What Happens When a Star Dies and Goes Supernova?

When a star dies and goes supernova, there's still an enormous amount of hydrogen left over. This is why the star doesn't die in a quiet fizzle. It's not just like burning through all of its fuel but what's happening is that this balance between gravity and fusion is getting upset. Gravity actually kind of a weakling, not really a very powerful force. So you just need something to be able to resist it. But again, neutron stars are not something that we understand very well.