Border Disputes at the Edge of the Universe

Scientists say our universe is expanding. This raises the question, "Expanding where?" Is there some sort of empty space outside our universe? Or is there absolutely nothing there, in which case our universe must be creating more "universe stuff" somewhere? Or is our universe sprawling into someone else's universe?

I certainly hope not. I don't even like for my tree branches to overhang my neighbor's yard. I really wouldn't want to encroach on someone's whole universe.

I wonder if there's a universe out there, somewhere, where astronomers look through their big ol' telescopes and say, "Our universe is contracting. It is being overrun by another, expanding universe. In 85 billion years or so, this other universe will have completely obliterated our own."

Would that cause unrest? Could "universal contraction" become a hot-button political issue on some planet in that universe? Would people raise a cry for better immigration laws and border security? Would governments draw a line in space and say, "This far and no farther!" Might they even go to war to put an end to the threat?

Maybe somewhere there's a guy blogging, "I wonder if there are people in that universe that's spreading into ours. Do they realize what they're doing? Can they stop it? Do they like Zlxichthyliglimch fries?"