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Natural Science Forum / Physics / Relativity / July 2005GR ?
Would anybody that understands GR dispute the statement that the geometry of GR is non-Euclidean due deformation of length and duration under presence of mass and that this deformation has the aspect and equivalence to energy? -- Significant Zero E-field = Electric field, M-field =Magnetic field, two unbound field effects http://home.freeuk.com/paulps/ Maybe updates. The spuds, beans and onions are coming up nicely. Ooh ah.{:-) > Would anybody that understands GR dispute the statement that the geometry of > GR is non-Euclidean due deformation of length and duration under presence > of mass and that this deformation has the aspect and equivalence to energy? If what you are trying to say is do gravitational fields have energy - then I would say yes with caveats. Energy in GR is a rather slippery concept due to the fact that energy is the conserved Noether charge related to time symmetry of the lagrangian - it is rather difficult to define such when that symmetry is lacking due to space-time curvature - see the FAQ - http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html Bill > -- > Significant Zero E-field = Electric field, M-field =Magnetic field, two > unbound field effects > http://home.freeuk.com/paulps/ > Maybe updates. The spuds, beans and onions are coming up nicely. Ooh > ah.{:-) | > Would anybody that understands GR dispute the statement that the geometry | of [quoted text clipped - 7 lines] | symmetry of the lagrangian - it is rather difficult to define such when that | symmetry is lacking due to space-time curvature - see the FAQ - Thanks Bill that is the energy definition that I have some disagreement with and to a large degree is what much of my postings are in dispute with and are grouping for a more complete, accurate and satisfying definition. My position is that all energy is a function of relative states of length and time deformation with the use of the word deformation not implying that any intrinsic force is present in this deformation. The energy being present due to the relationship of different length/duration states which from your previous posting I thing you violently oppose {:-) . | http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html Maybe I don't understand this but it seems to me to have more conceptual holes than a moth eaten jumper but if you are prepared to pick it to bits with me I'll give it a try, you may be able to educate me out of my dispute but I am hard to educate about something that is itself in dispute.{:-) | Bill | [quoted text clipped - 4 lines] | > Maybe updates. The spuds, beans and onions are coming up nicely. Ooh | > ah.{:-) > | > Would anybody that understands GR dispute the statement that the > geometry [quoted text clipped - 21 lines] > to the relationship of different length/duration states which from your > previous posting I thing you violently oppose {:-) . For your definition to make sense you need to do a few things. First express it mathematically so it can be used to make quantitative predictions. Secondly show it agrees with the current definition in all cases where such agreement is possible. And thirdly show why your edition is superior. You have not even done the first bit. > | http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html > > Maybe I don't understand this Unfortunately that seems likely. > but it seems to me to have more conceptual holes than a > moth eaten jumper Then detail those supposed holes. > but if you are prepared to pick it to bits with me I'll > give it a try, you may be able to educate me out of my dispute but I am hard > to educate about something that is itself in dispute.{:-) Ok. Just make you objections specific - not some vague semantic waffle. Bill > | Bill > | [quoted text clipped - 5 lines] > | > Maybe updates. The spuds, beans and onions are coming up nicely. Ooh > | > ah.{:-) | > | > Would anybody that understands GR dispute the statement that the | > geometry [quoted text clipped - 5 lines] | > | | > | If what you are trying to say is do gravitational fields have nergy - | > then | > | I would say yes with caveats. Energy in GR is a rather slippery concept [quoted text clipped - 21 lines] | cases where such agreement is possible. And thirdly show why your edition | is superior. You have not even done the first bit. Thanks for the advice Bill. I was aware of what I may need to do to convince you that your view might be improved by some subtle changes was a mountain to climb but as I had the rest of my life, so I thought I'd give it a go{:-) I am on the first bit trying to familiarise myself with your notation OK {:-) | > | http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html | > | > Maybe I don't understand this | | Unfortunately that seems likely. That crack is clearly an attempt by somebody with uncertainties to try and gain some sort of psychological advantage as to the accuracy of the document in question. Do you agree with this Bill ? I wrote 'Maybe I don't understand this' to indicate that I would try and have an open mind about it. I may be able to close my teeth on your head if I need to at any time Bill so lets not bite each other untill we need to Eh?{:-) and keep it amusing when you need to and then I might not bite so hard back ?. | > but it seems to me to have more conceptual holes than a | > moth eaten jumper | | Then detail those supposed holes. First Hole It starts with a semantic hole that I know you love debating about 'energy and conserved' that it never seems to address except with clichés. You might like to do better ? Second hole 'In flat spacetime (the backdrop for SR).....' It then degenerates into some semantic waffle to presumable come out the other side with curved space-time that is not flat. Hold on clarifying this until you have dealt with 'energy and conserved' | > but if you are prepared to pick it to bits with me I'll | > give it a try, you may be able to educate me out of my dispute but I am | hard | > to educate about something that is itself in dispute.{:-) | | Ok. Just make you objections specific - not some vague semantic waffle. See the first hole introduced by the paper you linked The stuff you presented in your link is vague semantic waffle IMHO its not me thats introducing its you. In the header post I made my view as plain as I could at that moment and asked for comments by posting it you then referred my to a load of semantic waffle as presumable my posting did not have enough semantic waffle in it. ? | Bill | [quoted text clipped - 7 lines] | > | > Maybe updates. The spuds, beans and onions are coming up nicely. Ooh | > | > ah.{:-) > | > | > Would anybody that understands GR dispute the statement that the > | > geometry [quoted text clipped - 42 lines] > to climb but as I had the rest of my life, so I thought I'd give it a go{:-) > I am on the first bit trying to familiarise myself with your notation OK How about actually addressing the issue? - namely your definition lacks any quantitative predictive content or indeed makes any sense. > {:-) > [quoted text clipped - 7 lines] > gain some sort of psychological advantage as to the accuracy of the document > in question. Do you agree with this Bill ? No. > I wrote 'Maybe I don't understand > this' to indicate that I would try and have an open mind about it. I may be > able to close my teeth on your head if I need to at any time Bill so lets > not bite each other untill we need to Eh?{:-) and keep it amusing when you > need to and then I might not bite so hard back ?. So you admit your agenda is not to discuss physics? > | > but it seems to me to have more conceptual holes than a > | > moth eaten jumper [quoted text clipped - 6 lines] > and conserved' that it never seems to address except with clichés. You might > like to do better ? How about addressing the issue rather than your pathetic attempts at misdirection? > Second hole > [quoted text clipped - 12 lines] > > See the first hole introduced by the paper you linked You mean the hole you said was 'you love debating about 'energy and conserved' that it never seems to address except with clichés'. How about sticking to the issue at hand instead of wandering off into appraisals of what I love and do not love. But this kind of misdirection is central to your style and indicative of my hypotheses that your agenda is not to actually discuss physics but to engage in senseless semantic waffle. To be specific what is wrong with the definition of energy as the conserved Noether charge related to time symmetry? Or is it as I suspect your math is not much beyond kiddy level - yet you believe you can intelligently discuss modern physical theories? There is no shame in admitting you do not know what conserved Noether charge is or that you are not fluent in more advanced math or that you do not know the generalization of Newtonian potential is the metric - the shame is in avoiding the issue that you do not really understand what you are criticizing and trying to take the discussion into senseless semantics. Bill > The stuff you presented in your link is vague semantic waffle IMHO its not > me thats introducing its you. In the header post I made my view as plain as [quoted text clipped - 15 lines] > Ooh > | > | > ah.