# Beyond space?

A common misconception from friends studying outside a Bsc. is the impression that our universe is expanding out in space, that space is infinite and that simply matter traverses into voids. They seem to have a hard time understand that the expanding universe is space itself expanding and that beyond the outer boundary there is no space for which to measure distance. Any help on other method to explain or conceptualize an image for them to help assist in understanding our world?

Also this brings me to something I’ve been pondering regarding multiverse/parallel universe theories. Between the many theoretical universes there is no space for which to measure distance between them, so not even a meter separates them because a meter doesn’t exist beyond space. So could we say the separation between universes is zero because space isn’t defined? As we expand, do they reciprocate in time, I see it as a ripple in water I suppose. So what would be your conceptualization on this matter, when speaking multidimensional, does that regard the fact that we aren’t on the same membrane of space, so no distance is truly between us?

I’m aware this is a bit amateurish but I'm here to discuss and listen.

#### confinement

Ask your friends to imagine a space with finite size but no boundaries Typically they will say that this impossible, but then you can point them to the (surface of a) sphere (actually the boundary of any finite shape will suffice, because boundaries do not themselves have boundaries).

#### robousy

Hey, great question. I had similar questions from friends (and similar problems answering them) when I was undergoing my undergrad training.

1. The balloon analogy, although cliched is really (IMO) the best visualization tool.
2. The expanding balloon plays the role of the expanding universe.
3. The 2D surface of the balloon is the anaolgy of our 3D space.
4. The 2D surface of the balloon is the arena for which all the laws of physics exists, including the concept of space and time.
5. There is no 'space' beyond the surface of the balloon.
6. There is no 'time' beyond the balloon.
7. You do not talk about fight club.
8. Anyone who cannot grasp the concept of 'there is nothing beyond space' has to admit that the human mind is finite, and that our brains may not be fully equipped to comprehend the complexities of the cosmos, and that analogies will have to suffice.
9. Anyone who cannot accept the concept of 'there is nothing beyond space' has to come up with a better paradigm themselves that survives a mathematically rigorous test.
10. Anyone who does not like the idea of 'there is nothing beyond space' has to acknowledge that human beings are not gods, that we merely inhabit this universe and our doing the very best we can to understand it.

:)

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#### atyy

5. There is no 'space' beyond the surface of the balloon.
6. There is no 'time' beyond the balloon.
7. You do not talk about fight club.
Because fight club is in the space and time beyond the balloon?

#### Naty1

So could we say the separation between universes is zero because space isn’t defined?
Yes. absolutely. but it's not experimentally verified yet.

Multidimensional space in string theories in which nearby membranes (branes) might constitute parallel universes is an example. In typical 11 dimensional string theory, many of the additional dimensions are hypothesized to be curled up and tiny and perhaps able to only pass gravity to other dimensions and or worlds.

But a large 11th dimension might dilute gravity and offer a solution to the hierarchy problem. In WARPED PASSGES, Chapter 11, Lisa Randall (Harvard) discusses large extra dimensions based on ideas from Arkani-Hamed, Dimopolous, and Dvali ("ADD"). The bottom line is that if particles (not gravity) are confined to a brane, extra dimensions might be much larger than previously thought.....and right nearby....

#### Fra

Another angle to this is to ponder the utility of constructing a measure of distance. From an abstract configuration-space point of view, what's the meaning of spatial distance?

Some simple but good thoughts on this is from Ariel Caticha
"Towards a Statistical Geometrodynamics"
"...Can the spatial distance between two identical particles be explained
in terms of the extent that one can be distinguished from the other?..."
-- http://arxiv.org/PS_cache/gr-qc/pdf/0301/0301061v1.pdf

His idea is to simply define space, from a probabilistic point, there points that
are almsot in agreement (the amount of information needed to make a transition is mall) are taken to be close spatiallly. So that a measure of distance, is constructed from various information measures, defined on the configuration space.

So defining the measures of space in terms of some more abstract configuration space can possible unify the spatial structure with information structures. The probability that two points are mixed up, or fluctuations into each other, is a measure of their "distance" information-wise.

In this picture a locality priciple seems almsot built in, because by construction neighbouring "points" have strong correlation, while remote points have not. To similarly ponder the distance between two other (non-spatial) possibilities their transition probability should be a clue. Perhaps some universal unit of a standardise transition probability unit could be used. If the possibilities exists in two totally disconnected probabiliy spaces, then I think something is wrong. At some level I think there must exists a connection, otherwise there is no sense why one observer would evaluation two possibilities that can not relate to each other via transformations.

/Fredrik

I have told my friends about the balloon analogy, or the sphere analogy or any other analogy there is, but where they get stuck on is the fact they believe space is infinite, then i go on to say there is no such thing in reality that is infinite (or so we believe). I think its becoming an issue of definition, on whether they know what space, empty space, and without the space time continuum a solid object of certain size can not be represented. Thinking of starting at the basics, definitions, then analogies, then the current physical representation of how we think the show is ran. Id just like them to know about it because it paints a new image of reality which gets them asking questions.

Also while typing up the original thread i had string theory in mind, on how cosmic inflation stretched the 3 space dimensions along with linear time, which would imply that past the boundaries of space is an infinite "sea" of tiny curled up 6 dimensional Calabi-Yau space...well not infinite but much larger then what we are dealing with even at a cosmic scale would still be minimal. But even then this "sea" would still just represent a membrane in possibly a series of membranes where string theory says gravitational pulses between branes can be experiences. Which brings me to the next point, maybe quantum properties can represent distance between those membranes, even though string theory states against it.

