The Symmetric Twin Paradox
in [Relativity]
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From: colp on 20 Jun 2010 02:33 On Jun 20, 1:11 am, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > colp wrote: > > truth: SR predicts that each twin observes the other twin to age more > > slowly both on the outgoing leg and the return leg. > > > truth: In no case does SR predict that a twin observes the other to > > age more quickly. > > > inference: SR predicts that each twin will younger than the other at > > the end of the experiment. > > All three of those are wrong. Would not a true believer in relativity deny the truth of any argument which showed such a paradox? > You MUST learn what SR ACTUALLY says. What do you think that SR actually says about the symmetric twin thought experiment?
From: harald on 20 Jun 2010 04:39 On Jun 20, 2:07 am, train <gehan.ameresek...(a)gmail.com> wrote: [..] > > >> >> >> Instead > > >> >> >> they used a comic-book description of SR such as "moving clocks run > > >> >> >> slow" -- SR does NOT say that; Einstein wrote that in a scientific paper in 1905; it's not a "comic book description" but correct and without problems if correctly understood. [..] > My point is that the assertion that the twins show the same age is in > contradiction with the fact that the twins have moved relative to each > other. I cannot make it more simple than that In SR, just as in Newtonian mechanics, motion relative to other objects is *not* what matters. > The moving clock runs slow In SR, *both* moving clocks run slow. I bet that you never tried to *calculate* this... > The stay at home twin ages faster means that all stay at home twins > age faster than the all traveling twins that follow the exact same > flight profile. Yes. > But a particular traveling twin`s clock is always in motion with > respect to another traveling twins clock if they move in paths 90 > degrees to each other for example. See above: that doesn't matter for either classical mechanics or SRT. Einstein's introduction sentence of his 1905 paper is misleading: not relative motion between any objects, but motion relative to inertial systems is used for the calculations. > Is this not true? > > oh maybe as AE said we have to give up common sense. And reason? Where did he say that? SRT can be very common-sense, if you want to. Harald
From: Inertial on 20 Jun 2010 05:09 "colp" <colp(a)solder.ath.cx> wrote in message news:d909afc3-3c9b-4e50-80e2-e1a97793fbad(a)23g2000pre.googlegroups.com... > On Jun 19, 8:08 pm, "Inertial" <relativ...(a)rest.com> wrote: >> "colp" <c...(a)solder.ath.cx> wrote in message >> >> news:97c45dd7-e152-4e3d-8197-42bc43980300(a)y18g2000prn.googlegroups.com... > >> > In reality the twins age the same as each other, >> >> As SR predicts > > ... if you ignore what SR predicts that each twin will individually > observe throughout the entire experiment. you are the one ignoring what SR predict and making up your own nonsense. >> > but SR does not >> > predict that result >> >> WRONG > > No, not wrong. Yes .. WRONG .. show the math is you think otherwise So far nothing from you at all >> > if you examine the experiment from the point of >> > view of either twin. >> >> WRONG > > Nope. Nope > You can hack my statement anyway you like, No need .. you are simply wrong > but the fact is that SR > predicts that an observer observing a non-local clock moving in a > inertial frame at a relativistic velocity will observe that clock to > be running slow. Yes it will > This observation applies both on the outgoing and return legs, and it > applies for both twins. Yes it does ... but ignores the turnaround >> Show the supposed SR analysis you claim does this. And don't just look >> at >> the two legs individually .. > > So you don't want me to talk about the essential element of the > paradox, right? Wrong >> as in the usualy twins paradox, the main point >> is the change in rest reference frame at hte turnaround. ignore that, >> and >> its NOT SR. > > I haven't ignored the turnaround Yes .. you have > I have previously posted an > explanation of why turnaround can't eliminate the paradox with an > example of pulsed radio waves that are measured by a third observer on > Earth. But it does. Do the math
From: Inertial on 20 Jun 2010 05:07 "Paul Stowe" <theaetherist(a)gmail.com> wrote in message news:0a3a7ed7-17b1-41ee-8393-b1285126b234(a)k25g2000prh.googlegroups.com... > On Jun 19, 9:23 am, "Inertial" <relativ...(a)rest.com> wrote: >> "Dary McCullough" <stevendaryl3...