Isn't that quote actually the opposite of what Einsteins second postulate actually says;
Einstein wrote:As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body.
Einstein has defined this postulate within an inertial frame of reference, so to then add "state of motion of the emitting body" at the end makes no sense. It only makes sense if he if referring to an inertial frame of reference moving within absolute space. He specifically says that c is independent
of the state of motion of the emitter. To measure c in all directions from an emitter would require that c surely be dependent
of the state of motion of the emitter.
If Einstein truly meant for this to be interpreted the way it has been, then why does it need the second part, its superfluous. He could have just wrote "As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c".
First, lets get straight what an “inertial frame of reference” is: We refer to“inertial frame of reference” as all physical objects that are at rest with each other, and are at rest with an arbitrary, usually orthogonal, set of three reference axis meeting at an origin. None of these objects are subject to any sort of acceleration. They do not move in relation to each other. As a group, they can and do move in relation to other “inertial frames of reference.”
We can refer to any and every emitter as the origin of an “inertial frame of reference,” as long as it is not subject to any form of acceleration. The light wave front expands away from this emitter/origin spherically at the speed of light. As you state “To measure c in all directions from an emitter would require that c surely be dependent
of the state of motion of the emitter;” and this is well documented to happen in our domain here on Earth. (For all intents and purposes, we are at rest with all emitters here on Earth and including the Sun, however at times our relative speed with various planets do approach measurable “relativistic speeds.”)
To truly understand this discussion, a single high intensity, short pulse of light must be considered. This creates a hollow expanding shell of light, centered upon the source emitter. The “shell” of light is not exactly a part of the source inertial frame, since it is expanding in all directions. However, all observers in the source inertial frame, fixed at a given distance from the source, will all see the flash at the same time. For the sake of this discussion, let's make the given distance 10 feet. Light travels about a foot per nanosecond.
Now, let's consider a group of observers in a moving frame of reference, whose origin was at the source origin when the flash occurred. This moving frame of reference is moving at one half the speed of light. These observers just so happen to cluster around the same place in space that the observers in the source frame do at ten feet and ten nanoseconds from when the source pulse was emitted and are observing the expanding sphere at places corresponding to where the observers in the source frame observe at this time and place.
If you follow this scenario closely, you will understand that observers in both frames observe the same size sphere at the same time and distance from the source. This abrogates Einstein's problem with simultaneity as well as his problems with time and distance.
The other thing that happened while the sphere was expanding for ten nanoseconds is that the moving observers' origin has moved five feet past the source origin. Thus five units must be added (in the direction of travel) to each moving observer's coordinates when they are measured in the moving coordinate system. This is how the “transform” really works as opposed to the Voigt “Galilean” transform. Please note that some moving observers are approaching the on coming sphere head on, some are transverse to the sphere, and some are traveling in the same direction as the expanding sphere. The moving observers will see the source flash five feet beyond where the source really is at this time and distance.
Aardwolf wrote:Here's a simple thought experiment;
We have 3 points A,B & C in a line. We have a ship X traveling from A to C via B at 0.9c. A to B is 5 light years and B to C is also 5 light years so A to C is 10 light years. Ship X is carrying a lamp and at point B there is also a lamp. The circuit to power these lamps is not completed until ship X passes point B whereby they will both momentarily flash as it passes by on its way to C.
Now, I am absolutely certain that observers at point A and C will see both lamps flash at exactly the same time when the light reaches them from both lamps.
You are right on at this point in your scenario except that you have introduced two sources which are in separate reference frames. A,B, C and the lamp at B are in one frame; X and the lamp on X are in a different frame. Now we have two spheres of light each expanding as centered upon each respective source. Observers at A will see the initial flash at X as red shifted. C will see X's flash as blue shifted. Where as each A and C will see the flash at B to be unshifted.
Aardwolf wrote:This proves that light motion is independent of the motion of the source,
Actually, It doesn’t. Hopefully I have explained above how light expands in a sphere centered upon where the source was when the light pulse was emitted.
Aardwolf wrote:however, observers aboard the ship (under special relativity, time dilation etc.) experience an entirely different reality because they will try to determine light is propagating at c in all directions around them. Obviously there cannot be 2 realities so all special relativity amounts to is an observer only reality, not an actual reality, hence there is no need for time dilation etc. as it can all be resolved easily just calculating the delay in the propagation of light to the observers.
The observers at X see their own light unshifted, they see the light from B as red or blue shifted depending upon whether they are receding or approaching B.
I sense a disturbance in the farce.