Black holes, to put it frankly, are abominations. A select few of them are even the largest things in our universe. They are so big, in fact, that they bend the rules of space and time.
For a basic understanding of them, we need to understand how large objects in space work. When there is an object with an extremely high mass, our sun, for instance, it bends space in a way that causes other objects around it to fall into orbit. With a black hole, everything that orbits it slowly enters a place in the black hole called the event horizon: this is the border where anything that enters can not get out. That is why the middle of a black hole looks completely dark: no light can escape the empty void.
If you watched a person enter the event horizon, which is again the border around the black emptiness, it would not look like they would get absorbed: it would look like they are frozen in time and they would slowly fade away in a matter of seconds. This is because the body of the person as well as the light is simultaneously being sucked up, so it looks like he is just fading from existence.
If you were to enter a black hole's event horizon, you would be greeted with a black, empty void. All things here are slowly attracted to the infinitely small point in the middle of the black hole: the singularity.
The singularity is the point in the very middle of the black hole that holds all the matter. As I stated above, the laws of a black hole are so out-of-the-ordinary we can't even use common physics to explain it. How is it possible that millions of pounds of matter can be compacted into an infinitely small point? We don't know.
Now, all this applies to black holes that don't spin, and there are very few of them. If you entered a spinning black hole's event horizon, you would be constantly orbiting at insane speeds towards the singularity, and you could not stop no matter how hard you tried.
One obscure fact about any point of mass in the universe is that when we look at it through a telescope, what we are looking at is not what it is now. For example, the biggest black hole, TON 618, is so many lightyears away when we look at it, we are looking at the black hole 11 billion years ago. The reason being is that it took 11 billion years for the light of the black hole to reach our earth. Now you may be wondering: If a black hole is just a black canvas, how can it emit light? Well, when particles are orbiting to reach the event horizon, they rub against each other at insane speeds so fast that it heats to up to 1,000 degrees. As you may expect, this emits a ton of light, and that is how we can even see them in the first place. We can also detect black holes if we see mass being flung around in an orbit around a seemingly empty void when in reality there is a black hole there.
That is all I have studied about black holes, and there is still much, much more I haven't yet learned, such as the different sizes/categories of black holes, the different types of planets and stars, (which there are many) as well as different types of atoms. I look forward to writing about this in the future, but I hope by now you have learned something about black holes and had a good time while reading this! ~ Benny