The real twin paradox.
in [Relativity]
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From: Cosmik de Bris on 22 Nov 2007 19:52 colp wrote: > On Nov 23, 11:44 am, Cosmik de Bris > <cosmik.deb...(a)elec.canterbury.ac.nz> wrote: >> colp wrote: >>> On Nov 23, 3:18 am, "harry" <harald.vanlintelButNotT...(a)epfl.ch> >>> wrote: >>>> "colp" <c...(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_... >>>> http://en.wikipedia.org/wiki/Twin_paradox >>> Those arguments depend on the asymmetry of the original thought >>> experiment. Since asymmetry is absent in the thought experiment >>> descriped in the OP, they do not solve the paradox described in this >>> thread. >> Nothing is ever perfectly symmetrical, > > A circle is perfectly symmetrical. > >> how far out of symmetrical does >> something have to be before it becomes asymmetrical? > > A finite distance. > >> Nothing magical >> happens when the thought experiment becomes symmetrical, how can it? > > The paradox of the symmetric twins does not depend on magic. > > The paradox depends of the fact that (according to SR) a twin will > observe the other clock slowing down and never observe it speeding up, > and yet it must tell the same time as his own clock at the end of the > experiment. As Dirk has told you, and I have told you in the other newsgroup, you need to learn some basics. -- Posted via a free Usenet account from http://www.teranews.com
From: Sue... on 22 Nov 2007 19:53 On Nov 22, 7:20 pm, Bryan Olson <fakeaddr...(a)nowhere.org> wrote: > colp wrote: > > Special relativity says that both > > clocks are observed to run slower than each other, and this is > > impossible when the clocks are in the same frame of reference. Thus > > the only logical conclusion is that special relativity is wrong. > > You've gotten several good explanations of where your > reasoning on what relativity predicts went wrong: it's > all about the turn-around when the twins are far apart. > > More generally, thought experiment alone cannot refute > relativity. Lots of people who know lots of math have > gone over the theory. Whether or not it describes how > the universe works, challenging its self-consistency > is futile. > > When my own trials of thought experiments yield > conflicting outcomes, as they often do, I have to ask > myself: Did I just refute the work of all those > scientists and mathematicians, or did I think I knew > more than I did? Turns out one of those possibilities > is quite a bit more likely than the other. Perhaps you should compare the 1905 paper used by proponents of the twins myth with the 1920 paper which only couples to inertia by mass energy equivalence. http://www.fourmilab.ch/etexts/einstein/specrel/www/ http://www.bartleby.com/173/ Then you can debate with yourself whether 'tis more likely Einstein was right in 1905 or in 1920. Abstract Einstein addressed the twin paradox in special relativity in a relatively unknown, unusual and rarely cited paper written in 1918, in the form of a dialogue between a critic and a relativist. Contrary to most textbook versions of the resolution, Einstein admitted that the special relativistic time dilation was symmetric for the twins, and he had to invoke, asymmetrically, the general relativistic gravitational time dilation during the brief periods of acceleration to justify the asymmetrical aging. Notably, Einstein did not use any argument related to simultaneity or Doppler shift in his analysis. I discuss Einstein's resolution and several conceptual issues that arise. It is concluded that Einstein's resolution using gravitational time dilation suffers from logical and physical flaws, and gives incorrect answers in a general setting. The counter examples imply the need to reconsider many issues related to the comparison of transported clocks. The failure of the accepted views and resolutions is traced to the fact that the special relativity principle formulated originally for physics in empty space is not valid in the matter-filled universe. C. S. Unnikrishnan Gravitation Group, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India http://www.iisc.ernet.in/currsci/dec252005/2009.pdf Sue... > > -- > --Bryan
From: colp on 22 Nov 2007 20:05 On Nov 23, 1:20 pm, Bryan Olson <fakeaddr...(a)nowhere.org> wrote: > colp wrote: > > Special relativity says that both > > clocks are observed to run slower than each other, and this is > > impossible when the clocks are in the same frame of reference. Thus > > the only logical conclusion is that special relativity is wrong. > > You've gotten several good explanations of where your > reasoning on what relativity predicts went wrong: it's > all about the turn-around when the twins are far apart. Wrong. The turnaround does not have to occur at relativistic speeds. > > More generally, thought experiment alone cannot refute > relativity. Wrong again. A thought experiment which results in a paradox is a form of a reductio ad absurdum argument. http://en.wikipedia.org/wiki/Reductio_ad_absurdum
From: Bryan Olson on 22 Nov 2007 20:05 colp wrote: > "harry" cited: >> http://math.ucr.edu/home/baez/physics/Relativity/SR/TwinParadox/twin_intro.html >> >> http://en.wikipedia.org/wiki/Twin_paradox > > Those arguments depend on the asymmetry of the original thought > experiment. Since asymmetry is absent in the thought experiment > descriped in the OP, they do not solve the paradox described in this > thread. They explain the point you missed in your analysis: When a twin, far from his brother, change frames for the return trip, from his own point of view his brother's clock jumps ahead. You might start with: http://www.bartleby.com/173/9.html In your symmetric set-up, SR predicts the twins will be the same age upon their return to Earth. The contradictory conclusion was simply a mistake; you did not take all that relativity predicts into account. No paradox. In the Einstein/Langevin thought experiment, SR predicts the traveler will be younger than his twin brother upon return. Actual experiments support the theory. It's not really a paradox, just an astonishing phenomenon. -- --Bryan
From: colp on 22 Nov 2007 20:13
On Nov 23, 1:52 pm, Cosmik de Bris <cosmik.deb...(a)elec.canterbury.ac.nz> wrote: > colp wrote: > > On Nov 23, 11:44 am, Cosmik de Bris > > <cosmik.deb...(a)elec.canterbury.ac.nz> wrote: > >> colp wrote: > >>> On Nov 23, 3:18 am, "harry" <harald.vanlintelButNotT...(a)epfl.ch> > >>> wrote: > >>>> "colp" <c...(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_... > >>>>http://en.wikipedia.org/wiki/Twin_paradox > >>> Those arguments depend on the asymmetry of the original thought > >>> experiment. Since asymmetry is absent in the thought experiment > >>> descriped in the OP, they do not solve the paradox described in this > >>> thread. > >> Nothing is ever perfectly symmetrical, > > > A circle is perfectly symmetrical. > > >> how far out of symmetrical does > >> something have to be before it becomes asymmetrical? > > > A finite distance. > > >> Nothing magical > >> happens when the thought experiment becomes symmetrical, how can it? > > > The paradox of the symmetric twins does not depend on magic. > > > The paradox depends of the fact that (according to SR) a twin will > > observe the other clock slowing down and never observe it speeding up, > > and yet it must tell the same time as his own clock at the end of the > > experiment. > > As Dirk has told you, and I have told you in the other newsgroup, you > need to learn some basics. What you and Dirk think I need is irrelevant. Why are you unable to explain the paradox? |