A very good YouTube video on where Electromagnetism comes from.

[hamster_nz]

Electromagnetism as a Gauge Theory

"Why is electromagnetism a thing?" That's the question. In this video, we explore the answer given by gauge theory. In a nutshell, electromagnetism arises from local phase symmetry. But what does that mean, and how exactly does that work? That's what this video is all about!



It's 3 hours long, and has some advanced math that is beyond me at the moment, but I'm about an hour in and it is offering insights.