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Can space be perceived in more then one way?

  1. Dec 10, 2005 #1
    Its hard to explain,but it is posible to see the same space not just as it is but also the oposite of it?The image in the mirror?
     
  2. jcsd
  3. Dec 10, 2005 #2
    Perhaps you could state your question more clearly, and then someone here might be able to provide a better answer. It turns out that mirror image processes are important in physics, but I am not sure that is what you mean. We talk about duality, chirality, and parity, all of which have mirror image qualities about them.

    Of course it is possible to see many things, but that does not mean that all of them are useful. I am curious to know what you have seen that makes you want to come here to ask your question.

    I hope this helps.

    Richard
     
  4. Dec 10, 2005 #3
    Nice question. I would expect the conventional answer is that space - being homogenous and isotropic - would be self-dual. The reflection would be the same.

    This would be a reflection of space at the same scale - across the axis of symmetry.

    But there may be also the axis of asymmetry - the axis of fractal self-similarity - which runs from largeness to smallness.

    Over a large range of scales, space would still seem unchanged under reflection. But when you stretch out so you can see the whole universe and Planckian fine grain, then opposites may begin to look different.

    The opposite of global is local. A model of this is the Basic Triadic Process in hierarchy theory.
     
  5. Dec 10, 2005 #4
    Excellent answer, mccrone! I wish I had said that. In fact I have learned something from your answer, I hope. I am not sure what Basic Triadic Process in Heirarchy Theory is, but I am now eager to find out.

    Thanks!

    Richard
     
  6. Dec 11, 2005 #5
    Mccrone, I have done some searching for the Basic Triadic Process in Heirarchy Theory terms and come up empty. Perhaps you could give some direction?

    Thanks

    R
     
  7. Dec 11, 2005 #6
    google on Stan Salthe but I think his stuff on the web mostly concerns his "specification" hierarchy rather than his "scalar" hierarchy. It is in his 1985 book evolving hierarchical systems.

    I would explain but the posts would get censorsed as "not physics".
     
  8. Dec 12, 2005 #7
    I am not familiar with this work. A quick google search seems to suggest that it is in the Biology sector. I majored in Biology at University. Nowadays Biology, always the poor sister of the sciences, is subsumed under chemistry, which is subsumed under physics. So I guess it still has a place here somewhere.

    In any case, if Salthe's ideas can be generalized all the way to Strings, Branes, and LQG, then why would anyone censor them? Perhaps you can make some progress by showing how this obscure corner of biology connects to our obscure corner of physics?

    Thanks,

    Richard
     
  9. Dec 12, 2005 #8
    I want to return to this post because it sparked a few thoughts that might lead somewhere interesting if I am lucky.

    I like starting from the standpoint of space being homogenous and isotropic. My understanding of this is that space is pretty much the same everywhere, no matter how you look at it, except that there are everywhere some small gradual local changes which, at certain scales, might be mistaken for asymmetry. These small gradual local changes would be as small ripples on what is otherwise a large unbroken expanse of calm water, except of course space is not limited to two dimensions, as a surface of water is.

    One might imagine a small water bug noticing that the surface is here bent downward, as at the crest of a small ripple, and then a moment later is here bent upward, as at the trough. These local variations would be a broken symmetry at a scale chosen to accentuate them, as for example a very small mirror placed normal through the slope of a ripple would seem to show a sharp V shape as the wave is inverted in the mirror. The point of the V would be non-differentiable, so the mirror image would seem to show a region which is not isotropic, but instead has a sudden break or change in apparent direction under the mirror image.

    Now there is the idea that there may be a large asymmetry having to do with fractal dimensions when the axis of symmetry is taken along the line of scale. This seems to me to relate to what Loll is saying about the existance of fractal dimensions at small length scales. I have wondered in another post about how these small scale fractal dimensions differ from the large scale ones we observe when measuring objects like the coastline of England, for example. I would have to search for the reference but IIRC Loll said specifically that space becomes fractal at small length scales, which seemed to me to imply some kind of special condition or change from the quality of fractal dimension we view from the ordinary human perspective. I have seen no confirmation or contradiction of this idea from other posters, so I continue to be curious about it.

    Anyway since we seem generally interested in the idea that space itself has structure at small scales, and since symmetry breaking is seen in the standard model of cosmology to be the source of forces and particles as we observe them, it seems worth discussion and clarification if possible. Are we justified in treating scale as an axis of symmetry? If we do so, what evidence do we have that symmetry is broken along that axis? In other words, how exactly is space different at small scales than at large ones? How is it different in the compact six dimensional Calabi-Yau manifolds of string theory?

    Also, what happens, I wonder, if we accept the idea of scale as a dimension, if we try other dualities with the same logic? What happens if we try the symmetry of velocity, for example?

    Thanks,

    Richard
     
    Last edited: Dec 12, 2005
  10. Dec 12, 2005 #9
    Our minds have an issue with 'nothing' ( No Thing ). They (our minds) cannot grok (grasp) non-things and attempt to assign adjectives in order to paint a picture that the mind can understand.

    If 'space' has an opposite it is, in my thinking, a black hole which is the absence of space.

    I am, however, convinced that 'space' is actually a non-physical element; and that objects do not occupy space but, rather, displace space. It is the displacement of space that produces gravity. (like a bowling ball in a tub of water). I call my theory The Displacement Theory of Gravity.

    I suppose that I could conclude that 'matter' (generally) is the opposite of space.
     
  11. Dec 13, 2005 #10
    Hi Richard

    You raise a number of points that we will be forbidden to discuss as they will be deemed "not physics".

    So I only offer quick replies.

    Salthe is a theoretical biologist, but has developed a mathematically general framework that can apply to any kind of system.

