On May 5, 10:46*am, " wrote:
On 5 mayo, 09:43, kenseto wrote: On May 4, 10:43 pm, PD wrote:

On May 3, 10:03 am, kenseto wrote:

On May 2, 1:45 pm, PD wrote:

On May 2, 9:35 am, kenseto wrote:

What's wrong with these pictures???

1. In the twin paradox scenario SR claims that the traveling clock is
running at slower rate than the stay-at-home clock.

SR makes no such claim. Where are you reading such crap?
What SR tells you is precisely what will be *measured* -- that is, how
much time each twin will say has elapsed between the time of their
departure and the time of their reunion. SR does NOT make a claim
about which clock is running faster or slower in between.

So you are now saying that the SR stay-at-home observer doesn't claim
that the traveling clock is running at a slower rate....right??

Read what I said.

Previously you admitted that every SR observer claims that all clocks
moving wrt him are running slow.

I said no such thing. In fact, the last time you said it, I corrected
you.
What I said is that an *inertial* observer will claim that all clocks
moving *inertially* with respect to him are running slow. This doesn't
apply to the traveling twin, which is precisely the pedagogical point
of the twin puzzle to begin with. This seems to elude you and has
eluded you for a dozen years or more.

But no clock is in a state of inertial motion (including any Sr
observer's clock).....so are you saying that SR is not valid because
it is based on inertially moving clocks?

Is this not a valid claim anymore?

This means that
the passage of a stay at home clock second corresponds to the passage
of less than a clock second on the traveling clock. However when the
traveling clock rejoins the stay-at-home clock, the traveling clock
second is compared with the stay-at-home clock second *directly to
reach the conclusion that the traveling clock is younger. It seems
that SR is making the contradictory claims that: (a) the passage of a
traveling clock second does not correspond to the passage of a stay-at-
home clock second. (b) the passage of a traveling clock second does
correspond to the passage of a stay-at-home clock second.

2. In the pole and the barn paradox scenario:
SR claims that a physically longer pole can fit into a physically
shorter barn for a brief instant. However SR also claims that nothing
is physically happening to the pole. The question is: If nothing is
physically happening to the pole how can a physically longer pole can
fit into a physically shorter barn?

And the reverse question to you is: Why would you think that something
physical MUST happen to an object for its length to be different?

Because you said that the physically longer pole can fit into a
physically shorter barn.

But it's not physically longer. The pole is physically shorter, which
is why it fits in the barn.

This is an assertion. No moving pole is measured directly to be
shorter.

I have no problem with the SR explanation if you say that length
contraction is just a perspective geometric projection effect. But you
also insisted that the contraction of the pole is physically real.

Yes. This doesn't mean that something physical had to happen to the
pole to make it shorter.

Yes it does.

That where the problem comes in.

No problem.

Yes there is problem.

After all, I can record the kinetic energy of a rock from two
different reference frames and will have different answers for the
same rock, even though I never did anything physical to the rock to
add energy to it. The same thing is true for length.

Also, what about from the pole's
point of view? How can it fit into an already physically shorter barn
when the barn is under go further physical contraction?

The answer to this question has to do with what "being inside the
barn" means. What does it mean for the pole to be inside the barn for
an instant in the barn frame?

It means that the physical length of the pole is really shorter than
the physical length of the barn in the barn frame.

I think you can do better than that.
Here, let me give you a hint: The ends of the pole are both inside the
barn at the same moment. Right?

Right ....that's what you claimed and that's real physical
contraction.

Again it seems that SR is making contradictory claims.

3. The SR concept of Relativity of Simultaneity: Einstein used the
train and lightning strikes example to derive his concept of RoS..

No, not to derive it. He used it as a teaching example to explain it,
but the RoS lives independently of this example.

He
said that the track observer sees the strikes to be simultaneous
because the speed of light is isotropic in the track frame and the
track observer is located at equal distance from the strikes when the
strikes occur simultaneously.

No, that is NOT what he said. What he said is that BECAUSE the track
observer sees the strikes to be simultaneous and because the speed of
light is isotropic in the track frame and because the track observer
is located at equal distances from the strikes, THEN the strikes are
simultaneous.

NO....the strikes are stipulated to be simultaneous before the track
observer can see them to be simultaneous.

Not so. Where are you reading such crap? Cite the reference.

