Something about iron being the most stable element

Question

I remember watching a video by a scientist youtuber (I think) saying that iron was the most stable element and there was a theory or something like that that said if/when the universe degrades the only thing remaining will be iron. I don’t remember when was this who made the video or who they were referencing but if this is an actual theory I’d like to know more about

In: Physics

Answer 1

all elements (besides iron) release energy when split into smaller atoms (like uranium in a nuclear reactor) or when fused together with other atoms (like hydrogen in the sun).

and in both cases the path to releasing energy leads towards iron.

iron is *always* energy negative with fusion or fission, it sits at the very bottom of that “energy valley” so it doesnt want to do anything, and everything that tries to do something with iron needs energy to do so from somewhere else

stuff generally always wants to release energy if possible, so nuclear reactions tend towards moving closer to being iron in the end.

so at the very end, when theres every bit of nuclear energy released, theres only iron left.