A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: Ste on 25 Feb 2010 22:38 On 25 Feb, 09:46, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > And indeed, I said openly that I couldn't make that work, once I'd > been able to construct a graphic where I could see the proof with my > own eyes, and clearly the physical understanding on which that was > based is untenable. As it stands, I don't really have any workable > physical model for light under relativity. > > _________________________________ > > Relativity does not provide a workable physical model for light, in fact it > says nothing about it at all. > > The workable physical model for light is provided by Maxwell's eqns, which > tell us *exactly* what light is; it is two out of phase electric and > magnetic fields, and this uses the same maths and mechanisms as explain > radio broadcasting, transformers, generators etc. You know I actually got as far as reviewing Maxwell's equations before I started to fall over laughing at my gullibility. I really should have realised at the outset that "Maxwell's equations" were not going to involve anything physical. And incidentally, after realising this, but before responding, I actually scrolled down through the posts and found that Paul Stowe had also made exactly the same argument. > You would be well off learning this before you attempt SR, as much of the > experimentation and theory was motivated by physicists knowing that > Maxwell's equations - used a billion times a day - used a Lorentz transform, > and this would allow an absolute frame of reference to be established. > > In practice, the mathematics of Maxwell are harder than SR, but I will try > and explain some key concepts. Hell fire! Mathematically harder than SR? > Most importantly, Maxwell's eqns are said to give rise to light waves, but > these are fundamentally different what you think of as a wave. In water > waves, there is a single variable - water height - and the wave exchanges > energy with the medium through which it travels. Similarly with sound waves, > where it is air pressure. In Maxwell, there are two waves always generated, > the electric and the magnetic. The electric increases, it draws energy from > the magnetic, the magnetic runs out, the electric collapses which feed > energy into the magnetic, and so on ... multiply this by about 10^20 in > speed and you have light. This is a bit wooly. Obviously there is some sort of oscillation going on, but I suspect more work needs to be done on the concept. > The total energy of the photon/wave is constant, it simply exchanges energy > between its electric and magnetic fields. If you ask what the electric wave > is "waving through" - what is storing its energy as it goes up and down like > a water wave - its the waves magnetic field, and the waves magnetic field is > similarly beating against the electric field. This means there is no > connection to any underlying medium which is waving, like in a water wave, > it is self contained. This is ultimately why it has a Lorentz transform, and > if you do the maths on Maxwell's equations you actually get the Lorentz > contraction popping out automatically. The Michelson Morley experiment was > specifically designed to compare the transforms for light and a physical > object, and contrary to your opinion that physicists don't know how to > design tests, was deliberately testing to the limits the prevailing > understanding at that time, and found it to be wrong. > > The rest is now over 100 years of history; you are a little late to find a > problem. Lol. Perhaps a mistake more than 100 years ago is why there hasn't been much theoretical or conceptual advance in 100 years?
From: Ste on 25 Feb 2010 22:42 On 25 Feb, 17:15, mpalenik <markpale...(a)gmail.com> wrote: > On Feb 24, 10:22 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > I'm afraid I don't accept that this captures the certainty that many > > people have in various scientific theories. I've just responded to > > Mark who said that a theory with a 95% confidence should be accepted > > universally by all > > I said I'm done with this conversation, but I'm not going to let you > misquote me, you pathetic idiot. > > I said "it should be accepted by all as HAVING A 95% CHANCE OF BEING > TRUE". I did not say it should be accepted as being true. I said it > should be accepted that THERE IS A 95% CHANCE THAT IT IS TRUE BY > EVERYONE. THERE IS A DIFFERENCE. I REPEAT, I DID NOT SAY IT SHOULD > BE ACCEPTED AS TRUE--IT SHOULD ONLY BE ACCEPTED THAT THERE IS A 95% > CHANCE THAT IT IS TRUE. > > If you are so mentally degenerate that you can't understand the > difference, then it makes me wonder how you can make it through your > every day life, you moronic imbicile. > > Once again, I will not discuss anything with you, but I sure as hell > am going to call you on it if you make retarded inferences about > things that I've said and then try to pass that off as my viewpoint. Calm down. I see that perhaps I did explicitly misquote you, although I'm not sure the inferences were so wrong. If people accept that a particular theory has a 95% confidence, then what are you saying they should do as a result? Do you think they should devote just 95% of their time to that theory? 100% of their time? Some other percentage? And aside from what you think they should do, what do you think they *actually* do?
