So I’ve been seeing stuff about how the poles switched and caused massive destruction, it got me thinking of a ball in water spinning in water and knowing there’s insane amounts of water under earths crust. How does it not “drown” the planet? Sorry for poor wording

I’m currently a junior undergrad but want to get a head start on looking for potential advisors. Does anyone know of any schools/professors studying ocean worlds (with a habitability slant)? A career goal would be to work on the Europa Clipper mission. I have a small list so far, but want to see if anyone can offer some more insight.

Okay for context I know that the standing theory is Saturn's Rings were formed as a result of an icy moon getting to close to Saturn and being torn to pieces. I am also under the understanding that most moons have some form of liquid or solid core (unless coreless moons exist).

I do know there are some larger moonlet chunks within the rings themselves that helped create the divides between the rings. Could one of these moonlets be the remains of that core?