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The Secret to Einstein's Twin Paradox

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  The Secret to Einstein's Twin Paradox Pentcho Valev <pvalev@yahoo.com> - 2017-06-19 14:30 -0700
    Re: The Secret to Einstein's Twin Paradox Gary Harnagel <hitlong@yahoo.com> - 2017-06-19 14:48 -0700
      Re: The Secret to Einstein's Twin Paradox Eshiki Orakut <usa@iwikuh.ki> - 2017-06-20 13:45 +0000
        Re: The Secret to Einstein's Twin Paradox Mike Fontenot <mlfasf@comcast.net> - 2017-06-20 09:49 -0600
          Re: The Secret to Einstein's Twin Paradox Eshiki Orakut <usa@iwikuh.ki> - 2017-06-20 21:10 +0000
          Re: The Secret to Einstein's Twin Paradox mlwozniak@wp.pl - 2017-06-21 02:40 -0700
            Re: The Secret to Einstein's Twin Paradox JanPB <filmart@gmail.com> - 2017-06-23 04:42 -0700
              Re: The Secret to Einstein's Twin Paradox mlwozniak@wp.pl - 2017-06-23 04:48 -0700
                Re: The Secret to Einstein's Twin Paradox JanPB <filmart@gmail.com> - 2017-06-23 13:51 -0700
          Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-06-22 04:30 -0700
            Re: The Secret to Einstein's Twin Paradox JanPB <filmart@gmail.com> - 2017-06-23 04:44 -0700
              Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-06-27 07:06 -0700
                Re: The Secret to Einstein's Twin Paradox Mike Fontenot <mlfasf@comcast.net> - 2017-06-27 12:22 -0600
                  Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-06-27 22:44 -0500
                    Re: The Secret to Einstein's Twin Paradox Mike Fontenot <mlfasf@comcast.net> - 2017-06-28 07:40 -0600
                      Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-06-29 00:26 -0500
                        Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-06-29 04:01 -0700
                        Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-06-29 04:14 -0700
                          Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-06-29 08:30 -0500
                            Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-06-29 06:54 -0700
                        Re: The Secret to Einstein's Twin Paradox Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-06-29 14:41 +0200
                          Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-06-29 08:37 -0500
                            Re: The Secret to Einstein's Twin Paradox Poutnik <poutnik4nntp@gmail.com> - 2017-06-29 16:16 +0200
                              Re: The Secret to Einstein's Twin Paradox Jim Petroff <ruuri@twjotr.eo> - 2017-06-29 14:29 +0000
                            Re: The Secret to Einstein's Twin Paradox Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-06-29 16:45 +0200
                              Re: The Secret to Einstein's Twin Paradox Jim Petroff <ruuri@twjotr.eo> - 2017-06-29 15:00 +0000
                              Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-06-29 08:11 -0700
                                Re: The Secret to Einstein's Twin Paradox Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-06-29 17:19 +0200
                                  Re: The Secret to Einstein's Twin Paradox Jim Petroff <ruuri@twjotr.eo> - 2017-06-29 15:34 +0000
                                  Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-06-29 08:39 -0700
                                Re: The Secret to Einstein's Twin Paradox Jim Petroff <ruuri@twjotr.eo> - 2017-06-29 15:29 +0000
                              Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-07-01 12:29 -0500
                                Re: The Secret to Einstein's Twin Paradox Mike Fontenot <mlfasf@comcast.net> - 2017-07-02 12:35 -0600
                                  Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-03 08:18 -0700
                                    Re: The Secret to Einstein's Twin Paradox Mike Fontenot <mlfasf@comcast.net> - 2017-07-03 09:45 -0600
                                      Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-04 05:24 -0700
                                    Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-07-03 17:52 -0500
                                      Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-04 05:45 -0700
                                        Re: The Secret to Einstein's Twin Paradox Poutnik <poutnik4nntp@gmail.com> - 2017-07-04 15:03 +0200
                                          Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-07 13:56 -0700
                                            Re: The Secret to Einstein's Twin Paradox Poutnik <poutnik4nntp@gmail.com> - 2017-07-07 23:55 +0200
                                              Re: The Secret to Einstein's Twin Paradox mlwozniak@wp.pl - 2017-07-08 00:15 -0700
                                                Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-10 08:43 -0700
                                              Re: The Secret to Einstein's Twin Paradox Upech Bezradne <adeeia@bbzzeop.ic> - 2017-07-08 10:44 +0000
                                              Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-10 08:38 -0700
                                        Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-07-04 12:56 -0500
                                          Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-07 13:20 -0700
                                            Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-07-08 00:06 -0500
                                              Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-10 08:26 -0700
                                                Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-07-11 10:56 -0500
                                                  Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-11 13:40 -0700
                                                    Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-07-12 10:13 -0500
                                                      Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-13 10:07 -0700
                                                        Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-07-14 20:04 -0500
                                                          Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-15 13:49 -0700
                                                            Re: The Secret to Einstein's Twin Paradox The Starmaker <starmaker@ix.netcom.com> - 2017-07-15 14:26 -0700
                                                            Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-07-17 20:20 -0500
                                                              Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-20 07:25 -0700
                                      Re: The Secret to Einstein's Twin Paradox kenseto <setoken@att.net> - 2017-07-05 07:50 -0700
                                  Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-07-03 18:26 -0500
                          Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-06-29 07:05 -0700
                        Re: The Secret to Einstein's Twin Paradox Mike Fontenot <mlfasf@comcast.net> - 2017-06-29 09:31 -0600
                  Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-06-28 05:01 -0700
                    Re: The Secret to Einstein's Twin Paradox Mike Fontenot <mlfasf@comcast.net> - 2017-06-28 07:52 -0600
                      Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-06-29 03:47 -0700
                        Re: The Secret to Einstein's Twin Paradox Mike Fontenot <mlfasf@comcast.net> - 2017-06-29 10:19 -0600
                          Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-06-30 08:09 -0700
                            Re: The Secret to Einstein's Twin Paradox Lord Kronos Prime <fuller.david@hotmail.com> - 2017-06-30 08:39 -0700
                              Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-01 08:33 -0700
                            Re: The Secret to Einstein's Twin Paradox Mike Fontenot <mlfasf@comcast.net> - 2017-06-30 11:30 -0600
                              Re: The Secret to Einstein's Twin Paradox Jonathan Doolin <good4usoul@gmail.com> - 2017-07-01 08:11 -0700
    Re: The Secret to Einstein's Twin Paradox Pentcho Valev <pvalev@yahoo.com> - 2017-06-19 23:58 -0700
    Re: The Secret to Einstein's Twin Paradox JanPB <filmart@gmail.com> - 2017-06-20 03:18 -0700
      Re: The Secret to Einstein's Twin Paradox Lipek Mniak <iluka@sskwpiw.pp> - 2017-06-23 11:47 +0000
        Re: The Secret to Einstein's Twin Paradox The Starmaker <starmaker@ix.netcom.com> - 2017-06-23 11:18 -0700
    Re: The Secret to Einstein's Twin Paradox Eckard B <eckard.blumschein@arcor.de> - 2017-06-21 09:21 -0700
      Re: The Secret to Einstein's Twin Paradox Poutnik <poutnik4nntp@gmail.com> - 2017-06-21 19:33 +0200
        Re: The Secret to Einstein's Twin Paradox Poutnik <poutnik4nntp@gmail.com> - 2017-06-22 07:32 +0200
          Re: The Secret to Einstein's Twin Paradox mlwozniak@wp.pl - 2017-06-21 23:16 -0700
          Re: The Secret to Einstein's Twin Paradox Lipek Mniak <iluka@sskwpiw.pp> - 2017-06-23 11:33 +0000
        Re: The Secret to Einstein's Twin Paradox Eckard B <eckard.blumschein@arcor.de> - 2017-06-22 08:14 -0700
          Re: The Secret to Einstein's Twin Paradox Poutnik <poutnik4nntp@gmail.com> - 2017-06-22 18:13 +0200
            Re: The Secret to Einstein's Twin Paradox Lipek Mniak <iluka@sskwpiw.pp> - 2017-06-23 11:35 +0000
              Re: The Secret to Einstein's Twin Paradox The Starmaker <starmaker@ix.netcom.com> - 2017-06-23 11:15 -0700
          Re: The Secret to Einstein's Twin Paradox Tom Roberts <tjroberts137@sbcglobal.net> - 2017-06-22 15:38 -0500
            Re: The Secret to Einstein's Twin Paradox Eckard B <eckard.blumschein@arcor.de> - 2017-06-23 03:22 -0700
              Re: The Secret to Einstein's Twin Paradox Lipek Mniak <iluka@sskwpiw.pp> - 2017-06-23 11:38 +0000
              Re: The Secret to Einstein's Twin Paradox Poutnik <poutnik4nntp@gmail.com> - 2017-06-28 08:32 +0200
            Re: The Secret to Einstein's Twin Paradox mlwozniak@wp.pl - 2017-06-23 03:37 -0700
    Re: The Secret to Einstein's Twin Paradox bigal95210@gmail.com - 2017-06-21 16:48 -0700
      Re: The Secret to Einstein's Twin Paradox John Gogo <jfgogo22@yahoo.com> - 2017-07-14 19:00 -0700
    Re: The Secret to Einstein's Twin Paradox Lipek Mniak <iluka@sskwpiw.pp> - 2017-06-23 11:43 +0000

