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| physics for dummies; branes? | |
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| Tweet Topic Started: Nov 1 2005, 05:37 AM (730 Views) | |
| bachophile | Nov 1 2005, 05:37 AM Post #1 |
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HOLY CARP!!!
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from the ny times...![]() "the ends of open strings whose osscilations are particles and forces other then gravity are stuck to our brane" anybody? |
| "I don't know much about classical music. For years I thought the Goldberg Variations were something Mr. and Mrs. Goldberg did on their wedding night." Woody Allen | |
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| apple | Nov 1 2005, 05:41 AM Post #2 |
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one of the angels
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a good example of why i hold the NY Times in such hi regard |
| it behooves me to behold | |
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| Nina | Nov 1 2005, 05:48 AM Post #3 |
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Senior Carp
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Main Entry: brane Part of Speech: noun Definition: in physics, any dimensional or extended object in string theory Example: Our universe is a 3-brane. Usage: science This should clear things up.
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| JBryan | Nov 1 2005, 06:23 AM Post #4 |
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I am the grey one
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I suppose the inside of a black hole is particularly "brany". Unlike the insides of some people's heads. |
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"Any man who would make an X rated movie should be forced to take his daughter to see it". - John Wayne There is a line we cross when we go from "I will believe it when I see it" to "I will see it when I believe it". Henry II: I marvel at you after all these years. Still like a democratic drawbridge: going down for everybody. Eleanor: At my age there's not much traffic anymore. From The Lion in Winter. | |
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| DivaDeb | Nov 1 2005, 06:39 AM Post #5 |
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HOLY CARP!!!
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I find this quote particularly inspiring: ""It's not completely obvious what gravity is, fundamentally, or what dimensions are, fundamentally," she said over lunch. "One of these days we'll understand better what we mean, what is the fundamental thing that's given us space in the first place and dimensions of space in particular." She held out less hope for time, saying, "I just don't understand it. "Space we can make progress with." Is time an illusion? "I wish time were an illusion," she said as she carved up the last of her chocolate bread pudding, "but unfortunately it seems all too real."" |
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| kentcouncil | Nov 1 2005, 07:21 AM Post #6 |
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Fulla-Carp
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Brian Greene's "The Elegant Universe" is a great introduction to string theory and the brane theory of co-existing dimensions. "If quantum mechanics hasn't profoundly shocked you, you haven't understood it yet." -Niels Bohr |
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It was a confusion of ideas between him and one of the lions he was hunting in Kenya that had caused A. B. Spottsworth to make the obituary column. He thought the lion was dead, and the lion thought it wasn't. - P.G. Wodehouse | |
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| John D'Oh | Nov 1 2005, 07:31 AM Post #7 |
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MAMIL
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Another good book, on Quantum Physics rather than string theory, for anyone who's interested is "The Quantum World" by John C. Polkinghorne. Polkinghorne was a professor of mathematical physics at Cambridge, who then became an Anglican priest, so he brings new perspective. The book is also free of hard math. |
| What do you mean "we", have you got a mouse in your pocket? | |
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| ivorythumper | Nov 1 2005, 07:50 AM Post #8 |
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I am so adjective that I verb nouns!
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ok, I got this space-time 4d thing -- someone please tell me what 5th Dimension is (other than the 1960s soul group), and whether anyone has been there or has any evidence of its existence apart from speculative physics. no formulas please. |
| The dogma lives loudly within me. | |
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| Aqua Letifer | Nov 1 2005, 07:55 AM Post #9 |
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ZOOOOOM!
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Sorry, Ivory, that's pretty much the only way you can talk about 5+ dimensions. Conceptually, it's not that bad! Three dimensions: length, width, height (in no particular order). "Fourth" dimension": time Well, let's say you have a baseball. You can easily see how to define the baseball in terms of the first three dimensions, and with some imagination you can see how those three dimensions change with time, right? Well okay, now you have a "4-D" baseball. Well, what if you wanted to further define the baseball with more than 4 parameters? How about how much the thing costs? Inflation rates (and baseball demand, I'm guessing) also fluctuate, just like the baseball's position with respect to time. You can then define how all 5 of these parameters change with respect to each other. There's your "5-D baseball formula". 'Course, you tell me how to plot the thing using our linear algebra and I'll give you five bucks. So the "other dimensions" of spacetime are about the same thing: somehow, they're other parameters of spacetime, other than just length, width, and time. Perhaps relating space to gravity, or light energy? Heck, you could prob'ly come up with a pretty big list. There you go, the ever-elusive "multi-dimensional universe". |
| I cite irreconcilable differences. | |
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| John D'Oh | Nov 1 2005, 08:03 AM Post #10 |
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MAMIL
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I think the big problem is we have no way to reference them that we can understand. Mathematically speaking, multiple dimensions are easy to define, and even possibly comprehend. Intuitively, if they do exist, we can't perceive them because it's the equivalent of a man drawn on a piece of paper in a 2 dimensional world trying to see into next-door's garden. This stuff always made my brain numb. |
| What do you mean "we", have you got a mouse in your pocket? | |
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| Aqua Letifer | Nov 1 2005, 08:12 AM Post #11 |
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ZOOOOOM!