{:-) | > | > | > Would anybody that understands GR dispute the statement that the | > | > geometry [quoted text clipped - 53 lines] | How about actually addressing the issue? - namely your definition lacks any | quantitative predictive content or indeed makes any sense. What are you on about ? I am only trying to compare my conceptual model with others and my experimental data is the same as yours I hope. What do you think the issue is Bill other than your claim that what I write is senseless and your response of 'rest of semantic senseless rubbish sniped', which is a bit of a broad criticism to address {:-) | > {:-) | > [quoted text clipped - 10 lines] | | No. A totally unexpected reply {:-) | > I wrote 'Maybe I don't understand | > this' to indicate that I would try and have an open mind about it. I may [quoted text clipped - 4 lines] | | So you admit your agenda is not to discuss physics? I don't know how you managed to conclude that from what I wrote? I am trying to compare my model of reality with others on this group, in my book that is discussing physics. If it can be made amusing and entertaining then so much the better, are you in disagreement with that ? | > | > but it seems to me to have more conceptual holes than a | > | > moth eaten jumper [quoted text clipped - 10 lines] | How about addressing the issue rather than your pathetic attempts at | misdirection? What issue have you moved to now Bill ? | > Second hole | > [quoted text clipped - 17 lines] | conserved' that it never seems to address except with clichés'. How about | sticking to the issue at hand You linked me to the paper Bill so I was trying to address its content, pathetic red herrings is more your style. | instead of wandering off into appraisals of | what I love and do not love. But this kind of misdirection is central to [quoted text clipped - 6 lines] | what conserved Noether charge is or that you are not fluent in more advanced | math I have read noethers paper and I do admit that the notations is difficult and beyond me at the moment but one of the statements about her paper was that it ' Proves both the theorems described above (Langrangian, Lie Group) and there converses. This reads to me as a academic exercise that may have no bearing on physical reality. Now if you can give a simple provable physical example that can be proved both with and without Emmys theorem then please do and I will give the paper more study and see if I agree with your statements in which you use this as proof of. | or that you do not know the generalization of Newtonian potential is | the metric - That is your definition but mine is that the Newtonian potential is a gravitational gradient and nearest I can come to it in GR terms is a momentum 4 vector this view I find support for in the FAQ paper you linked me to. | the shame is in avoiding the issue that you do not really | understand what you are criticizing and trying to take the discussion into | senseless semantics. You may think that semantics is senseless but without a common meaning for things no communication can occure. | Bill | [quoted text clipped - 3 lines] | > I could at that moment and asked for comments by posting it you then | > referred me to a load of semantic waffle as presumable my posting did not | > have enough semantic waffle in it. ? | > [quoted text clipped - 11 lines] | > Ooh | > | > | > ah.{:-) > | > | > | > Would anybody that understands GR dispute the statement that the > | > | > geometry [quoted text clipped - 62 lines] > > What are you on about ? Your definition of energy as 'My position is that all energy is a function of relative states of length and time deformation with the use of the word deformation not implying that any intrinsic force is present in this deformation.' This time no evasion - what is wrong with the modern definition of energy as the conserved Noether charge related to time symmetry. Bill > I am only trying to compare my conceptual model with > others and my experimental data is the same as yours I hope. What do you [quoted text clipped - 3 lines] > > | > {:-) http://math.ucr.edu/home/baez/physics/Relativity/GR/energy_gr.html > | > | > Maybe I don't understand this > | > | [quoted text clipped - 136 lines] > | > Ooh > | > | > | > ah.{:-) | > | > | > | > Would anybody that understands GR dispute the statement that | the [quoted text clipped - 76 lines] | definition of energy as the conserved Noether charge related to time | symmetry. *Note* that you asked me to criticise you when this thread was about you constructively criticising me if you wished. For a start its considerably more obscure than my definition, to me anyway . Secondly it refers to a mathematical theorem proving a physical reality. Thirdly I have no idea what time symmetry in that context means so could you explain what this means to you ? Fourthly I don't believe that charge as defined by the electron is fundamental etc , is that enough for the moment but we can go into detail if you start by answering the above question. | Bill | [quoted text clipped - 165 lines] | > | > Ooh | > | > | > | > ah.{:-) > | > | > | > | > Would anybody that understands GR dispute the statement that > | the [quoted text clipped - 87 lines] > *Note* that you asked me to criticise you when this thread was about you > constructively criticising me if you wished. Quit evading - I did not. > For a start its considerably more obscure than my definition, to me anyway . That is because you do not understand the terminology. Have you made the effort to investigate it? > Secondly it refers to a mathematical theorem proving a physical reality. So? Do you deny Pythagoras's theroem proves something about physical reality or are surveyors deluding themselves? > Thirdly I have no idea what time symmetry in that context means so could you > explain what this means to you ? Now we are getting somewhere. It refers to symmetries in a systems lagrangeian. If you do not know what a lagrangeian is check out http://alamos.math.arizona.edu/~rychlik/557-dir/mechanics/ Noethers theroem loosely speaking says to every symetry in a systems lagrangeian there corresponds as conserved quantity. The conserved quantity associated with symmetry in time is called energy - http://www.mathpages.com/home/kmath564/kmath564.htm > Fourthly I don't believe that charge as defined by the electron is > fundamental etc , is that enough for the moment but we can go into detail if > you start by answering the above question. Quit evading - the above has nothing to do with the definition of energy. Bill > | Bill > | [quoted text clipped - 182 lines] > | > | > Ooh > | > | > | > | > ah.{:-) | > | > | > | > | "Significant Zero" <paulpsremove@freeuk.com> wrote in | message | > | > | > | > | news:1120901128.24485.0@echo.uk.clara.net... | > Secondly it refers to a mathematical theorem proving a physical reality. | | So? Do you deny Pythagoras's theroem proves something about physical | reality or are surveyors deluding themselves? No they are working in a local context were space and time curvature\distortion are not usually significant to their measurements and the physical reality ~proves the theorem not the other way about. Come down off cloud 72435 {:-) Are you by any chance claiming that Pythagoros holds true under GR ? Is this is how you justify using a lagrangeian and its derivatives as some sort of definition in GR ? | > Thirdly I have no idea what time symmetry in that context means so could | you | > explain what this means to you ? | | Now we are getting somewhere. On your ground you think Bill. {:-) | It refers to symmetries in a systems | lagrangeian. If you do not know what a lagrangeian is check out | http://alamos.math.arizona.edu/~rychlik/557-dir/mechanics/ Yes I had a little understanding of L but felt it might not be applicable in a modern electric field statement which I was trying to construct using ~GR as a component. The main reasons being that it contained no terms for the adjustment of energy as a function of time and distance. You perhaps think that this is not a dependency ? The other being that its conceptualisation may have predated the most primitive understanding of electricity. Yes I know that J.L.L. (1736-1813) was a peer of C.de C (1785) but they were early days and I have some trouble with C.de C. That was >200 years ago and I hope we might have moved on a little. I don't dispute the use of lagrangeians for some applications but as a tool to explain the fundamentals of nature I feel it may be a bit worn out. This is just one of the reasons I feel that GR might need a little update (but I'm not sure and that is why I'm trying to put it into conceptual terms that are modern and adjustable, see original posting and header? Justify the inclusion of a lagrangein in a definition of GR up to and including c and mass up to event horizon otherwise I must conclude that your definition was nothing more than pompous posing. | Noethers theroem loosely speaking says to every symetry in a systems | lagrangeian there corresponds as conserved quantity. The conserved quantity | associated with symmetry in time is called energy - | http://www.mathpages.com/home/kmath564/kmath564.htm As this theorem includes lagrangeians the same comments apply. I would try and debate with you the validity of a lagrangeian if the space/time it was being applied to had been deformed\curved into an ellipse by motion or mass but we seems so far apart on this matter and your views are based on such old thinking that I doubt we can communicate unless you are prepared to examine your fundamental knowledge base for misunderstandings in a variable time/distance cosmos. | > Fourthly I don't believe that charge as defined by the electron is | > fundamental etc , is that enough for the moment but we can go into | > detail if you start by answering the above question. | | Quit evading - the above has nothing to do with the definition of energy. This presumably means that you think charge is not an aspect of energy ? This seems to contradict your ealier statement 'Energy in GR is a rather slippery concept due to the fact that energy is the conserved Noether charge related to time symmetry of the lagrangian - it is rather difficult to define such when that symmetry is lacking due to space-time curvature' Which might be a reason that I don't take your statements to seriously as they seem riddled with misconceptions and contradictions. -- Significant Zero E-field = Electric field, M-field =Magnetic field, two unbound field effects http://home.freeuk.com/paulps/ Maybe updates. (1-(1/(1/3))^2)/(1 + (1/(1/3))^2) = - 0.08 = FTL ? -p<+p or (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? > | > | > | > | > | "Significant Zero" <paulpsremove@freeuk.com> wrote in > | message [quoted text clipped - 11 lines] > > Are you by any chance claiming that Pythagoros holds true under GR ? I am claiming something that is totally obvious except to the cranks that post here. A mathematical theory contains logical deductions called theorems. If the theory is found by experiment to be true to high accuracy then the theorem is true to high accuracy - which is the reason surveyors use Pythagoras's theorem and energy can be defined using Noethers theorem. > Is this is how you justify using a lagrangeian and its derivatives as some > sort of definition in GR ? Learn