The way I understand it is that there is not really an edge. Spacetime itself is expanding, the best analogy I've heard is consider a spherical balloon that is being inflated. We exist as two dimensional beings on that balloon. No matter where you put two dots on that balloon, they will move further apart.
You could also draw a circle on the surface of that balloon which represents the furthest points that we can reach if we traveled at the speed of light. Nothing outside that circle would be observable to us, so it could be argued that it doesn't exist.
You could also draw a circle on the surface of that balloon which represents the furthest points that we can reach if we traveled at the speed of light. Nothing outside that circle would be observable to us, so it could be argued that it doesn't exist.