Half of the 2020 Nobel Prize in Physics was awarded to Roger Penrose “for discovering that black hole formation is a robust prediction of general relativity” and half jointly to Reinhard Genzel and Andrea Ghez “for discovering a supermassive, compact object in the center of the Milky Way„.
What’s going on there?
There are no black holes, as the general theory of relativity postulates. M87 falsifies the theory. You will find a fairly standard explanation for how galaxies behave in the following essay.