I’m watch an episode of *The Universe* about parallel universes and it’s got me doing some thinking…

First, the thing I find most fascinating and difficult to work out in my head is the idea that for everything that happens there is another universe in which something else happened. For example, according to this idea, there is another parallel universe where I didn’t write this post and you didn’t read it. In fact, there is yet another universe where you never read this blog ever and I never learned how to read or write.

I’ve been annoyed with this idea since it basically just says, eh, everything happens. But then I started thinking and I realized that there could actually be a measurable amount of universes if this is true. To figure this, however, we need to assume that the universe is finite. To be honest, I think I sort of do. Or at least for this thought experiment, I am going to consider a finite universe.

Okay, so let’s say that in this finite universe there are 100 atoms and the universe, being finite, will “die” or run out of energy or whatever after 10 years. So that means that for every instance of time during the 10 years of that universe, all 100 atoms can do only however many options an atom has. So let’s say that each of those atoms only has four choices: it can move up, down, left, or right. Over the course of 10 years there will be a universe for each and every option that an atom can do at each time slice. One of those universes may have the atoms moving over a course of time to create a star while another of those universes may have the atoms moving over a course of time to do nothing but just move around and not even interact.

So in the end you can do some really long permutation equation and come up with a number of possibilities. Even for my “small” universe of 100 atoms with 4 possible actions lasting 10 years the number of universes will be huge — but it would be quantitative. Apply that on a much larger and more complicated scale, and you’ve got our universe.

Let’s say, however, that you believe that the universe is infinite. Do you realize that if you believe this and based on probability, again, that somewhere in this huge universe there is another Earth? If the universe is infinite than why wouldn’t there be another place in the universe where nearly the exact same things happened that created what we know as Earth and now? That’s how big infinite is!!

My favorite parallel universe-related thing to think about, however, is what I just learned is called a level 4 parallel universe (aka the ultimate ensemble).

The idea of a level 4 universe actually plays into an idea I posted a couple of years ago: that the final step of evolution is creating a new reality. As I understand it, the level 4 parallel universe theory says that if you consider the universe to be a mathematical equation of sorts (which I think most people do), then that means that there are other universes that exist where the “laws of mathematics” are different.

The example I like to use is pi — a mathematical constant. In our universe the notion of pi equals a numerical value we understand as roughly 3.14. But where did this come from and why is this constant what it is?

Consider back in the days when I used to do some computer programing. Let’s pretend I’m writing a really simple computer game. At the top of the game I might define some constants. For example:

#define CHANCES 4

#define NAME "Jason"

These are constants for the entire program. Even if I tried to make a variable called “NAME” and give it another value, it wouldn’t be possible since at the top of the program I defined the name.

So let’s extend that idea into the universe. In our universe, let’s say there is something like this “coded” somewhere:

#define PI 3.14159 26535 89793 23846 26433 83279 50288

#define zero 0

#define one 1

#define NAPIER 2.71828 18284 59045 23536 02874 71352 66249

That means that in another universe, the “code” might read:

#define PI **3.12**159 26535 89793 23846 26433 83279 50288

#define zero 0

#define one 1

#define NAPIER 2.71828 18284 59045 23536 02874 71352 66249

If pi was off by just that might I can imagine that the universe would be a very different place. Maybe planets wouldn’t form the way they do, etc. In fact, I bet we could figure this out if we wrote a super complicated computer program to see what happens. This goes back to my earlier idea about the next step of evolution being an intelligent species writing a computer program or tweaking the with mathematical formula that explains the universe in some sort of simulated reality.

I admit, I’m not much (or at all!) of a physicist or mathematician, but somehow this makes sense to me in an abstract way. I’ll also admit that there probably isn’t much value in even thinking about these things since I don’t think anyone has devised or even theorized on a good way to prove any of this — and if we did prove it, what would the point be? What is the ultimate implication of knowing/thinking that the universe works this way? I’m not sure… but if nothing else it’s fun and gives your brain a nice exercise!

**Edit a few minutes after first posting:** Now that I think about it a bit more, I think there actually are very important reasons to think about these things:

First, it shows that even crazy-unproven-and-out-there science is just as interesting and exciting as “religion” with god and stuff. It also begs the question that if the universe/multiverse/etc. is really set up this way, then there is no way “god” or anything like that could keep track of everything. Another reason to give up on a simplistic religion-based understanding of live.

Second, if we ever hope to investigate time travel or teleportation, understanding how multiverses work will be crucial. For example, it might be easy to teleport oneself into a parallel universe but impossible to teleport within one’s own universe. So is there a threshold of “acceptable differences” between universe A and universe B — that is, if the universe I teleport into is only different in the fact that 1,000 years ago a leaf fell 2 centimeters different than my original universe and scientists or whoever can conclude that this action shouldn’t cause any noticable difference, is teleportation from universe A to universe B acceptable? (Think of the TV show *Sliders*.) Likewise, if time traveling within one’s own universe is impossible, is traveling to a different universe with minimal differences OK?

So there you go: reasons this matters!