• The use of words in special relativity

    From Richard Hachel@21:1/5 to All on Tue Dec 12 18:13:12 2023
    It is not superfluous that the use of words reserved for science be as beautiful and precise as possible.

    “Writing well has never been synonymous with writing badly”
    Doctor Richard Hachel. Kyoto speech
    November 2023

    In common use, physicists speak of the relativistic transverse Doppler

    The term is not very pretty, and above all it is very semantically false
    and physically imprecise.

    This effect is not "transversal", it is pangeometric, that is to say that
    it exists and diffuses whatever the direction of the mobile, and only
    depends on its speed and not at all on its direction or its sense.

    Conversely, the classic longitudinal effect depends on the direction of movement, in addition to the speed.

    So why talk about a “transverse” Doppler effect?
    While the term is improper (there is no transverse Doppler effect in
    nature: it is an antinomy).

    Answer: because this effect is as pure as possible when we observe a
    body moving transversely, since there no longer exists any superimposed longitudinal Doppler effect.

    It's true ; nonetheless it is improper.

    The most correct term, I think (after forty years of reflection on the
    theory of special relativity), is that of the internal Doppler effect.

    It's more beautiful, more precise, more intuitive.

    There are therefore, in special relativity, two physical effects to take
    into account:
    - the longitudinal, classic, external Doppler effect, resulting from the science of Nexton and Galileo, due to the speed and direction of movement.
    - the internal, relativistic, second-degree Doppler effect, coming from Poincaré physics, and due to the speed whatever the direction of

    Thank you for your attention.


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