Perhaps the greatest idiocy in the history of science:

In 1918 Einstein informed the gullible world that, as the traveling clock (twin) turns around and experiences acceleration, a HOMOGENEOUS gravitational field emerges. This homogeneous gravitational field somehow affects the distant stay-at-home clock and makes it run very fast (makes the stay-at-home twin get very old) during the turning-around period:

Albert Einstein 1918: "A homogeneous gravitational field appears, that is directed towards the positive x-axis. Clock U1 is accelerated in the direction of the positive x-axis until it has reached the velocity v, then the gravitational field disappears again. An external force, acting upon U2 in the negative direction of the x-axis prevents U2 from being set in motion by the gravitational field. [...] 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." http://sciliterature.50webs.com/Dialog.htm

David Morin, Introduction to Classical Mechanics With Problems and Solutions, Chapter 11, p. 14: "Twin A stays on the earth, while twin B flies quickly to a distant star and back. [...] 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." http://www.people.fas.harvard.edu/~djmorin/chap11.pdf

"When the twin in the spaceship turns around to make his journey home, the shift in his frame of reference causes his perception of his brother's age to change rapidly: he sees his brother getting suddenly older. This means that when the twins are finally reunited, the stay-at-home twin is the older of the two." http://topquark.hubpages.com/hub/Twin-Paradox

Einstein's 1918 idiocy was a crucial fudge factor that saved the "theory". Without recourse to "enough strangeness" (see David Morin's text above), either twin will find his brother younger when they reunite after the trip. Feynman taught the idiocy diligently but never mentioned the "homogeneous gravitational field" (it is too idiotic, even for the standards of Einstein's schizophrenic world):

Richard Feynman: "So the way to state the rule is to say that the man who has felt the accelerations, who has seen things fall against the walls, and so on, is the one who would be the younger." http://www.feynmanlectures.caltech.edu/I_16.html

Pentcho Valev