some basics - theories are not definitions - they often contain definitions - but they are not definitions. > | > Thirdly I have no idea what time symmetry in that context means so could > | you [quoted text clipped - 3 lines] > > On your ground you think Bill. {:-) On the grounds of those who have some intelligence that may be reading this stuff. > | It refers to symmetries in a systems > | lagrangeian. If you do not know what a lagrangeian is check out [quoted text clipped - 5 lines] > reasons being that it contained no terms for the adjustment of energy as a > function of time and distance. Quite evading - the above has nothing to do with the definition of energy. > You perhaps think that this is not a dependency ? > [quoted text clipped - 26 lines] > are prepared to examine your fundamental knowledge base for > misunderstandings in a variable time/distance cosmos. Quit evading - that has nothing to do with the symmetries of a lagrangeian. > | > Fourthly I don't believe that charge as defined by the electron is > | > fundamental etc , is that enough for the moment but we can go into [quoted text clipped - 3 lines] > > This presumably means that you think charge is not an aspect of energy ? It means it has nothing to do the with modern definition of energy and is simply another attempt at your usual tactic of evasion. > This seems to contradict your ealier statement 'Energy in GR is a rather > slippery concept due to the fact that energy is the conserved Noether charge > related to time symmetry of the lagrangian - it is rather difficult to > define such when that > symmetry is lacking due to space-time curvature' Quit evading - in this context Noether charge is nothing to do with electric charge other than they both contain the word charge. And if you do not understand the terms well enough to know that post back when you have done a bit of investigation. Bill > Which might be a reason that I don't take your statements to seriously as > they seem riddled with misconceptions and contradictions. [quoted text clipped - 5 lines] > Maybe updates. (1-(1/(1/3))^2)/(1 + (1/(1/3))^2) = - 0.08 = FTL ? -p<+p or > (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? | > | > | > | > | "Significant Zero" <paulpsremove@freeuk.com> wrote in | message [quoted text clipped - 23 lines] | then the theorem is true to high accuracy - which is the reason surveyors | use Pythagoras's theorem and energy can be defined using Noethers theorem. That is avoiding the question Bill.{:-) | > Is this is how you justify using a lagrangeian and its derivatives as some | > sort of definition in GR ? | | Learn some basics - theories are not definitions - they often contain | definitions - but they are not definitions. Again avoiding the question ' some sort of defintion in GR' try again Bill {:-) | > | > Thirdly I have no idea what time symmetry in that context means so | could [quoted text clipped - 23 lines] | | > You perhaps think that this is not a dependency ? Again not answered. | > The other being that its conceptualisation may have predated the most | > primitive understanding of electricity. [quoted text clipped - 31 lines] | | Quit evading - that has nothing to do with the symmetries of a lagrangeian. It may not be in your mind Bill but it may be relevent to its use in GR. | > | > Fourthly I don't believe that charge as defined by the electron is | > | > fundamental etc , is that enough for the moment but we can go into [quoted text clipped - 7 lines] | It means it has nothing to do the with modern definition of energy and is | simply another attempt at your usual tactic of evasion. Again not answered | > This seems to contradict your ealier statement 'Energy in GR is a rather | > slippery concept due to the fact that energy is the conserved Noether [quoted text clipped - 7 lines] | understand the terms well enough to know that post back when you have done a | bit of investigation. Well I hope there are some who are intelligent enough reading this group to parse that up as you seem to have at least two definitions of charge and a new definition of energy. For those who might be confused by Bills statements, claims and definitions. ENERGY:- A measure of a system's ability to do work. Like work itself, it is measured in joules. Energy is conveniently classified into two forms: potential energy is the energy stored in a body or system as a consequence of its position, shape, or state (this includes gravitational energy, electrical energy, nuclear energy, and chemical energy); kinetic energy is energy of motion and is usually defined as the work that will be done by the body possessing the energy when it is brought to rest. For a body of mass m having a speed v, the kinetic energy is mv^2/2 (classical) or (m - m_0)c^2 (relativistic). The rotational kinetic energy of a body having an angular velocity w is Iw^2/2, where I is its moment of inertia. The *internal energy of a body is the sum of the potential energy and the kinetic energy of its component atoms and molecules. CHARGE :- A property of some *elementary particles that gives rise to an interaction between them and consequently to the host of material phenomena described as electrical. Charge occurs in nature in two forms, conventionally described as positive and negative in order to distinguish j between the two kinds of interaction between particles. Two particles that have similar charges (both negative or both positive) interact by repelling each other; two particles that have dissimilar charges (one positive, one negative) interact by attracting each other. The size of the interaction is determined by *Coulomb's law. The natural unit of negative charge is the charge on an *electron, which is equal but opposite in effect to the positive charge on the proton. Large- scale matter that consists of equal numbers of electrons and protons is, electrically neutral. If there is an excess of electrons the body is negatively charged; an excess of protons results in a positive charge. A flow of charged particals, especialy a flow of electrons, constituetes an electric current. Charge is measured in coulombs, the charge on an electron being 1.602 x 10E-19 coulombs. ENERGY(Bill) ?????? Please fill in Bill CHARGE (Bill) ??????? Please fill in Bill CHARGE NOETHER ?????? Please fill in Bill NOETHER'S THEOREM Noether's theorem Every continuous symmetry under which the *Langrangian (or *Hamiltonian) is invariant in form is associated with a ''conservation law. For example, invariance of a Langrangian under time displacement implies the conservation of energy. Not all conservation laws are associated with continuous symmetries, since some conservation laws are associated with *topology, particularly for *solitons. It does not automatically follow that if there is a conserved quantity in a .classical field theory associated with Noether's theorem, there is a conserved quantity in the corresponding *quantum field theory; this raises the possibility of an anomaly. Noether's theorem was stated in 1918 by the German mathematician Amalie Emmy Noether (1882-1935). RED HERRINGS ? to my original post Bill {:-) | Bill | [quoted text clipped - 8 lines] | or | > (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? > ENERGY:- A measure of a system's ability to do work. [...] That is an old and often not very useful definition. In modern physics, energy is the conserved Noether current corresponding to a time translation. In systems without time translation invariance, energy is not conserved, and loses much of its usefulness. In cases where your definition can be used, the new one yields the same answer. > CHARGE :- A property of some *elementary particles that gives rise to an > interaction between them and consequently to the host of material > phenomena described as electrical. [...] Such circular "definitions" are not useful at all. In modern physics, charge is the conserved Noether current for a global gauge transformation. There are no systems which do not have invariance under such transforms, so charge is always conserved. > NOETHER'S THEOREM > Noether's theorem Every continuous symmetry under which the > *Langrangian (or *Hamiltonian) is invariant in form is associated with a > ''conservation law. [...] Yes. This is one of the most powerful concepts in theoretical physics. Tom Roberts tjroberts@lucent.com | > ENERGY:- A measure of a system's ability to do work. [...] | | That is an old and often not very useful definition. Fair enough its the one used in my text books and physics dictionary but I'm not one to hang onto the old if a better model comes along, as long as its cheap enough in brain power {:-) | In modern physics, energy is the conserved Noether current corresponding | to a time translation. In systems without time translation invariance, | energy is not conserved, and loses much of its usefulness. A point I am interested in Tom, thanks. So do you think that in GR time translation is invariant ? and can you conceptualise a system in which time and distance proportionate variance produced a conserved energy situation ? and would this have any relevance to GR ? | In cases where your definition can be used, the new one yields the same | answer. [quoted text clipped - 4 lines] | | Such circular "definitions" are not useful at all. From a modern physics dictionary Tom | In modern physics, charge is the conserved Noether current for a global | gauge transformation. There are no systems which do not have invariance [quoted text clipped - 6 lines] | | Yes. This is one of the most powerful concepts in theoretical physics. But can a *Langrangian (or *Hamiltonian) always be considered as being applied to a continuous symmetry in GR.? Its certainly confusing to me as it appears that a Langrangian is based on Pythagoras's and Euclidean geometry which seem incompatible with GR. | Tom Roberts tjroberts@lucent.com > | In modern physics, energy is the conserved Noether current corresponding > | to a time translation. In systems without time translation invariance, > | energy is not conserved, and loses much of its usefulness. > > A point I am interested in Tom, thanks. So do you think that in GR time > translation is invariant ? In GR, any manifold that has a timelike Killing vector will have invariance for time translation along that vector (that's what "Killing