General Relativity from what I have read in several places, is a body of work that is not typically fully understood by more than 3 living people in the world at a time. That said I am not one of those people, but every college kid in a physics class claims to understand this fully and puts Einstein up on a God pedestal. I am going to say this and it is based on fundamental logic, which is claiming to have proof mathematical or otherwise (the math dictates that 85 percent of the universe is missing)(it's not missing, we just do not know what the universe is) that nothing can travel faster then light, without having knowledge of everything in the universe is an unprovable hypothesis or theory. We all have the same percentage access to all knowable knowledge of the universe which might be expressed as 1 trillionth, of 1 trillionth, of 1 trillionth of a single percent. Claiming that nothing can exceed light speed requires knowledge that we just do not possess.
Note I do not reject any of theoretical physics, I just keep it in perspective
Theory is not the best it gets in science. Physics is basically the study of everything, many if not most things are clear cut and proved. People get mixed up and believe that theoretical physics is the main body of science. It's not, in fact it only exist to explain what we really do not know