The real twin paradox.
in [Relativity]
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From: Sue... on 21 Nov 2007 23:04 On Nov 21, 8:33 pm, bz <bz+...(a)ch100-5.chem.lsu.edu> wrote: [...} > > Oh, light clocks are not difficult to build. > You can take a fiber optic transceiver and a mirror and a bit of > electronics. > > Do a little optical impedance matching to free space and set up your mirror > at a convenient distance. > Set the electronics so that every time a tick is received, a new tick is > launched. > Press the little 'starter' button. > You have a light clock. > > Any high school kid can build one. > > The real trick is to build a 'normal clock' that ACTS like sue says a > 'normal clock' should act. Have you read the chapter is SR about Fizeau's experiment? Do you know how to use vector addiion to compute the round trip of an aeroplane? You and Dave still seem unfamilar with this material. http://www.glenbrook.k12.il.us/gbssci/phys/Class/vectors/u3l1f.html Do you know how to use it to compute how much a light-clock slows? Sue... >
From: bz on 22 Nov 2007 03:27 "Sue..." <suzysewnshow(a)yahoo.com.au> wrote in news:7c3700d6-75df-4a6d-a7d2-ff1a5d44a7a8(a)o6g2000hsd.googlegroups.com: > On Nov 21, 8:33 pm, bz <bz+...(a)ch100-5.chem.lsu.edu> wrote: > [...} >> >> Oh, light clocks are not difficult to build. >> You can take a fiber optic transceiver and a mirror and a bit of >> electronics. >> >> Do a little optical impedance matching to free space and set up your >> mirror at a convenient distance. >> Set the electronics so that every time a tick is received, a new tick >> is launched. >> Press the little 'starter' button. >> You have a light clock. >> >> Any high school kid can build one. >> >> The real trick is to build a 'normal clock' that ACTS like sue says a >> 'normal clock' should act. > > Have you read the chapter is SR about Fizeau's experiment? 'the chapter is SR'? perhaps you mean 'in'? Fizeau measured effects of moving medium on light. Does the Fizeau Experiment Really Test Special Relativity? Authors: Clement, Gerard American Journal of Physics, v48 n12 p1059-62 Dec 1980 The motivation and interpretation of the Fizeau experiment are reviewed, and its status as a test of special relativity is discussed. It is shown, with the aid of a simplified, purely mechanical model of the propagation of light in matter, that the experiment actually cannot discriminate between Galilean and relativistic kinematics. (Author/SK) The Experiment of Fizeau as a Test of Relativistic Simultaneity Curt Renshaw -- he thinks Fizeau falsifies SR. He includes Doppler effects in his calculations in a way that may not be valid. > Do you know how to use vector addiion to compute the > round trip of an aeroplane? yes. I can even use vectors to calculate instantaneous power in a reactive circuit. I don't need to use imaginary numbers or suppose that the power is imaginary. [quote from http://www.maths.abdn.ac.uk/events/einstein/reid.html] Much more recently, there was some controversy over what happens when the medium is moving at right angles to the direction of travel of the light. The result was settled by an experiment carried out here in Aberdeen in 1971, with Prof R.V. Jones building the equipment and with Prof Mike Player covering the theory. The result vindicated the predictions of Maxwell�s equations and the predictions of special relativity. [unquote] > > You and Dave still seem unfamilar with this material. > > http://www.glenbrook.k12.il.us/gbssci/phys/Class/vectors/u3l1f.html > > Do you know how to use it to compute how much a light-clock slows? Light clocks gave Einstein a simple way to derive the Lorentz equations. You seem to think that ONLY light clocks are effected by relativistic motion. The fact remains that ALL of our clocks seem to be 'ab'"normal clocks" by your definition of normal. All seem to be influenced by relativistic motion. [quote from http://www.maths.abdn.ac.uk/events/einstein/reid.html] Rossi & Hall experiment The original experiment was done by Rossi & Hall in 1941 who measured muon fluxes not 10 km high but at the top of Mt Washington in New England, about 2 km high, and at the base of the mountain. The effect is less for a height difference of only 2 km but for their muon speeds of 0.994c, relativistically the reduction should have been only a factor of 1.26 whereas without time dilation the reduction would be a factor of 8.5. Rossi and Hall�s