On May 24, 2:52 pm, Marc Fleury <marcf...@gmail.com> wrote: > On May 23, 10:56 pm, Darwin123 <drosen0...@yahoo.com> wrote: > > > > > > > > > > > On May 23, 4:39 pm, Prai Jei <pvstownsend.zyx....@ntlworld.com> wrote:> Koobee Wublee set the following eddies spiralling through the space-time > > > continuum: > > > > > This is the twins? paradox, and it is never resolved. > > > > How much acceleration does the travelling twin experience as he turns round? > > > > How much acceleration does the stay-at-home twin experience as the > > > travelling twin turns round? > > > > There ain't no symmetry between the twins. > > > > Twin paradox resolved. > > > May I add the the acceleration that breaks the symmetry has to be > > associated with an external force on the observer's instruments. > > What confuses people is the mistaken belief that there is no > > absolute acceleration in SR. There is no absolute velocity in SR but > > there is absolute acceleration. > > By absolute acceleration, I mean the external force on the > > observer's instrument divided by the mass of the instrument. Perhaps I > > should call that the dynamic force. > > The dynamic force places the observer in a series of inertial > > frames. The observer can not stay in one inertial frame if a dynamic > > force is acting upon it. Therefore, the law of reciprocity does not > > apply to an observer that switches from one inertial frame to the > > other. In this one sense, the force is important in SR. > > If there were no such thing as absolute acceleration, then the > > cranks would be right. There would be a symmetry between the twins. > > very simply put this is not the twins paradox. At all. > > Landau (in a post in another thread) is bang on, but dismisses the > symmetry based on the fact that you have to compare one clock to many > other clocks and that is not symmetric. refer to the other threads. This is the twins conundrum. It is not a paradox because an external force acts on the rocket twin and not on the earth twin. In order to turn around, the rocket has to turn on its engine. A contact force is applied to all the instruments in the rocket, including the twin himself. The measurement protocols correct for all effects of the stress on the instruments. The instruments and the twin supposedly is immune to the stress caused by the contact forces. However, the force has an effect on the objects other then stress. The force effects the time as seen by rocket twin, not earth twin. Unless some force accelerates the earth twin. I will put it another way. The twin in the rocket is jumping through several inertial frames. While a force is acting on him, his instruments are passing from one inertial frame to another. Therefore, the law of reciprocity can not apply to the rocket twin. While the rocket twin stays in one inertial frame, the law of reciprocity applies to him. The same laws of the universe that apply to him applies to all inertial frames. However, while he jumps frames then different laws of physics applies to him then to his earth twin.
