New universes are constantly being created in phenomenal numbers. Every time a quantum event takes place the universe splits so that all possible outcomes occur but in different universes. With each split whole entire universes are created and in each of these universes is a copy of ourselves, but they are not ordinary copies for they are actually us. It is after this split that differences begin to occur for then each world is on its own, though with an identical past. Visiting ourselves in other worlds When our minds are unlinked from this world in sleep, the way is open for us to experience the other universes through our doppelgingers.
Dreams are the result.
Like with splitting universes there is no actual cataclysmic sense of being ripped asunder when moving from one world to another. If we visit 10,000 worlds per earth second our doppelgingers in those 10,000 worlds may not perceive the same thoughts or sensations we perceive. Visiting worlds which could have been ours. One indication that we are moving from one world to another is the difficulty encountered in reading a piece of text in a dream. Even with the force of will available in lucid dreams it is nearly impossible to stabilize the image and stop the words from changing at every blink of the eye or even before your eyes.