I do not understand why people downvoted the question, it is a perfectly legitimate one for a person who does not have the knowledge of how a star works and how it dies.
I am not an astronomer either, but I have always been interested in how the universe functions and our understanding of it.
Therefor, I can safely say that a star's life is based on two things : the incredibly high pressures (generated by all that mass pushing down on the core) that make thermonuclear fusion possible, and the resultant fusion energy that, in effect, pushes away that mass and prevents gravity from collapsing it all into a black hole.
A star is thus perpetually walking a tightrope between collapsing in on itself and blowing its mass away. Stable stars, such as our Sun, have found a balance. That balance can last billions of years (generally the case for yellow dwarfs, of which our Sun is part), or only a few million (the case of humongously gigantic stars that end up as supernovas), but in the end, it always ends badly, though not always spectacularly.
Our Sun is most likely going to go the red giant path, bloating itself until its volume encompasses the orbit of our very own planet, then, at the very end, go nova by shedding the outer layers, leaving a small dwarf remnant that will radiate for eons upon eons until it just cools down.
A supernova, on the other hand, will not shed its outer layers, it will expel them violently. However, in most cases, the core remains. And, without the mass of the external layers to ensure the necessary pressure that allows for continuous thermonuclear reaction, the intense gravitational attraction of all that mass will win over the diminishing thermonuclear reaction that subsists, and it will collapse upon itself, creating the black hole of legend.
It is, in any case, a truly fascinating subject, and I can only encourage one and all to read up about it on the very many Internet sites that deal with the subject.
Biting the hand that feeds IT
