On the Real and Apparent Positions of Moving Objects in Special Relativity: The Rockets-and-String and Pole-and-Barn Paradoxes Revisited and a New Paradox

Abstract

The distinction between the real positions of moving objects in a single reference frame and the apparent positions of objects at rest in one inertial frame and viewed from another, as predicted by the space-time Lorentz Transformations, is discussed. It is found that in the Rockets-and-String paradox the string remains unstressed and does not break and that the pole in the Barn-and-Pole paradox never actually fits into the barn. The close relationship of the Lorentz-Fitzgerald Contraction and the relativity of simultaneity of Special Relativity is pointed out and an associated paradox, in which causality is apparently violated, is noted.

arXiv comment23 pages, 5 figures, 4 tables. See also physics/0004012. The resolution of the causal paradox is presented in physics/0501043. In v3 the text of Section 2 and Fig.1 is revised to avoid confusion between configurations in primary and reciprocal experiments. This change does not affect the remainder of the paper