Hello everyone ! I am new here, so before to post my question, I'll just introduce myself shortly. I'm a French student in schools that we call CPGE - highly selective classes to prepare for national competitive entrance exams to leading French "grandes écoles", specializing in mathematics and physics. Each year, we have to write a report about a chosen topic, and mine is the Roche limit and its application to Saturn's rings. Surfing through the web, I found several websites who answered most of my questions, but one of them remains unanswered, so I dare post it here. In fact, many people say that most of the Saturn's rings lie within this Roche limit, but the problem is that the Roche limit depends on satellites and primary densities. So, why is it assumed that a unique Roche limit can be calculated ? And if there is a unique Roche limit for Saturn's rings (for example), why just do we take the same densities ? Indeed, why a meteorite that could be a part of the rings should be the same density as Saturn ? I thank you all for all your answers, hoping not to have wasted your time ! :shy: And by the way, sorry if my English isn't as perfect as yours. Thanks again ! Damien.