A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: Ste on 17 Feb 2010 14:18 On 17 Feb, 18:24, PD <thedraperfam...(a)gmail.com> wrote: > On Feb 17, 11:39 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > On 17 Feb, 16:00, Paul Stowe <theaether...(a)gmail.com> wrote: > > > > On Feb 17, 7:04 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > As we discussed earlier, it may be that we are only AWARE of four > > > > > dimensions. It may well be that there are more. Then the way to > > > > > entertain this notion is to ask the question, how would something that > > > > > is only AWARE of two dimensions become convinced that there is a third > > > > > dimension? This turns out to be very answerable. > > > > > I'm afraid that was not my conclusion. As I've said, these > > > > possibilities only seem credible to those who already hold them to be > > > > credible. > > > > What I've seen here, and even in some books, is a vague improper use > > > of the term dimension. From what I can tell, the term is strictly as > > > used, a mathematical concept. See: > > > >http://mathworld.wolfram.com/Dimension.html > > > > It is often confused with the concept of physical properties such as > > > mass, length, time, charge. Since two of these (length and time) are > > > modeled using geometrical dimensionality this leads to the confusion. > > > Adding further to this is the unitary systems we assign to the > > > physical properties (kilogram, meter, second, Coulomb, ... etc.). A > > > dimension has no physical existence and a physical property has no > > > inherent unitary values, we must combine these concepts to make, > > > quantify, and describe physical systems and processes. > > > > As time goes on we get more creative on assigning the term. In > > > relativity where we have, > > > > dx^2 + dy^2 + dz^2 - ds^2 = 0 > > > > The s (ct) term isn't itself a simply point, it's a computed > > > projection of a destination (point) dependent upon a physical > > > property, the speed c. To have strict orthogonal axes c must remain > > > constant over infinite space. In turn, if this were true, there would > > > be no need for the hydrodynamical equation of General relativity. In > > > fact, all observational evidence to date supports the fact that, by > > > strict definition of the term dimension only three primal or actual > > > dimensions exist and time is 'mapped' into pseudo forth using the > > > physical property of c to do so. > > > Indeed. Some people look at you funny when you talk of something like > > a "five-dimensional database". > > > I'm convinced that the essential need for the 4th dimension in > > relativity, and the significance of 'c', is simply because > > electromagnetic propagation delays have become practically > > significant. > > Then you are erroneously convinced. > You may recall that we were discussing how to determine simultaneity > when those propagation delays are fully accounted for. Well, we'll work though that after I have a clear picture of how light moves. > > Before the end of the 19th century and the development of > > electromagnetic communications over long distances, electromagnetic > > effects for all practical purposes moved instantaneously. > > And that's just flat wrong. Well before the 19th century, the > aberration of the orbit of Jupiter was *known* to be due to the > propagation delay of light. I know. I didn't say "no one knew the speed of light was finite". I'm saying that there was no need to formalise it for any practical purpose.
