On Sat, 7 Dec 2024 11:03:24 +0000, J. J. Lodder wrote:
ProkaryoticCaspaseHomolog <tomyee3@gmail.com> wrote:
>
On Fri, 6 Dec 2024 20:00:10 +0000, J. J. Lodder wrote:
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Finaly, you really need to get yourself out of the conceptual knot
that you have tied yourself in.
Something is either defined, or it can be measured.
It can't possibly be both,
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Sure it can, provided that you use a different measurement standard
than the one used in the definition.
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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]
You don't "get" the point that I was trying to make. Let us review
| Resolution 1 of the 17th CGPM (1983)
| Definition of the metre
| The 17th Conférence Générale des Poids et Mesures (CGPM),
| considering
[Skip over the first several considerations]
| - that a new definition of the metre has been envisaged in various
| forms all of which have the effect of giving the speed of light an
| exact value, equal to the recommended value, and that this
| introduces no appreciable discontinuity into the unit of length,
| taking into account the relative uncertainty of ± 4 ´ 10–9 of the
| best realizations of the present definition of the metre,
[Skip over the last two considerations]
| decides
| - The metre is the length of the path travelled by light in vacuum
| during a time interval of 1/299 792 458 of a second.
| - The definition of the metre in force since 1960, based upon the
| transition between the levels 2p10 and 5d5 of the atom of
| krypton 86, is abrogated.
https://www.bipm.org/en/committees/cg/cgpm/17-1983/resolution-1Gamma 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.
Current theory holds that the gamma rays are part of the "prompt
emission", while the visible light results from the "afterglow".
======================================================================
Let us presume that I want to experimentally explore various
alternative hypotheses to account for the difference in arrival times.
The shortest visible light pulses have a duration of about 10^-15 s,
this shortest duration roughly equal to Δt = λ/c
Let us presume that some future technology enables us to generate, at
will, short pulses of gamma radiation of duration comparable to or
shorter than that of the visible light pulses mentioned above.
I set up a 10000 meter vacuum chamber. At various points along the
chamber, I set up visible light and gamma ray detectors.
At 10 meters from the source, I can't tell which pulse arrives first.
At 100 meters from the source, I'm getting the notion that the gamma
rays are maybe (???) arriving ahead of the light pulse by 3e-22
seconds, although given that the width of the light pulse is
10^-15 s, detecting whether the offset is real is a challenge.
At 1000 meters from the source, I'm starting to get reproducible
results indicating that the gamma rays are arriving ahead of the light
pulse by 3e-21 seconds. I have to analyze zillions of pulses to get
statistically significant results, and of course I worry a lot about
systematic errors and all that.
At 10000 meters from the source, I'm now reasonably sure that the
gamma rays are arriving ahead of the light pulse by 3e-20 seconds.
I still have to analyze zillions of pulses, but after a year of
running the experiment, I'm at the five-sigma level of significance.
Note that the 17th CGPM (1983) definition does not specify the
wavelength of light used in its definition.
Should I conclude that under the conditions of my experiment, gamma
rays travel faster than the defined c by about 1 part in 10^15 ?
Or should I go the other way around, and conclude that under the
conditions of my experiment, visible light travels slower than the
defined c by about 1 part in 10^15 ?
======================================================================
Definitions are BASED ON state-of-the-art known physics. They do not
DETERMINE physical law.
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)
>
So E=mc^2 can no longer be verified by any possible experiment.
Now:
Ex1) Does this make the experiment you quoted worthless?
Not at all.
Ex2) If not, what does that experiment demonstrate?
It would demonstrate an inadequacy in the definitions that must be
addressed in some future conference when the discrepancies have been
better characterized.
E = 3/4 mc² or E = mc²? The forgotten Hassenohrl 1905 work.
Re: E = 3/4 mc² or E = mc²? The forgotten Hassenohrl 1905 work.