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Evidence of 6 Dimensions or More? 277

Posted by ScuttleMonkey
from the so-thats-where-all-the-socks-go dept.
shelflife writes "Nature.com is reporting that there may be evidence of 6 dimensions. Galaxies seem to behave as there were more matter in them than is actually visible. 'One explanation, they say, is that three extra dimensions, in addition to the three spatial ones to which we are accustomed, are altering the effects of gravity over very short distances of about a nanometre.'" Update by J : Like most of string theory, this is acknowledged by its authors to be "extremely speculative."
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Evidence of 6 Dimensions or More?

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  • by bl968 (190792) on Sunday September 04, 2005 @04:35AM (#13475390) Journal
    That in at least one of the six that hopefully the geeks get the girls :P
    • by superdan2k (135614) on Sunday September 04, 2005 @08:39AM (#13476176) Homepage Journal
      So a dimenson where geeks bathe regularly and can make eye contact with a woman when talking to her, then?
  • ObTime Cube (Score:5, Funny)

    by zerblat (785) <jonas.skubic@se> on Sunday September 04, 2005 @04:39AM (#13475400) Homepage
    I am flabbergasted that the "big brother" hired pedants can brainwash and indoctrinate the powerful antipode human mind to ignore the simple math of 4 simultaneous 24 hour days within a single rotation of Earth, to worship one and trash three. Magnificient evil job by teachers.

    This is clearly false and evil. The Time Cube has exactly 4 dimensions.

    An open mind is a slop bucket, "THINK CUBIC [timecube.com]".

  • by Hannah E. Davis (870669) on Sunday September 04, 2005 @04:40AM (#13475402) Journal
    There may well be many more dimensions than those we're used to dealing with, but basically saying that if we can't see it, it must be in a different dimension makes part of me wonder if the scientists are trying to take the easy way out.

    But then again, if they do manage to actually find solid evidence (not just its apparent invisibility in our traditional 3 or 4 dimensions) of matter in an unexpected dimension, I will be extremely impressed. It's an interesting theory at any rate, and worth looking into.

    • by Anonymous Coward on Sunday September 04, 2005 @04:49AM (#13475432)
      It's simple: They plug what they observe into a mathematical model and see if they can come up with a model that matches observation. It's not simple blind guesswork.

      Someone came up with a model called string theory that includes systems with multiple "hidden" dimensions.

      The dark matter they're talking about in the article is behaving in a way predicted by one of the current string theory models, which doesn't fit the more traditional models, thus the assertion that it must be 6 dimensions at work.

       
      • by bm_luethke (253362) <luethkebNO@SPAMcomcast.net> on Sunday September 04, 2005 @06:02AM (#13475604)
        I agree, that's how it is done. Lots of times that produces pretty good results, sometimes less than stellar.

        One of the things they had us do in college, and it is interesting IMO, is to take a sport you know nothing about and observe it. Try to formulate the rules of game based on observation (that is, create the model). Then look the actual rules up and compare them.

        It's not a perfect experiment - there are things common amongst nearly all games that we simply just know, but it was interesting how correct you would normally get some things and how wrong others (this is even more true because we *do* have correct preconcieved notions, it gets worse when going blind into something). It's also interesting how you can be correct and wrong at the same time - accuratly predict the outcome but for totally incorrect reasons. And, in some sense, it raises the question of if it really matters if the path to get to the correct point is wrong. If you are correct 100% of the time that it is "pass interference" (in American Football) does it matter that you definition of "pass interference" is wrong?

        In really really complicated scenarios I always wonder which side is thier model on (though, of course, it's a sliding scale not just an absolute two sides). Especially given the magnitude that some of the models will evnetually have in our lifes.