vector" means [named after Prof. Killing, of course]). Manifolds without a timelike Killing vector do not. A "Killing vector" is necessarily a vector field on the manifold, but the word "field" is usually omitted. > and can you conceptualise a system in which time > and distance proportionate variance produced a conserved energy situation ? > and would this have any relevance to GR ? I have no idea what you are asking ("time and distance proportionate variance" means nothing to me). Note that any manifold with a timelike Killing vector is called "stationary" -- in essence as long as you use that Killing vector as a time coordinate, then nothing changes over time (nothing moves). Here's a short and incomplete list of such manifolds: Minkowski spacetime, everywhere Schwarzschild spacetime, exterior to the horizon Kerr geometry, external to the horizon ... there are others As we observe objects moving in the world we inhabit, any manifold modeling our world has no timelike Killing vector. > But can a *Langrangian (or *Hamiltonian) always be considered as being > applied to a continuous symmetry in GR.? Obviously you don't know what a Lagrangian is. That's too complicated for me to attempt to explain here -- find a good book and study it. But in a nutshell, the Lagrangian of a system expresses the "action" of the system as it evolves, and the principle of least action states that variations of the Lagrangian around the system's actual dynamical path must be zero. Using the calculus of variations can then yield differential equations for the system known as its "equations of motion"; they can be solved for the trajectories of the various components of the system. In Newtonian mechanics this can yield the trajectory of a cannonball, for instance. In GR the equation of motion is the Einstein field equation (originally discovered another way by Einstein). The "continuous symmetries" discussed here, and which are the subject of Noether's theorem, are SYMMETRIES OF THE LAGRANGIAN. That is, if energy is to be conserved in a given system then the Lagrangian for that system must not change under a time translation -- the Lagrangian must be independent of time. > Its certainly confusing to me as it > appears that a Langrangian is based on Pythagoras's and Euclidean geometry > which seem incompatible with GR. In Newtonian mechanics, Euclidean geometry is implicitly used, and geometrical terms do not appear in the Lagrangian. In GR, the Lagrangian explicitly includes the Ricci scalar, which is a geometrical term. This is why GR needs no prior geometry (geometry implicitly assumed and forever fixed) -- in GR the geometry of the manifold is dynamical, as are the trajectories and interactions of objects. Tom Roberts tjroberts@lucent.com | > | In modern physics, energy is the conserved Noether current corresponding | > | to a time translation. In systems without time translation invariance, [quoted text clipped - 10 lines] | A "Killing vector" is necessarily a vector field on the | manifold, but the word "field" is usually omitted. I was really referring to time invariance or variance as a function of the physical reality that a manifold was describing but this could easily degenerate into a debate on manifolds that might last till the cosmos freezes over so I'm not going down that route thank you{:-) Due you concur with the experimental facts that time and length are variant ? If so do you agree that to maintain the measured constancy of c locally their is a need for time and length to be changed in a proportionate manner so this apparent fact is maintained ? i.e A cubic meter of the vacuum state between galaxies has different characteristics to a cubic meter just outside an event horizon but in each place sol will be locally measured as constant but may not be the same relatively ? | > and can you conceptualise a system in which time | > and distance proportionate variance produced a conserved energy situation ? | > and would this have any relevance to GR ? | | I have no idea what you are asking ("time and distance proportionate | variance" means nothing to me). See above | Note that any manifold with a timelike Killing vector is called | "stationary" -- in essence as long as you use that Killing vector as a [quoted text clipped - 12 lines] | | Obviously you don't know what a Lagrangian is. Maybe not in your terms but Lagrangians seem to be describing the actions of particles in systems not explaining what energy is, which was the point of my original post and although I agree that explanations of the actions of objects is important and necessary it does not address what energy *is* as my original post was trying to do. . | That's too complicated | for me to attempt to explain here -- find a good book and study it. But [quoted text clipped - 25 lines] | forever fixed) -- in GR the geometry of the manifold is dynamical, as | are the trajectories and interactions of objects. Fine but are you letting the metric follow the geometry or are you using a flat Euclidean geometry and metric and referring GR's geometry to this ? -- Significant Zero E-field = Electric field, M-field =Magnetic field, two unbound field effects http://home.freeuk.com/paulps/ Maybe updates. (1-(1/(1/3))^2)/(1 + (1/(1/3))^2) = - 0.08 = FTL ? -p<+p or (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? | Tom Roberts tjroberts@lucent.com > Due you concur > with the experimental facts that time and length are variant ? Your question does not make sense. I'm going to guess that you mean that the spatial interval between a given pair of events, and the time interval between them, can be different for two different coordinate systems. If that's what you mean by "variant", then: yes. > If so do you > agree that to maintain the measured constancy of c locally their is a need > for time and length to be changed in a proportionate manner so this apparent > fact is maintained ? No. A simple counterexample is the Lorentz tranforms of SR in which the changes are not "proportionate" -- the different synchronization of clocks in different inertial frames is an essential aspect of SR. Yes, dx'/dx| = dt'/dt| = \gamma (d = partial), but in |t |x general one has NEITHER constant x NOR constant t. And it's not really appropriate to use the word "changed" here -- this is merely a geometric projection of an invariant interval onto different coordinate axes which are rotated wrt each other, so of course the projections are DIFFERENT, but not really "changed". On a piece of paper draw a 2-cm line L; draw Cartesian axes x-y, and x'-y' rotated wrt x-y. The projection of L onto the x axis is different from its projection onto the x' axis, but nothing has "changed" -- they were this way from the instant you drew L and defined the coordinate axes. This is a subtle but important point: nothing is "changing", various measurements are different; that's all. And at base the measurements are different because they are measuring different things (e.g. a length measurement in the unprimed frame measures at constant t, but one in the primed frame measures at constant t'). > i.e A cubic meter of the vacuum state between galaxies > has different characteristics to a cubic meter just outside an event horizon > but in each place sol will be locally measured as constant but may not be > the same relatively ? If by "characteristics" you mean some physical quantity like the metric or curvature tensors, or perhaps gas density, ... -- certainly they can be different in different locations. And yes, in GR any LOCALLY-INERTIAL measurement of the speed of light will yield the answer c. But your phrase "may not be the same relatively" does not make sense to me. > Maybe not in your terms but Lagrangians seem to be describing the actions of > particles in systems not explaining what energy is, Certainly the Lagrangian of a system does not, in general, by itself define energy. But if it is invariant over time translations then it does (via Noether's theorem). And if it is not so invariant, energy is not so useful.... > are you letting the metric follow the geometry or are you using a > flat Euclidean geometry and metric and referring GR's geometry to this ? The metric _IS_ the geometry. And in general it is not possible to "refer" a curved Lorentzian manifold to a "flat Euclidean geometry". Except for my (counter)example of SR above, I have been discussing GR and its general Lorentzian manifolds. Tom Roberts tjroberts@lucent.com | > Due you concur | > with the experimental facts that time and length are variant ? [quoted text clipped - 33 lines] | measurement in the unprimed frame measures at constant t, but one in the | primed frame measures at constant t'). This seems to be saying that length contraction and time dilation are just observational distortions in the same way that railway lines get apparenly nearer as they extend to the horizon. Is this the way you explain to yourself the experimental variation in muon decay and contraction in the direction of motion ? | > i.e A cubic meter of the vacuum state between galaxies | > has different characteristics to a cubic meter just outside an event horizon [quoted text clipped - 6 lines] | measurement of the speed of light will yield the answer c. But your | phrase "may not be the same relatively" does not make sense to me. This may be difficult to explain but perhaps you will agree that a clock in the in the two vacuum cases above will tick at different rates, so time according to the clocks is moving at a different rate ? If so then if c is measured locally constant in these two environments but the clocks are running at different rates then actual length must have changed to accommodate the actual but locally unobservable change in c ? | > Maybe not in your terms but Lagrangians seem to be describing the actions of | > particles in systems not explaining what energy is, [quoted text clipped - 3 lines] | does (via Noether's theorem). And if it is not so invariant, energy is | not so useful.... That makes no sense to me as energy is a dynamic and the only relatively static and invariant over time, form of energy that I can think of at the moment is a partical. Which implies that Lagrangian are not applicable to energy of fields. | > are you letting the metric follow the geometry or are you using a | > flat Euclidean geometry and metric and referring GR's geometry to this ? | | The metric _IS_ the geometry. I tend to think as the metric as being the scalars that might apply to a given metric space and the ratios and relationships as being the geometry and both being an attempt at a notational system to describe physical reality. | And in general it is not possible to | "refer" a curved Lorentzian manifold to a "flat Euclidean geometry". I don't see the difficulty in overlaying one metric space with another and translating between them other than the complexity. In fact curvature is a Euclidean statement based on the relationship of a line to straight so GR is already referenced to Euclidean space by that statement. | Except for my (counter)example of SR above, I have been discussing GR | and its general Lorentzian manifolds. As I understand it GR uses both and R............