An experiment is done in an inertial reference frame F0 where two objects leave the same point in space simultaneously, traveling at right angles to each other. They travel the same distance as measured in F0, hit a reflective surface and return to the starting point simultaneously. This experiment is initially done with one object traveling parallel to the earth's motion.. Now the experimental setup is rotated 90 degrees relative to the earth's motion and the experiment is repeated with identical results.

Now many in this group might say that the above experiment is what occurs in the famous Michelson-Morley experiment. But the experiment I was referring to was an experiment with two billiard balls setup an equal distance from the billiard cushions, such that they travel in perpendicular paths when struck, then traveling to and hitting the cushions, and returning simultaneously to the starting point. In that experiment, the simple explanation of the result is that the billiard balls travel as the vector sum of the each billiard ball velocity and the billiard table velocity. No one explains that by saying that the speed of the billiard balls is independent of the speed of the billiard table and the billiard table went thru a length contraction which explains the result.

So we cannot use the Michelson-Morley experiment as evidence that the speed of light is constant since the simplest explanation of that experiment is that the speed of light varied in an analogous manner to the billiard balls..
So what experiment do modern day physicists use that indicates that the speed of light is constant in each inertial reference frame? Many have said that since many conclusions of Einstein's theory have been observed, the concept of a constant speed of light as measured in each inertial reference system is correct. However in Logic 101 that is known as the logic error of affirming the consequent. So which experiment shows that light is a constant speed independent of the speed of the light source? And why does the velocity of light (speed and direction) vary with each inertial reference frame, but only the speed remains constant?

Thanks,
David Seppala
Bastrop TX

Den 27.05.2021 20:27, skrev sepp623@yahoo.com:
> So we cannot use the Michelson-Morley experiment as evidence that the speed of light is constant

Quite right.
The MMX shows that the speed of light is isotropic.

https://paulba.no/paper/Michelson_1887.pdf

> So what experiment do modern day physicists use that indicates that the speed of light is constant in each inertial reference frame?

The first was the KTX.

https://paulba.no/paper/Kennedy_Thorndike.pdf

And you can find a lot more here:

https://paulba.no/paper/index.html

--
Paul

https://paulba.no/

On Thursday, May 27, 2021 at 11:27:27 AM UTC-7, sep...@yahoo.com wrote:
> In that experiment, the simple explanation of the result is that the billiard balls travel as the vector sum of the each billiard ball velocity and the billiard table velocity.

Well, classical mechanics was relativistic, it just so happens that it was Galilean relativity, so yes, it's well known that a classical ballistic theory (with perfectly elastic bouncing) is consistent with the Michelson type of experiment, as is a fully dragged classical ether theory. However, the classical ballistic theory and the fully dragged ether wave theories are already inconsistent with other experimental results, so the theory being tested by Michelson was the stationary or partially dragged ether theories. It was expected (by some people) that the result would violate the Galilean principle of relativity, but instead it continued to support the principle of relativity.

> No one explains that by saying that the speed of the billiard balls is independent of the
> speed of the billiard table and the billiard table went thru a length contraction which
> explains the result.

Well, today we know that, in terms of the rest frame of the sun (for example), length contraction in the direction of the earth's motion applies, and we have time dilation and the skew of simultaneity, and the relativistic speed composition formula is used, so the speed of the ball moving parallel to the earth's motion is not the simple sum, etc., and the inertias of the balls in the two directions are different, etc., so all the relativistic effects still apply, but they are so slight as to be negligible for most purposes, since the speeds of the balls are so low.

> So we cannot use the Michelson-Morley experiment as evidence that the speed of
> light is constant...

Right, it is well known in the serious literature that Einstein did not cite the ether drift experiments in support of the light speed principle, he cited them in support of the principle of relativity. We get the same results for any orientation and at any season of the year, so this confirms the principle of relativity.

> the simplest explanation of that experiment is that the speed of light varied in
> an analogous manner to the billiard balls.

Well, "simplest" is in the eye of the beholder, but most people at the time thought the simplest explanation was a fully dragged ether. It depends at lot on what other phenomena you are taking into account. For example, a ballistic theory of light has a great deal of difficulty accounting for interference effects, which is why ballistic theories were gradually abandoned after the year 1800 and Young's experiments. A classical ballistic theory that accounts for interference ends up not being very simple at all.

> So what experiment do modern day physicists use that indicates that the speed of light
> is constant in each inertial reference frame?

