This is one of the most amazing things I ever learned in physics: you can derive Maxwell’s equations from Coulomb’s Law and Einstein’s two special relativity postulates. (I’ve never seen a good derivation of this online — pointers welcome…)https://twitter.com/elonmusk/status/1138858999309144064 …
Of course one can smuggle the source-free equation dF = 0 into the narrative by beginning with the (implicit) assumption that F = dA for some A. That is, one can from the outset make the (gauge-arbitrary) potentials the fundamental variables of the theory. But this is unnatural.
is relativistic side effect of 