Great article! Concise while also being thorough.

If nothing else, the beginning was a really nice refresher on this specific application of vector calculus, which is IMO fundamental to understanding basically anything about the universe.

I'm used to seeing plenty of screen reader inaccessible math around the web (fortunately less so these days than in the past), but every math expression being represented by a bunch of images nested inside an iframe is a new one for me.

What the hell?