>"Gary Harnagel" wrote in message
>news:89fe8b33-3a0d-43c1...@googlegroups.com...
>On Tuesday, April 28, 2020 at 1:33:18 PM UTC-6, Kevin Aylward wrote:
>
> >> "Gary Harnagel" wrote in message
> >> news:90b92ed8-0ce1-48ff...@googlegroups.com...
> >
> >> On Saturday, April 25, 2020 at 10:44:50 AM UTC-6, Keith Stein wrote:
> > >
> >> > Not true Gary, for Clock 2 and Clock 3 can not both be at rest
> >> > relative to a stationary medium,
>> >
>> > There is no stationary medium, Keith.
>
>> Well... even Einstein never claimed that. He actually stated :
>
>> "The introduction of a "luminiferous ether" will prove to be superfluous
>> in as much as the view here to be developed will not require an
>> "absolutely stationary space" provided with special properties, nor
>> assign a velocity-vector to a point of the empty space in which
>> electromagnetic processes take place. "
>
> and indeed SR gives a precise reason as why an aether, or otherwise
> background frame, could exist yet still not be detectable my detecting
> motion through it.
>
>
https://en.wikipedia.org/wiki/Lorentz_ether_theory
{snip pointless history}
You missed the point...
> No mathematical theory requires a physical process. F=d(mv)/dt
> doesnt care whether there is cause for inertia, but that doesn't
> imply that there isn't. Its just not a question any mathematical
> behavioural model addresses, by design. Indeed:
>
> Einstein specifically stated:
>
>> "The theory of relativity belongs to a class of "principle-theories...
>> As such, it employs an analytic method, which means that the elements
>> of this theory are not based on hypothesis but on empirical discovery."
>
>> Its pretty much a matter of taste as to whether one takes the SR model
>> or the LET model, or an equivalent model to LET, that does not even
>> have light as a disturbance in it, or even that it is stationary,
>> probably.
>The problem with the LET model is that it's only a kinematic theory.
>As such, it's a dead end. It's a matter of taste if 90% of your
>taste buds are dead.
Ahmmm......
> One only has to appreciate that QFE, with its "particles are an
> excitation in the a field " model that many mainstreamers are,
> apparently, heading to the same "disturbance in a medium" models.
>
> Royal Institution Lecture:
>
>
https://www.youtube.com/watch?v=zNVQfWC_evg 19:30 "... the ripples of the
> electron fluid....are what we call particles"
>
>> Ahmmmm.....
>
> >> > then only Clock 2
> > > would be justified in considering itself at rest i think,Gary.
>
>> > Think, Keith, there is no stationary medium.
>
> Ahmmm.....
>Einstein derived the LT from postulates that can be tested. None of
>the postulated assumed the existence of a medium.
Not exactly.
Einstein back derived what would be the most simplest postulates to derive
the LT. The LT already existed. He did what Plank did in arriving at the
black body radiation law. That is, he knew the correct formula, and worked
backwards to discover what was required to produce the formula.
Einstein knew that the LT was an accurate account of observations, so he
deduced his two axioms from those facts, then used those as the cornerstone
of SR.
He thus then proved that those axioms, after the fact, could then be used
as the basis of a theory. He didn't just postulate them from nowhere.
For example, if one takes the postulate (EFE):
T_ab = R_ab - 1/2 g_ab.R + lambda.g^ab
Where T_ab is the stress-energy tensor and the Rs are constructed from the
Riemann tensor, see for example my derivation here:
http://www.kevinaylward.co.uk/gr/riemann/riemann.html
Einstein did not just pick that fundamental axiomatic equation out of
space-time. It took around 7 years of hard slog from 1907 10 1914 to
discover what axioms led to some known correct results such as the
perihelion of Mercury.
> > > To correctly calculate what the clocks will be showing when you do
> > > need to know what the medium is doing, and if you fail to consider the
> > > medium, you will just get into the sort of mess Einstein did eh!
>
> > If you assume a medium when there is no evidence of one, you get
> > yourself into the mess that you ARE in.
>
>> That depends on ones definition of "evidence for".
>
>> One of the claims of LET is that clocks taken on round trips will read
>> less elapsed time from the one that stayed put, because of an interaction
>> between the aether and the clock. Thus, such known experiments are
>> evidence in support of LET.
