From: Inertial on
"colp" <colp(a)solder.ath.cx> wrote in message
news:e9264a25-c903-41a1-9995-2ab4a781a956(a)k17g2000pro.googlegroups.com...
> On Jun 18, 11:24 am, "Inertial" <relativ...(a)rest.com> wrote:
>> "colp" <c...(a)solder.ath.cx> wrote in message
>>
>> news:bd7d4a85-d7b3-40e3-884c-720b9255f608(a)11g2000prv.googlegroups.com...
>>
>>
>>
>> > On Jun 18, 8:14 am, PD <thedraperfam...(a)gmail.com> wrote:
>> >> On Jun 16, 1:25 am, colp <c...(a)solder.ath.cx> wrote:
>>
>> >> > The classic twin paradox is asymmetric in that one twin remains on
>> >> > Earth while the other leaves (i.e. only one of them accelerates and
>> >> > deaccelerates). In the symmetric twin paradox both twins leave
>> >> > Earth,
>> >> > setting out in opposite directions and returning to Earth at the
>> >> > same
>> >> > time. The conventional explanation for the classic twin paradox is
>> >> > since only one twin accelerates, the ages of the twins will be
>> >> > different. In the symmetric case this argument cannot be applied.
>>
>> >> > The paradox of the symmetric twins is that according to special
>> >> > relativity (SR) each twin observes the other twin to age more slowly
>> >> > both on the outgoing leg
>> >> > and the return leg, so SR paradoxically predicts that each twin will
>> >> > be younger than
>> >> > the other when they return to Earth.
>>
>> >> No. This is a basic misunderstanding due to oversimplification, and it
>> >> is exactly the kind of thing that the original puzzle was intended to
>> >> highlight for learners of relativity.
>>
>> > It is true that I haven't discussed what happens at turnaround, but
>> > only for the reason that turnaround cannot possibly compensate for the
>> > SR time dilation.
>>
>> So you just don't bother doing the math and just ASSUME that it isn't
>> important and then wonder why you get stupid results
>
> Maths is consistent with logic.

You have used neither

> Your snipped my argument as to why the
> turnaround cannot logically compensate for the SR time dilation.

Because it is just vague hand-waving based on lack of understanding. Show
the math for the entire trip for both twins.

Come up with the goods. Or is your faith the SR is wrong unsupported by
facts?


From: kado on
On Jun 17, 6:21 am, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote:
>
snip
>
> No. It is a GEDANKEN, not an experiment. There are no actual measurements of
> this situation.
>
> > In the experiment SR predicts that the twins will both be younger than
> > each other when they return to Earth, which is of course impossible.
>
> This is just plain not true. You and that paper did not actually use SR. The
> comic book used does not describe the actual theory accurately enough to be useful.
>
snip
>
> Those are not the real solution. The REAL solution is to actually use SR in the
> analysis of this gedanken.
>


You are correct in stating twin paradox is a gedanken, and not
an empirical experiment.
Everone understands (or should understand) that a thought
experiment is very susceptible to errors.
However, just because an empirical experiment is conducted,
this does not mean the researchers arrive at the correct
conclusions.

Nevertheless, what you do not seem to realize and be able to
accept is that the whole of Einstein's SR and GR are based
on gedankens, and not a bit of these are based on empirical
experimentation!

The gedankin based idea of relativistic mass was demonstrated
as false by the empirical Eotvos experiment of Dr. Robert Dicke.
This experiment empirically demonstrated that the mass of any
body remains constant to better than 99,999,999,999 parts in
100 billion regardless of speed.

So post Einsteinian Relativity now employs the notion of
invariant mass.

You and most relativists also cannot seem realize that post
Einsteinian Special Relativity and General Relativity are not
Einstein's SR or GR (e.g., relativistic mass is now invariant
mass, time contracrion is now dilated time, etc.,). So many
relativists cannot seem to accept that both are whole new
theories of relativity, wherein any and all the reasoning and
mathematics pertaining to mass and contracted time within
Einstein's SR and GR just do not apply in these 2 new
theories.

So what SR do you propose to analyze this gedanken?

Furthermore, the twin paradox cannot be empirically
modeled or duplicated.
Trying to empirically model/reproduce this paradox would
be just like trying to empirically change a pumpkin into the
coach and physically morphing mice into the coachmen of
the fairytale of Cinderella.

It is not possible to empirically model or replicate fairy tales.

Nevertheless, probably the primary reason there is so much
BS on both sides of this current argument is that this is a
subject concerning time.

Science still does not truly understand time!

Therefore I propose another paradox initiated by the tenets
of Einstein’s SR that is independent of time, i.e.,: The
paradox of rapidly spinning (rotating), absolutely rigid,
perfectly round discs moving near the speed of light.

(I conceived this paradox when writing the treatise titled:
‘The Search for Reality and the Truths’. Now I make no
claim that I was the very first to formulate this paradox, but
I found no mention of it in any of my studies of Relativity.
So to keep all the mediocre minds on this newsgroup from
making a big deal about who was first, let’s just say
that I independently developed this paradox.)