The stipulation that the track observer are at equal distance and the
speed of light is isotropic automatically stipulates that the strikes
are simultaneous.
Besides the RoS violates the PoR. Why? Because RoS means that the laws
of physics are different in the train than in the track.....in the
track frame the speed of light is isotropic and RoS says that the
speed of light in the train is anisotropic.

You have it backwards. Where are you reading such crap?

No you are the one who has it backward. If the strikes were not
stipulated to be simultaneous no observer at equal distance from the
strikes can see them to be simultaneous.

Also the track observer is not moving
wrt the light fronts from the strikes.

Of course he is. If the train observer were not moving relative to the
light fronts, they'd never reach him.

Hey idiot I said that the track observer is not moving wrt the light
fronts. Do you have a reading comprehension problem?

Sorry, I mistyped. If the track observer were not moving relative to
the light fronts, they'd never reach him.

Sigh....the light fronts are doing the moving isotropically. That's
why that speed of light is isotropic in the track frame.

OTOH he also claimed that the train observer is moving wrt the light
fronts from the strikes....

No, he didn't. Where are you reading such crap?

Hey idiot.... are you saying that Einstein didn't say that the train
observer is rushing toward the light front from the front of the train
and receding from the light front from the rear of the train and thus
he will see that light front from the front before he sees the light
front from the rear?

Yes, he did say this, and this is what the *track* observer says about
the light and the train observer. This is *not* what the train
observer would say is happening, of course.

This is where you gone wrong. What you said is based on the bogus
assertion that the RoS is correct. It is not. The correct SR
interpretation by the track observer on what the train observer will
see is as follows:
1/2 of the train = L
The light path length from the strikes in the train = L*gamma
Therefore the transit time for the light fronts to arrive at the train
observer = L*gamma/c
Therefore the track observer predicts that the train observer will see
the strikes to be simultaneous at a later time of (L*gamma/c)

You are so stupid.

the light front from the front of the train
will reach the train observer before the light front from the rear of
the train. This is why the train observer will not see the light
fronts to be simultaneous.

No, that's how the track observer makes physical sense (that is,
consistency) from his CONCLUSION that the strikes are simultaneous and
the FACT that the train observer does not see the strikes
simultaneously.

Sigh the train observer must make his own conclusion whether the
strikes are simultaneous.

And he concludes they are not. The track observer concludes they are.

Your assertion is based on the bogus concept of RoS. The train
observer makes no such conclusion. He concludes that the strikes are
stipulated to be simultaneous and the speed of light in his frame is
isotropic and therfore he too will see the strikes to be simultaneous.

The track observer cannot make that decision
for him. However the track observer can predict what the train
observer will see as follows:
The light path length from both strikes in the train = gamma*L
The transit time in the train for both light fronts to reach the train
observer = gamma*L/c
Therefore the train observer will see the strikes to be simultaneous
at a later time of (gamma*L/c).

That is certainly not what the train observer sees. Moreover, that is
not what the track observer predicts the train observer will see in
Einstein's writings.

That is certainly what the train observer will see. Otherwise the
speed of light in the train is not isotropic. Of course this disagrees
with what Einstein said because he bogusly believed that the train
observer is moving wrt the simultaneous light fronts.

However Einstein failed to realize that his
explanation violates his postulate that the speed of light is also
isotropic in the train.....at the time the strikes occur
simultaneously

But they don't strike simultaneous in the train frame. They only
strike simultaneously in the track frame.

Assertion is not a valid argument. The strikes are stipulated to be
simultaneous to be with.

Cite the reference. Title, publisher, page number, quotation, please.

That's what Einstein said in his book. That's what the text book "The
Fundamental of Physics" by Resnick and Holliday said. The strikes are
stipulated to be simultaneous to begin with. One oberver sees the
strikes to be simultaneous because he is not moving wrt the light
fronts and the other observer sees the strikes to be not simultaneous
because he is moving wrt the light fronts.

Ken Seto

This is what Einstein exactly said in "Albert Einstein (1879-1955).
Relativity: The Special and General Theory. *1920.", chapter 9.
"Up to now our considerations have been referred to a particular body
of reference, which we have styled a "railway embankment." We suppose
a very long train travelling along the rails with the constant
velocity v and in the direction indicated in Fig. 1. People travelling
in this train will with advantage use the train as a rigid reference-
body (co-ordinate system); they regard all events in reference to the
train. Then every event which takes place along the line also takes
place at a particular point of the train. Also the definition of
simultaneity can be given relative to the train in exactly the same
way as with respect to the embankment. As a natural consequence,
however, the following question arises:
Are two events (e.g. the two strokes of lightning A and B) which are
simultaneous with reference to the railway embankment also
simultaneous relatively to the train? We shall show directly that the
answer must be in the negative.

