Re: E = 3/4 mc? or E = mc?? The forgotten Hassenohrl 1905 work.

ProkaryoticCaspaseHomolog <tomyee3@gmail.com> wrote:

On Sat, 7 Dec 2024 21:35:57 +0000, J. J. Lodder wrote:
 

On 2024-12-07 16:03:31 +0000, ProkaryoticCaspaseHomolog said:
[missing article on my server, sorry about mixed up quote levels]
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On Sat, 7 Dec 2024 11:03:24 +0000, J. J. Lodder wrote:
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Sure, you can be inconsistent, if you choose to be.
Don't expect meaningful results.
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It would not make sense to quantify hypothetical variations in the
speed of light in terms of the post-1983 meter. But they would make
sense in terms pre-1983 meters. Or (assuming some incredible ramp-up
in technology, perhaps introduced by Larry Niven-ish Outsiders) in
terms of a meter defined as the distance massless gluons travel in
1/299,792,458 of a second. Or gravitons... :-)
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Completely irrelevant,
and it does not get you out of your conceptual error as stated above.
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Summmary: There must be:
1) a length standard, 2) a frequency standard [1], and 3) c
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Two of the three must be defined, the third must be measured.
Pre-1983  1) and 2) were defined, and 3), c was measured.
Post-1983 2) and c are defined, 1) must be measured.
So in 1983 we have collectively decided that any future refinement
in measurement techniques will result in more accurate meter standards,
not in a 'better' value for c.  [2]
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You don't "get" the point that I was trying to make. Let us review

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I do get it, and it is wrong.
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| Resolution 1 of the 17th CGPM (1983)

[snip boilerplate material]
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Gamma ray burst observations have constrained the arrival times
between the visible light and gamma ray components of the burst to
be equal to within 10^-15 of the total travel time of the burst.

[snip more irrelevancies]
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This is irrelevant for the issue of E=mc^2.
Differential travel times are a test for a non-zero photon mass, if any.
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Definitions are BASED ON state-of-the-art known physics. They do not
DETERMINE physical law.

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Are you really incapabable of understanding
that all this is about metrology, not physical law?
No definition of units can ever determine or change any physical law.
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Finally, an excercise for you personally.
You quoted a pre-2018 experiment that verified that E=mc^2
to some high accuracy. (using the measured value of Planck's constant)
Post-2018, Planck's constant has a defined value,
and  E=mc^2 is true by definition. (of the Joule and the kilogram)
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So E=mc^2 can no longer be verified by any possible experiment.
Now:
Ex1) Does this make the experiment you quoted worthless?
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Not at all.

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Correct.
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Ex2) If not, what does that experiment demonstrate?
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It would demonstrate an inadequacy in the definitions that must be
addressed in some future conference when the discrepancies have been
better characterized.

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I'm sorry, but this is not the right answer,

 
So what are you saying, then?

That you are confusing matters of units, (true by definition)
such as for example E=mc^2,  (nowadays)
with physical results, (which need experimental verification)
such as for example energy-momentum conservation.

Are you saying that, because of the
definition of E=mc^2, it is totally required that 1 gram of electrons
annihilating 1 gram of positrons completely to electromagnetic
radiation must NECESSICARILY yield the same amount of energy as 1 gram
of protons annihilating 1 gram of antiprotons completely to electro-
magnetic radiation?

No. That is a matter of energy-momentum conservation,
which is a physical result.
No one doubts it, but it can be verified.

That the equality of these two values is a matter
of definition, not something to be established by experiment?

No. Equalities of measured quantities can never be a matter of
definition.

Are you saying that because the current definition of c is
299,792,458 meters per second regardless of wavelength, that questions
as to whether gamma rays travel faster than visible light rays are
totally nonsensical?

That's your red hering.
The current definition of the meter says no such thing,
that is merely your mistaken reading of it.
Or non-reading even, for the definition of the meter
doesn't mention the wavelength of the light to be used at all. [1]

If the vacuum would turn out to be dispersive after all
the definition of the meter would have to be refined.

Jan

[1] It doesn't even use the fact
that there are states of the radiation field to which
a more or less well-defined wavelength can be assigned.
Those things are merely practicalities of the application
of the definition.