Absolute Distant Simultaneity in Special Relativity

What is simultaneous with an event is what can interact with it; events have duration; therefore, any given event has distant events simultaneous with it, even according to Special Relativity. Consequently, the extension of our pre-relativistic judgments of distant simultaneity are largely preserved.

Visualization of Thomas-Wigner Rotations

It is well known that a sequence of two non-collinear Lorentz boosts (pure Lorentz transformations) does not correspond to a Lorentz boost, but involves a spatial rotation, the Wigner or Thomas-Wigner rotation. We visualize the interrelation between this rotation and the relativity of distant simultaneity by moving a Born-rigid object on a closed trajectory in several steps of uniform proper acceleration. Born-rigidity implies that the stern of the boosted object accelerates faster than its bow. It is shown that at least five boost steps are required to return the object's center to its starting position, if in each step the center is assumed to accelerate uniformly and for the same proper time duration. With these assumptions, the Thomas-Wigner rotation angle depends on a single parameter only. Furthermore, it is illustrated that accelerated motion implies the formation of an event horizon. The event horizons associated with the five boosts constitute a natural boundary to the rotated Born-rigid object and ensure its finite size.

Anti-Relativity in Action: The Scientific Activity of Herbert E. Ives between 1937 and 1953

Between 1937 and 1953 the industrial physicist Herbert E. Ives pursued an extended research program with the aim of challenging the acceptance of relativity theories, and became the most important American opponent of Einstein during that era. As part of his anti-relativistic efforts Ives also performed the famous Ives-Stilwell experiment. Usually interpreted as the first direct confirmation of the time dilation formula of special relativity theory, this experiment was regarded by Ives as proof of what he called the Larmor-Lorentz theory. Ives’s heterodox views about relativity were mainly ignored by the scientific community during his lifetime. After his death, however, his criticisms of what the majority of physicists took for granted helped spark philosophical discussions in the late 1950s concerning the conventional stipulation of distant simultaneity in special relativity theory. Ives’s anti-relativistic beliefs and actions allow for an analysis of the heterodox efforts of an accredited member of the scientific community and the subsequent process of his professional marginalization in a specific historical and scientific context. This paper has three aims: to uncover the epistemic roots of Ives’s opposition to relativity; to analyze Ives’s rhetorical strategies and the reasons why he failed to persuade his peers; and to reveal the divergence between the public network of allies Ives built in scientific publications and the hidden network of allies present in his correspondence. It will become clear that the hardening of Ives’s tone against relativity and Einstein can be understood in light of his progressive marginalization and loss of recognized socioprofessional identity due to his unorthodox ideas. Ives’s case is illuminating for the historical, philosophical, and sociological perspectives it provides on the complex mechanisms by which the margins interact with the mainstream of science, both in the production of certified knowledge and in the contextually contingent redefinition and reconfiguration of the boundaries of acceptable scientific discourse.

On Relativity, Time Reckoning, and the Topology of Time Series

This chapter devotes equal attention to special relativity and general relativity. It first describes the history of the analysis of distant simultaneity, up to and including Einstein's procedure in his revolutionary 1905 paper which introduced special relativity. In particular, the discussion relates Einstein's procedure to the ensuing philosophical debate about whether distant simultaneity is a matter of convention. As to general relativity, the discussion gives a brief sketch of Einstein's path towards his discovery of general relativity. Thereafter, it focuses on the topological structure of time or, more precisely, of timelike lines (worldlines) in spacetime. It discusses the closed timelike lines first found in an exact solution of general relativity by Godel; and the open timelike geodesics that get arbitrarily close to the initial singularity (Big Bang) in a Friedmann solution.

Passage from Einsteinian to Galilean Relativity and Clock Synchrony

There is a general belief that under small velocity approximation. Special Relativity goes over into Galilean Relativity. Should this be interpreted exclusively in terms of the kinematical symmetry transformations (Lorentz vs. Galilei) a misconception could easily arise that would stem from overlooking the role of conventionality ingredients of Special Relativity Theory. It is observed that the small velocity approximation cannot alter the convention of distant simultaneity. In order to exemplify this point further, the Lorentz transformations are critically compared, under the same approximation, with two other space time transformations, one of which represents an Einstein world with Galilean synchrony whereas the other describes a Galilean world with Einsteinian synchrony