> Is it the case that a given particle is trying to settle into a "lowest energy state" possible? It's more accurate to think of the energy "spreading out" (re

> Is it the case that a given particle is trying to settle into a "lowest energy state" possible? It's more accurate to think of the energy "spreading out" (remember that mass is a form of energy too, since E=mc^2). The energy can rearrange (subject to conservation laws), between being one massive particle, or several lighter ones (in fact there's a superposition of possibilities, because quantum). In principle the probability of switching back-and-forth is equal, e.g. the probability of particle A decaying into a B+C pair, is identical to the probability of a B+C collision producing an A. However, most of the directions those light particles can take will result in them flying apart rather than colliding; that spreads out the energy, so it can no longer switch back into the massive particle configuration. Note that this is essentially the first and second laws of thermodynamics (energy is conserved, and concentrations tend to "spread out" over time)