(a)yahoo.com> wrote in message >> >> news:hvipdt01aeo(a)drn.newsguy.com... >> >> >> >> >> >> > colp says... >> >> >>Then what do you think the circumstances are in which SR predicts that >> >>a twin observes the other to age more quickly, and what mathematical >> >>relationship quantifies this? >> >> > Sure. Let's assume the following set-up. One twin stays at >> > home throughout. The other zips away and comes back. >> > Each twin sends out a radio pulse once per second (as >> > measured by his own clock). >> >> > From the point of view of the stay-at-home twin, the traveling twin >> > travels away at 0.866 c for 200 seconds, turns around rapidly, >> > and comes back at 0.866 c for 200 seconds. The traveling twin >> > experiences time dilation of a factor of two, so the trip takes >> > 400 seconds, as measured by the stay-at-home twin, and only >> > 200 seconds, as measured by the traveling twin. According to >> > the stay-at-home twin, the traveling twin sends out pulses at >> > the rate of one pulse every two seconds. >> >> > What about the pulses? The stay-at-home twin will receive signals >> > from the traveling twin at the rate of one signal every 3.73 seconds >> > for the first 373 seconds (for a total of 100 pulses). Then, the >> > stay-at-home twin will receive signals at the rate of one signal >> > every 0.27 seconds for the next 27 seconds, for a total of 100 more >> > pulses. >> >> > Why these numbers? On the way out, each successive pulse from >> > the traveling twin is sent from farther and farther away. Since >> > the traveling twin travels 1.732 light seconds between sending >> > any pulses. That means that the second pulse takes an additional >> > 1.732 seconds to travel back to Earth. Since it is sent 2 seconds >> > later, that means it will arrive at Earth 3.732 seconds later. >> >> > When the traveling twin is on his way back, each pulse is sent >> > from a closer and closer distance. One pulse is sent. Then the >> > next pulse is sent 2 seconds later. But since it is sent from >> > closer in, it takes 1.732 seconds *less* time to travel the >> > distance back to Earth. So the second pulse arrives only >> > 2 - 1.732 = 0.268 seconds later. >> >> > So the stay-at-home twin sees pulses arrive at rate once per >> > 3.732 seconds for part of the time, and sees pulses arrive at >> > the rate of once per 0.268 seconds for the rest of the time. >> > When does the changeover happen? Well, it happens when the >> > last pulse from the traveling twin's outward journey is sent. >> > Since the traveling twin travels outward for 200 seconds, he >> > is 200*0.866 = 173.2 light-seconds away. So it takes another >> > 173.2 seconds for that pulse to reach the Earth. So the >> > earth only gets that pulse at time 200 + 173.2 = 373.2 seconds. >> >> > So the earth receives at the rate of one per 3.732 seconds for >> > 373.2 seconds, for a total of 100 pulses, and then receives at >> > the rate of one per 0.268 seconds for the next 26.8 seconds, >> > for a total of 100 more pulses. So the Earth twin receives >> > 200 pulses from the traveling twin. >> >> > Now, let's look at the situation from the point of view >> > of the traveling twin: >> >> > The two rates are the same (by relativity): The traveling >> > twin receives pulses from the Earth twin at the rate of one >> > pulse per 3.732 seconds during his outward trip, which lasts >> > 100 seconds (according to his clock) for a total of about 27 >> > pulses received. In his return trip, he receives pulses from the >> > Earth at the rate of one pulse per 0.268 seconds for the >> > next 100 seconds, for a total of 373 more pulses. So altogether, >> > the traveling twin receives 373 + 27 = 400 pulses. >> >> > So the traveling twin receives 400 pulses from the stay-at-home >> > twin, while the stay-at-home twin receives only 200 pulses from >> > the traveling twin. By counting pulses, they both agree that >> > the traveling twin is younger. >> >> What would be instructive is to do the same analysis for the so-called >> symmetrical twins paradox. > > Too bad you can't do it... Too bad you wouldn't understand it if I did.
From: Inertial on 20 Jun 2010 05:10
"colp" <colp(a)solder.ath.cx> wrote in message news:c94ab20b-8084-47a2-8f71-d41e5de832bd(a)k17g2000pro.googlegroups.com... > On Jun 19, 8:10 pm, "Inertial" <relativ...(a)rest.com> wrote: >> "colp" <c...(a)solder.ath.cx> wrote in message >> >> news:07f2de62-4ba9-4b1b-99cd-dd05c284d2fa(a)b3g2000prd.googlegroups.com... >> >> >> >> > On Jun 19, 7:32 pm, "Inertial" <relativ...(a)rest.com> wrote: >> >> "colp" <c...(a)solder.ath.cx> wrote in message >> >> >>news:3f27a5b2-6fe9-4f52-9d45-033de8e4f473(a)g39g2000pri.googlegroups.com... >> >> >> > On Jun 19, 3:27 am, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: >> >> >> colp wrote: >> >> >> > It is not necessary for me to showing you the math in order for >> >> >> > you >> >> >> > to >> >> >> > identify the errors in the article. >> >> >> >> The basic error in that article is that they DID NOT use the math >> >> >> of >> >> >> SR. >> >> >> > That isn't necessarily an error. >> >> >> BAHAHAH .. Of course it is. How cam they show a contradiction in SR >> >> if >> >> they >> >> didn't USE SR. >> >> > It depends on the context of the question. >> >> Nope > > If the context is where they did use SR, you get one answer. > If the context is where they didn't use SR, you get a different one. You are getting the wrong answers .. so are not using SR .. only using the bits of it you want to use and ignoring the rest. |