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#423607

On Thursday, June 29, 2017 at 7:41:09 AM UTC-5, Thomas 'PointedEars' Lahn wrote:
> Tom Roberts wrote:
> 
> > From that information the observer knows the sender's age when the signal
> > was SENT, without reference to the CADO frame. But from that information
> > alone the observer cannot possibly know how old she is when it is
> > RECEIVED.
> > Because this is not a measurement of the distant person, it is a
> > measurement of a SIGNAL, and the observer does not know how long the
> > signal traveled from her to him.
> 
> I presume it could be calculated if the sender time would be encoded in the 
> signal (as with GPS), but it would only be trivial to do in flat spacetime 
> and non-complex (e.g., one-time) acceleration (as in the twin paradox).
> 

One would presume in some sense,
that the sender's time is already encoded into any
signal that the sender sends.  

For anyone with eyes to see, 
the sender is continually emitting or reflecting 
a signal that shows,
quite explicitly,
what they are doing at any given time.

However, this image will not give any information
about the observer's watch reading.
Unless, somehow, they are holding a big mirror,
from which the observer can read their own watch.

(which is the essential concept of radar time)

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#423621

On 6/28/17 11:26 PM, Tom Roberts wrote:
>
> On 6/27/17 6/27/17   1:22 PM, Mike Fontenot wrote:
>> The most important thing that distinguishes the CADO frame from other
>> alternatives is that it agrees with the accelerating observer's own
>> measurements and elementary calculations.

>> In order to make his measurements, the accelerating observer needs
>> only two things: his own watch, and transmissions from the distant
>> inertial person reporting her age at the time of the transmission.

> (Tom Roberts wrote):
> From that information the observer knows the sender's age when the
> signal was SENT [...]

Yes, that's what the received signals directly tell the observer. 
Getting from the home twin's age when a message was sent, to her age 
when that message was received, is accomplished by the observer via the 
elementary calculations that I referred to above.  For the specifics of 
those calculations, you'll have to read the paper:

   "Accelerated Observers in Special Relativity", PHYSICS ESSAYS, 
December 1999, p629.

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#423573

On Tuesday, June 27, 2017 at 1:22:43 PM UTC-5, Mike_Fontenot wrote:
> On 6/27/17 8:06 AM, Jonathan Doolin wrote:
> >
> > [...] And in the sense that the CADO frame meets some rubrics, it is correct and unique.
> 
> The most important thing that distinguishes the CADO frame from other 
> alternatives is that it agrees with the accelerating observer's own 
> measurements and elementary calculations.  Those measurements and 
> elementary calculations are detailed in my paper:
> 

If I understood CADO right, 
didn't you use the assumption 
that the distant object is not accelerating,
in order to calculate the CADO for that distant object?

