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Post by abacus9900 on Jan 18, 2011 16:59:40 GMT 1
Last night's Horizon programme (17/01/2011) dealt with the subject of what reality is.
It emerged later in the programme that we might possibly be living in a holographic universe where what appears to be a 3 dimensional reality is, in fact, an illusion, i.e. our environment is really a two dimensional arrangement made to look as though it is 3D, and that information stored at the edge of our universe may give rise to this. The idea arose because of Stephen Hawking's position some years ago that a black hole destroys information, which is an anathema to established scientific principles, and prompted the idea that perhaps information is really stored at the event horizon and preserved.
Anyone able to explain this a bit more?
Ta.
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Post by Progenitor A on Jan 18, 2011 17:12:49 GMT 1
Haven't a clue what they are talking about.
But shouldn't the NHS be giving us free 3D glasses?
It would also be useful if the world had sub-titles.
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Post by abacus9900 on Jan 18, 2011 17:34:26 GMT 1
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Post by speakertoanimals on Jan 18, 2011 17:51:50 GMT 1
What you mean by 'illusion' is rather difficult here, and prone to being hi-jacked by the usual woo-woo merchants...........
But as I understand it, the problems of black hole thermodynamics (we are used now to black holes having a temperature, but they also possess other thermodynamic properties like entropy -- you can also write this stuff in terms of information theory, which leads you to, in effect, where did all the information about the EXACT objects that formed the black hole go to, since the horizon seems pretty featureless?) and writing things down in terms of information theory,. lead to several; interesting relations. In particular, it seems as if the information content of a region depends on the AREA of the surface enclosing it, not the volume.
We are used to physics that sees the arena for stuff as being three dimensional -- and the number of degrees of freedom for stuff happening in a volume then depends on the volume! Yet the information results suggest area not volume.
Where do the information results come from? From trying to write down not a complete quantum theory of spacetime (we don't know how to do that yet), but certain reasonable-sounding estimates of the maximum number of degrees of freedom you can shove into a given volume.
Basically, if we have quantum gravity, then we expect that there is a meaning to 'smallest possible volume' in which you can have a quantum oscillator -- continuous spacetime replaced by a discrete grid, if you like, where the Planck length gives an idea of the size of the grid. For these quantum oscillators, you have an energy limit below (you can't have wavelengths larger than the volume you have chosen), and bounded from above by the Planck energy, the maximum energy you can shove into a fundamental volume. Which givesa finite number of states for the whole volume, hence a limit on how much information you can pack in.
Except that way of counting goes a bit wrong, because many of the higher-energy states would actually collpase into black holes, which would then take the information you were trying to store, and taking it outside this universe! Hence restricting to storage-system states that wouldn't collapse to black holes under their own gravity, we get a much SMALLER number of states, which happens to go as the area of the surface, rather than the volume.
Hence (bit hand-wavey here), the suggestion that the underlying theory (which encompasses quantum gravity and all that), will fundamentally be a theory of stuff on surfaces, not in volumes.
Except just because this is possible mathematically doesn't quite express what we mean by saying the world is really of lower dimensionality, that our perception of 3 of space and 1 of time is somehow an 'illusion' (as if we had faulty perception), rather than there just being fewer degrees of freedom than we might have thought.
I'm just rather sceptical about such ontological claims and how they get used (like the use of the word illusion).
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Post by Progenitor A on Jan 18, 2011 18:12:56 GMT 1
What you mean by 'illusion' is rather difficult here, and prone to being hi-jacked by the usual woo-woo merchants........... But as I understand it, the problems of black hole thermodynamics (we are used now to black holes having a temperature, but they also possess other thermodynamic properties like entropy -- you can also write this stuff in terms of information theory, which leads you to, in effect, where did all the information about the EXACT objects that formed the black hole go to, since the horizon seems pretty featureless?) and writing things down in terms of information theory,. lead to several; interesting relations. In particular, it seems as if the information content of a region depends on the AREA of the surface enclosing it, not the volume. We are used to physics that sees the arena for stuff as being three dimensional -- and the number of degrees of freedom for stuff happening in a volume then depends on the volume! Yet the information results suggest area not volume. Where do the information results come from? From trying to write down not a complete quantum theory of spacetime (we don't know how to do that yet), but certain reasonable-sounding estimates of the maximum number of degrees of freedom you can shove into a given volume. Basically, if we have quantum gravity, then we expect that there is a meaning to 'smallest possible volume' in which you can have a quantum oscillator -- continuous spacetime replaced by a discrete grid, if you like, where the Planck length gives an idea of the size of the grid. For these quantum oscillators, you have an energy limit below (you can't have wavelengths larger than the volume you have chosen), and bounded from above by the Planck energy, the maximum energy you can shove into a fundamental volume. Which givesa finite number of states for the whole volume, hence a limit on how much information you can pack in. Except that way of counting goes a bit wrong, because many of the higher-energy states would actually collpase into black holes, which would then take the information you were trying to store, and taking it outside this universe! Hence restricting to storage-system states that wouldn't collapse to black holes under their own gravity, we get a much SMALLER number of states, which happens to go as the area of the surface, rather than the volume. Hence (bit hand-wavey here), the suggestion that the underlying theory (which encompasses quantum gravity and all that), will fundamentally be a theory of stuff on surfaces, not in volumes. Except just because this is possible mathematically doesn't quite express what we mean by saying the world is really of lower dimensionality, that our perception of 3 of space and 1 of time is somehow an 'illusion' (as if we had faulty perception), rather than there just being fewer degrees of freedom than we might have thought. I'm just rather sceptical about such ontological claims and how they get used (like the use of the word illusion). ;D ;D ;D Hahaha! Un believable! Would anyone that supports this - ahem- convoluted ungrammatical critique- like to put thir necks on the line and try defending it? Then we can have some fun!
