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Merged Relativity+ / Farsight

Thinking back to Farsight's posts, this issue is the sort of thing that he'd seize on and claim that there is some great truth in it. Like how the original expresses some great truth that the revised versions obscure.

Sort of like a theologian interpreting a sacred book.

I've never in my life encountered anyone who argues physics in that way, so that's why I've been rather fascinated with Farsight and his arguments.
 
Farsight said:
Only when Einstein used it, he was talking about the limitations of the SR postulate. He was talking about speed. Here's some English translations. Unfortunately the word velocity used instead of speed:

1911: "If we call the velocity of light at the origin of coordinates c₀, then the velocity of light c at a place with the gravitation potential Φ will be given by the relation c = c₀(1 + Φ/c²)”.

1912: "On the other hand I am of the view that the principle of the constancy of the velocity of light can be maintained only insofar as one restricts oneself to spatio-temporal regions of constant gravitational potential".

1913: "I arrived at the result that the velocity of light is not to be regarded as independent of the gravitational potential. Thus the principle of the constancy of the velocity of light is incompatible with the equivalence hypothesis".

1915: "the writer of these lines is of the opinion that the theory of relativity is still in need of generalization, in the sense that the principle of the constancy of the velocity of light is to be abandoned".

1916: “In the second place our result shows that, according to the general theory of relativity, the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity and to which we have already frequently referred, cannot claim any unlimited validity. A curvature of rays of light can only take place when the velocity of propagation of light varies with position”.

There's a myth that he tried out a varying speed of light in 1911 then abandoned it. But he didn't abandon it.
Click to expand...

This myth is held by very few scientists. General relativity clearly allows for the speed of light to vary with distance in a gravitational gradient or in an accelerated reference frame. I thought pretty much everybody agreed with this.

You haven't quoted anyone after 1911 who said that Einstein abandoned the concept of a varying speed of light. So where is your controversy?

Einstein made the claim in 1905 that the speed of light was constant for any reference frame in 'uniform motion'. However, this qualifier already places a limit on the constancy of the speed of light.


Uniform motion was described in great deal when he describes the reference frame. Basically, it is any reference frame where the laws of physics are 'simplest'. Alternatively, it is any reference frame that is moving with a homogeneous velocity relative to a 'stationary frame', again defined as one where the laws of mechanics <Newtons> and electrodynamics <Maxwells> hold. The speed of light is the same in different reference frames defined this way. However, specifying the reference frames this way allows for the possibility of measuring in reference frames that don't satisfy these conditions. Hence, there was no statement even in Einstein's original article that the speed of light had to be always measured the same.

Clearly, the speed of light need not be constant in any reference frame that is not moving uniformly. This includes reference frames traveling on a curved path or reference frames. dynamic acceleration.

The postulate of general relativity that may give some people problems is that the 'local speed of light in a vacuum' is the same in all reference frames. However, not all measurements need to be made locally. When one looks at distant galaxies from the earth, the measurement is not local. When one is measuring the speed of light propagated a great distance in the vertical direction, it is not a local measurement. Physicists working in the area know that. I don't know any place where it is taught differently.

Obviously, there is some life in this thread yet. You made your last post in August 2014. That is only a few months. Relative to the time span of other posts, that is practically local. I confess I have replied to posts that are close to 9 years old. These are nonlocal replies !-)
 
Myriad said:
That doesn't seem geometrically possible. What if I looked at the electron from exactly the opposite side, but made the same slice (that is, the slice is in the same plane)? Wouldn't the spirals then be going the other way?

Then, suppose I move continuously around from one side to the other, examining perpendicular slices as I go. Wouldn't the image have to transform continuously from the clockwise pattern on one side to the counterclockwise pattern on the other?

Respectfully,
Myriad
Click to expand...

No, because of parity. On a subatomic length scale, chirality is called parity, but it is really the same geometric concept.

I think by spirals they mean screws. Screws have chirality. A clockwise screw would have the opposite chirality as a counterclockwise screw.

You can imagine an electron as a screw where the point of the screw faces in the direction of the magnetic North pole. The threads of the screw correspond to the electrons spin. An observer, standing above the North magnetic pole of the electron, sees a clockwise rotation which is the same as electron spin.


So if an electron where shaped like a clockwise screw, a positron would be shaped like a counterclockwise screw.

Suppose that an electron was shaped like a right shoe. A positron would then be shaped like a left shoe.

I thought of an analogy. I welcome skeptics to make pot shots at it! To add even more quantum weirdness to the analogy, let reimagine the shape of the electron to take into account the half spin. Like many fermions, the electron has a half spin. So it has to be rotated around its axis twice to get back to its original state. Make the north south magnetic axis of the electron

One can do this if the screw has a Moebius strip overlaying the screw shape. The rotation rolls the strip. So it has to be rolled twice to get back to the original position. So each separate rotation is just one roll of the Moebius strip.

With that, adeiu.
 
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