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Question: Greene's The Hidden Reality : the holographic principle

  1. Jan 7, 2012 #1
    Question: Greene's "The Hidden Reality": the holographic principle

    On pp. 260-261 of "The Hidden Reality" Brian Greene says the following:

    I puzzled over this for quite awhile and it seems as though Greene, probably inadvertently, phrased this somewhat more decisively than is justified - that is, the "then there's reason to think that the surface is where the... processes happen" part in particular. It seems that he hasn't provided reasons why something that can be is anything more than a theoretic possibility rather than what is the case.

    Perhaps I'm being too pedantic, but when I first read this I was led by his phrasing into thinking that what he was stating about the holographic principle was something that some physicists have good reason to think is more than a theoretic possibility.

    Of course, I could easily be misconstruing the whole issue or missing some critical aspect of it. I am also aware that scientists who popularize complex issues oftentimes understandably use imprecise language that can cause misunderstandings that are avoided by more precise formulations that scientists steeped in the technical language of the discipline are able to avoid. That's why I'm asking for help in understanding this. Is the holographic principle essentially only a theoretic possibility that is consistent with our best understanding of physics or are there actually other reasons to think that it is more than a "mere" theoretic possibility? Or am I misunderstanding the issue?
     
    Last edited: Jan 7, 2012
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  3. Jan 7, 2012 #2

    jedishrfu

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    Re: Question: Greene's "The Hidden Reality": the holographic principle

    I know they apply this to the surface of a BH.
     
  4. Jan 7, 2012 #3

    phinds

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    Re: Question: Greene's "The Hidden Reality": the holographic principle

    No, they apply it to the "event horizon" of the black hole, which is a place in space that does not exist in any material way. It's just the point at which light can no longer escape the gravitational pull of the black hole. How this insubstantial place can hold information is a total mystery to me, and if I understand it correctly "they" do NOT just say it COULD store the information, they say it DOES store it.

    If I understand it correctly, Suskind also believes that all of the information in the observable universe is contained on the sphere that is the boundary of the observable universe as seen from earth. This makes even LESS sense to me. At least the black hole event horizon has some effect that is measurable even if it is not a material place. The sphere that defines our observable universe is just a point we DEFINE in space. It has no real characteristics at all, so the concept that information can be stored there just seems like lunacy to me.

    Suskind seems like a really bright guy and a good physicist, so I figure I must be missing something in all this but I've never been able to figure out what. I hope this thread will lead me to some understanding of what just seems crazy to me.
     
  5. Jan 7, 2012 #4
    Re: Question: Greene's "The Hidden Reality": the holographic principle

    I should have been more clear - I have a separate question about how a person falling through a black hole can "simultaneously" appear to an outside observer to have vaporized at the horizon due to Hawking radiation and whatnot, but to the person they will seem to have gone "through" the horizon basically intact (at least for awhile until gravitational tidal forces cause other problems). That paradox seems somehow to be "resolved" by the holographic principle, but to my understanding, Greene doesn't explain how in his book (he seems to gloss over the issue).

    I meant to be referring to Susskind's conjecture that this could (does?) apply to the known universe as a whole rather than to only black holes.
     
  6. Jan 7, 2012 #5

    jedishrfu

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    Re: Question: Greene's "The Hidden Reality": the holographic principle

    Sorry for not being clear, I had leave in mid post but I think you knew that.
     
  7. Jan 7, 2012 #6

    phinds

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    Re: Question: Greene's "The Hidden Reality": the holographic principle

    The person does NOT appear to have "vaporized" at the event horizon; that's nonsensical. He DOES appear to an outside observer to have slowed down almost to a stop while he himself notices nothing and just keeps on going. This is not a paradox of any kind and does not need any resolution.

    I assume that by "known universe" you mean the observable universe. That's what my rant was about.
     
  8. Jan 7, 2012 #7

    phinds

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    Re: Question: Greene's "The Hidden Reality": the holographic principle

    No, I have no idea why you would think that I knew that.
     
  9. Jan 7, 2012 #8
    Re: Question: Greene's "The Hidden Reality": the holographic principle

    I did mean mostly "observable", except I wasn't sure that term is inclusive enough to include what physicists are talking about when they are applying the holographic principle to the "whole" universe.