You say "experiment" (singular), but physics is based on the whole array of phenomena. Fundamentally, once the principle of relativity is established (see above), there is really only a single degree of freedom in the form of the possible relationship between inertial coordinate systems, and that is represented by the constant of proportionality k between energy E and inertia kE. The constant k also appears in the most general transformation between inertial coordinate systems. If k=0 as Newton assumed, inertial coordinate systems are related by Galilean transformations, and hence a speed c in one system transforms to c+v in the other. However, many experiments of many different kinds have been performed (beginning with Kaufmann's early experiments with accelerating particles and measuring their energy E in relation to their inertia kE), essentially to measure the value of k, and we always find that k is not exactly 0, it is actually 1/c^2. This implies that inertial coordinate systems are related by Lorentz transformations, and hence a speed c in one system transforms to c in the other.

> Which experiment shows that light is a constant speed independent of the speed of the light source?

There have been many such experiments, both based on astronomical observations (x-rays from binary stars, etc.) and supernova timing, and also direct terrestrial tests such as Alvager's experiments. But, again, once we know how inertial coordinate systems are related to each other (E=mc^2), that really settles the matter. The rest are just confirmations.

> And why does the velocity of light (speed and direction) vary with each inertial reference frame,
> but only the speed remains constant?

The direction of a given ray of light (or anything else) transforms in accord with the Lorentz transformation, resulting in aberration, and of course the frequency of light is different in terms of different coordinate systems. The meaning of your question is unclear. The speed, frequency, direction, wavelength, energy, etc., all transform in accord with the Lorentz transformation. This transformation maps the speed c to the speed c.

On Thursday, May 27, 2021 at 1:44:02 PM UTC-7, Paul B. Andersen wrote:
> > So we cannot use the Michelson-Morley experiment as evidence that the speed of light is constant
> Quite right. The MMX shows that the speed of light is isotropic.

Michelson's experiment is a two-way experiment, so it can't really demonstrate isotropy. It is consistent with non-isotropic directional speed dependence, but it confirms the principle of relativity, i.e., that we get the same results, regardless of how the lab is moving or oriented. That's why, in Einstein's 1905 paper, he cites the failure of the ether drag experiments in support of the principle of relativity.

On 5/27/2021 6:19 PM, Al Coe wrote:
> You say "experiment" (singular), but physics is based on the whole array of phenomena. Fundamentally, once the principle of relativity is established (see above), there is really only a single degree of freedom in the form of the possible relationship between inertial coordinate systems, and that is represented by the constant of proportionality k between energy E and inertia kE. The constant k also appears in the most general transformation between inertial coordinate systems. If k=0 as Newton assumed, inertial coordinate systems are related by Galilean transformations, and hence a speed c in one system transforms to c+v in the other. However, many experiments of many different kinds have been performed (beginning with Kaufmann's early experiments with accelerating particles and measuring their energy E in relation to their inertia kE), essentially to measure the value of k, and we always find that k is not exactly 0, it is actually 1/c^2. This implies that inertial coordinate systems are related by Lorentz transformations, and hence a speed c in one system transforms to c in the other.

Is it mathematically possible to describe a "universe" where k is
negative? If so, what would that "universe" be like regarding "time" to
the x y z axes? Other than inertia seemingly having an imaginary
relation to the c ("speed" of light) if k= -1/c^2.

On 5/27/21 7:12 PM, Volney wrote:
> On 5/27/2021 6:19 PM, Al Coe wrote:
>> You say "experiment" (singular), but physics is based on the whole
>> array of phenomena.  Fundamentally, once the principle of relativity
>> is established (see above), there is really only a single degree of
>> freedom in the form of the possible relationship between inertial
>> coordinate systems, and that is represented by the constant of
>> proportionality k between energy E and inertia kE.  The constant k
>> also appears in the most general transformation between inertial
>> coordinate systems.  If k=0 as Newton assumed, inertial coordinate
>> systems are related by Galilean transformations, and hence a speed c
>> in one system transforms to c+v in the other.  However, many
>> experiments of many different kinds have been performed (beginning
>> with Kaufmann's early experiments with accelerating particles and
>> measuring their energy E in relation to their inertia kE), essentially
>> to measure the value of k, and we always find that k is not exactly 0,
>> it is actually 1/c^2.  This implies that inertial coordinate systems
>> are related by Lorentz transformations, and hence a speed c in one
>> system transforms to c in the other.
>
> Is it mathematically possible to describe a "universe" where k is
> negative? If so, what would that "universe" be like regarding "time" to
> the x y z axes?  Other than inertia seemingly having an imaginary
> relation to the c ("speed" of light) if k= -1/c^2.

