FEYNMAN WRONG ABOUT THE TWIN PARADOX

http://www.pbs.org/wgbh/nova/blogs/p...ds-philosophy/
Tim Maudlin: "...so many physicists strongly discourage questions about the nature of reality. The reigning attitude in physics has been "shut up and calculate": solve the equations, and do not ask questions about what they mean. But putting computation ahead of conceptual clarity can lead to confusion. Take, for example, relativity's iconic "twin paradox." Identical twins separate from each other and later reunite. When they meet again, one twin is biologically older than the other. (Astronaut twins Scott and Mark Kelly are about to realize this experiment: when Scott returns from a year in orbit in 2016 he will be about 28 microseconds younger than Mark, who is staying on Earth.) No competent physicist would make an error in computing the magnitude of this effect. But even the great Richard Feynman did not always get the explanation right. In "The Feynman Lectures on Physics," he attributes the difference in ages to the acceleration one twin experiences: the twin who accelerates ends up younger. But it is easy to describe cases where the opposite is true, and even cases where neither twin accelerates but they end up different ages. The calculation can be right and the accompanying explanation wrong."

Einstein also taught that the youthfulness of the travelling twin was due to the turn-around acceleration:

http://en.wikisource.org/wiki/Dialog...f_rela tivity
Dialog about Objections against the Theory of Relativity, 1918, Albert Einstein: "During the partial processes 2 and 4 the clock U1, going at a velocity v, runs indeed at a slower pace than the resting clock U2. However, this is more than compensated by a faster pace of U1 during partial process 3. According to the general theory of relativity, a clock will go faster the higher the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher gravitational potential than U1. The calculation shows that this speeding ahead constitutes exactly twice as much as the lagging behind during the partial processes 2 and 4."

John Norton teaches the same story:

http://www.pitt.edu/~jdnorton/teachi...yon/index.html
John Norton: "Then, at the end of the outward leg, the traveler abruptly changes motion, accelerating sharply to adopt a new inertial motion directed back to earth. What comes now is the key part of the analysis. The effect of the change of motion is to alter completely the traveler's judgment of simultaneity. The traveler's hypersurfaces of simultaneity now flip up dramatically. Moments after the turn-around, when the travelers clock reads just after 2 days, the traveler will judge the stay-at-home twin's clock to read just after 7 days. That is, the traveler will judge the stay-at-home twin's clock to have jumped suddenly from reading 1 day to reading 7 days. This huge jump puts the stay-at-home twin's clock so far ahead of the traveler's that it is now possible for the stay-at-home twin's clock to be ahead of the travelers when they reunite."

Feynman, Einstein and Norton are wrong of course but the problem is more serious than that. We all live in a schizophrenic world where the youthfulness of the travelling twin is due to the turn-around acceleration, on the one hand, and is not due to the turn-around acceleration, on the other:

http://www.fnal.gov/pub/today/archiv...lReadMore.html
Don Lincoln: "Some readers, probably including some of my doctoral-holding colleagues at Fermilab, will claim that the difference between the two twins is that one of the two has experienced an acceleration. (After all, that's how he slowed down and reversed direction.) However, the relativistic equations don't include that acceleration phase; they include just the coasting time at high velocity."

http://www.damtp.cam.ac.uk/research/...tivity2010.pdf
Gary W. Gibbons FRS: "In other words, by simply staying at home Jack has aged relative to Jill. There is no paradox because the lives of the twins are not strictly symmetrical. This might lead one to suspect that the accelerations suffered by Jill might be responsible for the effect. However this is simply not plausible because using identical accelerating phases of her trip, she could have travelled twice as far. This would give twice the amount of time gained."