    As to why I said "vaporized", here is what Greene says on page 257 of "The Hidden Reality":

    As a personal observation, if the attitude I sense in your response is indicative of what I'm likely to encounter on a regular basis here, I think I'll be inclined to ask my questions and make my comments on another forum.
     
    Last edited: Jan 7, 2012
  10. Jan 7, 2012 #9

    phinds

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    Re: Question: Greene's "The Hidden Reality": the holographic principle

    Well, I'm flabbergasted by Greene's comment. It makes no sense to me at all and I've never heard anything like it but he knows more than I do so I assume I'm missing something.

    "whole" universe is not a particularly meaningful term inasmuch as it seems to mean exactly the same thing as just "universe". Everything outside of the observable universe is just speculation, but many of us believe that it just goes on exactly as what is inside our observable universe. As I recall, Suskind talks bout the holographic information on the sphere of the Observable Universe, which is what my rant in post #3 was about.

    Yeah, this is a fairly hard-nosed forum. If you can't take blunt criticism, you may well not find this place congenial. BUT ... it's the best forum on the internet for getting good answers to questions about physics. Most of the good folks here are more patient than I am. In fact I was just complimenting DaleSpam in another thread for how patient he is and he's hardly the only one.
     
  11. Jan 7, 2012 #10
    Re: Question: Greene's "The Hidden Reality": the holographic principle

    I went back and read further along and realized why I had said that Greene had suggested a resolution to the seeming paradox, but I had not recalled some important parts of what he said - continuing from the quote I cited above:

    I really don't know how to interpret that and that's why I said Greene seems to gloss over the resolution to the seeming paradox. In my memory I thought he was suggesting that Susskind's thoughts about the holographic principle were the nature of the resolution, but on rereading what Greene says here, that isn't actually clear at all.

    Incidentally, this URL seems to have extended excerpts from "The Hidden Reality" book in case you wanted to read up on it some:

    http://www.epubbud.com/read.php?g=9QDTX6S4&p=126
     
  12. Jan 7, 2012 #11

    phinds

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    Re: Question: Greene's "The Hidden Reality": the holographic principle

    Good grief. I appreciate your attempt at "clarification" but I gather you're just as bemused by Green as I am. I just don't follow any of your quotes from him at all but I don't think I'm going to pursue it with him since what I've read here just makes my head hurt. :smile:
     
  13. Jan 8, 2012 #12

    jedishrfu

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    Re: Question: Greene's "The Hidden Reality": the holographic principle

    These statements by Greene are related to the holographic universe idea. It came from applying information theory to a BH event horizon and noting that as matter falls into the BH it's event horizon enlarges. It was theorized that the information was captured on it.

    Anyway, Wikipedia describes it under 'holographic principle'

    Sorry this may be a redundant post already know its holographic duh.
     
  14. Jan 8, 2012 #13
    Re: Question: Greene's "The Hidden Reality": the holographic principle

    if the holographic principle is right then every particle is simultaneously everywhere and is (potentially) interacting instantaneously with every other particle
     
  15. Jan 8, 2012 #14
    Re: Question: Greene's "The Hidden Reality": the holographic principle

    It seems to me that Greene is conflating an epistemological issue with an ontological one. That is, he seems to be saying that there isn't a paradox of whether he died at the event horizon or went through it alive because we can't KNOW whether or not he died. But whether or not he died is actually an ontological issue - an issue of what actually happened not an issue of what we know about what happened. Are there some situations where physicists equate the epistemological with the ontological? If so, what is the justification for that?
     
  16. Jan 8, 2012 #15
    Re: Question: Greene's "The Hidden Reality": the holographic principle

    Thanks for replying. Hopefully someone can shine some light on this holographic issue and we'll get a projection of the reality of the situation. :)
     
  17. Jan 8, 2012 #16
    Re: Question: Greene's "The Hidden Reality": the holographic principle

    I wasn't aware that that was an implication of the holographic principle. Assuming it is, then I wonder if that is a result of the mathematics of quantum mechanics. From what I can discern (which isn't a lot, I'll concede), it seems as though the mathematics of the wave function sort of suggest that every particle is actually interacting with every other particle.
     
  18. Jan 9, 2012 #17
    Re: Question: Greene's "The Hidden Reality": the holographic principle

    not only that but if every particle does interact instantaneously with every other particle then QM and relativity could easily be combined.
    You just set c=infinity
     
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