In a modern derivation of the coordinate transforms of SR, based on just
the principle of relativity [@], one obtains a generalized transform
between inertial frames. It is characterized by a parameter called k
that is a constant with units 1/(speed^2) [#]. Using Coe's sign convention:
k > 0: Lorentz group, k=1/c^2
k = 0: Galilei group
k < 0: Euclid group in 4-D, no common name for k
A world with k<0 treats "time" interchangeably with "space", so it
clearly does not correspond to the world we inhabit. Note also that k is
NOT a group parameter, but rather its value selects a group; groups with
the same sign of k differ only in units, but groups with different signs
of k are not subgroups of a larger group (i.e. they cannot be combined).

[@] Plus group theory, the definition of inertial
frames, and the other "hidden" postulate of SR:
clocks and rulers have no memory. Einstein's second
postulate is not needed, because two of the three
possible groups are solidly refuted experimentally,
leaving just the Lorentz group.

[#] In the transform equations between inertial
coordinates, k appears inside the usual gamma of
the Lorentz transform, replacing 1/c^2 with k.
The usual sign convention is opposite to Coe's,
and I'm not sure at all that k is "proportionality
between energy and inertia" (though it has the
same numerical value for the Lorentz group) -- I
would want to see that derivation in detail.

Also: Newton (and Galileo) did not really assume k=0. Rather, they
assumed the Galilean transform, from which a modern physicist with
knowledge of group theory can conclude k=0.

Tom Roberts

On Saturday, 29 May 2021 at 00:25:41 UTC+2, tjrob137 wrote:
> On 5/27/21 7:12 PM, Volney wrote:
> > On 5/27/2021 6:19 PM, Al Coe wrote:
> >> You say "experiment" (singular), but physics is based on the whole
> >> array of phenomena. Fundamentally, once the principle of relativity
> >> is established (see above), there is really only a single degree of
> >> freedom in the form of the possible relationship between inertial
> >> coordinate systems, and that is represented by the constant of
> >> proportionality k between energy E and inertia kE. The constant k
> >> also appears in the most general transformation between inertial
> >> coordinate systems. If k=0 as Newton assumed, inertial coordinate
> >> systems are related by Galilean transformations, and hence a speed c
> >> in one system transforms to c+v in the other. However, many
> >> experiments of many different kinds have been performed (beginning
> >> with Kaufmann's early experiments with accelerating particles and
> >> measuring their energy E in relation to their inertia kE), essentially
> >> to measure the value of k, and we always find that k is not exactly 0,
> >> it is actually 1/c^2. This implies that inertial coordinate systems
> >> are related by Lorentz transformations, and hence a speed c in one
> >> system transforms to c in the other.
> >
> > Is it mathematically possible to describe a "universe" where k is
> > negative? If so, what would that "universe" be like regarding "time" to
> > the x y z axes? Other than inertia seemingly having an imaginary
> > relation to the c ("speed" of light) if k= -1/c^2.
> In a modern derivation of the coordinate transforms of SR, based on just
> the principle of relativity [@], one obtains a generalized transform
> between inertial frames.

Be proud of brilliant coordinate frames working fine in all
inertial frames, i.e. nowhere. As a general rule, of course,
your bunch of idiots can't provide any coordinate solutions
and you've admitted it many times.

On 5/28/2021 6:25 PM, Tom Roberts wrote:
> On 5/27/21 7:12 PM, Volney wrote:
>> On 5/27/2021 6:19 PM, Al Coe wrote:
>>> You say "experiment" (singular), but physics is based on the whole
>>> array of phenomena.  Fundamentally, once the principle of relativity
>>> is established (see above), there is really only a single degree of
>>> freedom in the form of the possible relationship between inertial
>>> coordinate systems, and that is represented by the constant of
>>> proportionality k between energy E and inertia kE.  The constant k
>>> also appears in the most general transformation between inertial
>>> coordinate systems.  If k=0 as Newton assumed, inertial coordinate
>>> systems are related by Galilean transformations, and hence a speed c
>>> in one system transforms to c+v in the other.  However, many
>>> experiments of many different kinds have been performed (beginning
>>> with Kaufmann's early experiments with accelerating particles and
>>> measuring their energy E in relation to their inertia kE),
>>> essentially to measure the value of k, and we always find that k is
>>> not exactly 0, it is actually 1/c^2.  This implies that inertial
>>> coordinate systems are related by Lorentz transformations, and hence
>>> a speed c in one system transforms to c in the other.
>>
>> Is it mathematically possible to describe a "universe" where k is
>> negative? If so, what would that "universe" be like regarding "time"
>> to the x y z axes?  Other than inertia seemingly having an imaginary
>> relation to the c ("speed" of light) if k= -1/c^2.
>
> In a modern derivation of the coordinate transforms of SR, based on just
> the principle of relativity [@], one obtains a generalized transform
> between inertial frames. It is characterized by a parameter called k
> that is a constant with units 1/(speed^2) [#]. Using Coe's sign convention:
>     k > 0:  Lorentz group, k=1/c^2
>     k = 0:  Galilei group
>     k < 0:  Euclid group in 4-D, no common name for k
> A world with k<0 treats "time" interchangeably with "space", so it
> clearly does not correspond to the world we inhabit. Note also that k is
> NOT a group parameter, but rather its value selects a group; groups with
> the same sign of k differ only in units, but groups with different signs
> of k are not subgroups of a larger group (i.e. they cannot be combined).
>
In other words, in this case t is another space dimension, and no time
dimension involved. Am I correct?

