* Redshift: When light from distant galaxies is observed, it appears shifted towards the red end of the spectrum. This is known as redshift.
* Doppler Effect: The redshift is analogous to the Doppler effect we experience with sound. If a sound source is moving away from us, the sound waves are stretched out, resulting in a lower pitch (a shift towards lower frequencies). Similarly, light waves from objects moving away from us are stretched out, resulting in a shift towards longer wavelengths (redder light).
* Cosmic Expansion: The observed redshift of galaxies is consistent with the idea that the universe is expanding. As space itself expands, the distance between galaxies increases, causing the light emitted from them to be stretched and shifted towards the red end of the spectrum.
Key Points:
* The further away a galaxy is, the greater its redshift. This indicates a faster rate of expansion.
* The redshift of galaxies is one of the strongest pieces of evidence supporting the Big Bang theory, which describes the expanding universe.
Let me know if you'd like more details about any of these points!
