black hole histroy and facts

A black hole is a probable remnant of a star that is at least 3 solar masses in mass. A black hole has practically infinite density due to zero size (and consequently very high gravitational effect) and curves the space-time around it, stretching it like rubber to the point of making a "hole" in it. Since light travels on the space-time, its path is affected by the effects of the black hole. What this means is that you can never really see a black hole. If light gets too close, it gets sucked in. Without light touching it and reflecting off, it's invisible. Hence, it's called a black hole. There are other ways to detect black holes, though. Give me a follow-up question if you have any doubts