# Thread: creating a universe

1. Originally Posted by Hunter2
>>In three dimensions, we have shown space is curved.
Cool... so some sort of 3D mobius strip or something?
Yeah, and heres' something that I have wondered about for a very long time: Why did the chicken cross the mobius strip?

Regards,

Dave

2. Haha! That is great!

3. Isnt' repeating forever infinity? So an infinite plane would be like a car racing game driving into the horizon forever.

4. >>So an infinite plane would be like a car racing game driving into the horizon forever.<<

yes, that is what I wasthinking about, but with the ability to go back - that is where it gets tricky, because you have to either have some way of storing what happened or follow certain rules, which lead to repetition etc etc.

5. If you want to create 3d animation and dont want to touch opengl :-) then you could use a developers toolkit ie OpenInventor or open scene graph.

These integrate into c++ and remove much of the coding ie 50 lines of ogl code can be 2 lines in OIV.

6. You would never be able to track a truly infinite plane (and be able to go back). You could track a large one, though, so long as you have a nice way of recreating it from stored parameters or actually reversing the function. (Of course, it really doesn't have to be a plane, per se.)

7. >>You would never be able to track a truly infinite plane (and be able to go back).
Not even with an incredibly ingenious random generation algo?

8. Originally Posted by Hunter2
Kind of hard to create a 100% accurate universe. For example, you'd have to store positions with infinite accuracy/precision for an infinite number of points, and once you've done that you have to take into account light's screwed up time properties.
According to quantum therory, everything (time, mass etc.) comes in very small packages.
The shortest amount of time is around 10^-43 seconds.
The shortest distance is 10^-35 meters.

Infinite precision isn't neccessary, 256-bit integer will probably be enough.

Just make a loop like this to simulate movement:
Code:
```int256 time;
while (true)
{
pos += speed * 1e-43f;
time++; //Stepforward one interval
}```

9. Even with that brilliant algorithm. The problem is not the algorithm, but the data stored. Imagine that you used a true random source (regardless of wether or not you think such a thing exists, we'll assume it does) to generate frames of your plane (never mind tracking them), you only grab a finite (but perhaps very large) amount of data from it each time (measuring in bits seems natural). The result is that, no matter how big your parameters, they only have a finite number of possible states.

10. >>According to quantum therory, everything (time, mass etc.) comes in very small packages.
But what about very large packages? I.e. the edge of the universe and eternity? Or does it come down to the 'ol mobius strip of the universe where we keep going but end up where we started, thus creating only an illusion of infinity?

Haha, I was just there yesterday as I went to look up "Planck Length", inspired by zach's post...

**edit**
>The result is that, no matter how big your parameters, they only have a finite number of possible states.
If you mean that eventually you'll run into an area of terrain which is a duplicate of another, that isn't really a problem is it? Because there's no physical rule of the universe that decrees that each object must be unique... it's just that you don't want to run into a loop that keeps generating the same terrain endlessly - but if by pure random chance you run into a clone of another area for an instant, that's entirely within the rules of the universe isn't it?

11. Perhaps the universe is infinite, but its mass isn't. There is no need to simulate the parts of the universe that has no mass.
Originally Posted by Hunter2
Haha, I was just there yesterday as I went to look up "Planck Length", inspired by zach's post...

12. >>Perhaps the universe is infinite, but its mass isn't. There is no need to simulate the parts of the universe that has no mass.
But if its mass is spread to infinity (and I suppose someone has already proven it isn't ), then the data used for storing the position data would also need infinity - unless, again, you're dealing with random terrain But if it's spread far enough that the amount of resources readily available on the Earth won't be enough to build a supersupersupercomputer with enough memory for it, then I suppose technically it still is impossible (assuming we run out of resources before colonizing other planets). I'll rephrase that, if we can't harvest enough resources without causing some drastic environmental disaster that will destroy the computer anyway [/edit]

**EDIT2**
[offtopic^2]
Well, you could create a 'universe'... like... the BattleTech universe. If you write a nice story and history, you can create a ripoff of the real universe and name it something else, and you'll have a whole new universe!
[/offtopic^2]

13. Well, as long as you don't mind looping through terrain you've already been through, you can continuously generate terrain as long as you want. Unless it is an easily reversible function (in which case, it is bound to be periodic simply due to the nature of functions that computers can deal with), you won't be able to back-track too long.

The theory isn't that the universe is a mobius strip, but rather that our particular three-dimensional space is inflating (like a balloon's surface in the two-dimensional case). We can see things speeding away from each other in this manner. And, if the universe had spread out infinitely, then we would not bee able to see the distant objects (the average matter density of the universe would be 0).

The problem with modeling every piece of matter in the universe is 1) the most efficient way would just be to put a particle there and ask it where it is, how massive it is, etc. (in other words, a one-to-one correspondence, the universe itself would have to be the computer, otherwise you would need more matter than exists -- but the mechanism for polling/communicating with these particles is unclear), and 2) you really have to take into account particle-wave duality.

14. >>the average matter density of the universe would be 0
Right, I realized that shortly after I posted

Well, as long as you don't mind looping through terrain you've already been through, you can continuously generate terrain as long as you want. Unless it is an easily reversible function (in which case, it is bound to be periodic simply due to the nature of functions that computers can deal with), you won't be able to back-track too long.
I didn't mean looping through terrain you've already been through - although I suppose that's what it would come to eventually... Perhaps you're right that it won't work. But it sure would be cool Just imagine the creatures in the universe... "Ahh, the camera's moving away, we're gonna go out of scope.. hurry, run!!!!!"

>>the most efficient way would just be to put a particle there and ask it where it is, how massive it is, etc.
Well, if you have a really neat compression or prediction algo then perhaps it could be done

15. Yeah, it would start looping over eventually (there are only a finite, but really bloody large, number of possible states), but for all intents and purposes, it may have an "infinite" cycle.

Hehe.. I would be worried about the "lossless" part of the compression algorithm. "Oops. That galaxy appears to have been corrupted."

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