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Thread: gravity as an emergent phenomenon

  1. #1 gravity as an emergent phenomenon 
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    I recommend people check out the recent nytimes article:

    http://www.nytimes.com/2010/07/13/sc...ml?ref=science

    Verlinde proposes that gravity is not a fundamental force like electricity/magnetism, but one that emerges from the laws of entropy.

    I think that this is a very interesting idea, and it's coming from a pretty major player in the theoretical physics community.


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  3. #2 Re: gravity as an emergent phenomenon 
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    Quote Originally Posted by salsaonline
    I recommend people check out the recent nytimes article:

    http://www.nytimes.com/2010/07/13/sc...ml?ref=science

    Verlinde proposes that gravity is not a fundamental force like electricity/magnetism, but one that emerges from the laws of entropy.

    I think that this is a very interesting idea, and it's coming from a pretty major player in the theoretical physics community.
    Have you read the paper? I have and the level of hand waving is pretty high.

    http://front.math.ucdavis.edu/1001.0785


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  4. #3  
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    Nope, gravity is fundamental.
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

    "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

    "Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence"

    -Einstein

    http://boinc.berkeley.edu/download.php

    Use your computing strength for science!
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  5. #4  
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    Dr Verlinde is a string theorist, the existence of these wonderful strings has never been proven, so I would take Verlinde theories with a pinch of salt...
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  6. #5  
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    Quote Originally Posted by Cold Fusion
    Nope, gravity is fundamental.

    Why do they write articles about uncertain ideas being thrown around, and not real science backed by real math? Politics...err...socialtics.
    While I some misgivings about the Verlinde paperl, your dogmatic statement may well be wrong.

    The paper is speculative, and while I am not in the camp of accepting it, to call Verlinde's work other than real science, at the research frontiers, is to demonstrate lack of understanding of what research in theoretical science is.

    In short, you don't know what you are talking about. Read the damn paper. The link is there.
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  7. #6  
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    I've started discussion about this paper 3 days ago to remind the reason-result logic ... but it was moved to 'new hypothesis...' ??

    http://www.thescienceforum.com/Can-t...ult-25418t.php
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  8. #7  
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    I gave the paper a glance but didn't go through it carefully. I don't think Verlinde is claiming that this is anything more than a sketch of an idea. Given his enormous credentials, I'm inclined to give him the benefit of the doubt that the idea is, at the very least, interesting.
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  9. #8  
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    Quote Originally Posted by salsaonline
    I gave the paper a glance but didn't go through it carefully. I don't think Verlinde is claiming that this is anything more than a sketch of an idea. Given his enormous credentials, I'm inclined to give him the benefit of the doubt that the idea is, at the very least, interesting.
    I would certainly concur that the idea is at least interesting.

    It has a long way to go to be any sort of real theory though. I am personally skeptical that it can be fleshed out and turned into a theory in which gravity is in fact emergent.

    There have been some criticisms of Verlinde'paper and Verlinde's defense, as I recall, seems to indicate that he thinks it is more than just a sketch.

    http://arxiv.org/PS_cache/arxiv/pdf/...001.0785v1.pdf

    http://motls.blogspot.com/2010/01/er...y-cant-be.html
    http://motls.blogspot.com/2010/01/er...-entropic.html

    http://badphysics.wordpress.com/2010...erik-verlinde/

    http://www.letstalkphysics.com/2010/...-cool-but.html

    I am in the very skeptical camp, but could be converted by a more rigorous argument that would result in a real demonstration of gravity as emergent. That would require a clear definition of what he calls the "holographic screen " and from which he claims to show that the notion of space is emergent. I find no such demonstration or even hint of a demonstration in the paper.
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  10. #9 Entropy - Gravity 
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    The information containrf in a particle crossing a black hole horizon is supposed to become encoded in a finite number of bits on the horizon. This assumes, then, that the information cannot be an irrational or transcendental number, like the ubiquitous pi or e. Sounds like if this is true and if there are attributes that are in these categories, information will be lost as the particle crosses. This would mean that black holes are indeed information sinks and decrease the entropy of the universe. Am I missing something here? :-(.
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  11. #10 Re: Entropy - Gravity 
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    Quote Originally Posted by CharlyAndy
    The information containrf in a particle crossing a black hole horizon is supposed to become encoded in a finite number of bits on the horizon. This assumes, then, that the information cannot be an irrational or transcendental number, like the ubiquitous pi or e. Sounds like if this is true and if there are attributes that are in these categories, information will be lost as the particle crosses. This would mean that black holes are indeed information sinks and decrease the entropy of the universe. Am I missing something here? :-(.
    Yes. The point, and the nature of information, among other things.
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  12. #11 Entropy - Gravity 
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    Enlighten me and perhaps others. Remember, this is a Physics discussion, not a forum for clever repartee.
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  13. #12 Re: Entropy - Gravity 
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    Quote Originally Posted by CharlyAndy
    Enlighten me and perhaps others. Remember, this is a Physics discussion, not a forum for clever repartee.
    Try using the link provided earlier to actually read the paper.

    Remember that this ia Physics discussion and not a baby-sitting service.
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  14. #13 Entropy - Gravity 
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    It's OK, Dr., if you don't know the answer to my question. (I'm surprised you took the time to respond at all.) It is at the core of Verlinde's work but it involves some careful and fundamental thinking. I found the answer in Bousso's lecture. It's nice to hear a clear lecture on the subject that is intended to inform. :?
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  15. #14 Entropy - Gravity 
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    Oh, by the way, (for those in this forum interested in Physics) the short answer to my question, according to the identification of a black hole's entropy with the area of its horizon, is that there is not an infinite amount of information in the universe. ALL the information corresponding to matter that has entered a black hole CAN be encoded in the set of little Planck-length-squared tiles that cover its horizon even though there must only be a finite number of these tiles. This means that there is a "bottom" to the possible knowledge of the universe. The emergence of gravity along with the world itself is based on this. Pretty amazing stuff!
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  16. #15 Re: Entropy - Gravity 
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    Quote Originally Posted by CharlyAndy
    Oh, by the way, (for those in this forum interested in Physics) the short answer to my question, according to the identification of a black hole's entropy with the area of its horizon, is that there is not an infinite amount of information in the universe. ALL the information corresponding to matter that has entered a black hole CAN be encoded in the set of little Planck-length-squared tiles that cover its horizon even though there must only be a finite number of these tiles. This means that there is a "bottom" to the possible knowledge of the universe. The emergence of gravity along with the world itself is based on this. Pretty amazing stuff!
    Actually it is pretty speculative stuff, which is yet to be proved.
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  17. #16 Entropy - Gravity 
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    Speculative, right. Bousso comments, an echo of Dirac, that sometimes one does physics by devising a theory that brings order to mysterious phenomena. For example Quantum Mechanics. Sometimes one follows logic and mathematics, to predict the outcomes of experiments not done. For example General Relativity. I guess we are in the latter regime with the holographic universe and hence with entropy - gravity. Science marches on.
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