A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: PD on 17 Feb 2010 13:24 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. > 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.
From: Paul Stowe on 17 Feb 2010 13:34 On Feb 17, 10:24 am, 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. Define 'fully accounted for'. Did you include the physical length contraction in that? WSo does fully accounted for account for that? > > 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. Yes, but that was an abstraction, not associated with the fundamental properties of 'ponderous matter' systems. He's not wrong, physicists did not account for propagation delays UNTIL! the MMX slapped them in the face.
From: BURT on 17 Feb 2010 13:35 On Feb 17, 10:24 am, 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. > > > 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.- Hide quoted text - > > - Show quoted text - The constancy of the flow of light is through empty space-time. Mitch Raemsch
From: Ste on 17 Feb 2010 13:51 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. 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. 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. 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.
From: Ste on 17 Feb 2010 14:14
On 17 Feb, 18:04, mpalenik <markpale...(a)gmail.com> wrote: > On Feb 17, 12:51 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > On 17 Feb, 16:07, mpalenik <markpale...(a)gmail.com> wrote: > > > > On Feb 17, 10:04 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. > > > > Well, how could they seem credible to people who don't hold them > > > credible? > > > I fear the answer follows naturally from the question: they don't seem > > credible, to people who don't hold them to be credible. > > That is true by definition I know, which makes one wonder why you asked the question in the first place. > > > Or do you think we were born knowing these things? > > > I suspect the material reasons behind axiomatic beliefs are myriad, > > but I don't discount the possibility that people may indeed be > > psychologically predisposed to certain beliefs as a form of social > > specialisation. > > Except for you, right? No I meant including me. |