>   "Accelerated Observers in Special Relativity", PHYSICS ESSAYS, 
> December 1999, p629.
> 
> Using an alternative reference frame for an accelerating observer is 
> analogous to an inertial observer deciding to use some other inertial 
> reference frame, in which he is not stationary ... he can do that if he 
> wishes, but it will disagree with his own measurements and calculations.
> 

It only disagrees if the methods are claiming
to measure/calculate the same thing and get different answers.
But CADO, Radar Time, and PLCADO are all measuring different things.


> >
> > We could satisfy
> > rubrics 1, 3, and 5 with Dolby and Gull's Radar Time.
> >
> 
> The other problem I have with Dolby and Gull's accelerating reference 
> frame (other than that it disagrees with the above referenced 
> measurements and elementary calculations made by the accelerating 
> observer) is that it is NON-CAUSAL: In Dolby and Gull's method, the 
> current age of a distant inertial person at some instant in the 
> observer's life depends on how he will choose to accelerate IN THE 
> FUTURE.  I think that is absurd.

Well, let's put it this way.
The "radar time" coordinate of "current" distant events 
is a function of the future decisions of the observer.
I agree this is absurd, but it is not reductio ad absurdum.
You haven't proven anything incorrect; 
only pulled out your own hair in consternation.

What's more, "radar time", even once all the data is in,
is a function of the past-path of the observer.
That means that two attached observers, 
with different past-paths,
(such as a space-ship docked at a space station, )
would report wildly different values of radar-time and radar-distance, 
for distant events they are both currently observing
at the same place and same time.
To me, that's an even greater absurdity about radar-time and radar-distance.
But again, it's not reductio-ad-absurdum-absurd.  
It's just the pull-out-your-own-hair-in-frustration variety of absurd.

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#423581

On 6/28/17 6:01 AM, Jonathan Doolin wrote:
>
> If I understood CADO right,
> didn't you use the assumption
> that the distant object is not accelerating,
> in order to calculate the CADO for that distant object?
>

The CADO reference frame CAN provide the current age and location of a 
distant accelerating person, but it is more complicated.  The case of an 
inertial distant person is much simpler and easier, and since the 
standard twin "paradox" scenario involves an inertial "home twin", 
that's the case I usually focus on, because it is adequate to expose all 
the important issues.


-- 
   https://sites.google.com/site/cadoequation/cado-reference-frame

   "Accelerated Observers in Special Relativity", PHYSICS ESSAYS, 
December 1999, p629.

   All you ever need to know about the twin "paradox".

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#423596

On Wednesday, June 28, 2017 at 8:52:19 AM UTC-5, Mike_Fontenot wrote:
> On 6/28/17 6:01 AM, Jonathan Doolin wrote:
> >
> > If I understood CADO right,
> > didn't you use the assumption
> > that the distant object is not accelerating,
> > in order to calculate the CADO for that distant object?
> >
> 
> The CADO reference frame CAN provide the current age and location of a 
> distant accelerating person, but it is more complicated.  The case of an 
> inertial distant person is much simpler and easier, and since the 
> standard twin "paradox" scenario involves an inertial "home twin", 
> that's the case I usually focus on, because it is adequate to expose all 
> the important issues.
> 

But whether you are finding
the current age of a distant inertial person,
or the current age of a distant accelerating person,
you must assume, beforehand,
that they are inertial, or accelerating.
(that is, you cannot KNOW for sure, until the light 
from that "current" time reaches you)
correct?

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#423626

On 6/29/17 4:47 AM, Jonathan Doolin wrote:
>
> But whether you are finding
> the current age of a distant inertial person,
> or the current age of a distant accelerating person,
> you must assume, beforehand,
> that they are inertial, or accelerating.
>

Yes, when both accelerate, the acceleration profiles of each twin must 
be agreed upon in advance, before the beginning of the traveler's trip. 
(Or, more accurately, they must be known by anyone who intends to 
evaluate the CADO equation "in real time").  Of course, in the standard 
twin "paradox", the traveler knows that the home twin will be 
perpetually inertial.  He can then calculate her current age at each 
instant of his trip without knowing yet how he will choose to accelerate 
after that instant ... i.e., he doesn't need to know his acceleration 
profile in advance.  To do that calculation, the CADO equation requires 
first that he know the quantity CADO_H(t), which is the age of the home 
twin when the traveler is t years old, ACCORDING TO THE HOME TWIN'S 
INERTIAL REFERENCE FRAME.  If she doesn't know in advance what his 
acceleration profile will be, SHE can't know in real time what CADO_H(t) 
is, but the traveler can easily calculate it, and then use the CADO 
equation to determine her current age, according to him.

Keep in mind that the use of the traveler's own measurements and 
elementary calculations to determine the home twin's current age is NOT 
the routine way that the traveler would determine the current age of the 
home twin during the trip.  The routine way is to use the CADO equation, 
which is quick, easy, and (almost) fool-proof.  The value of "the 
measurements and elementary calculations procedure" is purely in showing 
why the CADO reference frame is the only reasonable choice of 
accelerating reference frame.

-- 
   https://sites.google.com/site/cadoequation/cado-reference-frame

   "Accelerated Observers in Special Relativity", PHYSICS ESSAYS, 
December 1999, p629.

   All you ever need to know about the twin "paradox".

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#423672

On Thursday, June 29, 2017 at 11:19:51 AM UTC-5, Mike_Fontenot wrote:
> On 6/29/17 4:47 AM, Jonathan Doolin wrote:
> >
> > But whether you are finding
> > the current age of a distant inertial person,
> > or the current age of a distant accelerating person,
> > you must assume, beforehand,
> > that they are inertial, or accelerating.
> >
> 
> Yes, when both accelerate, the acceleration profiles of each twin must 
> be agreed upon in advance, before the beginning of the traveler's trip. 
> (Or, more accurately, they must be known by anyone who intends to 
> evaluate the CADO equation "in real time").  

