1.)Do you have a degree in physics, too?
No, 'fraid not. Just an unhealthy interest in astrophysics.
2.)Isn't it possible that there is...something radiating from it, whether it is some form of light or not, that is either something we do not recognize or that we cannot measure?
Based on Einstein's premise that nothing can travel faster than the speed of light, we must assume that nothing can be radiating from it. But we don't know anything.
3.)About that infinitely dense thing: stupid question: does pure energy take up actual, physical space? Is it possible that when the density is sufficient, that matter in a black hole simply becomes pure energy, and stays there, not going anywhere?
Energy doesn't so much take up space, as exist in space and have an effect on space. In a black hole it is more likely that the energy becomes pure matter - the large "forces" providing the energy needed for the transformation. Having said that, the matter and energy aren't really there, the singularity is.
4.)Would you please elaborate on what combining matter and anti-matter create? It is more than nothing. Thank you.
I'm going to struggle on this one, I think. All (isolated) reactions must conserve momentum, mass-energy, charge and probably other stuff. When nothing becomes matter and anti-matter, energy is produced as well. Hence when matter and anti-matter combine, the process requires energy. If external energy is unavailable, there will be a resultant negative energy afterwards. However, there can be no such thing as anti-energy, so the universe pulls some weird stunt whereby a photon-like particle is created with whatever qualities it needs to ensure conservation of whatever needs conserving.
Or something like that.
