Do we know what causes the release of energy in nuclear fission?
I was trying to put together all the things I've read in the last couple of days and I realized that based on my current knowledge of the standard model and the way nuclear fission works, I'm not able to understand why would any number of nuclei packed together by the strong nuclear force, no matter how tight, release energy when split.
This took me on an interesting rabbit hole and then I found one answer. Leaving aside the rant, it made me wonder, do we really understand why the splitting releases energy, or we just know it does based on observations.
The way I see things now, since the nuclear forces are so strong, their tendency should be to always bring nuclei together, even if bombarded with an extra neutron. The extra neutron should stick, or if the kinetic force is strong enough, then break the binding and split the nucleus, but certainly not releasing energy, losing mass and shooting 1-3 neutrons in the process.
So, why is my expectation wrong, since experimentally it obviously is.