The real twin paradox.
in [Relativity]
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From: Sue... on 30 Nov 2007 16:41 On Nov 30, 4:04 pm, colp <c...(a)solder.ath.cx> wrote: [...] > > So the question that remains is: when does the travelling twin of the > classic example observe that time has compressed for the Earth-bound > twin in order that his observations agree with those of the Earth- > bound twin at the end of the experiment? If you fit the ship with both light-clocks which slow with motion through the free-space dielectric and also atomic clocks which slow with proximity to the earth's mass, then you should be able to work out what real clocks should do. Clocks don't measure time, they mark it like a dividing engine, so some caution is in order before the behavior of some particular clock is plugged into a statement from theory. I.E. << According to electromagnetic theory the speed of propagation of a light wave through a vacuum is [c] http://farside.ph.utexas.edu/teaching/jk1/lectures/img52.png (6) where eps_0 and mu_0 are physical constants which can be evaluated by performing two simple experiments which involve measuring the force of attraction between two fixed charges and two fixed parallel current carrying wires. According to the relativity principle these experiments must yield the same values for eps_0 and mu_0 in all inertial frames. Thus, the speed of light must be the same in all inertial frames. In fact, any disturbance which does not require a medium to propagate through must appear to travel at the same velocity in all inertial frames, otherwise we could differentiate inertial frames using the apparent propagation speed of the disturbance, which would violate the relativity principle. >> http://farside.ph.utexas.edu/teaching/jk1/lectures/node7.html http://en.wikipedia.org/wiki/Wave_impedance#Wave_impedance_of_free_space Sue...
From: colp on 30 Nov 2007 16:52 On Nov 30, 9:59 pm, Bryan Olson <fakeaddr...(a)nowhere.org> wrote: > colp wrote: > > Daryl McCullough wrote: > >> Colp, if you want to complain about what Special Relativity > >> says about the situation, you *MUST* understand what Special > >> Relativity says. You can't just make stuff up and then complain > >> that it doesn't make sense. > > > What am I making up? > > > SR says that time dilation is observed for a relativistically moving > > clock when the observer is in an inertial frame. > > That time dilation is observed regardless of whether the clock is > > moving closer or moving away. > > When A is moving away from B, A observes that B's time is dilated. > > When A is moving towards B, A observes that B's time is dilated. > > When A & B meet their clocks are the same. > > For their clocks to be the same time, A must have observed that B's > > time was compressed at some stage. > > SR does not describe time compression. > > That you made up. According to SR, A's change it frames will > result in A seeing B's age jump forward. Wrong. SR has nothing to say about non-inertial frames. Special relativity (SR) (aka the special theory of relativity) is the physical theory of measurement in inertial frames of reference proposed in 1905 by Albert Einstein in his article "On the Electrodynamics of Moving Bodies". http://en.wikipedia.org/wiki/Special_relativity > > You've made up other bits too, as we've pointed out. For example?
From: Daryl McCullough on 30 Nov 2007 16:56 colp says... >An observer can move between inertial frames, and the logic and math >must apply equally in one frame as is does in another. > >> >> Your apparent paradox VIOLATES the set of circumstances under which the >> logic and math are 'required to appear consistent'. > >Reality does not require that observations only be made from a >particular set of circumstances. I made this point in another post: You need to clearly distinguish an *observer* from a *coordinate system*. The fact that an *observer* is accelerating, and changing frames does not mean that a noninertial coordinate system must be used. There is no problem in using an inertial coordinate system to describe what is seen by an accelerating observer. -- Daryl McCullough Ithaca, NY
From: bz on 30 Nov 2007 19:29 colp <colp(a)solder.ath.cx> wrote in news:caf344e3-e0e0-40dc-a6e3-06c0382cdac9(a)d21g2000prf.googlegroups.com: > On Nov 30, 10:36 pm, bz <bz+...(a)ch100-5.chem.lsu.edu> wrote: >> colp <c...(a)solder.ath.cx> wrote >> innews:0d8d2519-d996-4397-8506-5fa467cc2aa2(a)i12g2000prf.googlegroups.com >> : >> >> > That nonsense is the paradox that I am talking about. Facts from one >> > coordinate system do get mixed and matched with facts from other >> > coordinate systems. An example of the is clock synchronisation for >> > GPS sattelites. >> >> But the logic and the math are only required to 'appear consistent' >> under certain sets of circumstances. > > I assume that you mean from within a single inertial frame of > reference. Or follow the proper rules when changing frames. > > An observer can move between inertial frames, and the logic and math > must apply equally in one frame as is does in another. Follow the proper rules when changing from one to another. Daryl showed you the figures. >> Your apparent paradox VIOLATES the set of circumstances under which the >> logic and math are 'required to appear