>They're also in support of SR,
Sure... no debate on that point
>in which an ether has no measurable effect.
I agree, direct effects of change in velocity of light are not detectable in
either SR or LET.
However, as I noted, the aether, according to the LET model, most certainly
has an effect. It claims that clocks will read different when moving it it.
That is an observation conformed by experiment.
I get the feeling from your latter and following text.... that you might not
be familiar with the term "devils advocate"
>> Furthermore, the LET model existed as a correct description
>> for these observations, prior to the SR model.
>Of course, because the used the same equations.
Indeed.
>> SR doesn't have a physical explanation at all, that is,
>Of course it does. One physical explanation for the LT is that the
>speed of light is invariant. THAT is experimentally verified.
No it doesn't. It "explains" by way of the *axiom* of invariant light speed.
Axioms are statements taken as an assumption, with no further explanation.
If the axioms had an explanation, they would not be axioms, er... by
definition....
Explaining the LT by the notion that the SOL is invariant, of which fact is
how one deduces the LT, is trivially a circular argument. Its a why is god
true, well it says so in the bible. Why is the bible true. Because god says
so..... Yeah...
As already noted, the invariant speed of light was back derived as the
simplest explanation for a range of results. It works as an axiom. Why it is
true, is another matter.
My own view is that the invariance property and relativity property may be
derived from anthropic principles. That is, if they were not true, we
wouldn't exist.
Essentially, the argument is that a method is required to construct clocks
of the accuracy of 1 in 10^18 stability for the Lego of this universe to
exist
For example:
http://www.kevinaylward.co.uk/qm/anthropic_physics.html
However, anthropic principles don't explain the physical process as to how.
>> for example, something that resolves, essentially, to exchange of
>> momentum. It has two axioms
>Actually, four. Einstein mentions the other two in his text.
Whatever...
> and chucks out results from a mathematical, behavioural model.
>One of the other presumptions is that space is uniform and homogeneous.
>Consequently, the generic transform i
Sure, however one can conclude that space must be uniform and homogenous
from the anthropic principle as a more fundamental explanation.
For example, we are made of atomic Lego. If the forces between the
components of that Lego, changed as that Lego was simply moving about about
the universe, it would dismantle itself in time, thus we wouldn't exist.
Or for example:
Suppose conservation of momentum was not true. For example, suppose that
every single interaction between atomic particles resulted in a net loss of
momentum. This would mean that all objects would eventually grind to a halt.
Clearly, we could not exist if all objects are not moving. Neither could we
exist, if all objects were continually increasing to infinite velocities.
So, we must live in a universe that has conservation of momentum.
>and motion in a given frame is x = x0 + v*t. Add the first postulate,
>or the part that says a sailor on a moving ship can consider himself
>at rest and can claim that the dock is moving away from the ship.
>Those three axioms are common to both the Galilean transform and the
>LT. Add one more, t' = t, and you get the GT; or put in invariant c
>and you get the LT.
Although certainly no Hawking, I do believe that I am a tad familiar with
the rudiments of Relativity.
However, regarding the aforementioned overview of the Riemann tensor, please
feel free to point out where I dropped the minus sign in:
http://www.kevinaylward.co.uk/gr/riemann/riemann.html
> It works, but so does LET, which does have a physical model.
>By postulating an unphysical ether.
Which, according to its model, results in an interaction with physical
objects such as a twins aging less than his other twin. That's about as
physical as one can get.
...and as I pointed out... mainstream academic, noted scientists are quite
content to claim aethers:
"... the ripples of the electron fluid....are what we call particles"
https://www.youtube.com/watch?v=zNVQfWC_evg 19:30
in what conceptual way, is that not also an aether?
>> The SR model itself, is actually a model that many deny its logical
>> physical consequences to. That is...
>
>> Odometers measure space travelled
>
>> Odometers measure how much space has been covered from LA to NY. If an
>> odometer always reads distance correctly, if it reads different from
>> another one one going from LA to NY, it must have covered more space.
>> That is it took a different route.
>
>> Clocks measure time travelled.
>
>> To be clear, clocks only measure time, not "space-time".