(cant remember the name at the moment). space | Tom Roberts tjroberts@lucent.com > | > Due you concur > | > with the experimental facts that time and length are variant ? [quoted text clipped - 41 lines] > yourself the experimental variation in muon decay and contraction in the > direction of motion ? That is not what it is saying at all. Perspective is an illusion - length contraction and time dilation is real - its explanation being different observers project different aspects of invariant space-time intervals onto their coordinate systems just like the rotating rod and the x coordinate. > | > i.e A cubic meter of the vacuum state between galaxies > | > has different characteristics to a cubic meter just outside an event [quoted text clipped - 12 lines] > the in the two vacuum cases above will tick at different rates, so time > according to the clocks is moving at a different rate ? For a stationary inertial observer right next to the clocks they tick at exactly the same rate (the so called proper time) so one can not say the clocks tick at different rates. It is different observers in regions that have different space-time curvature and/or are in different states of motion that measure it differently. The reason it is measured differently is not because the clocks behave differently - it is because of space-time geometry - the proper time is always the same - but different coordinate systems 'project' it differently. > If so then if c is > measured locally constant in these two environments but the clocks are > running at different rates then actual length must have changed to > accommodate the actual but locally unobservable change in c ? C is only measured constant in inertial frames. Unless you are in free fall an observer at the event horizon of a black hole is not inertial - and even if they were in free fall only extremely small objects would not experience tidal forces. > | > Maybe not in your terms but Lagrangians seem to be describing the > actions of [quoted text clipped - 9 lines] > moment is a partical. Which implies that Lagrangian are not applicable to > energy of fields. Defining energy as the conserved Noether charge related to tine symmetry does not mean it is static. You have been given the link that explains how for classical particles it arrives at kinetic angry as 1/2 mV^2 which is not static - it changes with particle velocity. > | > are you letting the metric follow the geometry or are you using a > | > flat Euclidean geometry and metric and referring GR's geometry to this ? [quoted text clipped - 5 lines] > and both being an attempt at a notational system to describe physical > reality. Knowing the metric at every point of a Riemannian space allows us to completely define the geometry. > | And in general it is not possible to > | "refer" a curved Lorentzian manifold to a "flat Euclidean geometry". [quoted text clipped - 3 lines] > Euclidean statement based on the relationship of a line to straight so GR is > already referenced to Euclidean space by that statement. The curvature tensor is a coordinate independent object defined from the metric that allows us to determine curvature without reference to Euclidian space. > | Except for my (counter)example of SR above, I have been discussing GR > | and its general Lorentzian manifolds. > > As I understand it GR uses both and R............(cant remember the name at > the moment). space I have no idea what you are trying to say. It is family obvious your problem is that you do not seem to want to study the math - if you did many of the questions you ask would be trivial. Bill > | Tom Roberts tjroberts@lucent.com > [...] > This seems to be saying that length contraction and time dilation are just > observational distortions in the same way that railway lines get apparenly > nearer as they extend to the horizon. Sort of -- both are effects of perspective, but different effects. > Is this the way you explain to > yourself the experimental variation in muon decay and contraction in the > direction of motion ? It is the way SR explains them. Just like rotations in 3D -- what "explanation" do you use for the fact that a 10-foot-long ladder will fit through a 3-foot-wide door in one orientation but not in another? I say it is because the PROJECTION of the ladder's length onto the axis of the door's width depends on their relative orientations. Similarly in SR, the PROJECTION of a rod's length, and the PROJECTION of a clock's tick-interval, depend on their orientation relative to the measuring apparatus. This is, of course, orientation in spaceTIME. On a Euclidean plane, the x' axis of Cartesian coordinates rotated relative to x-y coordinates has a nonzero dy/dx. In 2-d spacetime the x' axis of Minkowskian coordinates rotated relative to x-t coordinates has nonzero dx/dt -- that is clearly a relative velocity. The rotation is of course hyperbolic, not circular as in the Euclidean case. > | > i.e A cubic meter of the vacuum state between galaxies > | > has different characteristics to a cubic meter just outside an event > | > horizon[...] > > This may be difficult to explain but perhaps you will agree that a clock in > the in the two vacuum cases above will tick at different rates, No, I don't agree to that highly-ambiguous statement. Before you can say anything about this you have to define how the rates of the two clocks are compared. Once you realize that, you will realize that you cannot possibly separate "difference in tick rate" from "effects on the signals used to compare them". In GR this is modeled as geometry in spacetime. To do that the intrinsic rate of a clock cannot depend on its environment. For instance if you define "comparison of tick rates" by placing a standard clock next to each clock to be compared and then comparing those clocks to the standard clocks, you will immediately see that their tick rates are the same. > so time > according to the clocks is moving at a different rate ? The word "moving" does not apply to "time". A simple way to avoid such nonsense is to remember that in physics anything worth discussing must be MEASURABLE. How could one possibly measure "motion of time"??? > If so then if c is > measured locally constant in these two environments but the clocks are > running at different rates then actual length must have changed to > accommodate the actual but locally unobservable change in c ? See above. You confuse yourself by attempting to use incomplete sound bites to describe things instead of complete and detailed descriptions. Most people, especially around here, do not realize how important precision in thought and word is. Modern physics is quite subtle, and precision is ABSOLUTELY ESSENTIAL. My insistence on such precision is not "nit picking", but is ESSENTIAL to understanding the concepts. > | Certainly the Lagrangian of a system does not, in general, by itself > | define energy. But if it is invariant over time translations then it [quoted text clipped - 5 lines] > moment is a partical. Which implies that Lagrangian are not applicable to > energy of fields. You clearly do not understand Lagrangians. Study them. Don't merely fling words around without understanding. > | The metric _IS_ the geometry. > > I tend to think as the metric as being [...] You clearly do not understand differential geometry. Study it. Don't merely fling words around without understanding. > | And in general it is not possible to > | "refer" a curved Lorentzian manifold to a "flat Euclidean geometry". > > I don't see the difficulty in overlaying one metric space with another and > translating between them other than the complexity. You clearly do not understand differential geometry. Study it. Don't merely fling words around without understanding. Specifically: the topology of a curved manifold can be, and usually is, incompatible with the topology of a flat Euclidean manifold. So such "referal" or "translating" is simply not possible. Why do you think that it is impossible to cover the surface of a sphere with a single coordinate system? That is directly related to the impossibility I discuss here. > In fact curvature is a > Euclidean statement [...] Not true. You clearly do not understand differential geometry. Study it. Don't merely fling words around without understanding. Tom Roberts tjroberts@lucent.com | > [...] | > This seems to be saying that length contraction and time dilation are just [quoted text clipped - 10 lines] | "explanation" do you use for the fact that a 10-foot-long ladder will | fit through a 3-foot-wide door in one orientation but not in another? Nice example but neither the doorway or the ladder change in physical reality only the relationship between the ladder and door. The pov can change as much as it likes it still will not enable the ladder to fit through the door in the inappropriate orientation. The physical fact of the ladder and door are not changed by observation or measurement and any measurement that fails to correct for factors it is aware are imbedded in its methodology needs a poke in the eye with a sharp stick. BTW try a piano as they take no notice of observational distortion or perspective but are effected by gravity and velocity.