I was reading an interview from Bruce Boxleitner, and in addition to the main part of the article talking about Tron: Uprising, he also at the end mentioned another project he’s working on.  I’ll give you a taste – think Game of Thrones, but Steam Punk.  For more info check out the website – lanterncitytv.com.

But that’s not (entirely) what this post is about.  This is a bit more “heady” and more in the hypothetical nerd thinking category.  Over on their facebook page, the posed a question which instead of my typing a yes/no, resulted in a paragraph instead. Here’s the question:

Dictionary.com states a ‘parallel universe’ is “a theory that there is a mirror universe and when one makes a decision in this universe, an alternate ‘you’ in the other universe makes the opposite decision.” Do you agree with this definition?

And my answer?

Parallel universes implies that the run along our own.  How they do this in science fiction is open to interoperation.  Far as I can tell there are 3 standard types of parallel universes.  #1) is your quantum choice theory – that is every decision splits into one (or many) different possible outcomes.  In this situation there is an unlimited amount of universes all slightly different.  Stargate SG1 had an episode that exemplified this that showed the further away from “your” universe, the more drastic the changes were.  Sliders also  touched on this (although might be more of the next type).  #2) Then there are “event” splits.  Not every decisions makes a branched off universe, but there are “major” differences.  Germany won the war, magic was found, penicillin never invented.  Many time travel movies also fall into this situation as traveling back creates a “branched off” universe. In this situation there isn’t an unlimited amount of universes, but might as well be for all practical purposes, as more are created every so often. Then there is #3) what I call “sibling” universes.  At the start (whatever you determine that to be) there were “x” amount of universes.  Some follow similar paths, others radically different.  These are offshoots of our own universe, just a different universe, another space

From reading the description on the site, I’d wager that this world closer fits the 3rd option.  History moved forward to the point where humans exist (or were transported there… ) but the world itself, the geography, etc are different.

But I wanted to elaborate a bit more.  I haven’t had a good “geek” chat in a while or a mental exercise post.  So if I haven’t scared you off yet let me continue.

Perennially I think #3 is the most practical of likely scenarios (at least speaking physics wise), but in terms of “science fiction” all are possible scenarios, all with their own rules, functions, problems, and uses (although I use “uses” loosely).

Quantum Choice Universes:

This is what most people think of when they think Parallel Universes.  For every choice that is made, an alternative choice is done in another universe.  As such there is an infinite amount of universes.  Most people think of “Mirror/Mirror” from Star trek as the example of this.  Everyone is evil who is good and vice vera.  This isn’t technically true, as although good and evil are opposite decisions, life rarely works in such simplistic manners.

This Quantum Choice doesn’t just apply to people, but all things down to the smallest level.  As such you could have a radically different earth, a periodic table that reacts differently, or even a universe that exists primarily of anti-protons and anti-electrons.  For every possible outcome in this scenario, there exists a universe that this has happened.  (This is also considered the 10th dimensional space… but that’s a different post.  If you are curious, I recomend checking out the YouTube video – Imagining the Tenth Dimension part 1 of 2 – YouTube)

Personally I think the show/movie that handles, and explains this idea the best is the Stargate series.  Specifically with the 3rd season episode “Point of View”.  As choices are made, they splinter into new universes.  However the universe is ordered.  Decisions are located near each other.  Think of this as a endless stack of cards that duplicate.  Each card has more in common with those near it than they do much further away as they share a more common past.

As such if we were able to travel between universes (which cause all sort of other issues), we would be able to travel to other version that are very similar to our own, and would require more and more energy to travel to more drastically different versions of our own.  Or even if the energies solution is solved (or ignored), you still have the problem of dialing in another universe that is different enough to be of use or of interest to you.  Getting to something significantly different becomes increasingly difficult as every possible outcome is creating different outcomes instantly.

Alternative History Universes:

This, more often than not, is what SciFi writers actually end up talking about when they use the function of parallel universe in stories.  This gives a lot of the narrative advantages of Quantum Choice Universes, without having to deal with all the extra choices in between that don’t matter.  In this scenarios, you functionally can still have an endless amount of universes, but in a much more manageable way.  Events splinter only in recognizable ways typically, or when they are forced to do to time interrupting individuals.  As such it’s actually interesting instead of “This atom moved left, instead of right, a moment ago”.  So this primarily fills up 2 types of SciFi Multiverse scenarios – Alternative History stories, and Time Travel.

In Alternative History you can travel to a world in which the axis won the war, the dinosaur killing asteroid never hit, or pangea never split apart.  Also as there are less possible outcomes it because much easier (relatively to a quantum version) to travel to the “right” location.

In Time Travel stories (those that result in alternative futures/pasts… there are other time travel stories, but that’s a different post) injecting earlier in their history will split off all future points into a new parallel universe.  If the characters have sufficient enough technologies they would be able to control which of the two universes they return to.  Typically I’ve only seen stories where the future versions can effect the past, but return to “their” universe (think Dragon Ball Z), and those that can’t go back to their’s since they cant jump universes (think Back to the Future).

Sibling Universes:

This is my personal favorite of the parallel universes.  Here there are a set amount of universes, all which can be the same, or different, from each other.  Basically at “the creation” all the possible universes are made.  From there they can continue along similar developmental paths, or widely diverge.  This is often used where one world “magic” exists, or the laws of the universe are different, or the planet(s) is populated with advanced species besides just homo Sapiens.

Another large advantage of these worlds are that they are fixed.  That is to say travel between them should be much easier than between any of the previous worlds.  Or rather reliable travel I should say would be easier.  In the other two you are more likely to not get to where you want, as the target would be constantly changing.  And the chances of two or more items hitting the same target are even harder.  In this scenario, the universe is more ordered, like houses on a road.  Much easier to mail a letter when you know where it’s supposed to go.  As such stories that rely on travel back and forth (or even just multiple items/people traveling from one world to another) are more likely in this situation.