figures were consistent with the relativistic prediction. The experiment has since been repeated by others with convincing results. .... In 1979 Bailey et al at a CERN accelerator reported a similar experiment with CERN generated muons of speeds 0.9994c, trapped in a particle accelerator, that were observed in the lab to have 29.3 times the muon rest lifetime, completely consistent with time dilation. .... One of the consequential results in relativity is that no bodies can travel at a faster speed than the speed of light. Nobel prize winner Sheldon Glashow and collaborator Sidney Coleman showed in 1997 that the argument could be taken further. The mere existence of very high energy cosmic ray photons reaching the Earth is strong proof, without any extra experiment, of the existence of an upper limit of the speed of light c for material bodies. Their argument is that photons decay by pair production into electrons and positrons at a rate that can be calculated from particle physics. If the upper limit to the speed of electrons differed from c by a small amount, then high-energy photons (~20 Tev) would decay in nanoseconds and never travel any significant distance from their point of creation. The detection of these particles on Earth sets a tight bound of an upper limit to the speed of matter being within 1.5�10-15 of c. ..... Would you bet your life on Special Relativity being true? Anyone who relies on GPS in bad weather may be doing just that. Probably thousands of aircraft passengers and crew do so every day. .... Conclusion I�m showing as a final slide a table that made an impression on me when I first saw it many years ago. It lists 13 key experiments that have a testing relevance to Special Relativity in the columns, and the predictions of 6 alternative theories to Special Relativity in the rows. The red boxes mark the places where the experimental results disagree with the predictions of the theory. Only Special Relativity is in agreement with all testing experiments. .... 1: Aberration, 2: Fizeau convection coefficient; 3: Michelson-Morley; 4: Kennedy-Thorndike; 5: Moving sources and mirrors; 6: De Sitter spectroscopic binaries; 7: Michelson-Morley, using sunlight 8: Variation of mass with velocity; 9: General Mass-Energy equivalence; 10: Radiation from moving charges; 11: Muon decay at high velocity; 12: Trouton-Noble; 13: Unipolar induction, using moving magnet. [unquote] You, on the other hand seem to be a proponent of fringe science theories such as those at http://www.wbabin.net/physics/light.htm [quote] Assigning the properties of superfluid to the physical vacuum allows us to provide a physical model of the interaction of the photon with the measurement system (to make more concrete, the physical meaning of the dynamics "hidden" in the four-dimensional kinematics of special relativity). Namely, at the interaction between the photon and the measurement system a precession of the spins of the micro-particles constituting the superfluid physical vacuum is generated in the vacuum (the so-called uniformly precessing domain is created). The frequency of the precession is the frequency of the photon detected by the measurement system. [unquote] Maybe L. B. Boldyreva and N. B. Sotina, HW, KS, and Sue are right. Maybe time IS absolute and independent of motion through space. Maybe the clocks in the GPS satellites only SEEM to be influenced by relativity. Maybe when they are brought back to earth the missing ticks will be found to have accumulated in a little 'tick bucket' and the clocks will be shown to be the exact same age as their earthbound twins. Maybe the sun rises in the west and sets in the east. Show me one clock that doesn't appear to be influenced by relativistic motion. [besides the pendulum clock which doesn't even run at zero G]. Why do we need to postulate some magical property of space [that we are unable to observe here] and tie the observed slowing of all kinds of clocks to the way that magical property interacts with moving matter? -- bz please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. bz+spr(a)ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap
