Why do stars explode when they evolve into supernovae?

Everything has life. Animals and plants, including us, will die one day, but do you know that planets and stars in the universe will also have life? These celestial bodies can't avoid the topic of death in the end, just like human birth, aging, illness and death. In fact, nuclear fusion reactions occur all the time inside stars. This reaction will be accompanied by a lot of light and heat, which is how we usually feel about sunlight. The nuclear fusion reaction of stars will consume hydrogen and helium in the universe. Hydrogen will become helium through nuclear fusion reaction, helium will become carbon, carbon will become oxygen, oxygen will become heavier elements such as sulfur or silicon, and silicon will eventually become iron, forming a big iron knot, which is the iron core of a star.

A common process of star death is this. They are called nuclear collapse supernova explosions. The core mass of this kind of star is more than 1.4 times the mass of the sun, and this kind of star will collapse unsteadily, which will produce a chain reaction, leading to the collapse of the shell of a massive star, accompanied by a supernova explosion in the collapsed core. When a supernova explodes, it will produce a lot of light and heat, and it will emit very dazzling light, which can also be seen during the day.

The second type of supernova explosion is formed by the evolution of small and medium-mass stars, which are called white dwarfs. If this white dwarf has a companion star, it can increase its mass to 1.4 times the mass of the sun by absorbing the matter of the companion star, and at this time, it will also produce a very strong thermonuclear explosion. This kind of supernova is called thermonuclear supernova.

In the Song Dynasty, there was a supernova explosion, which was also the brightest supernova explosion in history. When the person in charge of the supervision department saw this phenomenon every day, so did the people, but they were afraid to report it to the emperor immediately. But after divination, I dare to report it, thinking that it represents auspiciousness. At that time, when the supernova exploded, it was really bright. According to records, at that time, you could take out your books and read them at night without any difficulty.