Recently,1 a half-page derivation of the Thomas precession effect2 has been presented (see also all the references in Ref. 1 for the history and prehistory of the problem). In this short note, we provide a much simpler, three-line derivation of that effect which, to our knowledge, is the simplest in the literature.
Consider Bob B moving relative to Alice's frame A with a relativistic velocity v, as shown in Fig. 1. If Bob's velocity changes by an infinitesimal value relative to his initial reference frame B, Alice will observe his new velocity to be some . The new Bob's frame is now rotated relative to Alice's frame by a Thomas–Wigner angle . In the non-relativistic theory, we have and the rotation is absent. Therefore, the Thomas–Wigner...