Twin Paradox, Lorentz Transformation, Relativity.
of time t_1 is equal to x(t)*γ^(-1)(t_1) or d_1m (t_1) = x (t)*γ^(-1) (t). The last relation is important as it also means that, in the case where the speed of the body is equal to zero, d_1m(t_1)= x(t). When the body is stationary in the frame S all distances have the same measure for all