Question: What is a supernova, and how does it occur?

Mike Heyns answered on 6 Oct 2022:

A supernova is most typically the explosive finale of a dying massive star. As massive stars get to the end of their lives, they start burning more and more of their fuel. This process creates a lot of heat, which generates pressure that balances out the gravitational force trying to collapse the star. At some point the fuel will run out and the star will cool, with the pressure balance failing and star collapsing within moments. The resulting explosion is extremely bright, often outshining the entire host galaxy in observations. In the end, for the particularly massive stars, a super dense core is left behind – a black hole!