The concept of tensors (i.e., the contraction of the length
a body in the direction of motion, but not the height or
width) is a fundamental tenet of both Einstein’s, and post
Einsteinian SR and GR. Furthermore, this idea was
originated by Lorentz, and is an integral part of the
Lorentz Transformation. So this paradox is applicable to
not only SR and GR, but also the ether theory of Lorentz.

So all are open to the paradox of very rapidly rotating,
perfectly round, RIGID discs (e.g., a Frisbee) moving
near the speed of light wherein length, but not height
and width contracts as tensors (so the physical form
must continually change depending on the speed and
rotation).

Furthermore, all these continual changes of form (that
depends of both the rate of spin and change of position)
must occur without generating any heat and/or sound.
(Sound is the physical aural result of vibration and is a
form of energy). So if the deformations responsible for
sound requires energy, how does this affect the tensor
mechanics without also violating the Laws of
Thermodynamics. Moreover, the need for this
deformation energy would then prevent Einstein’s uniform
motion that SR is all about.

In other words; the deformations would also ‘tire’ inertia,
and the motion would not be uniform, but nonuniform,
i.e., deceleration, so only explainable by GR, because SR
would be invalid if uniform motion is a fallacy. But how
can GR be valid if both SR and the Lorentz Transformation
are both invalid?

So are not the whole ideas that Nature is time symmetrical
and the tensors of Einstein in the same category as the
notion of the relativity of mass?


D.Y. Kadoshima

From: paparios on
On 17 jun, 22:33, colp <c...(a)solder.ath.cx> wrote:
> On Jun 18, 2:13 pm, "Inertial" <relativ...(a)rest.com> wrote:

>
>
>
> > Please reproduce your working, and I'll point out the errors.  I don't have
> > access to the article, only your comments on it.
>
> Here's the relevant text from the article. The previous version being
> discussed was the classic twin paradox (Taurai and Tauwi are the names
> of the twins).
>
> B. Twin Paradox (Symmetric)
> We shall set forth a new version of the twin paradox which is
> truly symmetric and this will introduce a true paradox and we
> shall provide a solution. Suppose Taurai unlike in the previous
> version, decided to be adventurous too. He decides to rocket
> into space and travels not with his twin brother but all by himself
> and instead of Alpha-Centauri he travels at the same constant
> relativistic speed as Taurwi [this speed is measured by
> the Earth bound observers] to an imaginary constellation (call
> it Constellation Alpha-Christina) which is equidistant and directly
> opposite to Alpha Centauri along the line of sight joining
> the Earth and Alpha Centauri.
>
> On their day of departure, their family and friends bid them
> farewell and wish thema safe travel. Withoutmuch say, on the
> day of reunion, the family and friends [who all have studied
> physics at university and understand very well the STR] have
> no doubt that they [the Twins] will all have aged the same.
> The big question is, will the twins agree with their family and
> friends that they have aged the same? The truth is that, each
> of the twins will see the other as having aged less than they so
> they would not agree with their family and friends that they
> must be the same age. Herein we have a paradox! Who is
> older than who here?

First typical mistake of students. What is relevant is that each twin
has a clock which, according to his own readings and knowledge, is
ticking exactly like it was before the travel. No calculation is
needed at all and what SRT affirms is that, when both twins return to
Earth, their respective clocks will show the same time and, both
clocks, lag the clock of the Earth twin.

> If V is the speed with which the Earth bound observers (family
> and friends) see the twins travel at, then, according to the
> twins in their own respective frames of references, the Earth is
> receding at a speed V and the other twin is receding fromthem
> at a speed 2V. This scenario is perfectly symmetric and each
> of the twins has every right according to the STR to say the
> other twin is the one that is younger and they will not agree
> that their ages are equal upon reuniting. We are here presented
> with a true paradox which the STR in its presently understood
> form [as is found in most if not all the textbooks of physics
> that deal with the subject of the STR], is unable to provide an
> answer.

This is completely wrong, of course, since what they are saying is
that these calculations represent what the other clock is doing. Each
clock is just doing its business, that is ticking at, say, 1 tick
every second.
In http://en.wikipedia.org/wiki/Twin_paradox there are two Minkowski
diagrams which would help you to understand. The symmetric twin case
is obtained by just drawing an specular image on the first diagram.
The second diagram shows that this "slowing" effect is due to
relativistic Doppler shift. The stay at home twin sees light signals
from the traveling twin running slow with respect to his own clock
(assuming all three clocks emit a light signal at regular intervals)
and, viceversa, the traveling twin sees light signals from the stay at
home twin also running slow with respect to his own clock (this is
represented by the red color on the diagram). When the traveling twin
returns to Earth, the light signals start to arrive faster, both to
the traveling and the stay at home twin (see lines on blue color on
the diagram).

