TITLE:
Non-Invariant One-Way Speed of Light: Advancing the Selleri Transformations
AUTHORS:
Stephan J. G. Gift
KEYWORDS:
Lorentz Transformations, Selleri Transformations, One-Way Light Speed, GPS Synchronization Equation, GPS Range Equation, Time Transfer, Michelson-Gale Experiment, Relativistic Beaming
JOURNAL NAME:
Journal of Applied Mathematics and Physics,
Vol.14 No.4,
April
13,
2026
ABSTRACT: In a recent paper [1], the author shows that in spacetime physics, the Selleri transformations (STs) are viable alternatives to the Lorentz transformations (LTs) of special relativity. However, the STs predict a non-invariant one-way speed of light which implies a violation of the foundational light speed invariance principle of special relativity. We confirm the correctness of this prediction of the STs using two independent and experimentally implemented procedures within the Global Positioning System (GPS): the range equation, and the clock synchronization equation. The predicted light speeds of both the LTs and the STs are further tested by applying them in the derivation of the ITU time transfer equation. The finding is that the STs do not require a supplementary correction as do the LTs. These light speeds are also applied to the Michelson-Gale experiment (configured in a local inertial frame) showing that the STs reproduce the observed fringe shift, a result further confirmed through direct timing using GPS clocks. The LTs are unable to address this experiment since they predict constant light speed in the arms of the apparatus and hence a null result as occurs in the Michelson-Morley experiment. Finally, we show that despite their different light speeds, the STs, like the LTs, accurately reproduce relativistic beaming, a well-established physical effect in high-energy physics. These results directly confirm light speed non-invariance that invalidates the light speed constancy postulate of special relativity and indicate that the STs provide a more accurate and complete framework for relativistic physics than the LTs.