The good ol' Maxwell Equations have two very big concepts: the $\vec{E}$ and $\vec{B}$ fields. But it can be shown, adding relativity into the stew, that what we call the $\vec{E}$ and $\vec{B}$ fields are just a single Electromagnetic field. When talking about the same frame of reference, this Electromagnetic field behaves just like what we call the $\vec{E}$ field. And if the charge is viewed from a different frame of reference, after proper Lorentz Transformation, another force field seems to come into play which is what we call the $\vec{B}$ field. It's not a new concept.
But according to the Wikepedia page of Relativistic Electromagnetism:
Relativistic electromagnetism is a modern teaching strategy....
Teaching strategy? Why isn't such an approach used more commonly? This would make understanding Electromagnetism more intuitive since all that's required that way is $\nabla\cdot\vec{E} = \rho_v/\epsilon$ (Gauss' Law) which is not to hard to explain. Why are Maxwell's Equations and $\vec{E}\,\vec{B}$ fields not regarded as "approximations" or "tools to make electromagnetism simpler"?
Moreover, permanent magnets work because of electron spin. Why does electron spin arise?
It's because of the bispinor wavefunction result of the Dirac Equation (going into quantum mechanics here), which is like older QM, plus.......? Special Relativity. Damn.
Its pretty easy for me to say here that all magnetism is a result of basic non-relativistic ideas plus relativity, but still this idea is not given as much attention as seeing how important it is. Is there a reason?
