>>/16218/
Yes. It is all one and the same. No multiple universes.
One universe, many dimensions.

 >>/16212/
>  If I'm not looking, does it exist?
That depends on how large you make your existence.
You may not be able to see it directly, but it does grow.
How much can a bacteria see VS a larger mammal, with developed complex eyes?

Grow or recede, there is no staying the same.