Right.  That was my main point.  

For each twin to evaluate the current age of the other twin,
they must have prior knowledge of the path of the other twin,
which they have not yet observed,
because the light has not reached them.

So it is not a "real-time" measurement, 
but rather a interpolation based on the expectation
that the distant twin has continued to follow
the planned acceleration profile.

> Of course, in the standard 
> twin "paradox", the traveler knows that the home twin will be 
> perpetually inertial.  He can then calculate her current age at each 
> instant of his trip without knowing yet how he will choose to accelerate 
> after that instant ... i.e., he doesn't need to know his acceleration 
> profile in advance.

But the expectation that the stay-at-home twin will not accelerate, is still an acceleration profile.  It's just an acceleration profile of continuous zero acceleration.

>  To do that calculation, the CADO equation requires 
> first that he know the quantity CADO_H(t), which is the age of the home 
> twin when the traveler is t years old, ACCORDING TO THE HOME TWIN'S 
> INERTIAL REFERENCE FRAME.  If she doesn't know in advance what his 
> acceleration profile will be, SHE can't know in real time what CADO_H(t) 
> is, but the traveler can easily calculate it, and then use the CADO 
> equation to determine her current age, according to him.
> 

Sure.  The observer only need to interpolate the distant twin's path up to the current time.  He already knows his own path up to the current time.

> Keep in mind that the use of the traveler's own measurements and 
> elementary calculations to determine the home twin's current age is NOT 
> the routine way that the traveler would determine the current age of the 
> home twin during the trip.  The routine way is to use the CADO equation, 
> which is quick, easy, and (almost) fool-proof.  The value of "the 
> measurements and elementary calculations procedure" is purely in showing 
> why the CADO reference frame is the only reasonable choice of 
> accelerating reference frame.
> 
> -- 
>    https://sites.google.com/site/cadoequation/cado-reference-frame
> 
>    "Accelerated Observers in Special Relativity", PHYSICS ESSAYS, 
> December 1999, p629.
> 
>    All you ever need to know about the twin "paradox".

If you'd explain why, though.

It seems to me we've got a number of options.... At least four.

(1) we could use the changing inertial reference frame of the observer 
at the moment the observation takes place 
(2) We could use the radar-time and radar distance, which warps the space and time, so that time isn't time, and distance isn't distance.
(3) We could use the CADO frame, which splices together events as they cross the plane of simultaneity of the observer.
(4) We could use the PLCADO frame, which splices together the events as they cross the past light-cone of the observer.

When you say that one of these is the "only reasonable choice" 
you have to first acknowledge the existence of the other choices,
and explain by what rubric you're saying yours is reasonable,
and the others are not.

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#423674

Jonathan Doolin wrote 
On Thursday, June 29, 2017 at 11:19:51 AM UTC-5, Mike_Fontenot wrote: 
> On 6/29/17 4:47 AM, Jonathan Doolin wrote: 
> > 
> > But whether you are finding 
> > the current age of a distant inertial person, 
> > or the current age of a distant accelerating person, 
> > you must assume, beforehand, 
> > that they are inertial, or accelerating. 
> > 
> 
> Yes, when both accelerate, the acceleration profiles of each twin must 
> be agreed upon in advance, before the beginning of the traveler's trip. 
> (Or, more accurately, they must be known by anyone who intends to 
> evaluate the CADO equation "in real time").   

Right.  That was my main point.   

For each twin to evaluate the current age of the other twin, 
they must have prior knowledge of the path of the other twin, 
which they have not yet observed, 
because the light has not reached them. 

So it is not a "real-time" measurement, 
but rather a interpolation based on the expectation 
that the distant twin has continued to follow 
the planned acceleration profile. 

> Of course, in the standard 
> twin "paradox", the traveler knows that the home twin will be 
> perpetually inertial.  He can then calculate her current age at each 
> instant of his trip without knowing yet how he will choose to accelerate 
> after that instant ... i.e., he doesn't need to know his acceleration 
> profile in advance. 

But the expectation that the stay-at-home twin will not accelerate, is still an acceleration profile.  It's just an acceleration profile of continuous zero acceleration. 

>  To do that calculation, the CADO equation requires 
> first that he know the quantity CADO_H(t), which is the age of the home 
> twin when the traveler is t years old, ACCORDING TO THE HOME TWIN'S 
> INERTIAL REFERENCE FRAME.  If she doesn't know in advance what his 
> acceleration profile will be, SHE can't know in real time what CADO_H(t) 
> is, but the traveler can easily calculate it, and then use the CADO 
> equation to determine her current age, according to him. 
> 

Sure.  The observer only need to interpolate the distant twin's path up to the current time.  He already knows his own path up to the current time. 

> Keep in mind that the use of the traveler's own measurements and 
> elementary calculations to determine the home twin's current age is NOT 
> the routine way that the traveler would determine the current age of the 
> home twin during the trip.  The routine way is to use the CADO equation, 
> which is quick, easy, and (almost) fool-proof.  The value of "the 
> measurements and elementary calculations procedure" is purely in showing 
> why the CADO reference frame is the only reasonable choice of 
> accelerating reference frame. 
> 
> -- 
>    https://sites.google.com/site/cadoequation/cado-reference-frame 
> 
>    "Accelerated Observers in Special Relativity", PHYSICS ESSAYS, 
> December 1999, p629. 
> 
>    All you ever need to know about the twin "paradox". 

If you'd explain why, though. 

It seems to me we've got a number of options.... At least four. 

(1) we could use the changing inertial reference frame of the observer 
at the moment the observation takes place 
(2) We could use the radar-time and radar distance, which warps the space and time, so that time isn't time, and distance isn't distance. 
(3) We could use the CADO frame, which splices together events as they cross the plane of simultaneity of the observer. 
(4) We could use the PLCADO frame, which splices together the events as they cross the past light-cone of the observer. 

