Twin paradox

paradox is: say there are two twins A and B. A takes a space ship and travels near the speed of light. B remains on earth. After some time A returns to earth. A will be younger than B. A, since it travels near speed of light will experience time dilation and his clocks including his biological clock will run slow compared to his earth twin B- Scenario X

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It becomes a paradox why the same thing don't happen to B. Why only A gets younger and not B. B also will be traveling in the other direction compared to A.

The explanation given is, A first starts to accelerate to attain the required speed. Then after traveling it will decelerate to stop, it will turn and accelerate again coming back to earth, then it will travel to earth and decelerate to stop. When accelerating and decelerating A ceases to be in initial frames. But B always is in an initial frame. Therefore A and B are different.

This is a very lose explanation.It is very strange this explanation is accepted so long. Maybe success of time dilation experiments or a sham, obscured the correctness of the thought experiment.

Consider the same experiment - Scenario Y. After A makes the outward traveling and stops at some place, B will make the same travel to teach A. It is very obvious that now both A and B should be of the same age now. 

If we compare B's outward travel in Scenario Y,  to A's inward travel in Scenario X, there's only one difference, only the direction has changed. Because acceleration f, velocity v and declaration -f are same for both

Therefore this paradox cannot be explained by non-initial frames that A undergo. The same can be said of the grandfather paradox - you travel faster than light and go back in time to kill your grandfather, you cannot be born though you exist now.

Special Relativity was intended to solve the problem created by the Michelson Morley Experiment that light does not travel in a preferred reference frame. Therefore, logically, in one reference frame, one twin grows older than the other twin in a different reference frame cannot be true, because either twin cannot be in a preferred reference frame than the other.