From: harry on 22 Nov 2007 05:16 "colp" <colp(a)solder.ath.cx> wrote in message news:45e50819-65f6-46a3-a821-5c3698dd146a(a)p69g2000hsa.googlegroups.com... > On Nov 21, 11:40 pm, "Dirk Van de moortel" <dirkvandemoor...(a)ThankS-NO- > SperM.hotmail.com> wrote: >> "colp" <c...(a)solder.ath.cx> wrote in >> messagenews:06b84031-18aa-4644-bfb7-43f49f46ae6a(a)i37g2000hsd.googlegroups.com... >> > This thought experiment is like the classic twin paradox, but in this >> > expirement both twins leave earth and travel symmetric return trips in >> > opposite directions. >> >> > Since the paths taken by the twins in this experiment are symmetric, >> > they must be the same age when they meet on their return to earth. >> >> > In this experiment the twins maintain constant observation of each >> > other's clocks, from when they depart until they return and find that >> > their clocks tell the same time. >> >> > Special relativity says that each twin must observe that the other's >> > clock is running slow, and at no time does special relativity allow >> > for an observation which shows that the other clock is running fast. >> >> No, special relativity says much more precise than that >> "moving clocks" are running slow. > > The Lorentz-Fitzgerald transform is more precise that my description, > but that doesn't mean that my description is wrong. > >> >> It says something about intertial observers who measure >> times between ticks on remote, moving clocks. >> >> When your two clocks fly apart, each clock will measure >> this time to be longer and conclude that the other clock >> is "running slower". >> While clock A is coasting, according to clock A, each >> tick on clock A is simultaneous with some tick on clock B >> with a smaller time value. >> While clock B is coasting, according to clock B, each >> tick on clock B is simultaneous with some tick on clock A >> with a smaller time value. > > Yes, that is the standard theory. > >> >> After clock A has made its turnaround, it has shifted to >> another inertial frame, in which according to clock A, each >> tick on clock A is simultaneous with some tick on clock B >> with a larger time value. >> After clock B has made its turnaround, it has shifted to >> another inertial frame, in which according to clock B, each >> tick on clock B is simultaneous with some tick on clock A >> with a larger time value. > > Wrong. The other clock tick is still observed to have a smaller time > value. > This is because in the Lorentz-Fitzgerald transform the relative > velocity term is squared, making the the issue of the clocks > separating vs the clocks approaching irrelevant to the amount of time > dilation. > > http://en.wikipedia.org/wiki/Time_dilation That is indeed irrelevant but you are still mistaken because time dilation is ALSO irrelevant at the instant of switching reference frames. Try: http://en.wikipedia.org/wiki/Relativity_of_simultaneity Harald
From: Sue... on 22 Nov 2007 06:33 On Nov 22, 3:27 am, bz <bz+...(a)ch100-5.chem.lsu.edu> wrote: > "Sue..." <suzysewns...(a)yahoo.com.au> wrote innews:7c3700d6-75df-4a6d-a7d2-ff1a5d44a7a8(a)o6g2000hsd.googlegroups.com: > > > > > > > On Nov 21, 8:33 pm, bz <bz+...(a)ch100-5.chem.lsu.edu> wrote: > > [...} > > >> Oh, light clocks are not difficult to build. > >> You can take a fiber optic transceiver and a mirror and a bit of > >> electronics. > > >> Do a little optical impedance matching to free space and set up your > >> mirror at a convenient distance. > >> Set the electronics so that every time a tick is received, a new tick > >> is launched. > >> Press the little 'starter' button. > >> You have a light clock. > > >> Any high school kid can build one. > > >> The real trick is to build a 'normal clock' that ACTS like sue says a > >> 'normal clock' should act. > > > Have you read the chapter is SR about Fizeau's experiment? > > 'the chapter is SR'? perhaps you mean 'in'? > > Fizeau measured effects of moving medium on light. > > Does the Fizeau Experiment Really Test Special Relativity? > Authors: Clement, Gerard American Journal of Physics, v48 n12 p1059-62 > Dec > 1980 The motivation and interpretation of the Fizeau experiment are > reviewed, and its status as a test of special relativity is discussed. It > is shown, with the aid of a simplified, purely mechanical model of the > propagation of light in matter, that the experiment actually cannot > discriminate between Galilean and relativistic kinematics. (Author/SK) > > The Experiment of Fizeau as a Test of Relativistic Simultaneity > Curt Renshaw -- he thinks Fizeau falsifies SR. He includes Doppler effects > in his calculations in a way that may not be valid. > > > Do you know how to use vector addiion to compute the > > round