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Well, there's ways to do it, I'm sure. Or at least slim it down to something we can sort of comprehend. For example, You can draw a 3-D box (i.e., represent three dimensions) on a 2-D piece of paper, correct? |
| I cite irreconcilable differences. | |
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| kentcouncil | Nov 1 2005, 08:13 AM Post #12 |
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Fulla-Carp
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AL has it right, IT. The 11-dimensional universe is currently popular with M-theory (the successor to string theory), and essentially multiple dimensions are necessary to make the equations "work", especially with regards to gravity, the one fundamental force that has been difficult to reconcile with the other fundamental forces. I'm sure you're familiar with the medieval concept of "aether", the pervasive conducting medium. It used to be thought that higher dimensions were like that as well, beyond our field of perception. But the new theories of hyperspace suggest that higher dimensions may in fact be folded upon themselves and infinitesimally small, though again beyond our field of perception. As John says, it's very unfamiliar to the way our 3-dimensional brains picture things, but the computer models have been growing ever more sophisticated. I bet Frank M, if he were still posting, would be able to explain much better. |
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It was a confusion of ideas between him and one of the lions he was hunting in Kenya that had caused A. B. Spottsworth to make the obituary column. He thought the lion was dead, and the lion thought it wasn't. - P.G. Wodehouse | |
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| schindler | Nov 1 2005, 08:15 AM Post #13 |
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Fulla-Carp
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I think it's absolutely facinating but I never got the math. I didn't even get high-school algebra. ![]() Madeline L'Engles book A Wrinkle in Time deals with the 5th dimension. Cool stuff |
| We're all mad here! | |
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| John D'Oh | Nov 1 2005, 08:15 AM Post #14 |
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MAMIL
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Yes, *we* can draw it, but we live in 3 dimensions. Could the man on the paper draw it, since he can't see the dimensions? I've seen drawings which purported to represent 4 and 5 dimensional space, but I couldn't 'see' how it worked. I'm a lot happier thinking in terms of algebreic maths (weird, I know), and I've always been rather weak at geometry, so it might just be me. |
| What do you mean "we", have you got a mouse in your pocket? | |
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| ivorythumper | Nov 1 2005, 08:21 AM Post #15 |
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I am so adjective that I verb nouns!
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Aqua: (This is a bit stream of consciousness, so forgive the ramble as I try to grasp what you are saying) Am I to understand that there is no "one" fifth or sixth dimension which is conventionalized in the way that 3d is H, W, L and 4th is T? I get the concept of a fifth "value" by which to evaluate a thing -- I can conceptualize that the matter (say, the baseball) is being affected by another force (say gravity) which we can assume even affects the sub atomic structure of the matter. (Stop me if I've missed the point) How do we know that gravity is truly a 5th dimension, and not just an property of matter, which always and only exists in space and time? How do we know that light energy (I asssume this is contained in photons????) is another dimension, rather than a primary component of matter? (And also exists only in space and time -- and I have some concerns about Schrodinger's Cat). And even if there is a relational effect between, say, light energy and gravity (that one or the other affects the other or mutually) why need this be considered another dimension? Or is it more a way of bracketing it for analysis, and the term "dimension" is really used by way of analogy? |
| The dogma lives loudly within me. | |
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| ivorythumper | Nov 1 2005, 08:23 AM Post #16 |
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I am so adjective that I verb nouns!
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Kent: Is there a convention to the 11 dimensions? |
| The dogma lives loudly within me. | |
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| John D'Oh | Nov 1 2005, 08:25 AM Post #17 |
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MAMIL
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Oh don't worry, it died years ago, solving that little conundrum ![]() I'll leave your serious questions to someone who knows what they're talking about. |
| What do you mean "we", have you got a mouse in your pocket? | |
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| ycul | Nov 1 2005, 08:28 AM Post #18 |
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Junior Carp
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It's a no-braner. |
| How now, brown cow. | |
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| Aqua Letifer | Nov 1 2005, 08:33 AM Post #19 |
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ZOOOOOM!