        Of course, this is what makes these fields so interesting to me, the combination of "right or wrong" with the amount of "feel" and "intuition" in the system.
    • One possible way to detect those additional dimensions are artifical black holes created in particle accelerators. These black holes cannot be created unless the gravitation becomes stronger on small scales than predicted by the classical 4-dim theory, due to the additional dimensions. Only if this increase is present the required mass density for the formation of artifical black holes can be reached (by LHC for example). So if they can ideed produce these little black holes that's a pretty good indication
      • Wouldn't that be very dangerous? Wouldn't the artifical block suck in matter and become bigger and bigger, ultimately sucking in our solar system?
        • No, because these black holes are highly unstable. They last for a few fractions of a second before disolving into nothingness.
  • by ReformedExCon (897248) <reformed.excon@gmail.com> on Sunday September 04, 2005 @04:40AM (#13475405)
    The way I understood this phenomenon, as it was explained in Kaku's book, was that the extra dimensions were curled up on themselves so that they were smaller than could be detected.

    The thought experiment was similar to the following. Imagine a sheet of paper with a line crossing from one edge to the opposite edge. You can see that the line exists when viewing the sheet in two dimensions. However, imagine if you rolled the sheet of paper up tightly with the line not directly aligned with the roll. Now you would have instead of a line a single dot or a series of evenly-spaced dots. The line hasn't gone anywhere, it has simply been rolled onto itself so that it seems to have become small and barely detectable.

    Now extend that idea to multiple spatial dimensions beyond just two or three. Since we humans can only perceive three spatial dimensions, it is hard to imagine what multiple extra dimensions would be like. However, if we can take the extra dimensions and "roll" them into themselves, we can make a little more sense of the concept.
    • The string theorists have certainly been rolling somthing...
    • You physics gods, humor me for a minute (please.)

      Some of the more recent discoveries, like quantum action at a distance stuff makes sense from the Occams Razor point of view. On one hand, we have these bizzare behaviors that involve unseen forces, etc... On the other, our 4 dimensional universe is really a function of a multi-dimensional one, with the interactions in the other dimensions embodied as complex behavior here in our 4 dimensional world.

      The latter makes more sense than the former does to me, be
  • Great! (Score:3, Funny)

    by Frodo Crockett (861942) on Sunday September 04, 2005 @04:43AM (#13475413)
    Now I'll be getting email about increasing the size of my penis' fourth, fifth, and sixth dimensions!
  • dotted... (Score:5, Funny)

    by mmThe1 (213136) on Sunday September 04, 2005 @04:51AM (#13475435) Homepage
    Alert: The fourth, fifth, and sixth dimensions were slashdotted today due to uncontrollable inflow of nerds, geeks, and other creatures.

    To keep the traffic flow normal, mirrors have been provided on the seventh, eighth, and ninth dimensions for the earthlings...

  • by Tomah4wk (553503) <tb100&doc,ic,ac,uk> on Sunday September 04, 2005 @04:51AM (#13475441) Homepage
    An old professor of mine who was a string theory expert (i very much am not) once told me most of the maths he does deals with 11 dimensions.
    • This was my first thought but if you read the article it mentions this at the end:

      The most popular versions of string theory suggest that there are as many as eight extra dimensions, not just three. But thankfully this needn't be a problem. There's no reason why, in addition to the three large extra dimensions predicted by Silk and colleagues, there might not be several other small ones too.
      • This was my first thought but if you read the article it mentions this at the end:

        The most popular versions of string theory suggest that there are as many as eight extra dimensions, not just three.


        Yes, exactly. Three space dimensions we know exist plus eight extra (including time) equals eleven total dimensions. So apparently, there's no inconsistency between this research and current string theory.
    • by william_w_bush (817571) on Sunday September 04, 2005 @05:22AM (#13475516)
      superstring theory and yang-mills theory deal with 11-D subspaces and their intersection with 2D string worldsheets (think a 1 dimensional string flying through the air, but extended along the temporal dimension, forming a 2 dimensional sheet).

      This has been worked on for a while, and the equations are getting there. If you think about it though, a fifth dimension can be easily produced from the equations of general relativity, and maxwells equations of electro-mag produce yet another micro-dimension to govern the electromagnetic force.

      So this isn't that surprising, the problem is the math for 11 dimensions doesn't work well yet, because it's freaking hard to do energy waveform equations in 11 dimensions, when you don't even know how those 11 dimensions are laid out.

      The next breakthrough in physics will be a model for at least some of the underlying dimensional geometry, leading to a final m-theory, likely the long sought theory of everything.

