# Intro to Redshift - The Doppler Effect Galaxies. Stars. GLASS-z13. When you read articles about far-flung galaxies or about the discovery of the Universe's age, one thing pops up - **redshift**. 'Red'shift is the *shifting of the apparent frequency of a wave due to motion.* In other words, when an object moves **away** from us, it looks **redder**, while if the object is moving ***towards*** us makes it look ***bluer***. One commonly-used example is the blue car-red car. As the car moves towards us, it sounds as if it is at a higher pitch, and when it moves away from us it sounds deeper, at a lower pitch. %%diagram of redshift%% Have you ever read articles which talked about redshift, how if objects moved away from you at high-enough speeds their light or sound would become distorted. This is Redshift is defined by the equation $1+z = \frac{\lambda_{observed}}{\lambda{emitted}}$ where $z$ is the redshift $z = \frac{v}{c}$ to find redshift, $v$ is the radial velocity of the object and $c$ is the speed of light # Redshift due to Extinction *See [[Intergalactic Dust (Astro)]] for more details!* caused by dust, interstellar extinction obscures objects, preferentially decreases blue light more than red light and forces objects to undergo "reddening" --> where less red light is removed by the dust than blue light. # Further Reading If you're interested in reading past the casual astronomy enjoyer's toolbook, you can go to the 'Physics' section's note about the same topic. There, I'll go over the relativistic corrections for redshift - yes, [[Special Relativity - Foundations|special relativity's]] got a part to play here too. Click here for the article: [[The Doppler Effect (Waves)]] CURRENTLY INCOMPLETE