consistent'. > > Reality does not require that observations only be made from a > particular set of circumstances. But it does require that you wear the same watch OR you change watches OR you change the watches settings when you change time zones. Changing direction of travel in your example is much like changing time zones. You want to keep your watch set the same even though you changed time zones, AND THEN you complain when you end up missing your appointments and blame the watch. It isn't the watches fault. Reality does NOT require that observations only be made from a particular frame of reference, but logic and math requires that you take the fact you have change iFoRs into account. You refuse to take the change into account and then complain about the results you get. >> The fact that things do not appear consistent is thus neither >> remarkable nor odd nor indicative of a problem in relativity. > > It is a problem for relativity because relativity is supposed to > describe what happens in reality. It does, when you follow the rules. When you break the rules don't expect the results to describe what happens in reality. >> It is only indicative of a lack of understanding. >> >> I am 50 miles from a mountain. I am 1/4 mile from a telephone pole. >> The pole looks taller than the mountain. The mountain is taller than >> the pole. >> >> Paradox? > > Apparently. No. Not a paradox. A failure to understand perspective. > But if I travel to the mountain (by changing my frame of > reference) I notice that the poles appear to get smaller compared to > the mountain It gets bigger! It gets SMALLER when you travel away from the mountain. > and I become aware of perspective effects. You have to PASS the pole before it gets smaller, in your rear view mirror. But the mountain looking closer does NOT mean that you have traveled toward it. You might be looking through a telescope. You see the mountain as bigger [the pole is bigger too, but you ignore that fact] and then complain about the paradox that the mountain is closer but you haven't moved an inch. That is exactly the same kind of 'mixing and matching' of facts that you keep doing in order to sustain the illusion that there is a paradox. >> Only to those ignorant of perspective, which is based upon light >> traveling in 'straight lines'. >> >> Are the 'relativity examples' real paradoxes? > > If only delta t = gamma delta t0 is applied to the paradox in the OP > then the paradox is real because gamma is always greater than one. If you try to drive by looking in the rear view mirror, you will have paradoxes too. You are trying to restrict the tools that can be used. Why complain when that hammer doesn't do a good job of putting those wood screws into place when there is a perfectly good screw driver sitting right next to the hammer? You can use the hammer to START the screw and then use the screwdriver, or you can predrill the screw hole with a countersink bit. The wood you are using is really TOO hard for driving in screws with a hammer, yet you persist in banging away and complaining that the hammer is poorly made and the screws are bending and breaking. You skipped the sudden jump in counts when you jumped from one iFoR to the other. Daryl has pointed it out to you and you ignore it. >> Only to those ignorant of >> the temporal perspective views presented by relativistic motion through >> time-space. > > So what is it that you think that I am ignorant of? I begin to think you are feigning. > I am told that I can't 'mix and match' observations which are made > from different inertial frames of reference. Yet reality does not > limit observers from changing frames and making conclusions based on > their observations. They are free to change frames, as long as they take into account the fact that they have 'changed time zones' when they do change frames. You continue to refuse to do that. What joy do you get out of the game you are playing? -- 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: Bryan Olson on 1 Dec 2007 00:58
colp wrote: > Bryan Olson wrote: >> colp wrote: >>> What am I making up? [...] >>> For their clocks to be the same time, A must have observed that B's >>> time was compressed at some stage. >>> SR does not describe time compression. >> That you made up. According to SR, A's change it frames will >> result in A seeing B's age jump forward. > > Wrong. SR has nothing to say about non-inertial frames. > > Special relativity (SR) (aka the special theory of relativity) is the > physical theory of measurement in inertial frames of reference > proposed in 1905 by Albert Einstein in his article "On the > Electrodynamics of Moving Bodies". > > http://en.wikipedia.org/wiki/Special_relativity Reading the page you cite, we find: Special relativity does not account for gravity, but it can deal with accelerations. >> You've made up other bits too, as we've pointed out. > > For example? Before turning our attention to other cases, is this one now clear to you? Checking the Wiki article's editing history and the date of your post, one will find that the article said SR can deal with accelerations at the same time you cited it and made the claim, "SR has nothing to say about non-inertial frames." Please stop attributing your own wrong ideas to SR. -- --Bryan |