      I just like the fact that the standard model is showing it's flaws, trying to write theory to fit your experiments is never as good as trying to understand the underlying causes and drawing conclusions from the emergent properties of the basic model.
      • I just like the fact that the standard model is showing it's flaws, trying to write theory to fit your experiments is never as good as trying to understand the underlying causes and drawing conclusions from the emergent properties of the basic model.

        You mean like they do in Chemistry?
  • by geoff lane (93738) on Sunday September 04, 2005 @04:55AM (#13475452)
    Some lawyer sues someone citing some imagined harm caused by the additional dimensions.
  • Round and Round (Score:5, Informative)

    by Quirk (36086) on Sunday September 04, 2005 @05:01AM (#13475471) Homepage Journal
    Resources

    Greene's Elegant Universe [pbs.org]

    The Mechanical Universe [learner.org]

    Last book I enjoyed, Three Roads to Quantum Gravity [amazon.com] by L. Smolin... ya, ya, I know, nothing fits, is, isn't, yo momma... no yo momma... can, can't... I'm not touching you!

  • by Macphisto (62181) on Sunday September 04, 2005 @05:05AM (#13475480) Journal
    There are like twelve dimensions here. Don't feel jealous though, they are really boring. There is not even any ketchup, and not in the extra dimensions. When I went to the car, then the gravity was different, so I thought so. There is another dimension, but it is oriented left on top, so arranged laterally. With the extra dimensions, lucidity is beneficial but orthogonal to our clear destination. I anticipate an increase in coherency, thought may suffer but I think a good drive will clear my mind. There is health but in the yellow, it is vaporous, and at such speed some clouds are quite hard. Be oviparous, but not before it hatches!
  • string theory? (Score:5, Interesting)

    by krunk4ever (856261) on Sunday September 04, 2005 @05:25AM (#13475526) Homepage
    is this in anyway related to the string theory [wikipedia.org]?

    The only problem is that when the calculation is done, the universe's dimensionality is not four as one may expect (three axes of space and one of time), but twenty-six. More precisely, bosonic string theories are 26-dimensional, while superstring and M-theories turn out to involve 10 or 11 dimensions.
  • somewhere to start (Score:2, Informative)

    by martian67 (892569)
    If you need somewhere to start, and don't know any physics, try one of the free introductory physics books listed here [theassayer.org]. After that, if you want to try to bring yourself up to the level a book like the "road to reality" by Penrose is shooting for, try some of these:
    • Relativity Simply Explained by Martin Gardner
    • Black Holes and Time Warps: Einstein's Outrageous Legacy by Kip Thorne
    • Spacetime Physics by Taylor and Wheeler (special relativity, with a little more math)
    • Exploring Black Holes: Intro
    • I watched this DVD [shoppbs.org] and it gave me a really good introduction to Relativity, String Theory and Quantum Mechanics. I'm no physicist, but I am able to understand the key ideas through the video.

      Or you may prefer to visit their homepage here [pbs.org].

  • by volsung (378) <stan@mtrr.org> on Sunday September 04, 2005 @05:33AM (#13475545)
    The actual paper this article is about is here:
    Observational Evidence for Extra Dimensions from Dark Matter [arxiv.org]

    (It's actually a draft of a paper submitted to Physical Review Letters, not yet approved.)

    It's a nice phenomenology paper without any heavy math that puts together a bunch of theoretical ideas floating around. Even better, it has testable hypotheses! (unlike many papers these days)

    1. Gravity should deviate from the inverse-square law at the nanometer scale.
    2. Dark matter should be composed of a particle with mass 3e-16 GeV/c^2. (For comparison, mass of electron is 5e-4 GeV/c^2.)
    3. The large extra dimensions assumptions all this is based on would require us to see all sorts of quantum gravity interactions at the LHC.
    Now short-range gravity experiments are just approaching the micron scale, so we're 3 orders of magnitude away from testing hypothesis #1. I doubt anyone has an idea how to close that gap right now.

    Checking hypothesis #2 would require some independent way of determining the mass of dark matter particles. I don't know what the sensitivity range of the various dark matter experiments running or planned are. Maybe they would be able to see something this light.

    #3 however is going to start running in 2 years, and then we'll get some good information either way.