When you say that one of these is the "only reasonable choice" 
you have to first acknowledge the existence of the other choices, 
and explain by what rubric you're saying yours is reasonable, 
and the others are not. 

Ugg...
Bulk Modulus & Wave speed in a Medium can be used to solve the twin paradox 

Consider the Electron to be attached to its anti-Twin at a distance of the (charge radius *2)

Under force of acceleration, the charge distance "increases" proportional to the Lorentz Transformations. 
http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/ltrans.html

Under gravitational acceleration the charge Radius "Decreases".

The hidden Twin anti-particle of the Electron  is in actuality the volume of the space obscured by its charge Radius 

https://goo.gl/photos/K31rbPTwM7dLSFtN8

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#423757

On Friday, June 30, 2017 at 10:39:52 AM UTC-5, David (Kronos Prime) Fuller wrote:
> Jonathan Doolin wrote 
> 
>> When you say that one of these is the "only reasonable choice" 
>> you have to first acknowledge the existence of the other choices, 
>> and explain by what rubric you're saying yours is reasonable, 
>> and the others are not. 
> 

...

> Ugg...
> Bulk Modulus & Wave speed in a Medium can be used to solve the twin paradox 
> 

...

I think CADO is more reasonable explanation for the twin paradox than Bulk Modulus, based on the rubric that explanations for things to be relevant to the things they're explaining.

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#423685

On 6/30/17 9:09 AM, Jonathan Doolin wrote:

> On Thursday, June 29, 2017 at 11:19:51 AM UTC-5, Mike_Fontenot wrote:

>>
>> The value of "the
>> measurements and elementary calculations procedure" is purely in showing
>> why the CADO reference frame is the only reasonable choice of
>> accelerating reference frame.
>>

> (Jonathan Doolin replies):
> If you'd explain why, though.
>
> It seems to me we've got a number of options.... At least four.
>
> (1) we could use the changing inertial reference frame of the observer
> at the moment the observation takes place
> (2) We could use the radar-time and radar distance, which warps the space and time, so that time isn't time, and distance isn't distance.
> (3) We could use the CADO frame, which splices together events as they cross the plane of simultaneity of the observer.
> (4) We could use the PLCADO frame, which splices together the events as they cross the past light-cone of the observer.
>
> When you say that one of these is the "only reasonable choice"
> you have to first acknowledge the existence of the other choices,
> and explain by what rubric you're saying yours is reasonable,
> and the others are not.
>

#1 and #3 give the same result.  The CADO reference frame (using the 
CADO equation) is much easier, faster, and less user-error-prone than 
#1, and the terminology and variable names were chosen to reduce 
careless mistakes.

The reason that the result given by #1 and #3 is the only reasonable 
choice is that it agrees with the accelerating observer's own 
measurements and elementary calculations.  It's the same reason that 
perpetually-inertial observers don't choose to use as their reference 
frame some inertial reference frame that is in motion relative to 
themselves ... they can do that if they want to, but that would be stupid.


-- 
   https://sites.google.com/site/cadoequation/cado-reference-frame

   "Accelerated Observers in Special Relativity", PHYSICS ESSAYS, 
December 1999, p629.

   All you ever need to know about the twin "paradox".

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#423756

On Friday, June 30, 2017 at 12:30:21 PM UTC-5, Mike_Fontenot wrote:
> On 6/30/17 9:09 AM, Jonathan Doolin wrote:
> 
> > On Thursday, June 29, 2017 at 11:19:51 AM UTC-5, Mike_Fontenot wrote:
> 
> >>
> >> The value of "the
> >> measurements and elementary calculations procedure" is purely in showing
> >> why the CADO reference frame is the only reasonable choice of
> >> accelerating reference frame.
> >>
> 
> > (Jonathan Doolin replies):
> > If you'd explain why, though.
> >
> > It seems to me we've got a number of options.... At least four.
> >
> > (1) we could use the changing inertial reference frame of the observer
> > at the moment the observation takes place
> > (2) We could use the radar-time and radar distance, which warps the space and time, so that time isn't time, and distance isn't distance.
> > (3) We could use the CADO frame, which splices together events as they cross the plane of simultaneity of the observer.
> > (4) We could use the PLCADO frame, which splices together the events as they cross the past light-cone of the observer.
> >
> > When you say that one of these is the "only reasonable choice"
> > you have to first acknowledge the existence of the other choices,
> > and explain by what rubric you're saying yours is reasonable,
> > and the others are not.
> >
> 
> #1 and #3 give the same result.  The CADO reference frame (using the 
> CADO equation) is much easier, faster, and less user-error-prone than 
> #1, and the terminology and variable names were chosen to reduce 
> careless mistakes.

But they aren't the same.

#1 is a five-dimensional set, like a flip-book of 4-dimensional space-times.
Each for-dimensional page has a different portion of the traveling-twin's
world-line stationary, but represents the whole space-time from that perspective

whereas #2, #3, #4 are all four-dimensional sets.
#3 and #4 are each splicing together (2+1)-dimensional portions 
of #1.  

But CADO takes flat regions,
and PLCADO takes cone-shaped regions.


> 
> The reason that the result given by #1 and #3 is the only reasonable 
> choice is that it agrees with the accelerating observer's own 
> measurements and elementary calculations.  

Yes, but these "measurements" PLUS "elementary calculations" are not 
real-time measurements, as you've already explained, but are based
on the expected/assumed acceleration profile of the distant twin.

But PLCADO would agree with the accelerating observer's 
real-time measurements, without any further calculations, 
based on expected acceleration profile


> It's the same reason that 
> perpetually-inertial observers don't choose to use as their reference 
> frame some inertial reference frame that is in motion relative to 
> themselves ... they can do that if they want to, but that would be stupid.
> 
>

I could have included that as my fifth option. This would be like taking a single four-dimensional page out of the five-dimensional flip book.  Rather than splicing together a three-dimensional portion of each page, to form a single four-dimensional page.

