Title Text:Thank you to Katie Mack for teaching me about this effect, and to Janelle Shane for describing redshifts as ‘like galaxies sinking into a pool of dilute blood,’ which is how I’ll see them from now on. Origin:https://xkcd.com/2622/ https://www.explainxkcd.com/wiki/index.php/2622:_Angular_Diameter_Turnaround…