Call_of_the_Wild
Well-Known Member
So where does red shift come in?
The red shift is the Doppler Effect, except on the case of the universe, it is applied with light instead of sound. Light and sound travels through wave lengths. As a siren is moving toward us, the wave lengths are higher than it would be than if it was moving away from us. Light waves are able to compress/stretch, which will change their frequency/color. Blue light has shorter wave lengths than red lights. So if an object in space is moving towards us, it will have a shorter wave length (blue light), but if it is moving away from us, its wave light will stretch (red light). The further a galaxy is away from the earth, the faster it is moving. And the faster it moves, its red light becomes more redder. By measuring the red shift, you can measure how far the galaxy is away from us.
We can thank Edwin Hubble for this. His discovery put cosmology in a completely different perspective. The universe, once thought to be stationary, is expanding.