View the original post on Musing.io
A black hole as defined by Wikipedia is a region of spacetime exhibiting gravitational acceleration so strong that nothing—no particles or even electromagnetic radiation such as light—can escape from it. A black hole is formed when a sufficiently large star collapses at the end of its lifecycle. This leads to the formation of a black hole which will then grow by absorbing surrounding matter. If you've ever seen a black hole in movies, you'll know that they are usually black(lol) but have a ring of light around them. This ring is called the accretion disk and it is formed from the matter which fall into the black hole and are superheated by friction.
As I said earlier, black holes grow by absorbing surrounding matter. They absorb stars and can also fuse with other black holes to grow in size until they become supermassive black holes. There is a general consensus that these exist in the centre of every galaxy.