The many universes interpretation of quantum mechanics gives a possible location for dreams beyond this earth, yet in a certain sense in the same space. This interpretation, proposed by Hugh Everett in 1957, states that there are very many or perhaps an infinite number of parallel worlds existing beyond this one. Many of these universes are almost identical to ours, but others are quite different. 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. Before the split "I" am one person and after the split I am still one person only in more than one universe. It is after this split that differences begin to occur for then each world is on its own, though with an identical past.
The many universes theory tells us that there can be no physical contact between the split universes, however because our doppelg?ngers inhabit these other worlds we have no need to make physical contact - we are in a sense already there.
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. Our consciousness is the same as their consciousness and when in sleep we become unconscious of this world we have access to all our other selves. Dreams are the result.
The number of parallel universes we "visit" in the course of a dream may be as few as one or could be in the billions. Like with splitting universes there is no actual cataclysmic sense of being ripped asunder when moving from one world to another. We may experience bizarre scene shifts, anomalies in perception, strange sensations, etc., but we have learned to accept these as normal elements of the dreaming process. 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. Our stay in any one world may not be long enough for us to experience events in the same context in which our doppelg?ngers experience these events.
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. Larger elements such as rooms, buildings or streetscapes appear to have greater stability in dreams. Major changes that have occurred in other worlds can be noticed. Locations which are accepted as familiar (e.g. home) can in dreams look very different to what they look like on earth. This same difference can crop up consistently in a large number of dreams, giving the impression that this altered world is actually "out there" - that some time in the past(?) a significant number of universes followed the same different path and built the same different buildings. For example a planning permit may have been issued and all the houses around yours may have been demolished for a car park. In half of all the parallel worlds the permit may not have been issued and the original houses remain. Thus in half of the universes you are in the middle of a car park .... and that may become a "recurring" feature in your dreams - "I keep dreaming that we live in the middle of a car park". The issue of a permit may not have even been considered in this world so no clue exists as to why you continually dream of a car park. "Why do I always dream of a car park? It must be significant .... Let me consult my analyst".
Predicting the future
The direction of time may have no bearing or influence on where or how our consciousness travels in dreams. The "future" and the "past" (as long as they exist) are both valid destinations for our exploration, which could explain the "prophetic" dreams reported by a large number of people. These dreams take place in a future or many futures which could be similar to the one which is eventually experienced.