[delta_p_delta_x]

Thanks; this is much more concise than I could manage.

I think the key idea is fixed minimum/maximum boundaries for a lot of astrophysical phenomena—stellar protium fusion, the Chandrasekhar limit, Tolman–Oppenheimer–Volkoff limit, etc.

[ctippett]

I appreciated both yours and the parent's comment. I read the shorter answer first, which was accessible enough to a layman like me that I was left wanting more, which made reading your comment immediately after all the more satisfying.

[hparadiz]

It should have been obvious to me (fusion duh!) that the result of the fusion is a higher density material that then increases the conditions for the reaction to take place. Both comments were immensely helpful and interesting! Thank you.