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#423064

Theoretical physicists have discovered that doublethink (believing and teaching both thesis and antithesis) not only destroys human rationality but makes the process irreversible - the affected person will never restore his/her sanity.

Einstein was a powerful doublethinker. He was able to defend both thesis and antithesis with the same conviction, without any hesitation. So in 1911 he explained to the gullible world that the "sudden change of direction" is immaterial with respect to the clock (twin) paradox: 

http://einsteinpapers.press.princeton.edu/vol3-trans/368 
 Albert Einstein 1911: "The clock runs slower if it is in uniform motion, but if it undergoes a change of direction as a result of a jolt, then the theory of relativity does not tell us what happens. The sudden change of direction might produce a sudden change in the position of the hands of the clock. However, the longer the clock is moving rectilinearly and uniformly with a given speed in a forward motion, i.e., the larger the dimensions of the polygon, the smaller must be the effect of such a hypothetical sudden change." 

In 1918 the "sudden change of direction" involving acceleration, which had been immaterial a couple of years before, became crucial and produced a miraculous HOMOGENEOUS gravitational field: 

http://sciliterature.50webs.com/Dialog.htm 
 Albert Einstein 1918: "A homogeneous gravitational field appears, that is directed towards the positive x-axis. Clock U1 is accelerated in the direction of the positive x-axis until it has reached the velocity v, then the gravitational field disappears again. An external force, acting upon U2 in the negative direction of the x-axis prevents U2 from being set in motion by the gravitational field. [...] According to the general theory of relativity, a clock will go faster the higher the gravitational potential of the location where it is located, and during partial process 3 U2 happens to be located at a higher gravitational potential than U1. The calculation shows that this speeding ahead constitutes exactly twice as much as the lagging behind during the partial processes 2 and 4." 

Today's theoretical physicists prefer Einstein 1911 argument and teach that the "sudden change of direction" involving acceleration is immaterial, but an important minority sticks to Einstein's 1918 idiocy and teaches that the "sudden change of direction" is crucial: 

http://www.fnal.gov/pub/today/archive/archive_2014/today14-05-02_NutshellReadMore.html 
 Don Lincoln: "Some readers, probably including some of my doctoral-holding colleagues at Fermilab, will claim that the difference between the two twins is that one of the two has experienced an acceleration. (After all, that's how he slowed down and reversed direction.) However, the relativistic equations don't include that acceleration phase; they include just the coasting time at high velocity." 

http://www.damtp.cam.ac.uk/research/gr/members/gibbons/gwgPartI_SpecialRelativity2010.pdf 
 Gary W. Gibbons FRS: "In other words, by simply staying at home Jack has aged relative to Jill. There is no paradox because the lives of the twins are not strictly symmetrical. This might lead one to suspect that the accelerations suffered by Jill might be responsible for the effect. However this is simply not plausible because using identical accelerating phases of her trip, she could have travelled twice as far. This would give twice the amount of time gained." 

http://www.pbs.org/wgbh/nova/blogs/physics/2015/04/physics-needs-philosophy/ 
 Tim Maudlin: "...so many physicists strongly discourage questions about the nature of reality. The reigning attitude in physics has been "shut up and calculate": solve the equations, and do not ask questions about what they mean. But putting computation ahead of conceptual clarity can lead to confusion. Take, for example, relativity's iconic "twin paradox." Identical twins separate from each other and later reunite. When they meet again, one twin is biologically older than the other. (Astronaut twins Scott and Mark Kelly are about to realize this experiment: when Scott returns from a year in orbit in 2016 he will be about 28 microseconds younger than Mark, who is staying on Earth.) No competent physicist would make an error in computing the magnitude of this effect. But even the great Richard Feynman did not always get the explanation right. In "The Feynman Lectures on Physics," he attributes the difference in ages to the acceleration one twin experiences: the twin who accelerates ends up younger. But it is easy to describe cases where the opposite is true, and even cases where neither twin accelerates but they end up different ages. The calculation can be right and the accompanying explanation wrong." 

http://sciencechatforum.com/viewtopic.php?f=84&t=26847 
 Don Lincoln: "A common explanation of this paradox is that the travelling twin experienced acceleration to slow down and reverse velocity. While it is clearly true that a single person must experience this acceleration, you can show that the acceleration is not crucial. What is crucial is that the travelling twin experienced time in two reference frames, while the homebody experienced time in one. We can demonstrate this by a modification of the problem. In the modification, there is still a homebody and a person travelling to a distant star. The modification is that there is a third person even farther away than the distant star. This person travels at the same speed as the original traveler, but in the opposite direction. The third person's trajectory is timed so that both of them pass the distant star at the same time. As the two travelers pass, the Earthbound person reads the clock of the outbound traveler. He then adds the time he experiences travelling from the distant star to Earth to the duration experienced by the outbound person. The sum of these times is the transit time. Note that no acceleration occurs in this problem...just three people experiencing relative inertial motion." 

http://www.pitt.edu/~jdnorton/teaching/HPS_0410/chapters/spacetime_tachyon/index.html 
 John Norton: "We read from these hypersurfaces that the traveling twin judges the stay-at-home twin's clock to be running at half the speed of the travelers. When the traveler's clock reads 1 day, the stay-at-home twin's reads 1/2 day; just before the turn around, when the traveler's clock is almost at 2 days, the stay-at-home twin's clock is almost at 1 day. Then, at the end of the outward leg, the traveler abruptly changes motion, accelerating sharply to adopt a new inertial motion directed back to earth. What comes now is the key part of the analysis. The effect of the change of motion is to alter completely the traveler's judgment of simultaneity. The traveler's hypersurfaces of simultaneity now flip up dramatically. Moments after the turn-around, when the travelers clock reads just after 2 days, the traveler will judge the stay-at-home twin's clock to read just after 7 days. That is, the traveler will judge the stay-at-home twin's clock to have jumped suddenly from reading 1 day to reading 7 days. This huge jump puts the stay-at-home twin's clock so far ahead of the traveler's that it is now possible for the stay-at-home twin's clock to be ahead of the travelers when they reunite. Careful attention to the differing judgments of simultaneity of the two twins shows that there is nothing paradoxical in the twin effect. The brief moment of acceleration of the traveling twin completely alters the traveler's judgments of simultaneity and this alteration is key to seeing how relativity provides a consistent account of the effect." 