From: BURT on 17 Feb 2010 14:28 On Feb 17, 11:18 am, Ste <ste_ro...(a)hotmail.com> wrote: > On 17 Feb, 18:24, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > On Feb 17, 11:39 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 17 Feb, 16:00, Paul Stowe <theaether...(a)gmail.com> wrote: > > > > > On Feb 17, 7:04 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > As we discussed earlier, it may be that we are only AWARE of four > > > > > > dimensions. It may well be that there are more. Then the way to > > > > > > entertain this notion is to ask the question, how would something that > > > > > > is only AWARE of two dimensions become convinced that there is a third > > > > > > dimension? This turns out to be very answerable. > > > > > > I'm afraid that was not my conclusion. As I've said, these > > > > > possibilities only seem credible to those who already hold them to be > > > > > credible. > > > > > What I've seen here, and even in some books, is a vague improper use > > > > of the term dimension. From what I can tell, the term is strictly as > > > > used, a mathematical concept. See: > > > > >http://mathworld.wolfram.com/Dimension.html > > > > > It is often confused with the concept of physical properties such as > > > > mass, length, time, charge. Since two of these (length and time) are > > > > modeled using geometrical dimensionality this leads to the confusion. > > > > Adding further to this is the unitary systems we assign to the > > > > physical properties (kilogram, meter, second, Coulomb, ... etc.). A > > > > dimension has no physical existence and a physical property has no > > > > inherent unitary values, we must combine these concepts to make, > > > > quantify, and describe physical systems and processes. > > > > > As time goes on we get more creative on assigning the term. In > > > > relativity where we have, > > > > > dx^2 + dy^2 + dz^2 - ds^2 = 0 > > > > > The s (ct) term isn't itself a simply point, it's a computed > > > > projection of a destination (point) dependent upon a physical > > > > property, the speed c. To have strict orthogonal axes c must remain > > > > constant over infinite space. In turn, if this were true, there would > > > > be no need for the hydrodynamical equation of General relativity. In > > > > fact, all observational evidence to date supports the fact that, by > > > > strict definition of the term dimension only three primal or actual > > > > dimensions exist and time is 'mapped' into pseudo forth using the > > > > physical property of c to do so. > > > > Indeed. Some people look at you funny when you talk of something like > > > a "five-dimensional database". > > > > I'm convinced that the essential need for the 4th dimension in > > > relativity, and the significance of 'c', is simply because > > > electromagnetic propagation delays have become practically > > > significant. > > > Then you are erroneously convinced. > > You may recall that we were discussing how to determine simultaneity > > when those propagation delays are fully accounted for. > > Well, we'll work though that after I have a clear picture of how light > moves. > > > > Before the end of the 19th century and the development of > > > electromagnetic communications over long distances, electromagnetic > > > effects for all practical purposes moved instantaneously. > > > And that's just flat wrong. Well before the 19th century, the > > aberration of the orbit of Jupiter was *known* to be due to the > > propagation delay of light. > > I know. I didn't say "no one knew the speed of light was finite". I'm > saying that there was no need to formalise it for any practical > purpose.- Hide quoted text - > > - Show quoted text - Light is the dual Unified force that communicates in the universe. Mitch Raemsch
From: BURT on 17 Feb 2010 14:34 On Feb 17, 11:18 am, Ste <ste_ro...(a)hotmail.com> wrote: > On 17 Feb, 18:24, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > On Feb 17, 11:39 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 17 Feb, 16:00, Paul Stowe <theaether...(a)gmail.com> wrote: > > > > > On Feb 17, 7:04 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > As we discussed earlier, it may be that we are only AWARE of four > > > > > > dimensions. It may well be that there are more. Then the way to > > > > > > entertain this notion is to ask the question, how would something that > > > > > > is only AWARE of two dimensions become convinced that there is a third > > > > > > dimension? This turns out to be very answerable. > > > > > > I'm afraid that was not my conclusion. As I've said, these > > > > > possibilities only seem credible to those who already hold them to be > > > > > credible. > > > > > What I've seen here, and even in some books, is a vague improper use > > > > of the term dimension. From what I can tell, the term is strictly as > > > > used, a mathematical concept. See: > > > > >http://mathworld.wolfram.com/Dimension.html > > > > > It is often confused with the concept of physical properties such as > > > > mass, length, time, charge. Since two of these (length and time) are > > > > modeled using geometrical dimensionality this leads to the confusion. > > > > Adding further to this is the unitary systems we assign to the > > > > physical properties (kilogram, meter, second, Coulomb, ... etc.). A > > > > dimension has no physical existence and a physical property has no > > > > inherent unitary values, we must combine these concepts to make, > > > > quantify, and describe physical systems and processes. > > > > > As time goes on we get more creative on assigning the term. In > > > > relativity where we have, > > > > > dx^2 + dy^2 + dz^2 - ds^2 = 0 > > > > > The s (ct) term isn't itself a simply point, it's a computed > > > > projection of a