its an interesting idea in a way (I know its not punishers intention to be so), but what if there were no outer space. Would the universe end at the upper atmosphere. How would it end, would there be an impenitrable barrier.
The universe is beleived to be a 4 dimensional object (excluding time) so that there is no such thing as a edge to it. All points have the rigt to be considered the centre of the universe. If you were to represent the 4d universe as a 3d object it would be a doughnut; if you were on its surfice no matter which way you walked you would never come up against a wall or end, in fact go far enough and you end up where you started (although impossible with the actual universe since it is now expanding faster than the speed of light).

So go on punisher, describe in more detail what reality could be if there were no outer space.