Version 1
: Received: 28 June 2024 / Approved: 28 June 2024 / Online: 1 July 2024 (03:53:28 CEST)
How to cite:
Unnikrishnan, C. The Physical and Logical Necessity to Modify The Definition of The SI Standard of Length, The Metre. Preprints2024, 2024062040. https://doi.org/10.20944/preprints202406.2040.v1
Unnikrishnan, C. The Physical and Logical Necessity to Modify The Definition of The SI Standard of Length, The Metre. Preprints 2024, 2024062040. https://doi.org/10.20944/preprints202406.2040.v1
Unnikrishnan, C. The Physical and Logical Necessity to Modify The Definition of The SI Standard of Length, The Metre. Preprints2024, 2024062040. https://doi.org/10.20944/preprints202406.2040.v1
APA Style
Unnikrishnan, C. (2024). The Physical and Logical Necessity to Modify The Definition of The SI Standard of Length, The Metre. Preprints. https://doi.org/10.20944/preprints202406.2040.v1
Chicago/Turabian Style
Unnikrishnan, C. 2024 "The Physical and Logical Necessity to Modify The Definition of The SI Standard of Length, The Metre" Preprints. https://doi.org/10.20944/preprints202406.2040.v1
Abstract
The SI unit of length, the Metre, is presently defined by taking the fixed numerical value of the fundamental constant `c', the invariant speed of light in vacuum. This definition has the same physical basis as the previous definition, as the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second. With the atomic standard second defined in terms of the ground state hyperfine transition in Caesium-133, this definition is supposed to provide a universally reproducible standard of length. However, this relies on Einstein's singular postulate that the relative velocity of light in vacuum is an invariant constant that is independent of any inertial motion of the reference laboratory. I argue that the basis of the definition of the standard metre should be changed to the specific form, "the length of the path equal to the two-way propagation of light in vacuum during a time interval of 1/299 792 458 of a second", to be compatible and consistent with the fact that it is only the two-way relative velocity that is consistent with being an invariant. The null result in the Michelson-Morley two-way experiment, and in all such experiments to date, is consistent with a Galilean one-way propagation of light (relative velocity $c'=c\pm v$) as well as an invariant relative velocity of light. All practical methods and protocols related to the implementation of length standard involve also a two-way propagation, not conforming to the present definition. Besides, this redefinition is absolutely necessary because the relative velocity of light in one-way propagation is indeed Galilean, and not an invariant, as proved here in multiple ways including a direct experiment.
Keywords
the SI metre; metrology; Einstein’s light hypothesis; two-way relative velocity; galilean propagation; GNSS
Subject
Physical Sciences, Applied Physics
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