>
>> Before SR/LET there was only one way to travel from Monday to Friday. Not
>> anymore, apparently...
>
>> Thus, clocks measure how much time has been covered from getting from
>> Monday to Friday. If a clock always reads correctly, that is ticks at
>> the same rate, if it reads different than another clock it must because
>> it covered more time.
>
>> This is an inescapable deduction from the path integral formulation of
>> "space-time", a "longer path in space-time path" intrinsically means "a
>> longer time path". Clocks have no idea of what space-time is, they just
>> read "time".
>It's called "proper time."
Yeah....What it's called is one thing. What it actually means is another.
>> Thus, SR necessarily results in the Dr. Who and his TARDIS scenery as
>> an explanation as to how clocks that always tick the same rate, but
>> read different when compared with another clock, also ticking at the
>> same rate.
>
>> Dr. Who jaunts off in his TARDIS, heading into the future at say, 100
>> sec/s, and gets to meet a 40 year old how was only 20 year old when he
>> set off. That is, his clock and his age, just mosses on merrily as
>> usual, but he covers more time then that of another observer.
>
>> Which is where the problem arises. It makes professional relativists
>> sound a tad crazy.
>But experimentally verified. A crazy person is one who denies reality.
Oh dear....
I think you have missed the point again. There is certainly no doubt that if
one jaunts of at speed on a round trip, one will get to a point in time that
one would not otherwise been able to get to according physics prior to
SR/LET. That is, one twin, may meet an older twin. The physics that result
from SR/LET are a given to be a correct account of observations.
The crazy reference, is because many professionals that accept SR, are
unable to acknowledge the words that go along with it, because it makes them
sound crazy
To be even clearer:
If my twin, and I am a twin, sits in his van watching his odometer whilst
parked, and I travel to London and back, and then compare odometers, they
will be a difference, that will clearly be attributed to that fact that I,
COVERED MORE SPACE. We know the odometers are accurate and don't read
distance any differently. They just measure distance travelled.
Now, specifically according to SR:
If my twin, sits in his van watching his clock, and I travel really fast by
engaging my turbo charger, he might sit there for 10 years, I might travel
for 1 year, such that we both go from Friday Apr 2020 to Monday 2030. His
clock will say 10 years have passed, my clock will say 1 years have past.
Thus, as, according to SR my clock does not slow down, it just reads time.
However, the clocks read *different*, therefore I *must* have COVERED MORE
TIME, relative to by brother's time.
Thus, according to SR, the only physical interpretation of the euphuism of
"has a longer path in space-time" is "covered more time".
That is, the observational situation is that one has time travelled into the
future, as per Dr. Who and the TARDIS. Its truly that obvious.
However, there are very otherwise knowledgeable experts in Relativity, for
example, Tom Roberts, that are quite unable to deal with such an idea.
I have no such problem. Its a model that makes sense, physically.
>> Its why they use use such as "closed time-like curves" in GR as
>> a euphuism for "time travel into the past" which would really make them
>> sound demented...
> So your appeal to the TARDIS is ... demented? :-)
I don't quite understand your point.
The TARDIS explanation is about the way it is for the SR model. Its an
excellent description. In the LET model, it isn't time travel, but
interactions actually slow clocks down.
The point of my quote here, is that there is a reluctance to use certain
phrases by some.
On the secondary point of possibility of time travel to the past in GR, that
is false. Its trivially contradicted by physical reasoning. An issue here,
is that many are confused between models and reality.
Typically, when one has a non-linear equation there are many solutions. More
so for non-linear partial differential equations. Many of these solutions
can be rejected because of other physical conditions. Many have simply lost
the plot and don't understand this. The take the view that all the solutions
to equations are physically meaningful. Its daft.
>> So... the SR model produces a TARDIS, with its difficulty in physically
>> explaining how velocity profiles allow for different time paths, whilst
>> the LET model has interactions with a background field that effects
>> physical aging processes by physical means, and only has the illusion
> >of invariant c.
>You have to choose your reality. You appear to choose one that has an
>immeasurable ether. I choose an invariant c, not an illusion of one.
I guess you have some problems with English comprehension. I suggest that
you re-read what I actually wrote.
Hint: Devils Advocate.