destination (point) dependent upon a physical > > > > property, the speed c. To have strict orthogonal axes c must remain > > > > constant over infinite space. In turn, if this were true, there would > > > > be no need for the hydrodynamical equation of General relativity. In > > > > fact, all observational evidence to date supports the fact that, by > > > > strict definition of the term dimension only three primal or actual > > > > dimensions exist and time is 'mapped' into pseudo forth using the > > > > physical property of c to do so. > > > > Indeed. Some people look at you funny when you talk of something like > > > a "five-dimensional database". > > > > I'm convinced that the essential need for the 4th dimension in > > > relativity, and the significance of 'c', is simply because > > > electromagnetic propagation delays have become practically > > > significant. > > > Then you are erroneously convinced. > > You may recall that we were discussing how to determine simultaneity > > when those propagation delays are fully accounted for. > > Well, we'll work though that after I have a clear picture of how light > moves. > > > > Before the end of the 19th century and the development of > > > electromagnetic communications over long distances, electromagnetic > > > effects for all practical purposes moved instantaneously. > > > And that's just flat wrong. Well before the 19th century, the > > aberration of the orbit of Jupiter was *known* to be due to the > > propagation delay of light. > > I know. I didn't say "no one knew the speed of light was finite". I'm > saying that there was no need to formalise it for any practical > purpose.- Hide quoted text - > > - Show quoted text - The speed of light establishes that it is nonlocal. It does not move infinitely fast. Mitch Raemsch
From: PD on 17 Feb 2010 14:35 On Feb 17, 1:18 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 17 Feb, 18:24, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Feb 17, 11:39 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 17 Feb, 16:00, Paul Stowe <theaether...(a)gmail.com> wrote: > > > > > On Feb 17, 7:04 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > As we discussed earlier, it may be that we are only AWARE of four > > > > > > dimensions. It may well be that there are more. Then the way to > > > > > > entertain this notion is to ask the question, how would something that > > > > > > is only AWARE of two dimensions become convinced that there is a third > > > > > > dimension? This turns out to be very answerable. > > > > > > I'm afraid that was not my conclusion. As I've said, these > > > > > possibilities only seem credible to those who already hold them to be > > > > > credible. > > > > > What I've seen here, and even in some books, is a vague improper use > > > > of the term dimension. From what I can tell, the term is strictly as > > > > used, a mathematical concept. See: > > > > >http://mathworld.wolfram.com/Dimension.html > > > > > It is often confused with the concept of physical properties such as > > > > mass, length, time, charge. Since two of these (length and time) are > > > > modeled using geometrical dimensionality this leads to the confusion. > > > > Adding further to this is the unitary systems we assign to the > > > > physical properties (kilogram, meter, second, Coulomb, ... etc.). A > > > > dimension has no physical existence and a physical property has no > > > > inherent unitary values, we must combine these concepts to make, > > > > quantify, and describe physical systems and processes. > > > > > As time goes on we get more creative on assigning the term. In > > > > relativity where we have, > > > > > dx^2 + dy^2 + dz^2 - ds^2 = 0 > > > > > The s (ct) term isn't itself a simply point, it's a computed > > > > projection of a destination (point) dependent upon a physical > > > > property, the speed c. To have strict orthogonal axes c must remain > > > > constant over infinite space. In turn, if this were true, there would > > > > be no need for the hydrodynamical equation of General relativity. In > > > > fact, all observational evidence to date supports the fact that, by > > > > strict definition of the term dimension only three primal or actual > > > > dimensions exist and time is 'mapped' into pseudo forth using the > > > > physical property of c to do so. > > > > Indeed. Some people look at you funny when you talk of something like > > > a "five-dimensional database". > > > > I'm convinced that the essential need for the 4th dimension in > > > relativity, and the significance of 'c', is simply because > > > electromagnetic propagation delays have become practically > > > significant. > > > Then you are erroneously convinced. > > You may recall that we were discussing how to determine simultaneity > > when those propagation delays are fully accounted for. > > Well, we'll work though that after I have a clear picture of how light > moves. Alright, then all I ask is that you hold on pause your conviction that this is all due to propagation delays, since you have no solid grounds for believing that yet. > > > > Before the end of the 19th century and the development of > > > electromagnetic communications over long distances, electromagnetic > > > effects for all practical purposes moved instantaneously. > > > And that's just flat wrong. Well before the 19th century, the > > aberration of the orbit of Jupiter was *known* to be due to the > > propagation delay of light. > > I know. I didn't say "no one knew the speed of light was finite". I'm > saying that there was no need to formalise it for any practical > purpose. And that's STILL incorrect. It was important to know where Jupiter *really* was in orbit, compared with where it *appeared* to be due to propagation delays.
