Heys guys, I asked a similar question in one of the previous threads and therefore I apologize if anybody is offended or thinks I'm asking too much. I just want to clear and define some concepts in my head. So it is agreed that simultaneity is a convention and that in SR inertial frames have a standard convention or a set of rules which define what events are simultaneous relative to them. This part seems okay, but I really dont understand how we define simultaneous events relative to non inertial frames. It has been mentioned previously that non-inertial frames don't have a standard simultaneity convention, but what basically does that mean? Does it mean that there are no basic rules about simultaneity like in SR, but that we can still define a collectin of simultaneous events relative to a non inertial frame, of course if those events are trully simultaneous 'from a point of view' of a non inertial observer. I hope somebody can define this better to me. Thanks in advance.