    • More indirect data on galaxy clustering and galaxy dynamics (especially of small galaxies) to help constrain the properties of dark matter (in particular the interaction of dark matter with other dark matter) would also be useful, as is noted in the paper.

      This probably requires a number of astronomical surveys (mainly Sunyaev-Zeldovich effect surveys for galaxy clusters at microwave/mm-wave frequencies, and optical and radio surveys for galaxy dynamics) to give large datasets from which the statistical prop
      • Found some talks on CRESST II, and it doesn't seem like they will be sensitive to dark matter in the mass range predicted by this paper.

        Looks like the astrophysical observations will have to save the day. :)

  • by mikiN (75494) on Sunday September 04, 2005 @05:38AM (#13475556)
    Occam: I seem to have misplaced my razor...
  • by mrjb (547783)
    "This has never been tested experimentally: no one has measured how gravity behaves over distances below about a hundredth of a millimetre."

    On atomic scale, 1/100 mm is still pretty huge and I understand science itself has progressed enough to have the means to make such measurements. So before speculating any further, it seems it would make sense to start doing that first then, wouldn't it?
  • by mattkime (8466) on Sunday September 04, 2005 @05:54AM (#13475580)
    ...and if you call before the dupe is posted, we'll include an extra 2 dimentions at NO ADDITIONAL COST!*

    (*old people in korea need not apply)
  • by Beautyon (214567) on Sunday September 04, 2005 @05:55AM (#13475583) Homepage
    It's all explained vividly here [indiadaily.com].

    And I quoth:
    "The Physical Universe is connected with the underlying Hyperspace by some sparsely distributed particle size small windows called Fermions. These Fermions literally connect our universe with the 5-D Hyperspace."
    • Actually fermions [wikipedia.org] are "normal" particles, what we usyally calling "matter" - electrons, protons, neutrons, quarks. There two kind of particles - fermions(which represent matter) and bosons [wikipedia.org] which represent interactions or fields - photons, glueons, gravitons. In the string theory they both represented by strings - open (fermions) and loops (bosons)
  • by Anonymous Coward
    I think one of the problems here is how you actually define a dimension. Most people when they think about dimensions think about three spatial dimensions. Some people will then go on to say that time is a fourth type of dimension, yet time is very different to spatial dimensions. Likewise these new so called extra "dimensions" are only so because of the label we give them, they are obviously different again to spatial or time dimensions as most people understand them. So before the mind starts to boggle (l
  • by TheNarrator (200498) on Sunday September 04, 2005 @06:02AM (#13475603)
    Occam's Razor [wikipedia.org], which is a basic tenent of modern scientific thought says that the simplest explanation is the best. It seems that these dark matter explanations get more and more complex. When a theory is very complex it becomes suspect. For instance, when the Earth was though to be the center of the universe, Mars moving backwards in the sky caused much grief to astronomers. They invented all kinds of head spinning mathematics to describe the motion of mars and the other planets. Of course when the Sun was put in the center of the solar system and the laws of gravity were unearthed everything turned out to be far simpler than the theorists, working with broken premises had made it out to be. In the same way, something smells funny with String theory, and multi-dimensional explanations for dark matter, etc. Isn't science about experimentation and testing hypothesises in a laboratory instead of endless mathematical tricks to get theories to fit observations?
    • Well, adding new dimensions is very simple mathematically.

      To compare it with the situation of 3 vs 2 dimensions, most people couldn't plot a path from the surface of the Earth to the moon in 3+1(time) dimensions, so it's not like things suddenly get completely easy just because fewer dimensions are involved.
    • No, its not getting more complex. In fact, having more dimensions explaines the stuff _nicely_, that means without too many additional assumptions. No need for an arbitrary particle which, by chance, excatly behaves like dark matter on large distances, but is not observable otherwise. The problem only is, that the simple ideas of the string theory (which is usually the physical theory behind the multiple dimensional universe explainations) is mathematically difficult, and complex, and hence, all articles
    • by PsiPsiStar (95676) on Sunday September 04, 2005 @07:00AM (#13475772)
      I'm starting to think that Occam's razor is abused more often than it is used correctly.

