# Recapitulation (in american)

That is the reason why the speed of light cannot be physically invariant (within a quick and foolproof style of reasoning)

(Translated by Easy Translate)

It is impossible for the speed of light to be physically invariant, in all cases, with regard to the different inertial frames of reference, because the physics principle of the relativity of simultaneity, in the objection of the shuttle and the missile, results in two mathematically contradictory reasoning.

__The implications are__:

The physical invariance of the speed of light implies the physics principle of relativity of simultaneity, since that, in the physical context within the absolute simultaneity, the speed of light cannot be physically invariant.

The relativity of simultaneity considered at the physical level, within the objection of the shuttle and missile, leads to two mathematically contradictory reasoning.

__The speed of light cannot be physically invariant within the absolute simultaneity at the physical level:__

In the context of the Einstein train experiment, with the variant proposed by Zefram in the Futura-Science forum: we consider, in this variant, that the light rays arrive simultaneously to the two observers, when they cross each other. Whereas, in the Einstein version, the light rays are emitted simultaneously for the observer from the train station, in that moment.

Consequently, if we consider that both light rays were emitted simultaneously for the two observers, this means that they were emitted simultaneously for the observer of the train when the train was not yet in the station. At that time, the distance "between this observer and the light source at the head end of the train" and "between this observer and the light source at the rear of the train" were not the same. That means, therefore, that in the physical context of the absolute simultaneity, the speed of light cannot be physically invariant with regard to the two observers. That’s why, the invariance of the speed of light at the physical level implies theoretically the relativity of simultaneity at the physical level. However, since the latter leads in two mathematically contradictory reasoning, it is clear that the speed of light cannot be physically invariant with regard to all inertial frames of reference, and that it is necessary, at the same time, to change the representation of space-time.

__http://www.leprincipemoteurdelunivers.com/pages/the-thought-experiment-of-einstein-s-train.html__

http://www.leprincipemoteurdelunivers.com/pages/circular-letter.html

The equations of the special relativity can be interpreted in different ways, we can think that either the speed of light is physically invariant (an interpretation that can be perhaps attributed to Einstein), or thinking that it is only operationally invariant in all cases (an interpretation that can be perhaps attributed to Lorentz), to thinking that it is operationally invariant in some cases (my position). And the physics, at present, didn't choose between these first two interpretations; personally I would propose the third one.

I'm just trying to show that - from a theoretical point of view - the invariance at the physical level of the speed of light implies the relativity of simultaneity at the physical level. However, the latter leading to contradictions, this allows to eliminate certainly the first possibility. And, as we can probably eliminate Lorentz interpretation, what remains is the interpretation that I propose, a speed of light that is locally invariant with respect to some inertial observers, because of the constant adaptation of the speed of light to the spatial configuration. However, this aspect of things could probably be measured…

# Philippe de Bellescize