https://www.sciencealert.com/existing-string-theory-can-t-explain-why-space-expands-but-this-new-idea-might
Physicists have come up with a bold new idea to explain the enduring mystery of our expanding Universe – we might actually be living in a ‘bubble’ between other five-dimensional spaces.
If that makes your brain hurt, don’t worry, it’s supposed to. But we can break this down.
Our Universe as we know it has four dimensions: the three dimensions of space (up and down, left and right, back and forth), and one dimension of time that keeps us all ticking along.
But this new solution from physicists at Uppsala University in Sweden suggests that are other types of space that are five dimensional, and where two of those spaces come together, the junction forms an expanding bubble.
Jesus: Hey, Dad? God: Yes, Son? Jesus: Western civilization followed me home. Can I keep it? God: Certainly not! And put it down this minute--you don't know where it's been! Tom Robbins in Another Roadside Attraction