http://topquark.hubpages.com/hub/Twin-Paradox 
 "The Twin Paradox is a scenario that, at first glance, seems to make nonsense out of Einstein's theory of special relativity. The situation is that a man sets off in a rocket travelling at high speed away from Earth, whilst his twin brother stays on Earth. [...] What happens is that the twin on Earth, viewing himself as stationary and his brother as moving at high speed, sees his brother experiencing time dilation and thus ageing more slowly. At the same time, the twin in the spaceship considers himself to be the stationary twin, and therefore as he looks back towards Earth he sees his brother ageing more slowly than himself. Each sees the other as moving, and therefore as experiencing time dilation. But which brother is "correct" in the way he perceives the situation? Both are. Each sees the other as being younger than himself. How they were perceived by any onlooker would depend on which frame of reference the onlooker was in. It doesn't make sense to ask which brother is "really" older, because the answer depends on where you stand to ask the question! But what about when the brother in the spaceship returns to Earth? Surely the contradiction will be apparent then? Ah, but in order to return to Earth, the spaceship must slow down, stop moving, turn around and go back the other way. During those periods of deceleration and deceleration, it is not an inertial frame and therefore the normal rules of special relativity don't apply. When the twin in the spaceship turns around to make his journey home, the shift in his frame of reference causes his perception of his brother's age to change rapidly: he sees his brother getting suddenly older. This means that when the twins are finally reunited, the stay-at-home twin is the older of the two." 

The sudden ageing syndrome described in the last two quotations (and in Einstein's 1918 paper) deserves special attention - this is perhaps the greatest idiocy in the history of science: 

"When the twin in the spaceship turns around to make his journey home, the shift in his frame of reference causes his perception of his brother's age to change rapidly: he sees his brother getting suddenly older. This means that when the twins are finally reunited, the stay-at-home twin is the older of the two." 

Pentcho Valev

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#423071

On Monday, June 19, 2017 at 11:30:04 PM UTC+2, Pentcho Valev wrote:
> Calculations done by Einsteinians always show that the moving clock is slow while the stationary one is fast. Why? 

Yes, you, the ignorant idiot, is going to explain it to us.

> Because Einsteinians use a biased scenario. In this scenario the moving system (spaceship, observer in it, observer's clock) is always modeled as point-like while the stationary system is spatially extended. As the moving point-like system traverses distances in the spatially extended stationary system, calculations show that the moving clock runs slower and the moving observer remains younger. For this scenario, special relativity does not allow calculations producing an alternative result. 
> 
> For a scenario in which the stationary system is modeled as point-like, special relativity acts in an opposite way. Imagine that all ants spread out on the closed polygonal line have clocks and move with constant speed: 
> 
> http://cliparts101.com/files/131/AB2B0036DC553691775E012D449DEC62/ant_border_rectangle.png 

There we go. The same stupid question and the same stupid ant diagram pops
up every few months like clockwork.

This has been explained to you, Pentcho. Dozens of times. Get over it.

--
Jan

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#423317

W dniu poniedziałek, 19 czerwca 2017 15:00:36 UTC-6 użytkownik JanPB
napisał:

> There we go. The same stupid question and the same stupid ant diagram
> pops up every few months like clockwork. This has been explained to you,
> Pentcho. Dozens of times. Get over it.

Only in the capitalist fake news repetition makes reality. Real life, it 
never does. Waking up from that reality, you are going to ask "where am I, 
what is going on here??"

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#423331

Lipek Mniak wrote:
> 
> W dniu poniedziałek, 19 czerwca 2017 15:00:36 UTC-6 użytkownik JanPB
> napisał:
> 
> > There we go. The same stupid question and the same stupid ant diagram
> > pops up every few months like clockwork. This has been explained to you,
> > Pentcho. Dozens of times. Get over it.
> 
> Only in the capitalist fake news repetition makes reality. Real life, it
> never does. Waking up from that reality, you are going to ask "where am I,
> what is going on here??"


You forgot "who am I, what am I?" 

But of course, those are question not even You can answer...so you avoid them.

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#423195

Am Montag, 19. Juni 2017 23:30:04 UTC+2 schrieb Pentcho Valev:
> Calculations done by Einsteinians always show that the moving clock is slow while the stationary one is fast. Why? Because Einsteinians use a biased scenario. In this scenario the moving system (spaceship, observer in it, observer's clock) is always modeled as point-like while the stationary system is spatially extended. As the moving point-like system traverses distances in the spatially extended stationary system, calculations show that the moving clock runs slower and the moving observer remains younger. For this scenario, special relativity does not allow calculations producing an alternative result. 
> 
> For a scenario in which the stationary system is modeled as point-like, special relativity acts in an opposite way. Imagine that all ants spread out on the closed polygonal line have clocks and move with constant speed: 
> 
> http://cliparts101.com/files/131/AB2B0036DC553691775E012D449DEC62/ant_border_rectangle.png 
> 
> A single stationary ant, with a clock, is located in the middle of one of the sides of the polygon. As moving ants pass the single stationary ant, they check its (stationary) clock against their (moving) clocks. For this scenario, special relativity predicts that the single stationary clock will shows LESS AND LESS time elapsed than moving clocks consecutively passing it. This implies that the single stationary ant is getting YOUNGER AND YOUNGER than moving brothers it consecutively meets.
> 
> Clearly, the twin paradox is actually an absurdity, which means that the underlying premise, Einstein's constant-speed-of-light postulate, is false.
> 
> Pentcho Valev

In order to be able blaming the constant speed c postulate wrong, you should first clarify what reference and what definition of c Einstein was and which ones you are dealing with. 
Einstein wrote in his second postulate "any ray of light moving wrt the co-ordinate 'system at rest' ".
To me the confusion begins when Einstein at the beginning of his §1 introduced the system at rest. He wrote  "Es liege ein Koordinatensystem vor ... We are calling it the system at rest". 
 

