What goes on inside of black holes?
What do you mean by ‘inside’ a black hole? Do you mean inside the event horizon? Well no-one really knows is the short answer. What I was taught is that there is continued gravitational collapse into a ‘singularity’. This needs a little bit of explaining. Put simply (and I am REALLY simplifying things here so don’t be surprised if it seems odd or incomplete) singularities are a mathematical concept of where the rules just break down. For example take the function 1/x. As x approaches 0 the function diverges to infinity. When x=0 we just cannot calculate the answer. This is a mathematical singularity. A gravitational singularity is similar. Not to put too fine a point on it our laws of physics more or less fail us. We get infinities in the equations and things get messy. Very messy. Not that we can’t work with this somewhat but we don’t understand physics well enough yet to explain everything. Here’s a brief intro to both topics but I would advise reading up elsewhere for a deeper expla