Does the space in the expanding universe suggest that there is a point within that is fixed, which is maybe the centre, and to which all other points are relative to? Not all things can be relative, otherwise there would be nothing to be relative to. Can the same be true of time? If time is a variable, and ticks by at a different rate depending upon where you are and what speed you are travelling, is there a point/moment where time stands still, and could this even be the same moment in time as the point is in space?

What do you define as a point in space or a moment in time? I guess the Planck lengths could answer this, but how do you combine the two?

Could there be a super dimension which links all points in space and time? If so then I imagine that there is no need to think that the universe has a boundary.