https://en.wikipedia.org/wiki/Dark_matter#Observational_Evidence https://en.wikipedia.org/wiki/Dark_matter#Observational_Evid... Read the "Observational eviden

https://en.wikipedia.org/wiki/Dark_matter#Observational_Evidence https://en.wikipedia.org/wiki/Dark_matter#Observational_Evid... Read the "Observational evidence" section; it has a great overview of the current mainstream arguments in dark matter cosmology. (I don't link this to be snarky—it's a very good Wiki article and covers almost all the basic questions.)