{:-) | I say it is because the PROJECTION of the ladder's length onto the axis of | the door's width depends on their relative orientations. Yes as a physical fact. | Similarly in | SR, the PROJECTION of a rod's length, and the PROJECTION of a clock's | tick-interval, depend on their orientation relative to the measuring | apparatus. This is, of course, orientation in spaceTIME. This is not a physical fact its a observational or mathematically engineered one and has no comparison or effect on the ladder or the doorway or rod and clock. You appear to be mixing physical facts with observational and or mathematical ones and then forgetting which is which. | On a Euclidean plane, the x' axis of Cartesian coordinates | rotated relative to x-y coordinates has a nonzero dy/dx. [quoted text clipped - 11 lines] | | No, I don't agree to that highly-ambiguous statement. Well I did not think it was particularly ambiguous as if you don't agree to that then you must not agree that clocks generally run slower on earth than in space and you must now have switched to the view that GR is invalid ? | Before you can say | anything about this you have to define how the rates of the two clocks [quoted text clipped - 4 lines] | In GR this is modeled as geometry in spacetime. To do that the intrinsic | rate of a clock cannot depend on its environment. All the proof seems to contradict you as the intrinsic rate of clocks appears the be dependent on Gravityand and velocity. | For instance if you | define "comparison of tick rates" by placing a standard clock next to | each clock to be compared and then comparing those clocks to the | standard clocks, you will immediately see that their tick rates are the | same. Yes, because they are now in the same environment. | > so time | > according to the clocks is moving at a different rate ? | | The word "moving" does not apply to "time". I disagree, process is moving both in space and time. | A simple way to avoid such nonsense is to remember that in physics | anything worth discussing must be MEASURABLE. How could one possibly | measure "motion of time"??? With a clock. | > If so then if c is | > measured locally constant in these two environments but the clocks are [quoted text clipped - 8 lines] | precision is ABSOLUTELY ESSENTIAL. My insistence on such precision is | not "nit picking", but is ESSENTIAL to understanding the concepts. That's fine but I would like to nit pick some of your statements definitions and contradictions starting with your apparent contradictions with regard to physical reality, observational reality, personal conceptual reality and common conceptual reality. | > | Certainly the Lagrangian of a system does not, in general, by itself | > | define energy. But if it is invariant over time translations then it [quoted text clipped - 8 lines] | You clearly do not understand Lagrangians. Study them. Don't merely | fling words around without understanding. I might if I was convinced they applied to fields. | > | The metric _IS_ the geometry. | > | > I tend to think as the metric as being [...] | | You clearly do not understand differential geometry. Study it. Don't | merely fling words around without understanding. Thanks you can snip you own statments and views as well. | > | And in general it is not possible to | > | "refer" a curved Lorentzian manifold to a "flat Euclidean geometry". [quoted text clipped - 12 lines] | of a sphere with a single coordinate system? That is | directly related to the impossibility I discuss here. Latitude and longitude seem a fairly good system. | > In fact curvature is a | > Euclidean statement [...] | | Not true. You clearly do not understand differential geometry. Study it. | Don't merely fling words around without understanding. Perhaps you are pompously flinging concepts and words around without understanding them. -- Significant Zero E-field = Electric field, M-field =Magnetic field, two unbound field effects http://home.freeuk.com/paulps/ Maybe updates. (1-(1/(1/3))^2)/(1 + (1/(1/3))^2) = - 0.08 = FTL ? -p<+p or (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? . | Tom Roberts tjroberts@lucent.com snip > Yes as a physical fact. > [quoted text clipped - 8 lines] > You appear to be mixing physical facts with observational and or > mathematical ones and then forgetting which is which. This is a necessary procedure if you want a light-clock to change it's rate on command of your gaze. Spoonbending 101... or is that another class you were thrown out of? :o) Sue... snip | snip | > [quoted text clipped - 15 lines] | Spoonbending 101... or is that another class you were | thrown out of? :o) Hello Sue never went to those classes they used to nail the doors up if I looked as if I might be going that way, but it sounds like classes for psychopathic megalomaniacs to me who have adopted the philosophy of, if I'm not looking it don't happen. Some guy with his cat in a box thought up something along these lines, perhaps he forgot himself because I ain't heard of him recently, maybe the gas exploded that they were trying to kill the cat with and they all got blown up, good riddance to the cat destroyers I would have set the RSPCA on them if I had heard about it sooner{:-) Trying to sell my bike etc at the moments (to old and decrepit to ride it with fun) so my NG concentration and contact is a bit erratic AND EE decided to erase my NG records so I have only partly reloaded them off the server. Do you mean Tom and Bill are Ure Gella fans ? -- Significant Zero E-field = Electric field, M-field =Magnetic field, two unbound field effects http://home.freeuk.com/paulps/ Maybe updates. (1-(1/(1/3))^2)/(1 + (1/(1/3))^2) = - 0.08 = FTL ? -p<+p or (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? | Sue... | | snip > | snip > | > [quoted text clipped - 27 lines] > would have set the RSPCA on them if I had heard about it sooner{:-) Trying > to sell my bike etc at the moments (to old and decrepit to ride it with fun) If it should be a Raleigh 3 speed, be sure and find it a good home. They are becomeing quite a collector's piece. > so my NG concentration and contact is a bit erratic AND EE decided to erase > my NG records so I have only partly reloaded them off the server. Do you > mean Tom and Bill are Ure Gella fans ? I won't attest to that but they seem to get a little flustered when Randy (sp) :o) types start asking embarassing questions. Sue... > -- > Significant Zero E-field = Electric field, M-field =Magnetic field, two [quoted text clipped - 6 lines] > | > | snip > | > [...] > | > This seems to be saying that length contraction and time dilation are [quoted text clipped - 15 lines] > Nice example but neither the doorway or the ladder change in physical > reality only the relationship between the ladder and door. And the same in SR - neither the coordinate system or the clock change in physical reality only the relationship between them. > The pov can > change as much as it likes it still will not enable the ladder to fit > through the door in the inappropriate orientation. The same with SR - clocks will not measure time dilated unless they have the appropriate 'orientation's wrt the coordinate system. > The physical fact of the > ladder and door are not changed by observation or measurement The same with SR - the proper time is not changed either. > and any > measurement that fails to correct for factors it is aware are imbedded in > its methodology needs a poke in the eye with a sharp stick. And so does SR - which is why proper time is the only invariant time. Bill > BTW try a piano as they take no notice of observational distortion or > perspective but are effected by gravity and velocity.{:-) [quoted text clipped - 151 lines] > | > | Tom Roberts tjroberts@lucent.com > > | > [...] > > | > This seems to be saying that length contraction and time dilation are [quoted text clipped - 39 lines] > > Bill So... why don't you ever take Uncle Al to task when he post that crap about the H&K experiment. The theory says the flying clocks should keep proper time. The raw data says they were in fact keeping proper time but you consistantly support or fail to challenge an interpretation that says otherwise. Uncle Al wrote: << 2) Hafele-Keating Experiment <http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/airtim.html> <http://metrologyforum.tm.agilent.com/pdf/flying_clock_math.pdf> http://metrologyforum.tm.agilent.com/cesium.shtml http://arxiv.org/abs/physics/0008012 3) Idiot. <http://tycho.usno.navy.mil/ptti/ptti2002/paper20.pdf> Nature 425 374 (2003) >> http://groups-beta.google.com/group/sci.physics.relativity/msg/3d743bf48d251b0f?hl=en& If traveling clocks returned showing any but device dependant effects of accelerating forces then it *disproves* SR, whose postulates preserve the accuracy of the device with PoR and attribute for any obseved difference to the path delay. A.G. Kelly is the support for SR... not H&K. http://www.google.com/search?hl=en&q=Hafele+kelly&btnG=Google+Search Sue... > > BTW try a piano as they take no notice of observational distortion or > > perspective but are effected by gravity and velocity.