Lengths on rotating platforms

Abstract

The paper treats the issue of the length of a rotating circumference as seen from on board the moving disk and from an inertial reference frame. It is shown that, properly defining a measuring process, the result is in both cases 2piR thus dissolving the Ehrenfest paradox. The same holds good when considering that, for the rotating observer, the perceived radius coincides with the curvature radius of a space-time helix and a complete round trip corresponds to an angle which differs from the one seen by the inertial observer. The apparent contradiction with the Lorentz contraction is discussed.

14 pages, 2 figures. RevTex. To be published in Foundations of Physics. Section on the metric on the disk will become a separate paper, now it has been dropped. Typos corrected, references added

Cited by in corpus (10)

• Space geometry of rotating platforms: an operational approach
• Relativistic contraction and related effects in noninertial frames
• Charged Particles and the Electro-Magnetic Field in Non-Inertial Frames of Minkowski Spacetime: II. Applications: Rotating Frames, Sagnac Effect, Faraday Rotation, Wrap-up Effect
• Spatial geometry of the rotating disk and its non-rotating counterpart
• Relativistic Rotation: A Comparison of Theories
• The Relative Space: Space Measurements on a Rotating Platform
• Reference frames and rigid motions in relativity: Applications
• On the relation of Thomas rotation and angular velocity of reference frames
• Ehrenfest's paradox for tokamak plasma
• Geometry of an accelerated rotating disk