      Parent asserted;
      Occam's Razor, which is a basic tenent of modern scientific thought says that the simplest explanation is the best.

      This is an abuse of the version of Occham's Razor used in modern scientific thought, though an oft repeated misinterpretation.

      A better way of phrasing the desire for elegance in modern science is; "Given two identically predictive models, choose the one which requires the fewest assumptions." Reducing the number of assumptions is not always the same as 'simplifying' the problem.

      Also, remember that the purpose of science is to generate predictive value. If one of those models is more complex but also more predictive, then it is ALWAYS the better model, no matter how complex.

      The original version of Occam's Razor, as correctly expressed in the Wiki article, is "Entities should not be multiplied beyond necessity" where 'necessity' equates to generating the maximum level of predictive value.

      Check out the following link, which gives a better summation of the role of Occham's razor in science than the wiki article does.

      http://www.physics.adelaide.edu.au/~dkoks/Faq/Gene ral/occam.html [adelaide.edu.au]
    • Isn't science about experimentation and testing hypothesises in a laboratory instead of endless mathematical tricks to get theories to fit observations?

      Science is about explaining the observations by whatever means necessary. Occam's Razor means yes, we assume space doesn't have 6 dimensions as long as that has equal explanatory power to assuming it does. When we come across something that can't be explained by "normal" theories, at least without making them more complex than assuming 6 dimensions, we assu

    • No, Occam's Razor is still in effect. However the task of taking so much complex information and compressing it into a simple statement is very difficult. Also it takes someone of immense insight [wikipedia.org] and genius [wikipedia.org] to figure out.
    • by Aceticon (140883) on Sunday September 04, 2005 @07:47AM (#13475954)
      Quoting from the wikipedia link you provided:
      - "When multiple explanations are available for a phenomenon, the simplest version is preferred"

      Occam's Razor is a tool to, when faced with multiple explanations for the same situation, help one choose the best one.
      It is not some sort of philosophical statement on how there should be a simple explanation for everything.

      Although i too feel unconfortable with the increasing complexity of scientificy theories (and judging from the current moderation on your post i suspect many others also yearn for simplicity), i cannot stand by and see you missuse Occam's Razor (one of the first things i learned in philosophy).

      PS: At the risk of spoiling this post, i have to state a theory of mine: I suspect one of the things that turns some scientific minds to the belief on a "higher power" (aka almighty) is a yearning for simplicity and/or an inability/unwillingness to accept complex explanations to the mind-bogling complexity of the world.
    • Occam's Razor is often misunderstood as offering a way to choose which of two theories is better. But in fact, there is no evidence whatsoever that simple theories are more likely to be correct--if anything, the trend of history seems to be that simple theories eventually get rejected in favor of more complex ones.

      A better way of thinking of Occam's Razor is as a rule of thumb for ordering the universe of possible hypotheses for investigation. Simple theories have fewer free variables, which generally makes
    • Occam's Razor may state the simplest explanation is the best, but a simple explanation that does not explain known phenomena or predicts new phenomenon is of little use. For example, the theory that a superior being designed everything may meet the requirements of a simple theory, but does not provide specific predictions, not does it explain why certain things, like the human trouble feedback system, which seems to provide unnecessarily intense pain, seem to be designed so badly.

      Science is full of theor

    • Isn't science about experimentation and testing hypothesises in a laboratory instead of endless mathematical tricks to get theories to fit observations?

      Well, you have to have a hypothesis before you can test it; and if nothing simpler comes to your mind, you can try all kinds of mathematical tricks to form a hypothesis that will actually fit the observations.

      But you're right, in this case the tricks feel like the spinning and circling crystal balls in the skies on which the planets were located.

    • In the same way, something smells funny with String theory

      The string theory may be not in the great shape just now, but there is no better alternative(well, there is the loop quantum gravity, but it's not much better) The biggest problem of the modern theoretical physics is that it is proven that general relativity and modern quantum mechanics contradict each other. They can not both be exactly right in the same universe. Both theory verified experimentally. So if theoretical physics want to remain s

    • who used the so-called razor to help prove his theological arguments.

      It's a rule of thumb to help order one's already biased thinking. Nothing more.