{:-) [quoted text clipped - 163 lines] > > | > > | Tom Roberts tjroberts@lucent.com > > > | > [...] > > > | > This seems to be saying that length contraction and time dilation are [quoted text clipped - 43 lines] > crap about the H&K experiment. The theory says the flying clocks > should keep proper time. That is not what is said. Familiarize yourself with the clock postulate http://math.ucr.edu/home/baez/physics/Relativity/SR/clock.html. As usual your pasts consist of irrelevant misdirection. Bill > The raw data says they were in fact > keeping proper time but you consistantly support or fail to [quoted text clipped - 11 lines] > <http://tycho.usno.navy.mil/ptti/ptti2002/paper20.pdf> > Nature 425 374 (2003) >> http://groups-beta.google.com/group/sci.physics.relativity/msg/3d743bf48d251b0f?hl=en& > If traveling clocks returned showing any but device dependant > effects of accelerating forces then it *disproves* SR, whose [quoted text clipped - 173 lines] > > > | > > > | Tom Roberts tjroberts@lucent.com > > "Bill Hobba" <bhobba@rubbish.net.au> wrote in message > news:L3kEe.59411$oJ.36184@news-server.bigpond.net.au... [quoted text clipped - 58 lines] > > As usual your pasts consist of irrelevant misdirection. That has nothing to do with SR. It makes no mention or accounting of the optical path which is SR's basis for a clock to vary and it makes no mention of the H&K experiment. Perhaps you are misdirecting yourself with careless reading habits. Sue... > Bill > [quoted text clipped - 221 lines] > > > > | > > > > | Tom Roberts tjroberts@lucent.com | > | > [...] | > | > This seems to be saying that length contraction and time dilation are [quoted text clipped - 39 lines] | | Bill Thanks Bill that seems to say that environmental time is invariant but observational time is variant ? Is your view that the same is also true for length ? You also seem to be saying that SR needs a poke in the eye with a sharp stick but that may be because you misread my post ? -- Significant Zero E-field = Electric field, M-field =Magnetic field, two unbound field effects http://home.freeuk.com/paulps/ Maybe updates. (1-(1/(1/3))^2)/(1 + (1/(1/3))^2) = - 0.08 = FTL ? -p<+p or (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? > | > | > [...] > | > | > This seems to be saying that length contraction and time dilation [quoted text clipped - 45 lines] > Thanks Bill that seems to say that environmental time is invariant but > observational time is variant ? I am saying that in relativity what is measured is determined by a projection of invariant objects onto your particular coordinate system just like the projection of the rotating rod onto the x-y coordinate system. It is those invariant objects that are important in the theory (and is the reason the principle of general covariance is important) - not the projections - which is precisely what is meant by saying relativity is basically geometry. It was realized in the 19th century that, expressed rather loosely, geometry is the study of a theories invariants. For more detail do a search on the Erlangen program http://en.wikipedia.org/wiki/Erlangen_programme As I have said previously one of your problems is you are trying to understand a mathematical theory semantically. Study the math and the answer will be clear. Bill > Is your view that the same is also true for length ? > You also seem to be saying that SR needs a poke in the eye with a sharp [quoted text clipped - 6 lines] > Maybe updates. (1-(1/(1/3))^2)/(1 + (1/(1/3))^2) = - 0.08 = FTL ? -p<+p or > (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? | > | > | > [...] | > | > | > This seems to be saying that length contraction and time dilation [quoted text clipped - 66 lines] | | Bill This is saying study my notation and you will then write notation like me. Perhaps I might say that geometry is the study of the relationship of variants and varience and the only invarience is the geometry used. | > -- | > Significant Zero E-field = Electric field, M-field =Magnetic field, two [quoted text clipped - 3 lines] | or | > (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? > | > | > | > [...] > | > | > | > This seems to be saying that length contraction and time [quoted text clipped - 76 lines] > > This is saying study my notation and you will then write notation like me. That is not what it is saying. It is saying what has become obvious from the questions you ask - if you actually study the things you ask questions about then the answer is obvious. The fact you ask the kind of questions you do indicates you are not studying the concepts. For example you asked in another part of this thread how we know proper time is always constant. Proper time is the time read by an imaginary clock traveling along with a particle so obviously it is always the same regardless of what coordinate system you use or what cosmological model you hold to or pretty much anything you can think of. Once you understand the concept the answer is obvious. Concentrate on understanding the concepts instead of posting questions about them. > Perhaps I might say that geometry is the study of the relationship of > variants and varience and the only invarience is the geometry used. Physics or even mathematics for that matter is not about inventing your own definitions then expecting to understand the material from the perspective of the definitions you have invented. In fact that is trivially obvious for any domain of discourse. If you wish to be understood and understand then you must use words in the way that is standard in what you wish to discuss. Bill > | > -- > | > Significant Zero E-field = Electric field, M-field =Magnetic field, [quoted text clipped - 4 lines] > | or > | > (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? | Physics or even mathematics for that matter is not about inventing your own | definitions then expecting to understand the material from the perspective [quoted text clipped - 3 lines] | | Bill The hell it isn't! Mathematics has aways been about making definitions since before Euclid's 5th postulate, and Einstein's definition of time [quote] We have not defined a common ``time'' for A and B, for the latter cannot be defined at all unless we establish by definition that the ``time'' required by light to travel from A to B equals the ``time'' it requires to travel from B to A. [unquote] and if that isn't inventing your own definition I don't know what is. Here, I'll invent mine. WE establish by definition that the "time" required by SOUND to travel from A to B equals the "time'' it requires to travel from B to A. Want some postulates as well? "SOUND is always propagated in air with a definite velocity Mach1 which is independent of the state of motion of the emitting body" Using Einstein's math, gamma = 1/sqrt(1 -v^2/Mach1^2) Now time dilate that. Androcles. > | Physics or even mathematics for that matter is not about inventing > your own [quoted text clipped - 11 lines] > Mathematics has aways been about making definitions since before > Euclid's 5th postulate, and Einstein's definition of time It is not and never has been about changing standard definitions. Rest snipped. Bill | > | > | > | > [...] | > | > | > | > This seems to be saying that length contraction and time [quoted text clipped - 105 lines] | | Bill That would be true if everbody had the same concept for any given word but we all have our own personal idea of what words and notation mean and the point of debate is to try and detemine which view is the most coherent, from my pov anyway you will possibly attach a different meaning to my words and any notation I might post.{:-) I give you this as an extract from a defintion of proper time. "In Special Relativity neither length nor time interval are invarient under transformation between inertial frames." That appears to me as a word salad that has decayed into rubbish as per my interpretation below. I take this to read that the transformes are unable to correct for perspective\obsevational differences between inertial co-ordinate systems and you will just have to guess at any real physical differences between two or more real physical objects that were the same but are now in different inertial systems. And to cap it. However , there is a combination of length and time which is invariant , which is known as the (space-time ) interval. mathmatical mumble, mumble etc. Talk about covering every option with imprecision to ensure that you can never be pointed to as having been incorrect{:-) ROFLMAO Call this physics its more like a kiddies magic show performed by a VERY inexperienced (but persistent)magician. The extracts are from. http://www.pact.cpes.sussex.ac.uk/~markh/GR/node13.html DOES TIME AND LENGTH PHYSICAL CHANGE FROM WHAT IT MAY HAVE BEEN AS A RESULT OF A CHANGE IN MOTION AND OR GRAVITATIONAL INTENSITY, YES OR NO. I believe they do and have a good idea of why if its any help.{:-) I liked your statement above that I read as proper time is any time. Nice level of obscurity and uselessness {:-) Perhaps you now realise that its not that I don't study the stuff you have been trained in its just that it is frequently nonsense from my pov, so just in case it is not all nonsense I post to this group searching for coherence. | > | > -- | > | > Significant Zero E-field = Electric field, M-field =Magnetic field, [quoted text clipped - 5 lines] | > | or | > | > (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? > | > | > | > | > [...] > | > | > | > | > This seems to be saying that length contraction and time [quoted text clipped - 119 lines] > That would be true if everbody had the same concept for any given word but > we all have our own personal idea of what words and notation mean I beg yours. The notation and ideas both myself and Tom have mentioned are not personal - they are standard to physics. > and the > point of debate is to try and detemine which view is the most coherent, from [quoted text clipped - 7 lines] > That appears to me as a word salad that has decayed into rubbish as per my > interpretation below. It follows trivially from the Lorentz transformations. If you can not see that then you really so need to think harder. Indeed if that is not obvious I suspect physics is beyond you. No problem if that is the case - but just as there are those who can not understand the variables used in algebra and can not see how the x and y's etc can stand for unknowns the problem lies in you not the subject > I take this to read that the transformes are unable to correct for > perspective\obsevational differences between inertial co-ordinate systems [quoted text clipped - 12 lines] > ROFLMAO Call this physics its more like a kiddies magic show performed by a > VERY inexperienced (but persistent)magician. You may not be able to see it but all the above indicates is your inability to reason out very simple things. > The extracts are from. > http://www.pact.cpes.sussex.ac.uk/~markh/GR/node13.html > > DOES TIME AND LENGTH PHYSICAL CHANGE FROM WHAT IT MAY HAVE BEEN AS A RESULT > OF A CHANGE IN MOTION AND OR GRAVITATIONAL INTENSITY, YES OR NO. As usual that depends on what you mean by physically change. They measure different that is for sure - so if that is what you mean then the answer is yes. If you mean do the things that are considered fundamental in the theory like the actual lengths of a rod rather than their projections on an axis then no. You must stop this engaging in irrelevant semantics and understand the math. The math remains true regardless of what you mean by terms like physically change - which is one reason math is often preferred to English in physics. Bill > I believe they do and have a good idea of why if its any help.