Black holes are enormous amounts of matter that are packed into a very small area. The result of this is a gravitational pole, that is so strong that not even light can escape the black hole. Black holes where not even coined until 1967 by John Wheeler. However, black holes where predicted in Einsteins’ theory of general relativity. Scientists can’t directly observe black holes with any electromagnetic radiation. There is still a way to detect a black hole by their effect on the matter around them. If you are wondering how black holes are made it usually starts with a star dying or 2 stars that collide into each other. They are made by supernova explosions witch makes the star collapse under the force of gravity. Then the star reaches a point called the event horizon. Once it has reached the event horizon it becomes a frozen collapsing object, therefore making a black hole. That is what I have learned about black holes if you want to look up information black holes I would use http://science.nasa.gov/astrophysics/focus-areas/black-holes/ it is a helpful site.