For years I have been very fascinated by the "mystery" aspect of gravity. Functionally, we understand it perfectly for our all applications, but in my (limited to undergrad General Physics 3 quarters) understanding, we don't know WHY it exists or HOW the "pull" works.
I'm very sorry for what is surely trite pop-science term use, but, to provide an example of what I mean: there has to be SOME "measurable material" of gravity between say the earth and the moon -- some kind of 'graviton' (not that it needs to be a particle or anything, I have zero claims as to the nature of how gravity does what it does). The [butchered] saying of "pluck a flower and move the furthest moon," because gravity in theory, has an infinite range (?) and moving a flower on earth could maybe move an atom on jupiter ever so slightly (?)."
Anyway, similar to how we had "very good" hypotheses about the existence of higgs-boson that the LHC 99%+ confirmed, do we have any "very good" hypotheses in regards to the fundamental way how gravity does what we have long-known it to do?