trip of an aeroplane? > > yes. I can even use vectors to calculate instantaneous power in a reactive > circuit. I don't need to use imaginary numbers or suppose that the power > is imaginary. > > [quote fromhttp://www.maths.abdn.ac.uk/events/einstein/reid.html] > Much more recently, there was some controversy over what happens when the > medium is moving at right angles to the direction of travel of the light. > The result was settled by an experiment carried out here in Aberdeen in > 1971, with Prof R.V. Jones building the equipment and with Prof Mike > Player covering the theory. The result vindicated the predictions of > Maxwell's equations and the predictions of special relativity. [unquote] > > > > > You and Dave still seem unfamilar with this material. > > >http://www.glenbrook.k12.il.us/gbssci/phys/Class/vectors/u3l1f.html > > > Do you know how to use it to compute how much a light-clock slows? > > Light clocks gave Einstein a simple way to derive the Lorentz equations. > You seem to think that ONLY light clocks are effected by relativistic > motion. *Only* light clocks will match the Lornetz transform. Again: !!! <<A Lorentz transformation or any other coordinate transformation will convert electric or magnetic fields into mixtures of electric and magnetic fields, but no transformation mixes them with the gravitational field. >> http://www.aip.org/pt/vol-58/iss-11/p31.html http://en.wikipedia.org/wiki/Gauge_fixing http://arxiv.org/abs/physics/0204034 !!! Light does not move inertially. You have said so yourself. [...] > .... > Would you bet your life on Special Relativity being true? Anyone who > relies on GPS in bad weather may be doing just that. Probably thousands of > aircraft passengers and crew do so every day. .... > Conclusion You are not using GR. You are in fact inadvertantly arguing aginst its most basic assumtions. Inertial couplings can be modeled through mass energy equivalence when Newton's ether is abandoned. You keep putting the ether back into the interacton but you are not insisting on a mass to make the coupling. From the SUMO link you probably noticed moving mass is not condidered equivalent to moving light. If you believe it is then you need to offer your services to develop long-range atom lasers. > I'm showing as a final slide a table that made an impression on me when I > first saw it many years ago. It lists 13 key experiments that have a > testing relevance to Special Relativity in the columns, and the > predictions of 6 alternative theories to Special Relativity in the rows. > The red boxes mark the places where the experimental results disagree with > the predictions of the theory. Only Special Relativity is in agreement > with all testing experiments. .... > 1: Aberration, 2: Fizeau convection coefficient; 3: Michelson-Morley; 4: > Kennedy-Thorndike; 5: Moving sources and mirrors; 6: De Sitter > spectroscopic binaries; 7: Michelson-Morley, using sunlight 8: Variation > of mass with velocity; 9: General Mass-Energy equivalence; 10: Radiation > from moving charges; 11: Muon decay at high velocity; 12: Trouton-Noble; > 13: Unipolar induction, using moving magnet. [unquote] Is special relativity running for public office? That is no substitute for some evidence that light moves inertially. My automoble does not recoil backward when I switch on the headlamps so I am not hopeful you will find any evidence. > > You, on the other hand seem to be a proponent of fringe science theories > such as those at ht tp://ww w.wbabin.net/physics/light.htm Most of my URL's are to Einstien 1920 paper, his Nobel lecture Weinberg's articles or Fitzpatrick's lectures. Which are you calling *fringe science* ? > [quote] The article I never offered snipped and it's URL crippled. If you want to argue about something I offered, I am happy to do so, but don't ask me to support or refute something you can only attibute to a Vulcan mind-meld. ....and stop trying to read my mind. It is Written in Swahili. :o) > Maybe L. B. Boldyreva and N. B. Sotina, HW, KS, and Sue are right. Maybe > time IS absolute and independent of motion through space. Maybe the clocks > in the GPS satellites only SEEM to be influenced by relativity. Maybe when > they are brought back to earth the missing ticks will be found to have > accumulated in a little 'tick bucket' and the clocks will be shown to be > the exact same age as their earthbound twins. Maybe the sun rises in the > west and