Is the universe expanding into nothing?
The answer kind of depends on what you mean by "nothing". (I'm serious!)
How do you state this and make it sound sensible??
The universe is not expanding into nothing. This makes it sound as if there is a great emptiness beyond the universe that it is rushing outward to fill.
We believe the universe is not expanding into anything. It does not make sense to ask "What is beyond the edge of the universe?" because the concept of "beyond the edge of the universe" does not exist.
All reality, all space and time is being created as the universe expands outward.
So, I hope it doesn't sound too Zen to say "the universe is not expanding into nothing; it is not expanding into anything".