Re: Neutrons → Protons
A good part of the mystery lies in the fact that protons and neutrons are regarded as "balls" whereas they are more like churning assemblies of quarks in which you statistically have a good chance of finding the three up and down quarks in the numbers required. They also exchange mesons with nearby particles with abandon. All this in superposition. I don't think anyone has yet thrown this through a Lattice Quantum Chromodynamics computation, as these reach only 64 points on each side of the 4-D cube, then bump against processing limits.
Biting the hand that feeds IT