V - * * ‡ * * * M' * * *‡ * */ Train
----==========================---------
* * * * *A * * * M * * * B * * *Embankment

When we say that the lightning strokes A and B are simultaneous with
respect to the embankment, we mean: the rays of light emitted at the
places A and B, where the lightning occurs, meet each other at the mid-
point M of the length A -- B of the embankment.

Right that's because Einstein stipulated that M is at equal distance
from the strikes and that the speed of light is isotropic in the track
frame. These stipulations automatically specfied that the strikes were
simultaneous to begin with. Otherewise the track observer will not be
able to sees the strikes to be simultaneous.

But the events A and B
also correspond to positions A and B on the train. Let M' be the mid-
point of the distance A -- B on the travelling train. Just when the
flashes of lightning occur, this point M' naturally coincides with the
point M, but it moves towards the right in the diagram with the
velocity v of the train. If an observer sitting in the position M' in
the train did not possess this velocity, then he would remain
permanently at M, and the light rays emitted by the flashes of
lightning A and B would reach him simultaneously, i.e. they would meet
just where he is situated. Now in reality (considered with reference
to the railway embankment) he is hastening towards the beam of light
coming from B, whilst he is riding on ahead of the beam of light
coming from A. Hence the observer will see the beam of light emitted
from B earlier than he will see that emitted from A.

This point of view of the track observer by Einstein is wrong and
bogus.....it appears that Einstein didn't fully understand his own
theory and postulates. What he said above violates the isotropy of the
speed of light in the train and it violates the PoR. The track
observer must use the postulates to predict what the train observer
will see. According to SR the speed of light in the train is isotropic
and the laws of physics in the train is the same as in the track. From
these two postulates the track observer predicts what the train
observer will see as follows:
1/2 the length of the train = L
Therefore at the time of the strikes both M and M' are at equal
distance fron the strikes.
The light path length for the each light front to reach the M'
observer = gamma*L
The transit time for the light fronts to reach M'= gamma*l/c
Therefore the train observer will sees the strikes to be simultaneous
at time = gamma*L/c according to the track clock.

The track observer will see that he sees the strikes to be
simultaneous at time L/c according to the track clock.

What this means is that the strikes in the track frame occur
simultaneously at an earlier time of L/c and the strikes occur
simultaneously at a later time of (gamma*L/c) in the train.

This arguement preserve the isotropy of the speed of light and the PoR
in the train.

Observers who
take the railway train as their reference-body must therefore come to
the conclusion that the lightning flash B took place earlier than the
lightning flash A. We thus arrive at the important result:

This is a bogus conclusion. It violates the isotropy of the speed of
light in the train.

Ken Seto

Events which are simultaneous with reference to the embankment are not
simultaneous with respect to the train, and vice versa (relativity of
simultaneity). Every reference-body (co-ordinate system) has its own
particular time; unless we are told the reference-body to which the
statement of time refers, there is no meaning in a statement of the
time of an event.
Now before the advent of the theory of relativity it had always
tacitly been assumed in physics that the statement of time had an
absolute significance, i.e. that it is independent of the state of
motion of the body of reference. But we have just seen that this
assumption is incompatible with the most natural definition of
simultaneity; if we discard this assumption, then the conflict between
the law of the propagation of light in vacuo and the principle of
relativity (developed in Section VII) disappears.
We were led to that conflict by the considerations of Section VI,
which are now no longer tenable. In that section we concluded that the
man in the carriage, who traverses the distance w per second relative
to the carriage, traverses the same distance also with respect to the
embankment in each second of time. But, according to the foregoing
considerations, the time required by a particular occurrence with
respect to the carriage must not be considered equal to the duration
of the same occurrence as judged from the embankment (as reference-
body). Hence it cannot be contended that the man in walking travels
the distance w relative to the railway line in a time which is equal
to one second as judged from the embankment.
Moreover, the considerations of Section VI are based on yet a second
assumption, which, in the light of a strict consideration, appears to
be arbitrary, although it was always tacitly made even before the
introduction of the theory of relativity."

Miguel Rios