>>6469764>>6470466Doppler applies to any waveforms
Yes, it is most easily observable as we hear sound waves easily (a truck passing by)
But it has an effect on light waves as well, and as light travels, it undergoes a "red-shift" as the wave length is stretched depending on both perspective and things interacting on the wavelength (the black hole's gravity)
Source: My general understanding, correct me if i'm wrong but i think that's a high level understanding
Pape for your time
