Flat space-time or curved
If, as some astrophysical date suggests, that space-time is flat rather than curved, it could mean that the universe and its attendant #Multi-verse goes on forever. If you think of the multi-verse as having a quilted pattern that resembles a bubble then each bubble would contain its own universe. Every bubble would be the same as the first bubble but one item might be different. Multiply that by infinity and you can have some whopping deviations from the original bubble.
Quantum mechanics says there is a finite number of configurations within each bubble. However, with an infinite number of bubbles with a finite number of configurations it is quite possible there are multiple universes exactly like this one with people exactly like you living in an infinite number of bubbles that are in a very small or very large way just a tad different than you.
A solid definition
Perhaps it would help if we gave our universe a solid definition and call it all there is. In our world the universe is everything we can see back to the Big Bang which we cannot see but can be theorized to be there by measuring the expansion of our universe. Each universe within the multi-verse is unique unto itself and some physicists believe that every time there is a quantum measurement another universe is born. In this scenario, one universe may be suitable for life and one may not be suitable. The multi-verse is ever expanding while at the same time decaying making a big mess of things that are uniquely suited to each individual universe.
Our all that is can be thought of as one big inhale and the Big Bang a giant sneeze, spitting out particles that eventually attracted each other and began the universe we know today.
Before the Big Bang, it is theorized, that something very small began expanding. Think water molecule though that is thought to be too large, but it will work for now. One water molecule by itself is just that. Turn up the heat (we don't know who turned up the heat but it can be explained as the major observer) and that water molecule will start expanding. At some point the water molecule will begin to boil and within a few more seconds that bubble will pop creating an explosion that in our simulation created the universe.
The observable universe
#Physics dictates that the observer defines the universe he or she lives in. In a multi-verse there would have to be a major observer to create something that goes on for infinity. Our major observer, created an infinite number of yous in a multi-verse where just one small change can create the difference between replicas and uniqueness. In our universe all things are different and all are equally unique even if they look the same.
The most interesting theory is that the universe is like a pool game. All worlds are equally real, all interact on the same timeline, and they bump into each other sharing information along the way. Sometimes this can get confusing like when items get interchanged and you don't recognize them anymore. Some call this the Mandala Effect which might be faulty memory, but in an observable creation what difference does it make. To observe the change is to make the change and there you have it.
What I love most about this, is that means there is a world where I am perfect. I don't get sick, I have a huge family that never argues with me, friends that adore me, and I have the perfect work station that supplies me with all the chocolate I need that never makes me fat or allows my blood sugar to rise. Oh, and I hit the New York Times Bestsellers List.
Seriously, what more could a person ask for?