Hello everybody, First of all, I want to state that im an undergrad physics major who has yet to take a course in Special Relativity. What I have read in books state that Spacetime is one entity, my question is this: If Spacetime is one entity, is it correct to think that there are 3 separate spacial dimensions and one of time? Or are they really just meshed together and there is only one "true" dimension? And that it just helps us visualize spacetime by separating the qualities of it? Thanks for your time.