It's expanding into extenuating dimensional subspace. There are multiple universes, ours is not the only one. You see, in M theory, there are 11 different dimensional planes. Our universe, and conversely, all other universes existing within these planes simultaneously. So, yes, there is an "outside of our universe." Look at it from the point of view of linear algebra. You see, the plotting of matrices create on the graph different dimensions. You can have as many of these dimensions as you'd like, but, they all coincide, having one conversional subspace within all of them. This, is where ours, and all other universes would then be located.

It's expanding into extenuating dimensional subspace. There are multiple universes, ours is not the only one. You see, in M theory, there are 11 different dimensional planes. Our universe, and conversely, all other universes existing within these planes simultaneously. So, yes, there is an "outside of our universe." Look at it from the point of view of linear algebra. You see, the plotting of matrices create on the graph different dimensions. You can have as many of these dimensions as you'd like, but, they all coincide, having one conversional subspace within all of them. This, is where ours, and all other universes would then be located.