Foundations of Physics

, Volume 32, Issue 10, pp 1525–1556

Space Geometry of Rotating Platforms: An Operational Approach

  • Guido Rizzi
  • Matteo Luca Ruggiero

DOI: 10.1023/A:1020427318877

Cite this article as:
Rizzi, G. & Ruggiero, M.L. Foundations of Physics (2002) 32: 1525. doi:10.1023/A:1020427318877


We study the space geometry of a rotating disk both from a theoretical and operational approach; in particular we give a precise definition of the space of the disk, which is not clearly defined in the literature. To this end we define an extended 3-space, which we call “relative space:” it is recognized as the only space having an actual physical meaning from an operational point of view, and it is identified as the “physical space of the rotating platform.” Then, the geometry of the space of the disk turns out to be non Euclidean, according to the early Einstein's intuition; in particular the Born metric is recovered, in a clear and self consistent context. Furthermore, the relativistic kinematics reveals to be self consistent, and able to solve the Ehrenfest's paradox without any need of dynamical considerations or ad hoc assumptions.

special relativity rotating platforms space-geometry Ehrenfest non-time-orthogonal frames 

Copyright information

© Plenum Publishing Corporation 2002

Authors and Affiliations

  • Guido Rizzi
    • 1
  • Matteo Luca Ruggiero
    • 1
    • 2
  1. 1.Dipartimento di FisicaPolitecnico di TorinoTorinoItaly
  2. 2.INFNTorinoItaly

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