No, it is not. We found:
In any region of a space, the gravitational field cannot be eliminated. The speed of light in a vacuum has never been observed and cannot be observed with current technology. Till now, only the speed of light in a gravitational field has been observed. Here, it is presented that light could be dispersion in a gravitational field analogous to the dispersion of light in the Newtonian prism experiment.
www.preprints.org/manuscript/202207.0145/v3
I agree. In Contemporary Physics and in the Theory of Reference Frames the physical velocity of light is constant with respect to the same medium but the relativistic velocity of light is not constant and it depends on the reference frame in relative motion. In the gravitational field, the behavior of light is different from the behavior in an inertial field.
Daniele Sasso And, I think, it is important that "The speed of light in a vacuum has never been observed and cannot be observed with current technology. Till now, only the speed of light in a gravitational field has been observed", and the speed of light can be varied by the gravitational field.
What is sure, is that light undergoes a process of deflection in a gravitational field. Calculations prove also that gravitational deflection is the smallest with respect to optical deflection.
It depends on many factors.
1. What is the reference point and frame (inertial or not) which it is measured
2. What simultaneity convention is adopted,
3. Whether we ask about one way or average round trip speed
4. Let alone gravitatioinal effects
It is suitable to specify that in my considerations I adopt conventions accepted in the Theory of Reference Frames of Contemporary Physics.
Before we can discuss the invariance of the speed of light we have to agree about a couple of basic concepts.
The speed of light is directly related to the emission and absorption of quanta of energy – configured as an electromagnetic wave in vacuum space – by matter. The consequence is that without matter in the universe there are no electromagnetic waves. This is not an absurd idea because the Standard Cosmological model predicts that there existed no matter in the very early universe.
However, without matter there exist still the universal electric field and the corresponding magnetic field (together termed “electromagnetic” field). Because in modern QFT all the observable and detectable phenomena are local “excitations” of the underlying quantum fields and don’t represent solitary independent phenomena.
The electric field is a topological field because it has a volume, the volume has a structure and the structure transforms under invariance (the origin of the law of conservation of energy). The magnetic field is a vector field. Pure vectors are 1-dimensional “entities” thus a vector doesn’t transfer energy like the universal electric field. A vector determines the direction of the transfer of energy (mostly termed “by force”) and all the vectors in the universe are conserved too (law of conservation of momentum). The latter is obvious because vectors are generated by local energy variance and because all the energy changes are conserved (law of conservation of energy) the total amount of vectors is conserved too.
The electromagnetic wave “travels” about 300.000.000 m during 1 second within the spatial structure of the universal electric field. The size/metric of the structure – termed “the minimal length scale” – determines the linear pass on of the involved quanta of the electromagnetic wave. If Werner Heisenberg and others (Flint, Möglich, March, Goudsmit) were right the size of the minimal length scale is about 0,5 x 10-15 m. The result is that every unit of the structure of the universal electric field propagate 1 quantum of energy during 6 x 10-23 second.
The consequence is that without matter in the universe every unit of the structure of the universal electric field still changes about 6 x 1023 times its energy configuration. And every change of the configuration of a unit represents 1 quantum of energy, Planck’s constant. In other words, this turbulence in vacuum space is what we have termed “energy fluctuations in vacuum space”.
The description above shows that the invariance of the speed of light is a shared property of every unit of the structure of the universal electric field. Thus if the geometrical structure isn’t symmetrical in every direction (isotropic) we will measure (slightly?) different velocities. Besides that, the universal electric field and the magnetic field are corresponding fields. The vectors of Newtonian gravity as a push force from vacuum space around the matter are super positioned upon the vectors of the magnetic field. In other words, vectors can influence the velocity of the propagation of quanta in vacuum space.
Thus the speed of light in classic physics was some kind of an average velocity of electromagnetic waves (light). But in QFT the speed of light is a fundamental property of every unit of the structure of the universal electric field. Vectors cannot “stop” this fundamental property but vectors can force the topological changes of the universal electric field to transform in other – non linear – directions. That is why the observer will conclude that the constant speed of light isn’t a true constant.
With kind regards, Sydney
Sydney Ernest Grimm Physics is a science of experiment and observation. But, now, many incomprehensible terms and concepts, such as topological field, high dimension and curled space, etc., are used in physics. However, nobody really understands such kinds of terms and concepts.
Factually, this is a very simple question: can we measure a speed of light that cannot be acted by gravity?
The answer is clear: any speed of light is always acted and varied by gravity.
Therefore, no speed of light is constant.
Dear Yin Zhu
Your description of the “nature” of physics as a science is too limited. You forgot the most important part: the interpretation of the observations and the results of experiments to get a conceivable model of physical reality. Conceivable models are partly described with the help of mathematical concepts and you can find “everything” about geometrical concepts in Wikipedia.