Regarding the seperation of two points described by their information geometry, seems to be a fantastic method at conceptualizing distances between multiverses, particles are easily distinguish when far apart due to their probability space and hard to distinguish when close. We would have to make the assumption that universes act on those premises to successfully draw a conceptual distance where space doesnt technically exist. A great contribution to the visualization of where we live.

What would happen if someone moved beyond that space?

You simply cant move beyond space, there isnt space there to represent you, we suspect that the forces and dimensions we have in our universe are unique to our own, yes variaties might exist but beyond space you as a human can not sustain form. So if the theories of the big bounce do occur, where the coefficient of dark matter isnt high enough, the universe will collapse in on itself with a raining fall of blackholes dominating the last few moments, you could not escape beyond our universe to step back and watch yet another big bang...because after all it is OUR universe which is collapsing to singularity.

#### Fra

What would happen if someone moved beyond that space?
Now maybe I totally misunderstand you question, but in IMHO, there are even ways to imagine this, but it gets even more abstract. But I think it's an important point.

Usually, you have configuration space, microstructure and that defines a sort of "state space", one can see it mathematically as a container for possible states, and usually we picture that the states evolve, but always stick to that container.

On this space, we defined various information measures for our information about the state. It reflects our uncertainty in knowing the state (in the space).

This is somehow the basis for conservation of information - that regardless of how little you know, the state can not escape the configuration space.

But the real question is, where does the information about this SPACE come from? Usually, it is put in manually using outside information. And this does not always make sense, if the SPACE itself is also dynamical, then one can certainly picture a bigger space in which this first space "moves", but neverthelss the question remains as by which processes this information is acquired, and where the information is held. Also at some point this scheme may created horribly large spaces that simple wont fit into the representation capabilities at hand.

So I think, a new way of thinking is needed, where we can not with certainty KNOW that the state will not leave the original space. Instead one can ponder what the mechanism would be to have a dynamically assigned space, where the deformation of this space is driven by feedback about the state. If the state leaves the space, we reach an inconsistency, and this needs to be resolved, and deforming the space may be a solution.

So I think, what happens if the state, "doesn't fit space", is that the space itself needs to change, but what remains is to understand how this works. I picture it so that the picture itself, subject to an inconsistency such that finding a state escaping the microstructure of space, exerts a pressure of change on the microstructure. So that it either expands, or breaks. If this doesn't happen and the inconsistency persists, I think the microstructure will slowly loose it's "mass" and go away. Adapt or die.

So I think the question asked does make sense in an evolutionary picture of evolving space, because at some point the containers of states must also form. But during what might be called close equilibrium I think such things are rare.

So when something "seems to move outside space", then what happens is that space itself is encourage should expand at that point, it's how I see it.

The usual statistical picture, we have a state, and all possible states make up a state space. But how to you know in advance, that all possible states are? Certainly you don't unless you put in external information. This is what we do in statistical models of stuff, but sometimes this external information doesn't exists, THEN what does the observer do?

/Fredrik

Well what does our universe exist in? For something to exist it would need space correct?

the universe will collapse in on itself with a raining fall of blackholes dominating the last few moments, you could not escape beyond our universe to step back and watch yet another big bang...because after all it is OUR universe which is collapsing to singularity.
Then we would cease to exist or escape into another universe.

Then we would cease to exist or escape into another universe.
Yes to my knowledge this would be the only two options i suppose, but escaping to another universe would require technology which i realistic believe we are over thousands of years of acquiring if at all possible. Good thing its not happening any time soon though.

#### Fra

Well what does our universe exist in? For something to exist it would need space correct?
I'd say the point is that the question you ask makes no sense outside an observer beeing able to formulate it. And that doesn't mean verbally formulate, I mean beeing able to relate to the the degrees of freedom of space.

The point is that there is never anything more than an image of the universe. Where does this image exists? The answer that fully satisfies me is that it's encoded in the observers microstructure and microstate.

Because without the latter, the question has nowhere to exists either ;)

/Fredrik

#### Naty1

Another good read, without math, is Brian Greene's book THE FABRIC OF THE COSMOS, Chapter 13, The Universe on a Brane, discusses branes (from string models) and a cyclic cosmological model....speculative, but fascinating ideas about space....

#### Chronos

Gold Member
The speed of light is the measure of distance. Without a finite speed of light, no measure of distance is meaningful. This was largely Einstein's point, IMO.

#### Fra

The speed of light is the measure of distance. Without a finite speed of light, no measure of distance is meaningful. This was largely Einstein's point, IMO.
Yes and I think Einsteins idea can be generalized. Because in a general configuration space, or "state space", what is "light"? The important thing about the speed of light, that makes it natural to generalize, is that it serves the purpose of an observer invariant maximal information propagation speed.

Also in line with ideas of several people, some information models naturally comes with a maximum upper bound of communication. So i think the basic conceptual foundations of realtivity will do pretty well even at the next level of understand. From my understanding of this, the reason for the emergent maximum propagation speed is that when you account for the observers role in the observation, and define the arrow of time as the most probable direction of propagation, then the intrinsic time derivative of an intrinsically constructed measure of expected "change" is bounded.

Maybe when we have a new _intrinsic_ information theory which is more realistic than the simplistic one current theory is based upon, both the quantum logic and GR might pop out? :)

/Fredrik

Another good read, without math, is Brian Greene's book THE FABRIC OF THE COSMOS, Chapter 13, The Universe on a Brane, discusses branes (from string models) and a cyclic cosmological model....speculative, but fascinating ideas about space....
I have read the fabric of the cosmos and his other book the elegant universe, its all great theoretical string theory, but it leaves enough to the imagination that you can construct your own interpretation from where he stops.

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