What is a black hole?

A black hole is a highly dense substance in the universe,which gravitational pull is very high that it can pull anything .Not even light can escape it's gravitational pull.

Black hole are very small but their mass quantity is very large.
For instance:
The black hole equivalent to our sun mass will have the width of more than a kilometer.

How do black holes form?

Black holes form when anything is compressed into is smallest possible size.

The smallest possible size for anything in the world is plank length.
to find more how do black hole form click here

Black hole are  mysterious object floating around the space.
Black are categorized into two groups:

1. Rotating black holes
2. Not rotating black holes

What are rotating black holes?

They are the type of black holes which rotates on its own axis.why black holes rotate?click here.

What are non rotating black holes?

non rotating black hole holes don't rotate but have same gravitational pull according to their mass.

 layers of black holes

Black holes have two layers:

First layer: Event horizon
Event horizon is a first layer of black holes from where nothing can escape after it enter it but everything is safe outside it.

Second layer:point of singularity
it is a point where you can not move .you can think it  as a zero dimension
as you no you can move forward and backward in one dimension. Forward,backward,left and right in second dimension. Forward,backward,left,right,upwards and downwards in third dimension but in zero dimension you can do nothing.

Do black holes die.

in short answer yes, black holes do die . But in long term click here.

find more about black holes.