I just cannot understand the rationale behind the fact that whatever object we see 'enter' a black hole will appear to slow down to infinity next to the event horizon and never quite cross it. Would we not observe old black holes with a myriad of objects hanging around near it that it has captured over the billions of years? Since we never observe objects enter a black hole, does that then mean the mass of the black hole does not increase in our reference frame? However the idea that mass is relative I think is incorrect. (If energy is relative, energy is not conserved?) And hypothetically our universe collapses in 10 billion years. Would we not observe the matter finally collapsing into the singularity or will everything appear to stop still before the singularity of the big bang.