A constant speed of light in all reference frames? Surely you can't be serious. [Physics]

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From: Inertial on 7 Mar 2010 02:07

"rotchm" <rotchm(a)gmail.com> wrote in message
news:77f3f705-45fc-4505-855b-403619921122(a)o3g2000yqb.googlegroups.com...
>
>> > and I consider them two
>> > interpertations of the same thing.
>>
>> Not at all. Very different as far as how they explain reality
>
>
> Note that he said "and I consider...interpretations...". He did not
> say taht they are the same thing. he interprets them to be the 'same"
> or "equivalent".
>
> Nonetheless, LET and SR have identical predictions (for kinematical/
> optical) effects.
>
>
>> LET has and required a fixed (theoretically undetectable) aether in a
>> fixed
>> absolute frame.
>> SR does not specify nor require anything about an aether
>
> True. That is a reason why SR confuses many; there is not a "master
> reference".
>
>
>> LET has objects physically compressed due to absolute motion thru the
>> aether
>
> True. this can be taken as a postulate of LET or deduced via field
> eqs.
>
>> SR has no absolute motion, so objects are not affected by such motion
>
> That is why SR confuses many: The objects are not affected yet they
> shorten
> (measured length diminishes). Some call it "real", "physical",
> "visual", "projection"
> etc. In LET, there are no such confusions.
>
>
>> LET has processes physically slowed due to absolute motion thru the
>> aether
>
> True. This can be taken as a postulate in LET or deduced as above.
>
>> SR has no absolute motion, so processes are not affected by such motion
>
> That is why SR confuses many. The processes are not afected by such
> motion yet clocks slow down.
> In LET, clocks are affected and is the "cause" of the slowing down of
> clocks.
>
>
>> LET has a side-effect of the speed of light being measured as the same in
>> all frames of reference, due to measuring with compressed rulers and
>> slowed
>> clocks,
>
> True. From highschool kinematics one deduces that although the speed
> of light is not iso in i-frames, a (two way) measurement will always
> give c. A simple highschool exercise.
>
>
>> SR has no absolute compression and slowing, and the speed of light really
>> is
>> c
>
> SR has the side effect that the speed of light is c for all
> observers, contrary to other type of waves, contrary to common
> kinematics. That is why SR confuses many.
>
>
>> LET has a side-effect of an appearance of the lorentz transforms holding
>> on
>> measured values, due to measuring with compressed rulers and slowed
>> clocks.
>> SR has no absolute compression and slowing, so the lorentz transform hold
>
> As above...
>
>
>> > The LET interpertation had the
>> > advantage, for me, of showing how c + or - v could end up being
>> > measured c in all frames.
>
> I too prefer that model. The LET model has advantages as the SR model
> has its advantages.
> I use both but prefer "LET".
>
>
>> > Given that was possible I no longer had any
>> > problem accepting the second postulate. Eventually I became aware
>> > that the second postulate wasn't so much an assumption as a
>> > stipulation. We will consider the speed of light to be our standard.
>>
>> No .. it is an observed fact. Not a stipulation
>
> It is a stipulation. In fact it is a "defintion".
> What ever the behavior of light, it is used as a standard to measure
> lengths.

Only because it has been MEASURED to behave as SR says. It is an observed
'fact'.

Nature came first on this one .. light DOES travel at c in all frames of
reference.

That means we CAN use the speed of light to define length to give a very
easily reproduced and accurate standard for length.

> Length has an operational defintion that uses the integer 299792458.
> This definition implies/makes the speed of light constant.
>
>
> Who owes me 2 cents now ? :)

No idea.