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#423207

Dne 21/06/2017 v 18:21 Eckard B napsal(a):
> Am Montag, 19. Juni 2017 23:30:04 UTC+2 schrieb Pentcho Valev:
>> Calculations done by Einsteinians always show that the moving clock is slow while the stationary one is fast. Why? Because Einsteinians use a biased scenario. In this scenario the moving system (spaceship, observer in it, observer's clock) is always modeled as point-like while the stationary system is spatially extended. As the moving point-like system traverses distances in the spatially extended stationary system, calculations show that the moving clock runs slower and the moving observer remains younger. For this scenario, special relativity does not allow calculations producing an alternative result. 
>>
>> For a scenario in which the stationary system is modeled as point-like, special relativity acts in an opposite way. Imagine that all ants spread out on the closed polygonal line have clocks and move with constant speed: 
>>
>> http://cliparts101.com/files/131/AB2B0036DC553691775E012D449DEC62/ant_border_rectangle.png 
>>
>> A single stationary ant, with a clock, is located in the middle of one of the sides of the polygon. As moving ants pass the single stationary ant, they check its (stationary) clock against their (moving) clocks. For this scenario, special relativity predicts that the single stationary clock will shows LESS AND LESS time elapsed than moving clocks consecutively passing it. This implies that the single stationary ant is getting YOUNGER AND YOUNGER than moving brothers it consecutively meets.
>>
>> Clearly, the twin paradox is actually an absurdity, which means that the underlying premise, Einstein's constant-speed-of-light postulate, is false.
>>
>> Pentcho Valev
> 
> In order to be able blaming the constant speed c postulate wrong, you should first clarify what reference and what definition of c Einstein was and which ones you are dealing with. 
> Einstein wrote in his second postulate "any ray of light moving wrt the co-ordinate 'system at rest' ".
> To me the confusion begins ......

The confusion begins here.

The original 2nd postulate applies to vacuum speed of light
wrt any inertial coordinate system.

Therefore wrt the one that is by the choice considered at rest,
and wrt all others, that are moving wrt the "rest" one.

That is what the term "invariant vacuum speed of light" means.

The 2nd postulate was later omitted in reformulated SR
as the consequence of the 1st postulate.
The SR as the space geometry theory
completely detached from electromagnetism.
The theory dealing with light properties
is currently SR aware Quantum electrodynamics.

-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.

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#423232

Dne 21/06/2017 v 19:33 Poutnik napsal(a):
> Dne 21/06/2017 v 18:21 Eckard B napsal(a):

>> In order to be able blaming the constant speed c postulate wrong, you should first clarify what reference and what definition of c Einstein was and which ones you are dealing with. 
>> Einstein wrote in his second postulate "any ray of light moving wrt the co-ordinate 'system at rest' ".
>> To me the confusion begins ......
> 
> The confusion begins here.
> 
> The original 2nd postulate applies to vacuum speed of light
> wrt any inertial coordinate system.
> 
> Therefore wrt the one that is by the choice considered at rest,
> and wrt all others, that are moving wrt the "rest" one.
> 
> That is what the term "invariant vacuum speed of light" means.
> 
P.S.: and for the vacuum speed of light definition,
sufficient are definitions of speed, light and vacuum.

Einstein did not introduce any SR specific definitions
of these 3 terms, neither of vacuum speed of light.

-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.

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#423235

W dniu czwartek, 22 czerwca 2017 07:32:40 UTC+2 użytkownik Poutnik napisał:
> Dne 21/06/2017 v 19:33 Poutnik napsal(a):
> > Dne 21/06/2017 v 18:21 Eckard B napsal(a):
> 
> >> In order to be able blaming the constant speed c postulate wrong, you should first clarify what reference and what definition of c Einstein was and which ones you are dealing with. 
> >> Einstein wrote in his second postulate "any ray of light moving wrt the co-ordinate 'system at rest' ".
> >> To me the confusion begins ......
> > 
> > The confusion begins here.
> > 
> > The original 2nd postulate applies to vacuum speed of light
> > wrt any inertial coordinate system.
> > 
> > Therefore wrt the one that is by the choice considered at rest,
> > and wrt all others, that are moving wrt the "rest" one.
> > 
> > That is what the term "invariant vacuum speed of light" means.
> > 
> P.S.: and for the vacuum speed of light definition,
> sufficient are definitions of speed, light and vacuum.

A fanatic idiot doesn't really need ANY definitions
to know his Shit is right; but for a thinking
person the above isn't even a beginning.

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#423310

W dniu poniedziałek, 19 czerwca 2017 15:00:36 UTC-6 użytkownik Poutnik
napisał:

>> The confusion begins here.
>> The original 2nd postulate applies to vacuum speed of light wrt any
>> inertial coordinate system.

NOO! NOT to vacuum speed of light, but mostly to PHOTONS or EM waves 
travelling in Vacuum.

>> Therefore wrt the one that is by the choice considered at rest, and wrt
>> all others, that are moving wrt the "rest" one.

!!
 
>> That is what the term "invariant vacuum speed of light" means.

What else could, an invariant vacuum speed of light, be meaning?

> P.S.: and for the vacuum speed of light definition, sufficient are
> definitions of speed, light and vacuum.
> Einstein did not introduce any SR specific definitions of these 3 terms,
> neither of vacuum speed of light.

What on earth are you talking about. Give me a break.

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