the displacement of spectral lines toward longer wavelengths (the red end of the spectrum) in radiation from distant galaxies and celestial objects. This is interpreted as a Doppler shift that is proportional to the velocity of recession and thus to distance.
Input mode is not totally shut down over here. And this minute mind slightly understands this red shift theory however... I'm still of mind that regardless of how it's detected, that size and object... Millions of light years of size, and billions of lights years away, would have to be moving at an extremely astronomical rate to be detected in a span of 5... 10... 15 years. And if the big bang theory is true all these galaxies should be moving close to parallel not coming into each other from different angles... I must be missing something huge lol... Blame my trust of modern chemistry in the 70s for it!!