From: Inertial on 7 Mar 2010 02:08

"Y.Porat" <y.y.porat(a)gmail.com> wrote in message
news:fe409bc5-8cb7-40c9-85dc-a5a000ea7e83(a)z4g2000yqa.googlegroups.com...
> On Mar 5, 1:51 pm, "Inertial" <relativ...(a)rest.com> wrote:
>> "Y.Porat" <y.y.po...(a)gmail.com> wrote in message
>>
>> news:868926cb-233d-417e-86c8-cd8987c43419(a)q16g2000yqq.googlegroups.com...
>>
>>
>>
>> > On Mar 4, 7:44 pm, PD <thedraperfam...(a)gmail.com> wrote:
>> >> On Mar 4, 11:09 am, Ste <ste_ro...(a)hotmail.com> wrote:
>>
>> >> > On 4 Mar, 16:48, mpalenik <markpale...(a)gmail.com> wrote:
>>
>> >> > > On Mar 4, 10:19 am, Ste <ste_ro...(a)hotmail.com> wrote:
>>
>> >> > > > On 4 Mar, 12:19, "Inertial" <relativ...(a)rest.com> wrote:
>>
>> >> > > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message
>>
>> >> > > > > > Not really, because if the total acceleration is small, then
>> >> > > > > > so
>> >> > > > > > is the
>> >> > > > > > speed.
>>
>> >> > > > > That is a nonsense argument. Acceleration can be small and
>> >> > > > > speeds very
>> >> > > > > large.
>>
>> >> > > > When I went to school, you could not have a large change of
>> >> > > > speed
>> >> > > > with
>> >> > > > only a small amount of total acceleration.
>>
>> >> > > The problem is your use of the term "total acceleration". If by
>> >> > > total
>> >> > > acceleration, you mean integral(a dt), then yes, you are correct.
>> >> > > However, there is already a word for integral(a dt) -- it's called
>> >> > > "the change in velocity". The term "total acceleration" isn't
>> >> > > actually defined. Acceleration is defined, velocity is defined,
>> >> > > deltav is defined. But "total acceleration is not".
>>
>> >> > Essentially, I'm defining "total acceleration" as something akin to
>> >> > total force, so that even though the force may be small, if it
>> >> > continues for a long time then the total force will be the same as
>> >> > if
>> >> > a large force was applied for a short period of time. In this way,
>> >> > if
>> >> > the application of force is what is causing either part or the whole
>> >> > of the time dilation effect, then it is the final speed that counts,
>> >> > not how quickly the object reached that speed.
>>
>> >> Indeed. This should tell you that it is not the details of the
>> >> acceleration that matter.
>> >> The overly simplistic statement would be, "Yes, you see that is why
>> >> SR's effects are based on speed, not on acceleration."
>>
>> >> In fact, there is a speed time dilation effect on GPS satellites,
>> >> which are going around in a circular path at constant speed, relative
>> >> to earth clocks, and accounting for this is crucial to their proper
>> >> operation. This is the same speed dilation effect, though different
>> >> size, as seen in muons in a circulating ring. (Since, by the way, the
>> >> GPS satellites are certainly not inside a magnetic ring but still
>> >> experience time dilation properly calculated by SR, this is another
>> >> good way to be sure that the magnetic ring is not what's responsible
>> >> for the time dilation of the muons.)
>>
>> >> Regarding something I alluded to earlier, though, what really matters
>> >> is how straight the path through spacetime is. We're used to thinking
>> >> that the shortest path through space is the straight one (and that's
>> >> right), but the straightest path through spacetime yields the LONGEST
>> >> duration. Any change in motion (such as an acceleration) introduces a
>> >> kink in this path (something that can be illustrated visually very
>> >> easily) and so lowers the duration. Why this is, has to do with the
>> >> structure of spacetime and we could discuss that. But this is perhaps
>> >> the most intuitive way (once these concepts are explained) to
>> >> understand why the traveling twin returns younger.
>>
>> >> > > Also, you could just be dealing with a system where the velocity
>> >> > > started out high and you never measured any acceleration.
>>
>> >> > Indeed.
>>
>> > ----------------------
>> > (:-)
>> > to mix **biologic process** with
>> > inorganic physics
>> > is ridiculous!!!
>>
>> He didn't .. there was no biologic process mentioned in the above.
>>
>> > (i said it in a big understatement ...(:-)
>> > Y.Porat
>> > -----------------------
>
> here is a quote from PD
> quote
>
> 'and so lowers the duration. Why this is, has to do with the
> structure of spacetime and we could discuss that. But this is perhaps
> the most intuitive way (once these concepts are explained) to
> understand why the traveling twin returns younger.
> end of quote
> -------------
> so the tarveling twin returns younger ???!!!

