Physics (like all well done science) is the art of predicting the future by modelling the world with mathematics.
And predicting the future is the first step towards controlling it, i.e.: engineering.
Ciro Santilli doesn't know physics. He writes about it partly to start playing with some scientific content for: OurBigBook.com, partly because this stuff is just amazingly beautiful.
Ciro's main intellectual physics fetishes are to learn quantum electrodynamics (understanding the point of Lie groups being a subpart of that) and condensed matter physics.
Every science is Physics in disguise, but the number of objects in the real world is so large that we can't solve the real equations in practice.
Luckily, due to emergence, we can use uglier higher level approximations of the world to solve many problems, with the complex limits of applicability of those approximations.
Therefore, such higher level approximations are highly specialized, and given different names such as:
As of 2019, all known physics can be described by two theories:
Unifying those two into the theory of everything one of the major goals of modern physics.
xkcd 435: Fields arranged by purity
. Source. Reductionism comes to mind.
Physically accurate genie by Psychomic
. Source. This sane square composition from: www.reddit.com/r/funny/comments/u08dw3/nice_guy_genie/.Chemistry is fun. Too hard for precise physics (pre quantum computing, see also quantum chemistry), but not too hard for some maths like social sciences.
And it underpins biology.
100 Greatest Discoveries - Chemistry by the Discovery Channel (2005)
Source. Pretty good within what you can expect from popular science. The discovery selection is solid, and he interviews 3 Nobel Prize laureates, only one about stuff they invented, so you can see their faces. The short non-precise scenes of epoch are also pleasing. Part of 100 Greatest Discoveries by the Discovery Channel (2004-2005).Ciro Santilli likes to learn astronomy a bit like he learns geography: go down some lists of "stuff that seems most relevant in some criteria to us!", possibly at different size scales e.g.: