[jccc (OP)]

Strong and weak forces are doubtful.

Let's see if we can use electrostatic force to explain everything.

Nucleus are built by charges. U and D quarks. We know every nucleus is positive charged, but we should assume that every nucleus is polarized in nature.

Line up the nucleus polarity in a matter, create magnetic field.

The space fluid density is high near a pole and low near the other. The density is Dm=1/r^3. That matches the observation. And fits the equation f=q1q2/r^2.

Farther more, moving charges will create vertex in space fluid, the vertex is moving magnetic field.