What is a black hole? This was explained by Oier Lakuntza on the ARGIA blog:

"The blackest hole is something we hear often, but we don't really have anything clear. They say there are many kinds of black holes, but they all have the same characteristic, their huge mass. For example, in the center of our galaxy, the black hole that would be found in the center of the Milky Way is four million times heavier than the Sun. This large mass causes an enormous gravity in its surroundings, which causes the constant absorption of different materials and species. In addition, the matter falling into a black hole cannot be extracted from it.

The funny thing is that black holes absorb not only matter, but also light. Hence its name, black holes that don't emit any light. And of course, if they don't send any light, how do astronomers know? Well, to understand this, one thing has to be explained. In fact, as it approaches a black hole, matter experiences a huge rise in temperature and emits X-rays at those high temperatures. These are the X-rays that astronomers guess.

I would like to mention another feature, time dilation. It's also a strange concept, but for you to have an idea, close to a black hole, time is slower than far away. It's absolutely impossible to live in a black hole, but if we could withstand the temperatures of the place, and we lived there, we would get older much slower. Because, as has been said, near a black hole time slows down.

The accounts of the universe: as far away as the abstract ones. In any case, not only thousands of years from us, but also in us there are black holes. Who hasn't felt in his life, at some point, that everything is black, that everything is pessimistic? Well, that's also like a black hole. In any case, if you are at that time, encourage and move forward! The black holes in us are not as hard as those in the universe. It's hard to get out of it, but it's possible. It's about being optimistic.

More black holes:

Wikipedia

Presentation of Event Horizon Telescope image: