>>16840370
>So every black hole in theory has the same "size", the singularity.
>but it all is focused in the singularity at the centre
Singularities are mathematical concepts inside mathematical models. They may not exist in real life despite what scientists on TV say. The black hole itself is a star with extreme density in an unknown state of matter

>>16840515
>What makes the event horizon stretch out?
The horizon is just a boundary. It's not a physical thing. The centre of a black hole is just a really dense star. Like any celestial object, it has escape velocity. But for a black hole the escape velocity is over the speed of light. The event horizon is just the boundary where the escape velocity is the speed of light. So any light emitted by the star just falls back in and can't escape