Yes. Gees, don't you know this already?

> 2
> if you dont rmind
> EM radiation HAS MASS!

Nope

> therefore it i influenced by gravity

By space curvature .. yes

> SIMILAR BUT NOT EXACTLY AS ANY OTHER MASS!!
> no curvature and no shmervature of space

Except nature behaves as though there is. Nature knows better than you

> but that is again not for born parrots
> BYE

I wish

From: Inertial on 7 Mar 2010 02:11

"Bruce Richmond" <bsr3997(a)my-deja.com> wrote in message
news:1888cc4e-8e62-42ae-8716-b1340d6daa3e(a)t20g2000yqe.googlegroups.com...
> On Mar 5, 12:12 am, "Inertial" <relativ...(a)rest.com> wrote:
>> "Bruce Richmond" <bsr3...(a)my-deja.com> wrote in message
>>
>> news:7806715d-93d2-49ff-ad67-6dac8ea64d8c(a)e7g2000yqf.googlegroups.com...
>>
>>
>>
>>
>>
>> > On Mar 4, 10:48 am, PD <thedraperfam...(a)gmail.com> wrote:
>> >> On Mar 3, 10:59 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote:
>>
>> >> > On Mar 3, 11:21 am, PD <thedraperfam...(a)gmail.com> wrote:
>>
>> >> > > On Mar 2, 8:12 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote:
>>
>> >> > > > > It is not a function of finite propagation speeds, this we
>> >> > > > > know,
>> >> > > > > because we took into account the finite propagation speeds in
>> >> > > > > our
>> >> > > > > procedure for determining simultaneity/nonsimultaneity. Do you
>> >> > > > > not
>> >> > > > > remember that?
>>
>> >> > > > I beg to differ. It is not a "mere" or "simple" function of
>> >> > > > finite
>> >> > > > propagation speed, but it *is* a function of it IMO. RoS only
>> >> > > > took
>> >> > > > it
>> >> > > > into account by allowing us to use different time coordinates in
>> >> > > > each
>> >> > > > frame. If the speed of light was infinite there would be no
>> >> > > > RoS.
>>
>> >> > > I disagree. All that is needed in relativity of simultaneity is a
>> >> > > signal speed that can be VERIFIED to be the same from both events
>> >> > > by
>> >> > > either observer.
>>
>> >> > Well you are going to have problems with that. There is no way to
>> >> > *know* that the speed is the same both ways.
>>
>> >> Yes, there is. That's what isotropy experiments have determined. I'm
>> >> surprised you weren't aware of this.
>>
>> > Do you mean like this one?
>>
>> >http://mysite.verizon.net/cephalobus_alienus/papers/Gagnon_et_al_1988...
>>
>> > The author is kind enough to point out problems in some similar
>> > experiments, while failing to notice any in his own.
>>
>> > For example, has he made any assumption about contraction of his
>> > equipment in the direction of motion? Tom Roberts has written posts
>> > in this group showing where some of these experiments are in effect
>> > two way measurements.
>>
>> >> > That is why Einstein
>> >> > wrote, "But it is not possible without further assumption to
>> >> > compare,
>> >> > in respect of time, an event at A with an event at B. We have so far
>> >> > defined only an ``A time'' and a ``B time.'' We have not defined a
>> >> > common ``time'' for A and B, for the latter cannot be defined at all
>> >> > unless we establish by definition that the ``time'' required by
>> >> > light
>> >> > to travel from A to B equals the ``time'' it requires to travel from
>> >> > B
>> >> > to A."
>>
>> >> > > Since the distance from the events to the observer is
>> >> > > equal, as verifiable at any time by each observer, we learn from
>> >> > > this
>> >> > > that each observer KNOWS the propagation delays from each event to
>> >> > > the
>> >> > > observer are equal. This acknowledges the propagation delays
>> >> > > completely, but simply allows for verification that they are the