Every experimental physicist knows that we can measure the speed of light without a measurable influence of the force of gravitation on a trajectory in between 2 homogeneous gravitational fields (equal spherical macroscopic masses). However, this is not a theoretical conclusion about the nature of the speed of light because if we do experiments under identical conditions the result will always be identical too. At least identical in relation to the sensitivity of our measurement instrument.
Your idea of the nature of a constant is a bit outdated. The qualification “constant” doesn’t mean that the property cannot be influenced. It only means that the property represents a fixed value if there is no detectable influence from around.
With kind regards, Sydney
No! Look at my preprint (PDF)
The speed of light in the quantum vacuum: the "Equation of God" (researchgate.net)
Dear Sydney Ernest Grimm
First, about the incomprehensible terms and concepts in current physics, please reference
(PDF) Pondering and exploring of modern physics (researchgate.net)
Second, I do not agree with “Every experimental physicist knows that we can measure the speed of light without a measurable influence of the force of gravitation on a trajectory in between 2 homogeneous gravitational fields (equal spherical macroscopic masses).”
Why the speed of light is 3*10^8m/s? No one has known the reason now. If I say that it is the gravity that makes the speed of light be so, how can you know my conclusion is right or wrong?
In physics, a conclusion only can be judged with experiment. But, my conclusion cannot be proven or disproven with experiment.
For the same reason, as the speed of light cannot be measured in a vacuum, we cannot have the experiment to proven or disproven that the speed of light in a vacuum is 3*10^8m/s.
Best regards, Yin
Dear Yin Zhu
The drawing above shows 2 equal celestial bodies and the force of gravitation is drawn as concentric circles (curved spacetime). If you have te opinion that Einstein was wrong and gravity is a vector force, the concentric circles represent the local magnitudes of the vectors (simple).
The trajectory of the electromagnetic wave (red arrow) isn’t influenced by the gravitational fields of both celestial bodies because at the trajectory both gravitational fields eliminate each other. In other words, we can measure the speed of light in a precise way. There are other influences too but that is not the discussion.
The drawing doesn’t prove that the speed of light is a constant. The reason why it is a constant can be measured too. If we emit an electromagnetic wave (the red trajectory) while the velocity of the emitter in the same direction or opposite direction is 100 km/h or 10.000 km/h doesn’t change the velocity of the electromagnetic wave. That means that the speed of light is a primary property – a constant – of the electromagnetic field and doesn’t depend on the velocity of the emitter.
Anyway, I stop this discussion because this is basic physics (sorry).
With kind regards, Sydney
Dear Sydney Ernest Grimm
We need know that physics is a science of experiment. There are or were many hypotheses for physics, but, every of them need be confirmed experimentally and observationally.
It seems that you presented a very good hypothesis to measure the “net” speed of light. But, it is clear, your hypothesis cannot be experimentally measured.
It is noted that, the speed of light in your hypothesis is still in the gravitational fields. But, in my previous reply, I presented that, the speed of light that is not in gravitational field may not be 3*10^8m/s. Or, in other words, it may be the gravity that makes the speed of light is 3*10^8m/s. And, this conclusion only can be proven or disproven with experiment or observation.
In addition, you did not argue my main conclusion: till now all of the measured speed of light are varied by gravity, no invariant speed of light has been measured.
Best regards, Yin
Dear Sydney Ernest Grimm
As shown in you figure, as the two fields are of two black holes, the light could be stopped because light cannot escape from a black hole.
As a photon is attracted by two black holes with the same gravity in opposite direction, what should happen? We have not known. But, we know, a body shall be split into two bodies with same mass and be moved to the two black holes respectively. The speed of the original body disappears.
Then, what is the speed of a light ray in the weak field in your figure?
However, this is an interesting and complicated problem. But, it is certain, it is different from that the speed of light in a vacuum.
Best regards, Yin
The Shapiro delay shows a changed light speed. But the characteristic of Special Relativity is that it can be calculated as a ``time delay''.
Dear Yin Zhu
YZ: As shown in you figure, as the two fields are of two black holes, the light could be stopped because light cannot escape from a black hole.
Sidney does not state the figures are black holes - actually, to me they look more like images of the moon. If, in fact, they were black holes, the trajectory of an EM wave would be bisected and diverted to both of the black holes if the holes were close enough to one another and the gravitational pull was such that a mutually integrated event horizon influenced the EM wave.
Such would not be the case if the distance between the holes was large enough so that a true EH wasn’t generated, the front of the wave would be distorted and slowed with respect to an observer outside the pull of both of the holes. More specifically, if the wave could actually be observed, the central portion of the wave front would appear to slow as the wave front entered the realm of gravitational influence, and accelerate as it passed peak influence, until outside the G field it reached c with respect to the distant observer. Farther out, portions of the wave front directed toward the holes’ centers would be diverted to the holes and disappear from the perspective of the distant oBerber.
The above is a hypothetical two dimensional exemplification of a wave. If you add sphericality into the mix (as waves are actually three dimensional spheres) the visual complexity of the scenario heightens significantly.
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