From: Jerry on 25 Feb 2010 22:53 On Feb 25, 7:32 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > As you have seen here, some prefer to just flush the second postulate > and say everything is fine. I do not comprehend your desire to -intentionally- misunderstand and thus to -intentionally- misrepresent the modern understanding of relativity as various of us on these newsgroups have tried to explain it to you. You are not stupid, so the only explanation that makes sense to me is that you are a troll. In previous exchanges, you succeeded in wasting much of my time, so I imagine you were quite happy. Einstein's basic insight was that that the universe could be described as in terms of a certain particular geometry (in regions of sufficiently low gravity). Einstein explored the basic characteristics of this geometry in an axiomatic development starting with the two postulates plus several common notions. Other researchers discovered alternate means of deriving this same geometry. For example, Minkowski demonstrated a powerful alternate formalization of Einstein's theory which was essential to Einstein's later development of GR. In Minkowski spacetime, "c" is the proportionality constant that relates the time axis with the space axes. It happens to have the same numerical value as the speed of light, but that is not the primary importance of "c" in this alternate formulation of SR. An especially elegant derivation of SR, the group theory derivation, uses only the first postulate plus a single experimental data point: "Is c finite or infinite?" In the group theory derivation of SR, the constancy of the speed of light is a trivial consequence of the fact that photons are believed to be massless. The geometries described in these alternate derivations are all formally identical to the geometry that Einstein discovered. The speed of light is constant in all of these alternate derivations. They differ in whether the constant speed of light is a postulate or a theorem. Your use of the word "flush" is deliberately provocative, and is consistent with my hypothesis that you are simply being a troll. Jerry
From: Ste on 25 Feb 2010 23:44 On 25 Feb, 03:09, mpalenik <markpale...(a)gmail.com> wrote: > On Feb 24, 9:32 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > You came up with a bunch of hypotheses that have no basis in physical > > > reality--about how brightness could affect the location of > > > interference fringes (it doesn't, and I proved it doesn't), about the > > > speed of light and measured brightness being able to "compensate" for > > > each other--again none of which have any basis in physical reality-- > > > all because you wanted to dismiss the Michaelson-Morley type > > > experiments. Again, there was nothing sensible about any of it, > > > except that it was a way for you to attempt to justify not having to > > > believe the speed of light isotropy measurements. > > > And indeed, I said openly that I couldn't make that work, once I'd > > been able to construct a graphic where I could see the proof with my > > own eyes, and clearly the physical understanding on which that was > > based is untenable. As it stands, I don't really have any workable > > physical model for light under relativity. > > And if this were actually coming from someone attempting to practice > legitimate science or propose a realistic theory, he would have done > that work ahead of time, instead of coming here and insisting that > those claims were true before making any attempt to back them up and > dismissing everyone's attempts to explain the experiments. I didn't "insist that it was true". And I didn't dismiss your attempts to explain, I dismissed your failure to explain. And my refusal to take it on trust is because, frankly, there is no implicit trust in terms of your ability as an authority to comprehend my questions and give the answers in a comprehensible form. I accept all your mathematical knowledge, but you don't seem to accept that there is something more required. > > That said, I don't think anyone can accuse me of being insensible or > > lacking integrity in the way you suggest that it was a contrivance to > > avoid believing the obvious. > > It's not a matter of integrity, it's a matter of knowledge of the > scientific method and understanding of the requirements of scientific > theories. Listen, I didn't have to talk about the scientific method or scientific theories to realise that it becomes unworkable to assume a stationary medium. > > > > For example, consider this illustration: > > > > > A------B---C > > > > > Basically you can express the distance AB with the value x, the > > > > distance BC as value x/2, and the distance AC as value 3x/2. Or you > > > > can express it as AB = 2x, BC = x, and AC = 3x. But this form of > > > > expression always relies on comparison, and if you change the > > > > reference value of X then all the other values change numerically (but > > > > not physically - there is still some essential relationship that is > > > > physically invariant). > > > > First of all, physically, if you double the distance between two > > > objects, that does make a difference. For example, if you bring two > > > molecules close engouh together, they will start repelling instead of > > > attracting (this is the principle behind atomic force microscopy). If > > > you shrank the sun down into a small enough region, it would become a > > > black hole. > > > > The invariant quantity is the ratio of lengths: 2:1. And yes, this > > > can be expressed as 1:2. > > > Yes, but you've subtly introduced a comparison again, of expressing > > one length as a ratio of another. The question is how to express the > > distance of BC in such a way that, no matter how the distance AB > > changes, and without reference to any other standard, the expressed > > distance of BC does not change. By your ratio method, if we double the > > distance of AB (or halve the distance BC), then the ratios change to > > 4:1. > > That's just retarded, quite frankly. You don't want to use units to > measure it, and you don't want to compare it to anything else. You > don't want relationships of distances, you don't want it in terms of > meters, and presumably, you wouldn't accept the speed of light and > time, either. Honestly, I give up at this point, I'm done with this > conversation. If you don't even get why that's a stupid question, > there really is no hope for you. I have much better things to do with > my time. This is getting beyond idiotic. Because your an arrogant fool who doesn't like to listen or reflect on what you've heard. The question was simple: how to express a quantity without comparison. You're right I don't want it in terms of a comparison between *two* distances - either of which can change. Nor do I want it in terms of a comparison between a distance and a platinum bar - either of which can change. Time would be workable - except for the problem that its rate of flow can change. If you can't understand the significance of this question in the context of measurement and relativity, then god help you.
