Edge of the Universe

I think I would have to agree with the expanding universe model, the universe is simply immpossible to imagine, for me at least, and I can think of absolutely no way to represent it in any mental or physical form. So little is known and so little is seen of the universe, the possibilities are endless. I would never be able to get my head around it if the 'edge of the universe' was 'discovered'. What could the edge possibly be? How could it be a solid object, like a wall? That would be imppossible because then that wall would have to be created by something. How could it be simply nothingness? Just an endless black? Because nothingness in itself is not nothing, it still exists. Therefore I conclude that the only thing that could mark the end of the universe is some sort of spiritual realm, for nothing else makes sense.