{:-) > [quoted text clipped - 15 lines] > | > | or > | > | > (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? | > | > | > | > | > [...] | > | > | > | > | > This seems to be saying that length contraction and time [quoted text clipped - 157 lines] | can not see how the x and y's etc can stand for unknowns the problem lies in | you not the subject And I counter with a theory as apparently understood by you is irelevent to understanding the real physical changes that may happend due to motion and gravirational intensity. BTW I think I understand the application of this transform and the reality behind it in a more complete manner than you and will rewrite that phrase so it makes some relevent to physical reality sense. "In physical reality neither length nor time interval are invarient and under Special Relativity transformations between inertial frames, the true state of the observed object relative to the observer may be determined in some cases." And The local observer will have difficult determining any variance in time and distance by local measurement alown. | > I take this to read that the transformes are unable to correct for | > perspective\obsevational differences between inertial co-ordinate systems [quoted text clipped - 17 lines] | You may not be able to see it but all the above indicates is your inability | to reason out very simple things. I see you as having the same problem {:-) | > The extracts are from. | > http://www.pact.cpes.sussex.ac.uk/~markh/GR/node13.html [quoted text clipped - 9 lines] | axis then no. You must stop this engaging in irrelevant semantics and | understand the math. I would counter with you must stop engaginging in irelevent math that have no base in physical realitiy and are you not just playing with your geometry set using your statments as a base for your understanding of physical reality. {:-) | The math remains true regardless of what you mean by | terms like physically change - which is one reason math is often preferred | to English in physics. Math may indeed be a very useful tool to aid our understanding of reality but like any tool it can be abused as can also be said for words. | Bill | [quoted text clipped - 19 lines] | > | > | or | > | > | > (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? > | > | > | > | > | > [...] > | > | > | > | > | > This seems to be saying that length contraction and time [quoted text clipped - 194 lines] > state of the observed object relative to the observer may be determined in > some cases." That may be how you view it but my claim is phrases like 'in physical relaity' lie beyond experimental verification and are philoshical positions not particularly relevant to science. The view Tom and myself have been presenting follows quite simply from the principle of general covariance - that the laws of physics should be put in a form that are independent of coordinate systems - which really follows from the view there is a single objective reality out there. This means the key elements of the theory are invariants and since geometry was discovered in the nineteenth century to be basically a theory about invariants (loosely speaking) then the correct language to use is the language of geometry. However it is also well known that the principle of general covariance is without actual physical content (as was pointed out to Einstein by Kretchman) and so can not really be an objective basis for anything. However experience has shown it is a very valuable heuristic and it still retained. And that is the bottom line - experience has shown the most elegant and best way to view relativity is geometrically. If you want to form you own views - fine go ahead. But I think you would be wise to listen to Gerad t Hooft, http://www.phys.uu.nl/~thooft/theorist.html 'Do get me right: you don't have to believe anything you read on faith - check it. Try alternative approaches, as many as you can. You will discover, time and again, that really what those guys did indeed was the smartest thing possible.' It is fairly obvious you are the type that needs to learn it from experience. Bill > And > The local observer will have difficult determining any variance in time and [quoted text clipped - 81 lines] > | > | > | or > | > | > | > (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? | > | > | > | > | "Significant Zero" <paulpsremove@freeuk.com> wrote in | message [quoted text clipped - 144 lines] | posting | > | > | questions about them. What in vacuum {:-) This is me trying to understand yours and others views and concepts on various subjects. Your not a mind reader by any chance so I have no need to bother to post to find out what you think ?{:-) Perhaps you learned your views by some alien process of osmosis? Proper Time (informal) Proper time is time as measured by the clock for an observer who is traveling through spacetime. The concept of proper time is necessary in Einstein's theories of relativity because of effects such as time dilation, which result in observers travelling between the same positions different paths/world lines through spacetime experiencing time differently. Proper Time (mathematical) The formal definition of proper time involves describing the path that a clock, observer, or test particle is taking through spacetime and the metric structure of that spacetime. Using tensor calculus, proper time is defined as follows: Given a spacetime which is: a pseudo-Riemanman manifold mapped with a coordinate system x^u and equipped with a corresponding metric tensor g_uv the proper time T experienced in moving between two events along a timelike path P is given by the path integral etc. Latter in this post you state "If you mean do the things that are considered fundamental in the theory like the actual lengths of a rod rather than their projections on an axis then no." Which reads to me as if you are saying that the length of rods never physical changes and only their apparent length as projected on an axis changes. | > | > | > Perhaps I might say that geometry is the study of the relationship | > of [quoted text clipped - 72 lines] | relaity' lie beyond experimental verification and are philoshical positions | not particularly relevant to science. Fine if you wish to express the view that railway lines only measure one inch at the horizon then please do, only dont expect me to see it as other than art. | The view Tom and myself have been | presenting follows quite simply from the principle of general covariance - | that the laws of physics should be put in a form that are independent of | coordinate systems - which really follows from the view there is a single | objective reality out there. That fine and that is all I'm after the objective reality, the subjective reality which is what you seem to be presenting is fine as a picture on the wall or a natter down the pub but lets move beyond this and try to be as objective as possible about reality. |This means the key elements of the theory are | invariants and since geometry was discovered in the nineteenth century to be | basically a theory about invariants (loosely speaking) then the correct | language to use is the language of geometry. But this does not fit with the data that I have collected in that time and distance are physical varients that you then might be able to derive localy measured mathematical constants out of but as far as cosmic constants go its every person for themselves. | However it is also well known | that the principle of general covariance is without actual physical content [quoted text clipped - 5 lines] | think you would be wise to listen to Gerad t Hooft, | http://www.phys.uu.nl/~thooft/theorist.html Thanks Bill he writes like you, are you sure that Bill Hobba is not a nome de plume for Gerad t Hooft{:-) If my object in life was to become a *good* theoretical physicist and gain a Nobel prize that advise might be relevant, it did have some points that I'm thinking about but my objective is to *understand* the construction of objects\fields and the real physical relationships between objects\fields. Mind you if I find were they grow noble carrots I might tarry awhile, hee haw hee haw.{:-) | 'Do get me right: you don't have to believe anything you read on faith - | check it. Try alternative approaches, as many as you can. You will discover, [quoted text clipped - 5 lines] | | Bill I have not presented myself as other than that. | > And | > The local observer will have difficult determining any variance in time [quoted text clipped - 90 lines] | > | > | > | or | > | > | > | > (m*-v)<(m*+v) or (m*-c^2)<(m*+c^2) =g? > | It is the way SR explains them. Just like rotations in 3D -- what > | "explanation" do you use for the fact that a 10-foot-long ladder will > | fit through a 3-foot-wide door in one orientation but not in another? > > Nice example but neither the doorway or the ladder change in physical > reality only the relationship between the ladder and door. Right. Ditto for "time dilation" and "length contraction" in SR -- neither clock nor ruler "changes in physical reality", only the relationship between moving clock and stationary clocks, or between moving ruler and stationary ruler. A rotation is a rotation -- in Euclidean space or in spacetime. Rotations affect projections of objects onto axes, but THEY DO NOT AFFECT THE OBJECTS THEMSELVES. A relative velocity is merely a rotation in the x-t plane. <shrug> > | I say it is because the PROJECTION of the ladder's length onto the axis > of > | the door's width depends on their relative orientations. > > Yes as a physical fact. No. You need a MODEL of the world to describe this. The only "physical facts" are whether or not it fits each time you apply ladder to doorway. Both geometrical projection and rotation are such models (well, parts of such models). Just think of each application of ladder to doorway as a MEASUREMENT (of ladder's length projected onto the doorway's width), and you'll see the relationship between this and "length contraction" and "time dilation" in SR. It's just that the ladder/doorway is quite familiar to you, but the SR effects aren't -- to understand SR you need to change that familiarity.... > | Similarly in > | SR, the PROJECTION of a rod's length, and the PROJECTION of a clock's > | tick-interval, depend on their orientation relative to the measuring > | apparatus. This is, of course, orientation in spaceTIME. > > This is not |
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