Hello ! I'm having troubles with the causes of time dilation. I will to appeal to the twin paradox because it is known for everybody. A = Earth twin. B = traveller twin. We know B is younger than A when he returns. Now, why? I mean... from the viewpoint of A, he is younger because his time was dilated during his inertial trip (we can neglect the effect of acceleration here). But from the viewpoint of B, A was under the effect of "time dilation" too, but during the acceleration, B sees a uniform pseudo-gravitational field fill the universe. And this field is the cause of the final difference between B and A's clocks. We have 2 very different "causes" for the same effect. What is the correct? bye !