    There are many people who say similar things in system theory, but a key feature in Salthe's model is that the small is in some sense hyperbolic or open - a foam of possibilities. While the large is in some sense closed or frozen - it is the context that seems unchanging to the events that take place within it.

    So you have two boundaries or limits which have a different apparent nature. One - like the "smallness" of QM - is a creative forment. The other - like the "largeness" of relativity - closes over to form a stable spacetime continuum.

    Thus if hierarchy theory is a good model of physical systems, such as a universe, it suggests a rather different take on "quantum gravity". I dare not say more than that you no longer expect the large to be reduced to the small. Instead the unity of the two - the quantum and the relativistic views - is expressed in the cogent balance they form across the "middle ground" of the system.

    And it is the middle ground that is thus self-similar in appearance across a wide range of scales. A large stretch of the void looks just the same as its reflection, a very small patch. Until you approach the limits where you begin to see that the upper bound is closed - an event horizon - and the lower bound is open - a quantum foam of possibility.

    This is why the duality is described as asymmetric. The upper and lower bounds of scale are opposite and also exactly unalike in nature.

    Loll's CDT approach is said to find fractals at sub-Planckian dimensionality. The systems approach I describe would instead expect to find a hyperbolic roil of possibility (or a "vagueness").

    But the two views may be equivalent if Loll is modelling a sum over histories for all spacetimes and then saying that there is less that crisply exists by way of dimensionality at sub-Planckian scales.

    In the systems approach, the middle realm of the universe is also "fractal". But in a scalefree fashion - you cannot see scale as a factor when viewing the void. It only makes itself apparent to an accelerating observer - one that attempts to grow or shrink at a rate that is not that of the cogent background, the vacuum "at rest".

    This is why I said there is an axis of symmetry - a fractal one. But you cannot see it if you just reflect the void in a way that maps a large patch onto a small patch.

    In more standard physics speak, the void is renormalisable. Or in process physics speak, it is perhaps at the edge of criticality. In Salthe hierarchy speak, the term is cogent - the large and small are at equilibrium and no scale is preferred as fundamental.

    On your final question about the dual of velocity, this is quite clearly location. Position and momentum are neatly dual in physical theory. Or we can call them local and global - the constraint that makes a something concrete, like a particle, and then the freedoms that this constraint produces, such as the various motions and actions that are the properties of the particle and which it expresses within a global context.

    Cheers - John McCrone.
     
    Last edited: Dec 13, 2005
  12. Dec 13, 2005 #11
    Ha ha! What did I tell you.

    Read Schrodinger's classic What Is Life if you want to see why this kind of narrow-mindedness is so amusing.
     
  13. Dec 19, 2005 #12
    Well I'm happy that my question has started up so many....interesting ideas.And yes Richard I saw more the I shoud,I peeked a bit into the Universes secrets
     
  14. Dec 19, 2005 #13

    Tom Mattson

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    That may be the case if we envision space devoid of any matter. But if we consider 'real' space, complete with physical objects and processes, I don't think that would be the case. Nature doesn't respect parity in general. The reflection would cause, say, weak interactions to proceed differently than in our world, no?
     
  15. Dec 27, 2005 #14
    Take your point but it is probably right to say that the vacuum would be the lowest possible state of the system, the natural end state. Give the universe enough time and all those pesky matter/gravity bumps will be flattened out - dissipated - to make a flat spacetime void.
     
  16. Dec 31, 2005 #15
    Here is how I do it. For me, space is not empty, there are an infinity of energy waves that we can show this way ( / ) using keys on computer, perhaps the length of Planck's constant--thus very small--at the limit of the laws of physics as we know them. Now, I want you to get a mirror, place it next to your computer screen, and take a look at space first as "it is"
    ...( / )( / )( /) ... but then in your mirror, the opposite of as "it is", and you will see that it will appear as ...( \ )( \ )( \)... Thus, for me, the answer to your question is yes, space ( / ), and the opposite of space ( \ ), form a union ( /\ ), and now, when you again look in the mirror you see that the opposite of the union looks like ( /\ ), which is the union. Thus, when you see space, you see the opposite of it at the very same time, e.g., they are entangled ( /\ ). The two (space & its opposite) form what in philosophy is called a neutral monism, in physics a superposition. This is how I "see" your question, but I may be wrong because your question is very abstract indeed.
     
  17. Dec 31, 2005 #16
    But Rade this is just holding a mirror to one scale - how you imagine the very small Planck scale to be. So of course you see a simple reflection symmetry.

    There is also the second possible axis of symmety, the asymmetric one that is local~global or fractal in nature.
     
  18. Dec 31, 2005 #17
    One can "imagine" at any scale I would assume. Could you please provide a picture or internet link that gives a visual of the second possible axis of symmetry ? Is it in any way related to the rotation along the imaginary axis of a complex number, such as (a + bi) , which can be rotated 180 degrees to its opposite ?
     
  19. Jan 1, 2006 #18
    We perceive objects. Can a collection of objects which define a particular space be perceived in more than one way? Sure. But this might not be what you're asking. It isn't clear what you're asking.
     
  20. Jan 1, 2006 #19
    A fractal has an axis of scale symmetry - "move about", ie: move up and down in scale, and the world remains the same.

    See for example coastlines and menger sponges
    http://library.thinkquest.org/26242/full/ap/ap4.html
    http://mathworld.wolfram.com/MengerSponge.html

    Even in a universe filled with junk like atoms and galaxies, there is still a reasonably fractal occupation of space.
    http://www.fractaluniverse.org/13.php
     
  21. Jan 27, 2006 #20
    2 ways of seeing space.

    1. Try the old "is the glass half empty or half full?" philosophy.

    2. What kind of energy is keeping space where it is? Is space energy itself?
     
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