I read in your post that a black hole couldn't affect the earth. But why? I thought black holes have a huge mass, ans therefore have huge gravity. Let's say we swap out the sun in our solar system with a black hole. Same size but higher gravity, because of the density. Wouldn't that be enough to pull the earth to it's singularity? Or am I totally mistaken here. Thank you in advance. P.S.: I am not a native English speaker so I hope you understand what I'm trying to tell you
A black hole with the mass of the sun would only have about 3 km, the earth would be far from its event horizon, therefore would not be affected.