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Post by Progenitor A on Jan 18, 2011 18:16:06 GMT 1
I really am interested Abacus, even though it sounds like outrageous speculative BS Thanks for the link. PS. Only a mathematician could assert that reality is mathematical! (bit like a witch-doctor claiming that a mixture of toads, snails and lttle boys gonads , imbibed with young calf's blood and virgins menstrual fluids will reveal the truth) e.g. reality was illusionary before Euclid! ;DHahaha!
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Post by speakertoanimals on Jan 18, 2011 18:35:43 GMT 1
Naymissus, are you going to do ANYTHING other than quote my entire post (a totally useless pursuit surely, given that just saying -- see previous post -- would have handled what you meant perfectly well!), and laugh manically.......................
Although I suppose quoting does actually give your post some content, even if that is all totally borrowed.
So, come on, why not attempt to DISCUSS it, and say what exactly you don't understand? Information content? Entropy? Planck length and Planck mass? Number of degrees of freedom? Which basic terms do you have a problem with, or which connections between them don't you get?
It is really very simple. Let's take a very simple casae, where we have binary storage -- we have a grid of points for our universe, with at each point one bit, which can be either 0 or 1. Hence 2 possible states at each site, and 2^N different states of the whole system, where N is the number of sites.
So in this case, it depends on the volume (that is, N).
If we take the one state to be the equivalent of the higher-energy state, then suppose that we can't have too many ones without the system collpasing into a black hole. That is going to restrict the possible states that you can have. Okay so far?
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Post by abacus9900 on Jan 18, 2011 18:54:36 GMT 1
What you mean by 'illusion' is rather difficult here, and prone to being hi-jacked by the usual woo-woo merchants........... Well, when a famous scientist draws an analogy between a hologram on a flat screen with what our universe is really like then I should think it's obvious. Why don't you watch the programme yourself and then discuss what it all means? www.bbc.co.uk/iplayer/episode/b00xxgbn/Horizon_20102011_What_Is_Reality/
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Post by Progenitor A on Jan 18, 2011 19:03:53 GMT 1
. So, come on, why not attempt to DISCUSS it, ....... Hahahaha! This is quite hilarious!
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Post by abacus9900 on Jan 18, 2011 19:54:10 GMT 1
. So, come on, why not attempt to DISCUSS it, ....... Hahahaha! This is quite hilarious! What she really means is she wants you to accept what she has to say as the only thing that counts.
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Post by Progenitor A on Jan 18, 2011 20:43:19 GMT 1
Hahahaha! This is quite hilarious! What she really means is she wants you to accept what she has to say as the only thing that counts. ;D
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Post by speakertoanimals on Jan 18, 2011 21:10:19 GMT 1
Nope, I mean I want people on here to DISCUSS things, rather than just paste mindlessly, and laugh and disagree just for the sake of it, like a bunch of mindless idiots.
But heck, I'm not surprised (and neither is anyone else!).
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Post by abacus9900 on Jan 18, 2011 21:32:50 GMT 1
Nope, I mean I want people on here to DISCUSS things, rather than just paste mindlessly, and laugh and disagree just for the sake of it, like a bunch of mindless idiots. But heck, I'm not surprised (and neither is anyone else!). Haven't watched the programme then yet?
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Post by speakertoanimals on Jan 18, 2011 21:46:00 GMT 1
Why do you assume that someone has to have watched the Horizon program to know something about the Holographic principle? It's an idea that has been around for a few years, you asked for someone to try and explain.
If you want a frame-by-frame analysis of Horizon, I have better things to do than go watch an episode of a TV program that I gave up on years ago as having fallen from its previous heights of good popular science.
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Post by abacus9900 on Jan 18, 2011 22:54:42 GMT 1
Why do you assume that someone has to have watched the Horizon program to know something about the Holographic principle? It's an idea that has been around for a few years, you asked for someone to try and explain. If you want a frame-by-frame analysis of Horizon, I have better things to do than go watch an episode of a TV program that I gave up on years ago as having fallen from its previous heights of good popular science. The point is how can you reasonably discuss a programme I saw if you have not seen it yourself?
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