[Paper Review] The physical meaning of synchronization and simultaneity in Special Relativity

Rodrigo de Abreu|ArXiv.org|Dec 4, 2002

Relativity and Gravitational Theory1 references3 citations

TL;DR

This paper re-evaluates Einstein's 1905 synchronization and simultaneity in Special Relativity, arguing that only in a single 'rest system' is the one-way speed of light truly c. By reinterpreting Einstein's synchronization procedure, the author derives a 'Synchronized Transformation' where clocks are properly synchronized using the one-way speed of light, contrasting it with the Lorentz Transformation, which arises from a desynchronized time assignment. The key contribution is the claim that simultaneity is absolute, and that absolute velocity can be experimentally determined using synchronized clocks and light signals.

ABSTRACT

Based on two previous papers, the physical meaning of synchronization and simultaneity as is presented in Einstein's Special Relativity paper of 1905 is reconsidered. We follow Einstein's argumentation to introduce a criterium of synchronization and for the same arguments we arrive at a different criterium for synchronization. From that we conclude that simultaneity is absolute.

Motivation & Objective

• To re-express the physical meaning of synchronization and simultaneity in Einstein's 1905 Special Relativity using Einstein's own physical arguments.
• To challenge the conventional interpretation that simultaneity is relative, arguing instead that it is absolute when synchronization is properly defined.
• To demonstrate that the Lorentz Transformation arises from a desynchronized time assignment, not a physically necessary one.
• To propose a Synchronized Transformation where clocks in a moving frame are truly synchronized using the one-way speed of light.
• To show how absolute velocity relative to a rest system can be experimentally measured using synchronized clocks and light signals.

Proposed method

• Reconstructs Einstein’s 1905 synchronization argument using the assumption that only in the rest system is the one-way speed of light equal to c.
• Introduces a new time assignment t' such that x' = c_one-way * t', leading to a Synchronized Transformation where clocks in S' are synchronized.
• Derives the Lorentz Transformation as a transformation from the Synchronized Transformation by introducing a desynchronization of clocks in S' via t' → t' + (v/c²)x'.
• Uses the two-way speed of light being c in all frames (postulate I) and the one-way speed of light being c only in the rest system (postulate II) as foundational principles.
• Proposes a gedanken experiment using two moving frames S' and S'' with different velocities relative to the rest system S, where synchronized clocks at x' and x'' are used to measure time differences.
• Derives equations (39)–(44) to calculate absolute velocities v₁ and v₂ of S' and S'' relative to S by comparing clock readings at the origin of S'' when it passes a mark x' in S'.

Experimental results

Research questions

• RQ1 Does Einstein’s synchronization procedure lead to a physically consistent definition of simultaneity in all inertial frames, or only in the rest system?
• RQ2 Can the one-way speed of light be assumed to be c in all frames, or is it only c in a preferred rest system?
• RQ3 Is the Lorentz Transformation the only valid transformation between inertial frames, or does a Synchronized Transformation exist that preserves physical consistency?
• RQ4 Can absolute velocity relative to a rest system be experimentally determined using synchronized clocks and light signals?
• RQ5 Is simultaneity absolute when synchronization is defined via the one-way speed of light rather than the Einstein convention?

Key findings

• The Synchronized Transformation, derived from x' = c_one-way * t', results in properly synchronized clocks in a moving frame S', unlike the Lorentz Transformation.
• The Lorentz Transformation arises from a desynchronized time assignment in S', specifically by transforming t' to t' + (v/c²)x', which introduces a physical asymmetry.
• The one-way speed of light is not c in moving frames S' unless the rest system is privileged, implying that only in the rest system is the one-way speed of light truly c.
• Simultaneity is absolute because synchronization based on the one-way speed of light leads to consistent, frame-independent simultaneity relations.
• The absolute velocity of a moving frame relative to the rest system can be experimentally determined by comparing clock readings at the origin of a second frame when it passes a marked position in the first frame.
• The covariance of physical laws in different frames does not depend on the choice of transformation, but the physical meaning of time and synchronization does, especially in the Lorentz case where clocks are desynchronized.