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Myself as well, John. At the same time, we're quite 2-D thinkers, humans are. Look at our board games, our "3-D" topographic maps, etc... Even 3-D thinking can be a step up at times. I say, just gimmie the formulas! |
| I cite irreconcilable differences. | |
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| kentcouncil | Nov 1 2005, 08:34 AM Post #20 |
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Fulla-Carp
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Yes... 11 dimensions are now the standard for M-theory, though 10 and 26 (!) have been seriously postulated as well. As to the specifics of each one... my memory is too unreliable to give you a proper answer . But my reference was "The Great Beyond", by Paul Halpern, which is a wondeful book that discusses the higher dimensional questions you've been asking. I read it almost a year ago... probably re-read it tonight when I get home. |
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It was a confusion of ideas between him and one of the lions he was hunting in Kenya that had caused A. B. Spottsworth to make the obituary column. He thought the lion was dead, and the lion thought it wasn't. - P.G. Wodehouse | |
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| kentcouncil | Nov 1 2005, 08:35 AM Post #21 |
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Fulla-Carp
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It was a confusion of ideas between him and one of the lions he was hunting in Kenya that had caused A. B. Spottsworth to make the obituary column. He thought the lion was dead, and the lion thought it wasn't. - P.G. Wodehouse | |
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| Aqua Letifer | Nov 1 2005, 08:53 AM Post #22 |
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ZOOOOOM!
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Ivory,
Although I suppose some people could argue there is no one singular "fifth" dimension, I believe there is one, but obviously it's hard for us to conceptualize. Perhaps a measure of gravity, or energy, something like that? Hard to say. The baseball example was a (poor) illustration of how a "5h dimension" was possible. So, since you can define anything in more than 4 terms, it makes sense that spacetime (length, width, height, time) has more than "4" dimensions.
I'm only guessing gravity or light or energy, since they're pretty important parameters of the universe. Heck, it could very well be something else! Whatever the "5th" dimension is, however, it needs to be constantly related to the other 4 dimensions. That's a hard premise to live up to!
Well, to elaborate on the above, you can draw a 3-D graph of how a baseball moves through time; I believe you'd need to be able to relate this 5th dimension in terms of the other 4 in order for it to qualify. You couldn't graph it, but formulas would work just as well I suppose. There's other qualifiers in there I'm sure, but that's the main condition I can think of: this "5th dimension" has got to always relate to length, width, height, and time. So, I suppose there's no guarentees gravity, light or energy would come into play in the "extra" dimensions, but since they're a pretty important part of our universe I figure it's possible. They've "discovered" (though still under much scrutiny and analysis) some pretty crazy things about light and gravity, so the more we study these two, I think the more important they'll become. Not a fan of the Shrodinger's Cat hypothesis? I dunno if I totally buy into it myself, but it's an interesting concept. |
| I cite irreconcilable differences. | |
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| kentcouncil | Nov 1 2005, 09:00 AM Post #23 |
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Fulla-Carp
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Actually, the behaviour of light (or rather the electromagnetic force) is pretty consistent, consistent enough that it is the touchstone for relating to the other forces. As I mentioned previously, the behaviour of gravity has been the tough nut to crack, and has essentially required the existence of other dimensions. |
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It was a confusion of ideas between him and one of the lions he was hunting in Kenya that had caused A. B. Spottsworth to make the obituary column. He thought the lion was dead, and the lion thought it wasn't. - P.G. Wodehouse | |
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| Horace | Nov 1 2005, 09:06 AM Post #24 |
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HOLY CARP!!!
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I don't think anybody is coming up wth all these dimensions through a process of thought experiments or intuition. THey're running some equations and out pops a number. Sometimes 10, or 11, or 26.. etc. I doubt there's a formal definition for any of the dimensions past 5. |
| As a good person, I implore you to do as I, a good person, do. Be good. Do NOT be bad. If you see bad, end bad. End it in yourself, and end it in others. By any means necessary, the good must conquer the bad. Good people know this. Do you know this? Are you good? | |
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| ***musical princess*** | Nov 1 2005, 09:09 AM Post #25 |
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HOLY CARP!!!
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This stuff gets my brain buzzing! I live for stuff like this. ![]() Gimme a chance to read the thread and i'll share my 2c's (or pennies :P) x |
| x Caroline x | |
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12:36 AM Jul 11