It can happen, in books. One minute you're walking along the road minding your own business, next minute you've passed into a parallel universe, and things can only get better, or worse. It's a bit like the literary concept of time travel, except that a parallel universe can be even more outlandish and difficult to explain.
In Philip Pullman's book 'The Subtle Knife', Lyra says:
' ... No one can count how many worlds there are, all in the same space, but no one could get from one to another before my father made this bridge.'
Now, how can they all be in the same space? Worlds are made up of matter. Where is all that other matter?
The only way I can come to terms with millions of other worlds is by accepting that there are millions of other people and each person perceives a different world, but I don't think that is what Lyra means. On the other hand, when Lyra visits the museum in Will's world she sees the very same sledge that she had been carried on when she was kidnapped by the Samoyed hunters:
And even that rope had frayed and been re-knotted in precisely the same spot, and she knew it intimately, having been tied up in that very sledge for several agonizing hours ... What were these mysteries? Was there only one world after all, which spent its time dreaming of others?
I don't understand this. Philip Pullman's worlds apparently all sit on top of each other. Has the sledge 'dropped through the floor' from Lyra's world into Will's? Obviously, Dust drifts freely around through all the universes, so perhaps other things do. Lyra and Will manage it after all, don't they?
Perhaps in His Dark Materials Philip Pullman's point is that it is only through sheer, blind chance that we have evolved into what we are today. In countless other worlds, with countless other chance happenings, countless other species could evolve. Take the mulefa, for instance.They are conscious beings, with religious sensibilities, but they are four-leggety-wheeled beasties. And yet, despite the randomness of evolution, conscious species all develop some sense of God and Heaven.
Alas, I suspect there is no such thing as a parallel universe such as Philip Pullman describes. But I do think it's quite easy to walk into a real parallel universe. They're all over the place. Try spending the afternoon in any enclosed institution - school, for instance, or hospital, or your father's office, or a travelling circus - you can become so involved in the detail of what is happening that if you suddenly look up and out of the window you can be quite surprised to see 'ordinary life' going on in the street outside. Worlds within worlds.
Have a look at Philip Pullman's 'His Dark Materials' trilogy if you're interested in parallel universes.
Ashley, boy, age 14, from Fort Wayne, United States, on 22nd March 2006.
What we are forgeting, i think is that when Lord Asriel made the Bridge, all of the openings shifted, so to say that these alternate universes are not fixed in one spot indefinantly. So when we say they "share" the space with us, we are thinking inside the limits that we have known all of our lives. None of the laws of physics gives us an explanation, or allows for the possibility that there are alternate universes. The only feild of science that comes close enough is quantum physics. I've read somewhere, it was in the book "Timeline" by Michael Chricton, that q-physics, (excuse the abreviation), states that everytime someone makes a choice, like flipping a coin and it comes down heads, another "universe" branches off where it came down tails. Thus, with the literally countless decisions every single person makes every single day, we have an infinite number of universes that have seperated from ours. Like with the Mulefa, where somewhere in the space of evolution, our world chose a spinal developement, where they found the diamond shape worked for them. That decision clearly seperated their world from ours. Also in Timeline, they found that photons were interacting with those that weren't in our universe which explains the "shared space" theory.
Xelnaga, boy, age 15, from North East, United Kingdom, on 20th July 2005.
It is entirely posssibly that what Phillip Pullman describes is true. Each parrarlel reality would theoretically come into exsistance at the moment of a descision, where each reality takes a choice different to the other, there for, you could find a reality completely different to our ouwn, where say lfie was never created, or where the only difference is 1 descision made by some one. That one descision how ever could have lasting repurcussions, such as say soem one never beign born, or someone never inventing soemthing, this would drastically alter the time line in the afore mentioned parrarlel reality. Yes the Theory is sound, and due to the closeness of lyra and will's world I would hazard a gues at the only difference being in lyra's oncep erson chose to embrace their dmon, whilst in will's they chose to reject it and pretend it never exsisted, thus people forgot aobut them, and never saw them.
steph, girl, age 15, from Nevada, United States, on 18th July 2005.
I really like reading books with parallel universes and consequently have a few ideas of my own. :) When I was little, I used to play a game called 'Ghost.' Here is an example: I had a choice between going to the kitchen for a snack and going into my bedroom to get my book. I chose to go to my bedroom, and did. While doing this, I pictured a 'ghost' of myself going to the kitchen. I tried to keep the picture in my mind as long as I could. For example, the second I picked up my book, my 'ghost' was opening the fridge door. As I looked for my place, the 'ghost' looked for something to eat. I wrote a story built around this concept and while it didn't turn out so great, this is my favorite way to look at parallel universes: the same people in the same situation making different choices. Picture it like a series of lines (like the staff in written music) all moving at the same pace. As they move, they fluctuate differently. Sometimes the lines cross, sometimes they move parallel to each other. Those are the different worlds. That's the best I can put it into words so I hope it makes sense... :)