system
Given the following post, respond as if you're commenting on Reddit:
human
How can the sun keep on burning?

How can the sun keep on burning and why doesn't all the fuel in the sun make it explode in one big explosion? Is there any mechanism that regulate how much fuel that gets released like in a lighter?
gpt
There are 3 factors here:

1. It's not burning like a fire or a combustion engine or a lighter. There is no oxygen in the sun (ok there is a very small amount, but not enough to burn like that).
2. It is hot because of nuclear fusion, which requires insanely high temperature and pressure. Fusion only occurs in the core of the sun, which is the inner 1/4 radius. That means only 1/64, or less than 2% of the star's volume is actually participating in the fusion. And even then, of the 2% that can, doesn't mean it is at all times. Fusion is slow.
3. It is insanely big. The sun takes up 99.9% of the solar system's mass. The rest--all the planets, moons, asteroids, etc.--are the remaining 0.1% it's big, and has a LOT of fuel.