From: Bruce Richmond on 25 Feb 2010 23:49
On Feb 25, 9:51Â pm, "J. Clarke" <jclarke.use...(a)cox.net> wrote: > On 2/25/2010 8:32 PM, Bruce Richmond wrote: > > > On Feb 24, 1:31 am, "J. Clarke"<jclarke.use...(a)cox.net> Â wrote: > >> On 2/23/2010 11:38 PM, Bruce Richmond wrote: > > >>> On Feb 23, 9:50 pm, "J. Clarke"<jclarke.use...(a)cox.net> Â Â wrote: > >>>> On 2/23/2010 8:36 PM, Bruce Richmond wrote: > > >>>>> On Feb 21, 11:52 pm, "J. Clarke"<jclarke.use...(a)cox.net> Â Â Â wrote: > >>>>>> On 2/21/2010 10:24 PM, Bruce Richmond wrote: > > >>>>>>> On Feb 21, 6:10 pm, mpalenik<markpale...(a)gmail.com> Â Â Â Â wrote: > >>>>>>>> On Feb 21, 4:57 pm, Ste<ste_ro...(a)hotmail.com> Â Â Â Â wrote: > > >>>>>>>>> If we were to extrapolate a trend from history, then physics has not > >>>>>>>>> yet given us a single equation which describes how the universe > >>>>>>>>> functions. It has given us some rules of thumb and some cumbersome > >>>>>>>>> approximations. > > >>>>>>>> This just further illustrates that you don't understand how physics > >>>>>>>> actually works. Â The history of physics isn't a series of blunders > >>>>>>>> that we've thrown out as we get better and better equations, hampered > >>>>>>>> by our belief in the old equations. Â Rather, physics at just about > >>>>>>>> every point in time since the renaissance has been a journey from very > >>>>>>>> specific to more general rules--criteria by which any new physics must > >>>>>>>> be constrained. > > >>>>>>>> For example, Kepler, while not really a physicist per-se, devised > >>>>>>>> descriptions of the elliptical orbits that planets must follow. > >>>>>>>> Newton, then, discovered that this is a special case of the > >>>>>>>> conservation of angular momentum, which is a much more general > >>>>>>>> principle--however, conservation of angular momentum MUST be able to > >>>>>>>> reproduce the elliptical orbits of planets, or else it is wrong. > >>>>>>>> Kepler's rules constrained Newton's theories. > > >>>>>>>> Special relativity then changed Newton's laws, a bit. Â The basic > >>>>>>>> principles, like F = dp/dt remained, but Special relativity says that > >>>>>>>> space and time must transform differently than they do in Newtonian > >>>>>>>> mechanics. Â However, Newtonian mechanics is still a special case of > >>>>>>>> special relativity--as the speed of an object approaches zero, the > >>>>>>>> laws begin to reproduce Newton's laws. Â Newton's laws, in this way, > >>>>>>>> constrain Special Relativity. Â Because if it did *NOT* reproduce > >>>>>>>> Newton's laws at low speeds, it would be wrong. > > >>>>>>>> General relativity came along and it turns out that special relativity > >>>>>>>> only works as a limiting case of general relativity, specifically, > >>>>>>>> when there is no mass or energy present. Â As the amount of mass and > >>>>>>>> energy present goes to zero, general relativity reproduces special > >>>>>>>> relativity. Â If it could not do this, it would be wrong. > > >>>>>>>> Any new physics must be able to reproduce the old physics in the > >>>>>>>> regimes in which it has been tested. Â Any new theory that cannot do so > >>>>>>>> is necessarily wrong because it has already been ruled out by > >>>>>>>> experiment. > > >>>>>>> Thank you for bringing this up and explaining it so well. Â A few days > >>>>>>> ago in the DeSitter thread I wrote that in SR the speed of light is > >>>>>>> made a universal constant by the second postulate. Â The coordinate > >>>>>>> systems are constructed based on that fact. Â Because of that there is > >>>>>>> no way you can measure the speed of light to be anything but c without > >>>>>>> making a mistake. > > >>>>>> What point are you trying to support with that statement? Â If one > >>>>>> _measures_ a velocity of light other than the one that it is commonly > >>>>>> held to have and others replicate your result, and it is found that > >>>>>> light has different velocities under different circumstances then it is > >>>>>> not the measurement that is a mistake but you will have just thrown > >>>>>> relativity right out the window and they'll be seeing you in Stockholm > >>>>>> pretty soon. > > >>>>> Hold that prize. Â The discussion was about the basis of SR. Â I > >>>>> consider the second postulate to be a basic concept that SR was > >>>>> founded on. Â I was informed by some of the experts here that my > >>>>> thinking was outdated. > > >>>> You'll find some physicists who put mathematical formalisms over > >>>> physical insight--the constancy of the velocity of light was one of > >>>> Einstein's two basic postulates and special relativity can be derived > >>>> using those postulates. Â That it can be derived in other ways doesn't > >>>> alter that basic insight. > > >>> The reason I asked Mark's opinion was because of what he wrote just > >>> above my "Thank you". Â "Any new physics must be able to reproduce the > >>> old physics in the regimes in which it has been tested. Â Any new > >>> theory that cannot do so is necessarily wrong because it has already > >>> been ruled out by experiment." > > >>> The experts here have said that the second postulate could be violated > >>> without disproving SR. Â Considering your statement above about > >>> throwing SR out the window I would say you agree with me that they are > >>> wrong about that. > > >>> In SR the second postulate reads "light is always propagated in empty > >>> space with a definite velocity c which is independent of the state of > >>> motion of the emitting body." Â That is it travels at some constant > >>> speed in such a way that no ray of light could overtake another ray. > >>> Remember, I mentioned this exchange took place in the DeSitter > >>> thread. Â It was DeSitter that argued against the ballistic theory of > >>> light, as promoted by Ritz > > >>>http://www.datasync.com/~rsf1/crit/1908a.htm > > >>> In ballistic theory light can travel at c+v which would allow one ray > >>> to overtake another. Â That would mean there is no single "speed of > >>> light". > > >>>> The thing is, either relativity is a usefully accurate description of > >>>> reality or it isn't. Â If it isn't then someone should be able to conduct > >>>> an experiment that is inconsistent with relativity and show that it is > >>>> invalid. Â So far many experiments have been performed and none have > >>>> succeeded in showing it to be invalid. > > >>>>>>> I was then informed that the interpertation of SR > >>>>>>> has been improved upon since 1905 and that what I had written no > >>>>>>> longer applied. Â Further, relativity could survive even if it was > >>>>>>> found that the speed of light wasn't exactly c. > > >>>>>> Uh, by definition the velocity of light is exactly c. Â Grok the > >>>>>> concept--c is defined as "the velocity of light". Â Relativity makes no > >>>>>> statement concerning a specific value that c must have, only that it is > >>>>>> the same in all reference frames. Â It can be 2 millimeters per > >>>>>> millennium or forty quintillion kilometers per femtosecond and > >>>>>> relativity remains valid, as long as it demonstrably has that value and > >>>>>> only that value, within the limits of experimental error. > > >>>>> I am well aware that the speed of light is c by definition in SR. > > >>>> No, c is the speed of light, period. Â This has nothing to do with > >>>> special relativity or general relativity or Newtonian mechanics or > >>>> anything else. Â The physics community has chosen to write "c" instead of > >>>> spelling out "the speed of light, whatever that might be". Â You're > >>>> reading too much into it. Â It's just a shorthand. > > >>> In SR the second postulate reads "light is always propagated in empty > >>> space with a definite velocity c which is independent of the state of > >>> motion of the emitting body." Â That is it travels at some constant > >>> speed in such a way that no ray of light could overtake another ray. > >>> Remember, I mentioned this exchange took place in the DeSitter > >>> thread. Â It was DeSitter that argued against the ballistic theory of > >>> light, as promoted by Ritz > > >> You're acting like using a letter to refer to a velocity is something > >> magic. Â It's not, it's just a shorthand. > > > I was just pointing out that SR declared c a constant as opposed to a > > variable. > > >>>http://www.datasync.com/~rsf1/crit/1908a.htm > > >>> In ballistic theory light can travel at c+v which would allow one ray > >>> to overtake another. Â That would mean there is no single "speed of > >>> light". Â So it is a convention of SR, and ether theory, that c is the > >>> speed of light. Â