Not a physicist yet, temporarily a high school physics and maths teacher until I can start my PhD
Fe-56 is the heaviest nucleus that releases energy when other nuclei fuse into it. Everything heavier requires energy, that has to come from somewhere else, to fuse. All things tend to keep doing stuff that release energy, and they don’t like to do stuff that requires energy. So, in a long enough amount of time, nuclei keep fusing together while it releases energy, and stop when it starts to require energy.
At least that’s what happens inside regular old stars. The vast majority of them will have an iron core after a certain amount of time.
It pretty much only takes nuclear physics into account though, whereas the actual universe is a lot more complicated and will thus probably not turn itself into all iron.
Not a physicist yet, temporarily a high school physics and maths teacher until I can start my PhD
Fe-56 is the heaviest nucleus that releases energy when other nuclei fuse into it. Everything heavier requires energy, that has to come from somewhere else, to fuse. All things tend to keep doing stuff that release energy, and they don’t like to do stuff that requires energy. So, in a long enough amount of time, nuclei keep fusing together while it releases energy, and stop when it starts to require energy.
At least that’s what happens inside regular old stars. The vast majority of them will have an iron core after a certain amount of time.
It pretty much only takes nuclear physics into account though, whereas the actual universe is a lot more complicated and will thus probably not turn itself into all iron.