I honestly never knew just how cool black holes are until I saw this little interactive video. It’s a well done thing with some cool effects that helps you understand what exactly a black hole is and what it does.
There are two main processes constantly going on in massive stars: nuclear fusion (which tends to blow the star’s hydrogen outward from the star’s center) And gravity (which tends to pull all hydrogen back in the direction it had come). These two processes balance one another until all the star’s hydrogen is exhausted, allowing gravity to take over. Once gravity dominates, the star becomes unstable and starts to collapse. More massive stars tend to burn hotter and faster. Once all the hydrogen has been exhausted, such stars quickly collapse, shedding much of their mass in dramatic explosions called supernovae. Once the star starts to collapse, it does not stop, and the star (and ultimately its atoms) will cave inward upon itself, resulting in the formation of a black hole.