
In: Planetary Science
So, my understanding is that it’s less about distance, and more about velocity. Assuming a galaxy is emitting “yellow light” from around the middle of the visible spectrum, the fact that it’s moving away from us causes it to get strung out – so it arrives at a longer wavelength ( red shifted ). If however, it’s moving towards us, then the light waves arrive slightly compressed, at a shorter wavelength ( blue shifted ) – the process behind the change is the relativism Doppler effect
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