That is why I included the qualifier "in SR". > > >> The "ballistic theory" is ancient history. > > > Einstein's 1905 paper is also ancient history according to many around > > here. Â Be that as it may, in the DeSitter thread we were discussing > > how it was determined that light travels at "a definite velocity c > > which is independent of the state of motion of the emitting body." > > Which brought us to how c was determined, and my pointing out that > > since the meter is derived from c, you had better measure the speed of > > light to be c or you screwed something up. Â In retrospect I now > > realize that I was assuming the second postulate is correct. Â If > > ballistic theory were correct it would be possible for rays to travel > > at different speeds. > > >>>>> That is basicly what I said in the paragraph above that starts with > >>>>> "Thank you". Â Again the experts told me I was wrong, that the speed of > >>>>> light was the distance traveled divided by the time. > > >>>> So what else would be, the color of apples divided by the temperature of > >>>> a polar bear's nose? > > >>> If you defined c as the speed of light then the distance is derived > >>> from c, not c from the distance. > > >> What distance would that be? > > >> The _distance_ is derived from whatever means you use for measuring > >> distance. Â It has no bearing on using a letter to refer to the velocity > >> of light. > > >>> In effect the distance is ct. > > >> The distance to _what_? > > > The distance between photo sensors you are using to measure the speed > > of light. Â A meter is defined as the distance travelled by light in > > vacuum in 1â299,792,458 of a second. Â So in place of 100 meters > > substitute 100â299,792,458 light seconds. Â To eliminate the inaccuracy > > of measuring rods use light based measurements to place the sensors. > > If you have placed the sensors the correct distance apart so that it > > took the calibrating light 100â299,792,458 seconds to make the trip, > > how long do you think it will take the light you are measuring the > > speed of? > > Look, if you don't like the standard definition of a meter take it up > with the standards committee. Â That definition is quite recent and was > established after a century of research failed to reveal any variation > in the velocity of light. > > If you're trying to sell the notion that the velocity of light is > variable in any frame that is accessible to humans, that ship has sailed. > > Â >> Â > Â If > > > > >>> you now measure how long it takes light to travel that distance you > >>> had better get t or you have proven that the speed of light isn't > >>> constant. > > >> No, what you've done is made a measurement. > > > A circular measurement which you pointed out elsewhere in this tread > > is senseless. > > I have? Â In what post did I point this out? http://groups.google.com/group/sci.physics.relativity/msg/1db4e96725811e18?hl=en "That's why "if the velocity of light is different from c" is meaningless. It's like saying "if your height was different from your height" or "if the population of New York was different from the population of New York". > >>>> c is the velocity of light. Â By definition. Â That velocity has some > >>>> measurable numerical value, you measure the time it takes light to > >>>> travel a given distance and you have an approximation of the numerical > >>>> value of c. Â You measure again with an improved apparatus and you have a > >>>> more accurate approximation. Â The fact that the two approximations are > >>>> different has no bearing on calling the velocity of light "c". > > >>> When I pointed out that in SR the speed of light is c by definition > >>> due to the second postulate I was told by the "experts" that I was > >>> wrong. > > >> Which experts were these and why do you care so much what they think? > >> Read Einstein. > > >>>> Maybe is has more than one value, maybe it has two or three or a > >>>> billion--so far though it seems to have just one. > > >>> If it has more than one value then it is not a constant and SR just > >>> got flushed down the tubes. > > >> Precisely. Â What of it? > > > As you have seen here, some prefer to just flush the second postulate > > and say everything is fine. > > Who, specifically, give us an example of this "flushing". |