How to Understand the Twin Paradox

Abstract

The twin paradox is often misunderstood, both in textbook and science popularizations. This article is intended to help clarify misconceptions involving the famous thought experiment. Of special importance is how we define the inertial frame in special theory of relativity. Another common factor that is overlooked involves the difference between time dilation, which is a consequence of the Lorentz transformations and the concept of look back time, which is independent of that. The concept of the invariant space-time interval and Minkowski diagrams are used in making these issues clearer.