* The Doppler Effect: Redshift is analogous to the Doppler effect we experience with sound. When a sound source moves away from us, the sound waves stretch out, making the pitch lower (longer wavelength). The same principle applies to light.
* Expanding Space: As the universe expands, the space between galaxies stretches. This stretching affects the light traveling between galaxies, causing its wavelength to increase and shift towards the red end of the spectrum.
* Distance and Redshift: The further away a galaxy is, the more its light has been stretched by the expanding universe, and the larger its redshift. This relationship allows astronomers to estimate the distances to distant galaxies.
In Summary: Redshift is a direct consequence of the expanding universe. By measuring the redshift of distant galaxies, astronomers can learn about the rate of expansion and the age of the universe.