>> >> > > same.
>>
>> >> > Assuming the speed of light is the same in both directions.
>>
>> >> Which is an experimentally confirmed fact. Done well after Einstein's
>> >> comments on the matter, by the way.
>>
>> > Provide a link to an experiment and I'll take a look.
>>
>> >> > > Then the determination of simultaneity or nonsimultaneity of the
>> >> > > original events is completely unambiguous: If the observer
>> >> > > receives
>> >> > > both signals at the same time, then (because the propagation
>> >> > > delays
>> >> > > are the same) the original events were simultaneous; if the
>> >> > > observer
>> >> > > receives both signals at different times, then (because the
>> >> > > propagation delays are the same) the original events were
>> >> > > nonsimultaneous.
>>
>> >> > > Then the frame-dependence of simultaneity follows directly from
>> >> > > the
>> >> > > experimental *observation* that for the same pair of events, one
>> >> > > observer correctly and unambiguously concludes the events were
>> >> > > simultaneous, and the other observer correctly and unambiguously
>> >> > > concludes the events were nonsimultaneous.
>>
>> >> > > You've mentioned in the past that you found your disbelief in
>> >> > > relativity stems from being unable to find a good, understandable
>> >> > > explanation of it. I invite you to read back on this thread where
>> >> > > I
>> >> > > was trying to explain to Ste (who has a similar complaint) how
>> >> > > this
>> >> > > comes about.
>>
>> >> > No need. Lorentz showed how all frames could measure the speed of
>> >> > light to be c. That in effect confirms the second postulate, which
>> >> > is
>> >> > the stumbling block for many.
>>
>> >> Well then, you are just *choosing* what you would like to believe. In
>> >> this case, lodging a complaint against relativity that it is not well
>> >> explained, when you are not interested in pursuing a better
>> >> explanation, having settled on LET instead, is a bit on the
>> >> disingenuous side.
>>
>> > You are reading more into that than what I wrote. I am not choosing
>> > LET over SR. They use the same math
>>
>> Yes
>>
>> > and I consider them two
>> > interpertations of the same thing.
>>
>> Not at all. Very different as far as how they explain reality
>>
>> LET has and required a fixed (theoretically undetectable) aether in a
>> fixed
>> absolute frame.
>> SR does not specify nor require anything about an aether
>>
>> LET has objects physically compressed due to absolute motion thru the
>> aether
>> SR has no absolute motion, so objects are not affected by such motion
>>
>> LET has processes physically slowed due to absolute motion thru the
>> aether
>> SR has no absolute motion, so processes are not affected by such motion
>>
>> LET has a side-effect of the speed of light being measured as the same in
>> all frames of reference, due to measuring with compressed rulers and
>> slowed
>> clocks, even though its only really has that speed relative to the
>> aether,
>> SR has no absolute compression and slowing, and the speed of light really
>> is
>> c
>>
>> LET has a side-effect of an appearance of the lorentz transforms holding
>> on
>> measured values, due to measuring with compressed rulers and slowed
>> clocks.
>> SR has no absolute compression and slowing, so the lorentz transform hold
>
> Read what I actually wrote, not what you think I wrote. I wrote, "I
> consider them two interpertations of the same thing." The events are
> the same. The predictions are the same. The interpertation of why
> things appear the way they do is different.