      -FL

  • by martiojd (820719) on Sunday September 04, 2005 @06:03AM (#13475609)
    ... not new! String theory has been around for decades (Kaluza-Klein theory dates back to about 1920). For all my time in grad school, about four years ago, the fashionable space-time had dimension 10, 4 for "usual" space time plus 6 for a tiny little compact Calabi-Yau threefold (this is a complex manifold of dimension three, hence six real dimensions). Of course I was sitting around with algebraic geometers too much, and it might have just been a way to get the NSF to fund their projects by creating some applications for their abstract nonsense (time will tell...) One of my favorite memories from that time is a series of lectures given by a colleague on the basics of string theory. She gave a heuristic derivation of the dimension of space time (that time the dimension was 11, I apologize if it sounds inconsistent). She wrote down the series of all integers (the sum of n, for n from -infinity to +infinity, n being an integer) and said it was equal to -1/23; she took a short pause, thinking... then apologized, she forgot to mention: one should take the sum over n being a NONZERO integer! From that day on I quit going to that seminar (shouldn't that sum be -1/... 42 anyway?)
  • Is there evidence, or not? Is this a concrete advance in our understanding of nature, or is it just another article in Nature?
  • I'm probably not bright enough to really comprehend this subject but does this theory fit in with Occam's razor premise that the simplest answer is usually correct?

    It seems that sometimes fanciful theories pop up that seem to just shoot wildly in the dark for lack of observable/obtainable info.

    At least it's not a human-centric nonfalsiable unlimited paralell universes or time travel can't alter history theory........
    • Re:Not an expert (Score:3, Insightful)

      by SEE (7681)
      The alternative to complicating the universe with dark mattter, dark energy, and multiple dimensions is replacing General Relativity with a more complicated theory. Which we know needs to be done on the quantum scale at least, but which hasn't been successfully done yet.

      So, right now, we have GR. Which needs undiscovered "dark" matter to explain why galaxies are rotating faster than expected. And extra dimensions to solve the problem of different-sized galaxies. And "dark" energy to explain why these ga
  • ....another explanation is that you just can't see it BECAUSE IT'S VERY DARK. :P
    • That's wha the NASA is currently preparing to deploy the Very Lage Flashlight (VLF), which will give us insight even into quite dark matter.
      Unfortunately, they still have problems figuring out how to exchange the twenty million AA batteries powering it once it's in space.
  • explaination (Score:2, Informative)

    by Shinaku (757671)
    I watched a stream yesterday which explained how dimensions can be interweaved into our own, and how the laws of gravity and Quantum physics can be combined with string theory,

    http://www.pbs.org/wgbh/nova/elegant/ [pbs.org]
  • a dimension is an abstract mathematical idea. the dimensions of a system are the quantities required to describe its state. to quantify the space we see we need only 3. however, space is dynamic with time, and so now we have 4. to speculate more dimensions simply implies there is more that meets the eye. and to that I say: well, duh.

  • Some of these are actually measureable:

    - time
    - X axis
    - Y axis
    - Z axis
    - female perception of reality (this is the "Q" axis that will never be understood due to constantly changing parameters)

    And, yes, I've had sex with females before, they are quite squishy and nice.
  • In two dimensions, gravity only has to cover a circle arc. As you go further away from the source of gravity, the line grows longer proportional to the distance, and gravity has to cover more length. It's an inverse law. In three dimensions, gravity has to cover a circle. As you go further away from the source of gravity, the circle grows bigger proportional to the square of the distance, and gravity has to cover more area. It's an inverse square law.

    The pattern continues as the number of dimensions incr

  • I would like to ask a physicist in the room two questions.

    1) It sounds like the diamond-nanotube composite material mentioned in a separate slashdot article today would include nanoscale diamond chunks, nice hard, heavy things, nanoiron seeds, and conductive nanotubes. Would this not be an interesting candidate for use in the testing of this theory of how gravity works at the nanometer scale?

    2) I don't really understand the idea of a dimension only a nanometer wide, or the idea of dimensions being rolled u
  • At last, scientists have a chance to understand what is magic and mysticism about...

Things are not as simple as they seems at first. - Edward Thorp

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