Pentcho Valev

...they and Einstein too did not solved the question : speed or movement , from where?...this is the point !

http://www.fourmilab.ch/etexts/einstein/specrel/www/
ON THE ELECTRODYNAMICS OF MOVING BODIES, A. Einstein, 1905: "From this there ensues the following peculiar consequence. If at the points A and B of K there are stationary clocks which, viewed in the stationary system, are synchronous; and if the clock at A is moved with the velocity v along the line AB to B, then on its arrival at B the two clocks no longer synchronize, but the clock moved from A to B lags behind the other which has remained at B by tv^2/2c^2 (up to magnitudes of fourth and higher order), t being the time occupied in the journey from A to B."

http://blog.hasslberger.com/Dingle_S...Crossroads.pdf
SCIENCE AT THE CROSSROADS, Herbert Dingle, p.27: "According to the special relativity theory, as expounded by Einstein in his original paper, two similar, regularly-running clocks, A and B, in uniform relative motion, must work at different rates. (...) How is the slower-working clock distinguished?"

Dingle's question is rhetorical - the slower-working clock cannot be distinguished on the basis of Einstein's 1905 postulates alone. The postulates entail that, as judged from the respective system, either clock runs slower than the other. That is, for an observer in the moving clock's system, the stationary clock at B lags behind the moving clock; for a stationary observer, the moving clock lags behind the stationary clock at B.

So Einstein's famous conclusions that made him a superstar, "moving clocks run slow" and "travel into the future is possible", are based on two flaws. Initially Einstein advanced his false constant-speed-of-light postulate, which allowed him to validly deduce that:

moving clocks run slow, as judged from the stationary system.

Then he illegitimately dropped the second part of the above conclusion and informed the gullible world that:

moving clocks run slow, that is, travel into the future is possible.

Pentcho Valev

The world is beginning to ask the right questions:

http://physics.stackexchange.com/que...e-on-the-inter
Abc2000ro: "The solution to the twin paradox found on the internet is that the twin on Earth is on 1 frame the entire journey, while the twin in space is in 2 frames for the duration of the journey. However, in his own paper:

http://en.wikisource.org/wiki/Dialog...f_Rela tivity

Einstein gives a totally different explanation. He says that what matters is the moment of acceleration. So even if the acceleration happens in 1 second from 0 to 290.000km/s that's the only second that truly matters. So if Einstein says like this, how can anyone bring other explanations? (...) You can talk about the frame switching without saying anything about acceleration. You just draw 2 lines in a Minkowski diagram and that's it. Then you just apply the equations of special relativity and presumably you obtain the correct result. But Einstein says otherwise. That you have to use the equations of general relativity for the moment of acceleration (even though it is only 1 second or 1 year) and only then you obtain the correct results. So who should I trust?"

Abc2000ro asks the fatal question. Einstein was well aware that, unless the acceleration ("gravitational potential") camouflage is used, the clock (twin) paradox is an obvious absurdity:

http://en.wikisource.org/wiki/Dialog...f_rela tivity
Dialog about Objections against the Theory of Relativity, 1918, Albert Einstein: "During the partial processes 2 and 4 the clock U1, going at a velocity v, runs indeed at a slower pace than the resting clock U2. However, this is more than compensated by a faster pace of U1 during partial process 3. According to the general theory of relativity, a clock will go faster the higher the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher gravitational potential than U1. The calculation shows that this speeding ahead constitutes exactly twice as much as the lagging behind during the partial processes 2 and 4."

Nowadays most Einsteinians do not understand the problem but clever (even though dishonest) Einsteinians do:

http://www.people.fas.harvard.edu/~djmorin/chap11.pdf
Introduction to Classical Mechanics With Problems and Solutions, David Morin, Cambridge University Press, Chapter 11, p. 14: "Example (Twin paradox): Twin A stays on the earth, while twin B flies quickly to a distant star and back. Show that B is younger than A when they meet up again. (...) For the entire outward and return parts of the trip, B does observe A's clock running slow, but enough strangeness occurs during the turning-around period to make A end up older. Note, however, that a discussion of acceleration is not required to quantitatively understand the paradox..."

Pentcho Valev