OK .. I understand what you meant now. My comments about the differences
between the two stand, of course

From: Inertial on 7 Mar 2010 02:13

"kenseto" <kenseto(a)erinet.com> wrote in message
news:19d3efdd-b1d3-433f-ab2f-68e6e4d8eb50(a)q23g2000yqd.googlegroups.com...
> On Mar 5, 12:12 am, "Inertial" <relativ...(a)rest.com> wrote:
>> "Bruce Richmond" <bsr3...(a)my-deja.com> wrote in message
>>
>> news:7806715d-93d2-49ff-ad67-6dac8ea64d8c(a)e7g2000yqf.googlegroups.com...
>>
>>
>>
>>
>>
>> > On Mar 4, 10:48 am, PD <thedraperfam...(a)gmail.com> wrote:
>> >> On Mar 3, 10:59 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote:
>>
>> >> > On Mar 3, 11:21 am, PD <thedraperfam...(a)gmail.com> wrote:
>>
>> >> > > On Mar 2, 8:12 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote:
>>
>> >> > > > > It is not a function of finite propagation speeds, this we
>> >> > > > > know,
>> >> > > > > because we took into account the finite propagation speeds in
>> >> > > > > our
>> >> > > > > procedure for determining simultaneity/nonsimultaneity. Do you
>> >> > > > > not
>> >> > > > > remember that?
>>
>> >> > > > I beg to differ. It is not a "mere" or "simple" function of
>> >> > > > finite
>> >> > > > propagation speed, but it *is* a function of it IMO. RoS only
>> >> > > > took
>> >> > > > it
>> >> > > > into account by allowing us to use different time coordinates in
>> >> > > > each
>> >> > > > frame. If the speed of light was infinite there would be no
>> >> > > > RoS.
>>
>> >> > > I disagree. All that is needed in relativity of simultaneity is a
>> >> > > signal speed that can be VERIFIED to be the same from both events
>> >> > > by
>> >> > > either observer.
>>
>> >> > Well you are going to have problems with that. There is no way to
>> >> > *know* that the speed is the same both ways.
>>
>> >> Yes, there is. That's what isotropy experiments have determined. I'm
>> >> surprised you weren't aware of this.
>>
>> > Do you mean like this one?
>>
>> >http://mysite.verizon.net/cephalobus_alienus/papers/Gagnon_et_al_1988...
>>
>> > The author is kind enough to point out problems in some similar
>> > experiments, while failing to notice any in his own.
>>
>> > For example, has he made any assumption about contraction of his
>> > equipment in the direction of motion? Tom Roberts has written posts
>> > in this group showing where some of these experiments are in effect
>> > two way measurements.
>>
>> >> > That is why Einstein
>> >> > wrote, "But it is not possible without further assumption to
>> >> > compare,
>> >> > in respect of time, an event at A with an event at B. We have so far
>> >> > defined only an ``A time'' and a ``B time.'' We have not defined a
>> >> > common ``time'' for A and B, for the latter cannot be defined at all
>> >> > unless we establish by definition that the ``time'' required by
>> >> > light
>> >> > to travel from A to B equals the ``time'' it requires to travel from
>> >> > B
>> >> > to A."
>>
>> >> > > Since the distance from the events to the observer is
>> >> > > equal, as verifiable at any time by each observer, we learn from
>> >> > > this
>> >> > > that each observer KNOWS the propagation delays from each event to
>> >> > > the
>> >> > > observer are equal. This acknowledges the propagation delays
>> >> > > completely, but simply allows for verification that they are the
>> >> > > same.
>>
>> >> > Assuming the speed of light is the same in both directions.
>>
>> >> Which is an experimentally confirmed fact. Done well after Einstein's
>> >> comments on the matter, by the way.
>>
>> > Provide a link to an experiment and I'll take a look.
>>
>> >> > > Then the determination of simultaneity or nonsimultaneity of the
>> >> > > original events is completely unambiguous: If the observer
>> >> > > receives
>> >> > > both signals at the same time, then (because the propagation
>> >> > > delays
>> >> > > are the same) the original events were simultaneous; if the
>> >> > > observer
>> >> > > receives both signals at different times, then (because the
>> >> > > propagation delays are the same) the original events were
>> >> > > nonsimultaneous.
>>
>> >> > > Then the frame-dependence of simultaneity follows directly from
>> >> > > the
>> >> > > experimental *observation* that for the same pair of events, one
>> >> > > observer correctly and unambiguously concludes the events were
>> >> > > simultaneous, and the other observer correctly and unambiguously
>> >> > > concludes the events were nonsimultaneous.
>>
>> >> > > You've mentioned in the past that you found your disbelief in
>> >> > > relativity stems from being unable to find a good, understandable
>> >> > > explanation of it. I invite you to read back on this thread where
>> >> > > I
>> >> > > was trying to explain to Ste (who has a similar complaint) how
>> >> > > this
>> >> > > comes about.
>>
>> >> > No need. Lorentz showed how all frames could measure the speed of
>> >> > light to be c. That in effect confirms the second postulate, which
>> >> > is
>> >> > the stumbling block for many.
>>
>> >> Well then, you are just *choosing* what you would like to believe. In
>> >> this case, lodging a complaint against relativity that it is not well
>> >> explained, when you are not interested in pursuing a better
>> >> explanation, having settled on LET instead, is a bit on the
>> >> disingenuous side.
>>
>> > You are reading more into that than what I wrote. I am not choosing
>> > LET over SR. They use the same math
>>
>> Yes
>>
>> > and I consider them two
>> > interpertations of the same thing.
>>
>> Not at all. Very different as far as how they explain reality
>>
>> LET has and required a fixed (theoretically undetectable) aether in a
>> fixed
>> absolute frame.
>> SR does not specify nor require anything about an aether
>>
>> LET has objects physically compressed due to absolute motion thru the
>> aether
>> SR has no absolute motion, so objects are not affected by such motion
>>
>> LET has processes physically slowed due to absolute motion thru the
>> aether
>> SR has no absolute motion, so processes are not affected by such motion
>>
>> LET has a side-effect of the speed of light being measured as the same in
>> all frames of reference, due to measuring with compressed rulers and
>> slowed
>> clocks, even though its only really has that speed relative to the
>> aether,
>> SR has no absolute compression and slowing, and the speed of light really
>> is
>> c
>>
>> LET has a side-effect of an appearance of the lorentz transforms holding
>> on
>> measured values, due to measuring with compressed rulers and slowed
>> clocks.
>> SR has no absolute compression and slowing, so the lorentz transform hold
>>
>> > The LET interpertation had the
>> > advantage, for me, of showing how c + or - v could end up being
>> > measured c in all frames.
>>
>> In SR there is no c+v or c-v, because there is no fixed absolute aether
>> frame in which light really travels at c.
>
> Then why did Einstein say that M' is runshing toward the light front
> from the front (c+v) and receding away from the light front from the
> rear (c-v)??

