Looking for Extra Dimensions at the LHC

By Sean Carroll | September 7, 2012 11:13 am

Phd Comics, channeling physicists Daniel Whiteson and Jonathan Feng, explains how the LHC isn’t anywhere near done yet. Now that the Higgs(like) boson has been found, we’ll be looking for all sorts of other things, such as extra dimensions of space.

  • http://www.flisser.com Bob F.

    Finding higher dimensions is really what I was hoping the LHC would look for.

    The narrators of this video said that a particle moving through higher dimensions would be seen as multiple particles of varying mass, which is exactly what the Sphere was, moving through the plane in Abbott’s Flatland.

    But wouldn’t another manifestation be a particle that starts moving, disappears, then reappears elsewhere — or not at all? If space is structured like a Calabi-Yau manifold (one of the thousands of possible ones), I would think that particles would be able to zip through them, kind of like a miniature roller coaster. Maybe listen for the particle yelling “wheeee!” as it zips around…..

  • Chris

    When I heard about gravity leaking away, it must go somewhere. Probably just watching Fringe too much, but could what we interpret as dark matter really be gravity from some parallel universe leaking through?

  • Brett

    I realize this is about what else the LHC can find; but I can’t resist : I think perspective is highly overlooked. I don’t think it’s “why is gravity so weak?”, but “why is magnetism so strong?”

    That reminds me of this http://arxiv.org/pdf/1206.5078v2.pdf which is a theory of dark matter and dark energy that modifies some Einstein field equations…I know what your thinking, and let me just say, it’s pretty valid.

  • Jennifer West

    Lovely informative video.

    The extra dimensions idea seems to push the question into a different arena. So instead of asking why is gravity so weak, we ask why aren’t the other forces propagating into the other dimensions. Why only gravity squeezes through the portal.

    Or maybe that question is answered but in a non-comic book format?

  • Marshall Eubanks
  • Nolan

    To play devil’s advocate as a lay person, how would we ever establish that an electron and heavier versions of that same electron that were “stacked” were actually manifestations of the same particle? In other words, why would we ever be justified in using that explanation for that observation as opposed to proposing that a new previously unknown particle exists?

    Also, my understanding is that most physicists believe that even if they exist, gravitons could probably never feasibly be detected. But wouldn’t the energies needed to probe extra dimensions or create micro black holes be even higher?

  • martenvandijk

    I am afraid that the LHC’s physicists labor on tunnel-vision.

    Therefore I give them and you my definition of spatial dimensions: dimensions that shape the world endogenously, being generic and not independent, their properties being fully interrelated, continuously changing each other’s proportions.

  • Joel Rice

    any discussion of dimensions gets tangled up in the structure of algebra. The question is what makes algebraic sense, not that it isn’t tricky … like, is it n-body or n-dimensional.

  • no one important

    Oh hello, comic popularizations of somewhat-fringe and unaccepted ideas. String theory proponents have too much time.

  • Gavin Flower

    Are there any ideas that solve the conflict between relativity and quantum mechanics that are more ‘acceptable’, and less ‘on the fringe’, than String theory (or more accurately M-Theory)?

    I have heard no String theory proponent claim that their theory is the last word in Truth. To the contrary: from what I have read, String theorists are well aware of the problems in String theory.

    I am sure most Physicists would very much like a more tractable theory to explain Reality than String theory, though to date no other theory has been found as good as String theory to explain Reality – despite its many problems.

    Simply not liking a theory does not make it completely, or even mostly, wrong, no matter how strongly you feel!

    People attacking String theory so vehemently, seem to have a similar mentality to that of: Creationists, and Deniers of Global Warming.

  • Arko Bose

    I would like to know which part of reality (by reality, I mean what we know about the universe) String Theory explains, that is not already explained by GTR and the Standard Model.

  • Brett

    String theory predicts things that we have not seen in (know about) the universe.

    There’s a lot we don’t know about the universe. The intent of string theory is to go one step further in our understanding of existing knowledge. It is supposed to answer questions like: why is the standard model the standard model? Like the video above; why is gravity so weak compared to the other forces? String theory is intended to further explain the mechanics of fields in nature. Or so that’s my novice level understanding of it.

  • Matt

    String theory is suppose to combine quantum mechanics with einsteins theories, because the two use two separate sets of rules that dont make sense when compared. “the theory of everything”

  • Jeff

    Theorists love to tell us what we might see at the LHC. Let’s hope all the theorists are wrong, and the LHC reveals surprises that are completely unanticipated. I like to think that Nature is vastly more creative than even the most clever theorist. Otherwise, I guess I’d be a little disappointed in Nature.

  • Shantanu

    Btw I do hope the article points out that so far no evidence for extra dimensions has been found from ongoing LHC searches.
    See for example
    given all this, IMO its highly unlikely that LHC will find evidence for extra dimensions.

  • Elizabeth Davies

    This is a good one. I like things that make me think about stuff. Am I way off in suggesting that the environment inside of the LHC seems like a different dimension? Does gravity behave the same inside as outside?


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About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] cosmicvariance.com .


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