.. there to be an edge to the universe.....
We can compare the reality observation to the situation, when observing a laser ray through inhomogeneous atmosphere. If the environment would be completely homogeneous & clear, we would see nothing. If the atmosphere will be too cloudy and foggy, we would see the laser ray, but we wouldn't see too much as well.
So here exists an optimal density (and geometry, too) of environment fluctuations, which would enable us to see as much from the neighborhood, as possible. The vacuum is such environment.
But as we can see, the ability to see at least something is always connected with existence of some insintric inhomogeneities of the environment, which are result of the dispersion on both sides of the transparent region of electromagnetic spectrum. And the light will be always bended with the distance, and after certain distance limit, the level of light bending will achieve the limit of total refraction - the light will not be able to pass through space anymore. This is the boundary of Universe, which you have talked about.
Note that by this interpretation the Universe boundary is arbitrary - if we would travel towards it, it would recede accordingly. It doesn't say anything about physical boundary of Universe, it's just "visibility distance" limit.