Closing and separation speeds. This has been explained to you over and
over.

From: Jerry on 7 Mar 2010 08:19

On Mar 6, 2:56 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote:
> On Mar 6, 5:21 am, Jerry <Cephalobus_alie...(a)comcast.net> wrote:

> > There are no hidden assumptions concerning clock synchronization
> > in their experiment. They did make assumptions, however, about
> > their "test theory" that turn out to have been unwarranted.
> > Gagnon et al. believed that their setup was capable of
> > distinguishing between between LET and SR. In other words, they
> > believed their experiment capable of detecting a LORENTZIAN
> > aether wind. This turns out to have been wrong.
>
> That is why in my response to PD I asked if assumptions were made
> about contraction of the equipment. I had noticed that after pointing
> out the distinction between SR and LET he didn't use LET but GGT
> instead.

GGT was their "test theory". Tom Roberts explains better than I
can what test theories are all about:

"A test theory of SR is a generalization of the Lorentz
transforms of SR using additional parameters. One can then
analyze experiments using the test theory (rather than SR
itself) and fit the parameters of the test theory to the
experimental results. If the fitted parameter values differ
significantly from the values corresponding to SR, then the
experiment is inconsistent with SR. But more normally, such
fits can show how well a given experiment confirms or disagrees
with SR, and what the experimental accuracy is for doing so.
This gives a general and tractable method of analysis which
can be common to multiple experiments."
http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html

-----------------------------------------------------------------

One cannot just throw in additional parameters willy-nilly into
a theory and get a test theory out of it. Test theories need to
satisfy many of the same tests for physical reasonableness as
"real" theories.

One important physical reasonableness criterion is that a set of
transformations must form a group. If you apply the Lorentz
transform twice in a row, the result should also be a Lorentz
tranform. If you use the Lorentz transforms to map events from a
first frame onto a second frame, it should be possible to do an
inverse mapping from the second frame back onto the first, and
so forth.
http://en.wikipedia.org/wiki/Group_(mathematics)

It is trivial to demonstrate that the Galilean transforms form a
group. It is a somewhat tedious, but when you finally succeed,
rather satisfying exercise to demonstrate that the Lorentz
transforms form a group.

The GGT transforms do not form a group.

-----------------------------------------------------------------

On these newsgroups, one frequently sees the assertion that LET
is experimentally indistinguishable from SR. Remind me some time
to explain why I consider that to be a false statement, although
a few technological breakthroughs might be necessary before
definitive tests can be made...

Jerry