It will not help to call the GTR to our rescue because
> what we shall do with it for one twin, we shall have to do exactly
> the same with the other twin – we have a catch here. The
> situation exhibits a perfect symmetry that runders us imobile
> as along as we stick with the provinces of Einstein’s Philosophy
> of Relativity.

This is just garbage since they not consider the fact that, not using
GTR, this gedanken is also solved. For instance, instead of returning
to Earth, each traveling twin transfer the lecture of their clocks to
ships coming back to Earth (this also shows there are needed, for each
traveling twin, two different reference frames and therefore, the
whole traveling twin path is not inertial.

>
> The maths supports my point because the SR transforms always result in
> time dilation, never compression, and the time dilation must be
> compensated for with compression in order to avoid the paradox.

As it is clear you, and those guys, did not consider the relativistic
Doppler shift in the problem.

Miguel Rios
From: Tom Roberts on
colp wrote:
> It is not necessary for me to showing you the math in order for you to
> identify the errors in the article.

The basic error in that article is that they DID NOT use the math of SR. Instead
they used a comic-book description of SR such as "moving clocks run slow" -- SR
does NOT say that; what SR says is that if a moving clock's tick rate is
measured by using two SYNCHRONIZED clocks at rest in an inertial frame and
pre-positioned along the moving clock's path, then between meetings the moving
clock ticks fewer times than the inertial-frame clocks. In particular, the
METHOD of comparing the clocks is important.

Note that using this method the turn-around is important, and what
happens during each twin's turn-around resolves the inconsistency
you think is present -- a correct analysis shows no inconsistency.

In an earlier post you attempted to discuss measuring the other twin's clock via
radio pulses. That is a DIFFERENT way of measuring the moving clock's tick rate,
and IT GETS A DIFFERENT ANSWER than the previous paragraph's method. You got it
wrong in that earlier post, and SR does indeed predict an INCREASED rate of
received radio pulses during the inbound journey. This resolves the
inconsistency you think is present.

Using this method, nothing happens during the turn-around. This
method is DIFFERENT from the previous one, in several ways.

If either you or the authors of that paper had actually bothered to use SR in
the analysis, you would find the two twins return with identical ages. But the
comic-book you and they used gets it wrong.


Tom Roberts
From: Tom Roberts on
kado(a)nventure.com wrote:
> On Jun 17, 6:21 am, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote:
>> No. It is a GEDANKEN, not an experiment. There are no actual measurements of
>> this situation.
>
> You are correct in stating twin paradox is a gedanken, and not
> an empirical experiment.
> Everone understands (or should understand) that a thought
> experiment is very susceptible to errors.
> However, just because an empirical experiment is conducted,
> this does not mean the researchers arrive at the correct
> conclusions.

A correct analysis using the theory arrives at a correct conclusion AS PREDICTED
BY THE THEORY. Whether or not this is what actually occurs in the world we
inhabit is the subject of experiment, and cannot possibly be determined with
gedankens.

In this case, the usual "twin paradox" has been implemented experimentally, and
the result is as predicted by SR. The "symmetric twin paradox" has not been
implemented experimentally AFAIK, but can be considered as a straightforward
extension of the usual one.


> Nevertheless, what you do not seem to realize and be able to
> accept is that the whole of Einstein's SR and GR are based
> on gedankens, and not a bit of these are based on empirical
> experimentation!

This is WILDLY untrue. There are HUNDREDS of experiments that confirm various
predictions of SR, and directly refute Newtonian mechanics.

http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html

In particular, there are several experiments that DIRECTLY implement the "twin
paradox", and which confirm the prediction of SR.

The experiment by Bailey et al is a particularly appropriate one.


> You and most relativists also cannot seem realize that post
> Einsteinian Special Relativity and General Relativity are not
> Einstein's SR or GR (e.g., relativistic mass is now invariant
> mass, time contracrion is now dilated time, etc.,). So many
> relativists cannot seem to accept that both are whole new
> theories of relativity, wherein any and all the reasoning and
> mathematics pertaining to mass and contracted time within
> Einstein's SR and GR just do not apply in these 2 new
> theories.

This is just plain not true. It is true that the meaning of "mass" has evolved
since 1905, and now means an invariant quantity intrinsic to objects [#]. But
the basic theory known as SR is the same as Einstein presented in 1905 -- only
the vocabulary and mode of presentation is different.

[#] This is the most straightforward updating of the meaning of
"mass" from Newtonian mechanics to SR; "relativistic mass" was not.
That's basically why "relativistic mass" is now an anachronism.


> Furthermore, the twin paradox cannot be empirically
> modeled or duplicated.

Not true. See the above link, specifically the section titled "Tests of the Twin
Paradox".


> Therefore I propose another paradox initiated by the tenets
> of Einstein�s SR that is independent of time, i.e.,: The
> paradox of rapidly spinning (rotating), absolutely rigid,
> perfectly round discs moving near the speed of light.
> [... excessively naive discussion]

Look up the "Ehrenfest paradox".

Before attempting to criticize SR, you need to learn what the theory ACTUALLY IS.


Tom Roberts
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