sets in the east. I don't know about L. B. Boldyreva and N. B. Sotina but Einstein, Hilbert and Noether seemed to think time had to be as invariant as mass. << invariance with respect to time translation gives the well known law of conservation of energy >> http://en.wikipedia.org/wiki/Noether's_theorem If you want to trade energy for time then drive a faster car to work. The *time* you saved in transit will appear on you fuel bill. ....and you'll also find that silly plot of proper-time intervals used as a feeble prop for the twins myth, actually corresponds to a real world phenomena instead of absurd nonsense. It will correspond to the *energy* exchanged by your automobile. > > Show me one clock that doesn't appear to be influenced by relativistic > motion. [besides the pendulum clock which doesn't even run at zero G]. No... You need to better define terms if you want to prompt meaningful study of some particular clock design. *appear* *relativistic* Also consider the part played by mass, inertia and oscillator path length for any particular design. > > Why do we need to postulate some magical property of space [that we are > unable to observe here] and tie the observed slowing of all kinds of > clocks to the way that magical property interacts with moving matter? We need to do this because we do not have a mechanism for gravity. When a pushed car pushes back for a period of *time* we are attributing the effect to a mass elsewhere that the car cannot communicate with, faster than the speed of light. << I shall turn to those problems which are related to the development which I have traced. Already Newton recognized that the law of inertia is unsatisfactory in a context so far unmentioned in this exposition, namely that it gives no real cause for the special physical position of the states of motion of the inertial frames relative to all other states of motion. It makes the observable material bodies responsible for the gravitational behaviour of a material point, yet indicates no material cause for the inertial behaviour of the material point but devises the cause for it (absolute space or inertial ether). This is not logically inadmissible although it is unsatisfactory. For this reason E. Mach demanded a modification of the law of inertia in the sense that the inertia should be interpreted as an acceleration resistance of the bodies against one another and not against "space". This interpretation governs the expectation that accelerated bodies have concordant accelerating action in the same sense on other bodies (acceleration induction). This interpretation is even more plausible according to general relativity which eliminates the distinction between inertial and gravitational effects. It amounts to stipulating that, apart from the arbitrariness governed by the free choice of coordinates, the gm v -field shall be completely determined by the matter. Mach's stipulation is favoured in general relativity by the circumstance that acceleration induction in accordance with the gravitational field equations really exists, although of such slight intensity that direct detection by mechanical experiments is out of the question. >> http://nobelprize.org/nobel_prizes/physics/laureates/1921/einstein-lecture.html Sue... > > -- > bz > > please pardon my infinite ignorance, the set-of-things-I-do-not-know is an > infinite set. > > bz+...(a)ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap- Hide quoted text - > > - Show quoted text -
From: harry on 22 Nov 2007 09:18
"colp" <colp(a)solder.ath.cx> wrote in message news:43e6b051-fef5-444c-a97c-2f5500b8ca1e(a)b40g2000prf.googlegroups.com... > On Nov 22, 5:48 am, "Josef Matz" <josefm...(a)arcor.de> wrote: > <snip> >> Hello Dirk >> >> If you could mathematically demonstrate that the time delays of the >> symmetric clock A as viewed by B can be >> compensated somehow you have solved the paradox ! >> >> Would you tell us idiots how this runs in SR ? > > A solution could include an argument from general relativity as well, > since the twins must spend time in non-inertial frames in order to > accelearate/decelerate and turn around. I don't think it would solve > the paradox though because the dilation effects can be increased > arbitrarily by extending the amount of time spent in inertial frames. http://math.ucr.edu/home/baez/physics/Relativity/SR/TwinParadox/twin_intro.html http://en.wikipedia.org/wiki/Twin_paradox Regards, Harald |