Time dilation, accelerated frames, and the twin paradox

Abstract Although the twin paradox is as old as the special theory of relativity itself, understanding of its resolution is often obscured by student's miscarried intuition. That is usually a result of an incomplete understanding of some predictions of the theory or of its range of validity. In this article, we present a didactic solution to the problem aiming at elucidating some understanding gaps. Discussing the precise content of the time dilation predicted by special relativity, we eliminate a first intuition that might suggest the existence of a paradox. Then we show why special relativity alone is enough to solve the problem without any need to invoke the general theory of relativity. We conclude this work presenting a solution to the twin paradox from the point of view of the stationary twin as well as from the traveling twin.