Paul B. Andersen wrote:

> Den 27.05.2021 20:27, skrev sepp623@yahoo.com:
>> So we cannot use the Michelson-Morley experiment as evidence that the
>> speed of light is constant
>
> Quite right.
> The MMX shows that the speed of light is isotropic.

Actually, it does not. The only correct conclusion from the MMX is that
either there is no luminiferous aether or that it has very peculiar
properties. Lorentz and Poincaré assumed the latter, Einstein the former.

But what is the difference between “isotropic speed” and “constant speed
regardless of direction”?
> https://paulba.no/paper/Michelson_1887.pdf
>
>> So what experiment do modern day physicists use that indicates that the
>> speed of light is constant in each inertial reference frame?
>
> The first was the KTX.
>
> https://paulba.no/paper/Kennedy_Thorndike.pdf

It depends on whether you limit your answer to “modern day”; then this is
true for suitable values.
But the KTX was certainly not the first experiment to establish, or hint at,
this fact.

The first indication that the speed of light would be constant in vacuum
came from Cassini’s and Rømer’s observations of the "advance" and "delay" in
the occultation of Jupiter by Io, depending on where Jupiter was in relation
to Terra. Huygens later used Cassini’s and Rømer’s data for the first good
estimate of c:

<https://en.wikipedia.org/wiki/Speed_of_light#First_measurement_attempts>

A key experiment that, by his own account, Albert Einstein was influenced by
in formulating special relativity (1905), was the Fizeau experiment in 1851:

<https://en.wikipedia.org/wiki/Fizeau_experiment>

PointedEars
--
“Nature uses only the longest threads to weave her patterns
so that each small piece of her fabric reveals the organization
of the entire tapestry.”
—Richard Feynman, theoretical physicist, “Messenger Lecture” 1 (1964)

On Monday, 7 June 2021 at 04:45:10 UTC+2, Thomas 'PointedEars' Lahn wrote:
> Paul B. Andersen wrote:
>
> > Den 27.05.2021 20:27, skrev sep...@yahoo.com:
> >> So we cannot use the Michelson-Morley experiment as evidence that the
> >> speed of light is constant
> >
> > Quite right.
> > The MMX shows that the speed of light is isotropic.
> Actually, it does not. The only correct conclusion from the MMX is that
> either there is no luminiferous aether or that it has very peculiar
> properties.

For sure, conclusions not accepted by a poor pointed ears idiot
have no chance to be correct. Still, "peculiar properties" is something
that can easily be assigned to just anything.

> The first indication that the speed of light would be constant in vacuum
> came from Cassini’s and Rømer’s observations

Stop lying, trash, no observation ever indicated your constant
speed of light, it's nothing more than a postulate of your insane
guru.

Thomas 'PointedEars' Lahn wrote:

> The first indication that the speed of light would be constant in vacuum
> came from Cassini’s and Rømer’s observations of the "advance" and "delay"
> in the occultation of Jupiter by Io,

I have misunderstood. It was the occultation _of Io by Jupiter_ (which
makes a lot more sense given the lower telescope resolution at the time).

> depending on where Jupiter was in relation to Terra. […]

<https://en.wikipedia.org/wiki/R%C3%B8mer%27s_determination_of_the_speed_of_light#Eclipses_of_Io>

PointedEars
--
Q: What did the nuclear physicist post on the laboratory door
when he went camping?
A: 'Gone fission'.
(from: WolframAlpha)