The twin paradox was first formulated almost 100 years ago but still nowadays is one of the best ways to present the dependence on the definition of space and time of the state of motion of the observer. In this paper we present the conventional formulation of the twin paradox pointing out some of its key concepts and analyse one of its modification in which we compactify one of the spatial dimensions. Given the compactification, it is no more necessary to accelerate one of the twins to rejoin them. In this way, we circunvent the conventional explanation to the asymmetry between the twins. Following this reasoning, we move to clarify the fundamental role played by acceleration and conclude with some comments on synchronization of clocks and observables in special relativity.
relativistic epistemology; relativistic kinematics