From: PD on 17 Feb 2010 14:42
On Feb 17, 12:51 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 17 Feb, 16:09, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Feb 17, 8:46 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > I only agree with you that this is the burden of the expert in a > > > > constructed teacher-student environment, wherein there is a > > > > contractual arrangement that the student be taught something by the > > > > expert. > > > > > In an informal discussion group, and in particular a free one, there > > > > is no such arrangement and hence no such burden, although one might be > > > > undertaken on an ad hoc and completely voluntary basis. > > > > > You and I have already discussed this: that it is NOT the obligation > > > > of the expert to share knowledge. It is not true in law, medicine, > > > > plumbing, architecture, music, or engineering. Good musicians may > > > > offer lessons to students who want to learn, but that is usually under > > > > a contractual arrangement. It is the obligation of the expert to USE > > > > that knowledge to get work done. It is the obligation of a surgeon to > > > > USE his knowledge to make people well, but it is not his obligation to > > > > share his knowledge with others. > > > > As I say, there may be a moral difference here in some respects, but > > > I'm not really arguing whether or not there is a burden on an expert > > > to share knowledge. And indeed, if it is the intention of experts to > > > obfuscate a subject, strengthen their professional bargaining > > > positions, and exclude the majority, then it probably makes sense to > > > speak a different language. > > > But that isn't the only reason to use jargon, nor is it the reason > > that is used by scientists, AFAIK. > > I generally don't place too much emphasis on the explicit > justifications for certain behaviours. > > There is no doubt an argument that a specialised vocabulary increases > the efficiency of communication between professionals - but of course > the corollary to this is that a habitual reliance on such a vocabulary > dramatically increases the *inefficiency* of communicating with non- > professionals. That's OK. Because the priority is given to professionals getting their work done, which places a higher premium on them communication with *each other* than it does on communication with nonprofessionals. You'll note the same thing in a hospital, where doctors and nurses are communicating in a highly specialized language that is very efficient for the purpose of making people healthier. > > However, even this justification often does not stand up to close > scrutiny. Many people (and this is not confined to any particular > profession) use specialised words where general ones will do, unusual > words where common ones will do, big words where smaller ones will do, > foreign words where native ones will do, complex constructs where > simple ones will do, to the extent that communication even with > educated professionals in the same field is made difficult. I disagree that the communication between educated professionals is compromised as a result. At least in physics. You have evidence to support that contention? > > In these cases, whatever the real motivation for the vocabulary used, > it is not efficiency of communication (whether between professionals > or not). > > > > > > The point I'm making is that where "experts" are *purporting* to > > > desire productive communication with others who they know are not > > > experts, then they should recognise that this requires communication > > > skills, amongst which is the ability to converse in a common language.. > > > Yes, but there's a tradeoff, and this is the tradeoff that is seen in > > popularizations. > > Popularization authors DO tend to try to use conventional language. > > But the drawback is that conventional language is looser and vaguer > > than the precise meanings used in physics. As a result, what is > > conveyed is also looser, vaguer, and more prone to misinterpretation, > > although it is more accessible. This limits the function of a > > popularization to TEACH the material. The saving strategy is then to > > use the popularization as an incentivizer to encourage the reader to > > embark on reading more carefully prepared materials, where more > > attention is paid to defining and using jargon. > > Perhaps. Personally I'm not thinking of popularisations, and I'm not > even thinking of physics in particular. > > But even to take two words that we've clashed over: "theory" and > "material". The fact is that you attribute a specialised meaning to > these words, and yet they are used as loosely within the profession as > outside it. Document that, please. The definition I gave of both those terms is the one that is generally accepted in the physics profession. Do you have evidence otherwise? > There can be no argument that the use of these words > increases the efficiency of communication with professionals, and the > ensuing dispute over their use here increased the inefficiency of > communication dramatically. I've already explained to you, using the example of "mammal", why it is preferred to insist on the proper meaning of that word, even if a layperson may confuse it to mean tetrapod land animals. |