Is the LT for time correct?
xray4abc
different IRFs, one must refer to the endpoints
of the object as locatable simultaneously.
In fact, it seems that, this can be done only in
one IRF at a time, i.e. in the frame where the
object is not moving.
For the moving frame we can not attach a
certain time value to the L' length , can we?
If not, then, this makes the Lorentz transformation
for time, in it known form, questionable, doesn't it?
;--))
Regards, LL
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:246b7283-4867-46c4...@b40g2000prf.googlegroups.com...
> When comparing the length of an object from 2
> different IRFs, one must refer to the endpoints
> of the object as locatable simultaneously.
> In fact, it seems that, this can be done only in
> one IRF at a time, i.e. in the frame where the
> object is not moving.
> For the moving frame we can not attach a
> certain time value to the L' length , can we?
We can send radar signals to the endpoints of the moving
object and arrange things in such a way that the reflection
events of the signals occor simultaneously. By timing the
signals and their echos we get the distances to these
endpoints. The difference between these distances is
the lenght of the moving object.
Operational procedure:
- Send signal1 at local time ts1 to endpoint1.
- Send signal2 at local time ts2 to endpoint2.
- Receive echo1 from signal1 at local time te1.
- Receive echo2 from signal2 at local time te2.
- Time of reflection event1 on eindpoint1 = 1/2 (te1+ts1).
- Time of reflection event2 on eindpoint2 = 1/2 (te2+ts2).
- Distance of reflection event1 on eindpoint1 = 1/2 (te1-ts1) c.
- Distance of reflection event2 on eindpoint2 = 1/2 (te2-ts2) c.
- If times are equal, i.o.w. if
1/2 (te1+ts1) = 1/2 (te2+ts2),
then length of moving object is given by
| 1/2 (te1-ts1) c - 1/2 (te2-ts2) c |
Note that this length measuring method also works for
non-moving objects. In that case we don't even need
to arrange the simultaneity of the reflection events.
A less practical, but still possible, way is by measuring
the length of a moving object by putting 'fixed' clocks
all along its path and having these clock mark the time
when the endpoints are passing. The difference between
any pair of such clocks that mark the same time, is the
lenght of the moving object,
> If not, then, this makes the Lorentz transformation
> for time, in it known form, questionable, doesn't it?
> ;--))
Indeed it would. But the transformation was of course
conceived with the above measuring methods in mind.
After all, this is physics, remember, not philosophy.
Dirk Vdm
Androcles
"xray4abc" <lemh...@yahoo.ca> wrote in message
news:246b7283-4867-46c4...@b40g2000prf.googlegroups.com...
Correct. Einstein's twisted brain is apparent when he says
"the velocity of light in our theory plays the part, physically,
of an infinitely great velocity."
That is, he assumes the endpoints of the object are locatable
simultaneously when it suits him and not when it doesn't.
Catch 22:
http://www.fourmilab.ch/etexts/einstein/specrel/www/figures/img22.gif
http://www.fourmilab.ch/etexts/einstein/specrel/www/figures/img76.gif
Heller wrote: "There was only one catch and that was Catch 22, which
specified that a concern for one's safety in the face of dangers that were
real and immediate was the process of a rational mind.
"Orr (a character in the novel) was crazy and could be grounded. All he had
to do was ask, and as soon as he did, he would no longer be crazy and would
have to fly more missions.
"Orr would be crazy to fly more missions and sane if he didn't, but if he
was sane he had to fly them. If he flew them he was crazy and didn't have
to; but if he didn't want to he was sane and had to."
In Einstein's case if you use c+v you can derive c = (c+v)/(1+v/c) from
the cuckoo malformations he blamed on Lorentz. That says you can't
use c+v.
What troll kooks like Schwartz, Poe, McCullough, Roberts, Draper, Lawrence,
Andersen, Nieminen, ewill, Olson, Tom & Jeery et. al. fail to realise is
the existence of isomorphism
http://en.wikipedia.org/wiki/Isomorphism
between Sagnac's real experiment and Einstein's hallucination experiment,
shown here:
http://www.androcles01.pwp.blueyonder.co.uk/TwoSpeedRack.gif
Einstein sends light along the rack and back again, the rack
moving at velocity v in his pipe dream.
Sagnac sends the light around the gear wheel for real.
If you analyse one you should get the same result as the other, but
you cannot use SR to derive SR, that is petitio principii, circularity.
http://en.wikipedia.org/wiki/Begging_the_question
c+v is essential to the derivation of the cuckoo malformations, the
part where Einstein screws up is:
'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' because I SAY SO. -- Rabbi Albert Einstein
http://www.androcles01.pwp.blueyonder.co.uk/Smart/tAB=tBA.gif
Here are some mathematical proofs:
http://en.wikipedia.org/wiki/Mathematical_proof
Not included are
Proof by "because I say so",
Proof by "everybody knows",
Proof by "it is written",
the three most popular forms used in sci.physics.relativity.
You'll often see this pathetic mob muttering "Lorentz Transformations"
but they haven't a clue how they are derived and faithfully follow their
indoctrination like lemmings.
Catch 22:
http://www.fourmilab.ch/etexts/einstein/specrel/www/figures/img22.gif
http://www.fourmilab.ch/etexts/einstein/specrel/www/figures/img76.gif
Prediction:
The troll kooks will ignore it, they are too stooopid to understand a
proof.
RULES OF REASONING IN PHILOSOPHY.
RULE I.
We are to admit no more causes of natural things than such as are both true
and sufficient to explain their appearances.
To this purpose the philosophers say that Nature does nothing in vain,
and more is in vain when less will serve; for Nature is pleased with
simplicity,
and affects not the pomp of superfluous causes.
-- Sir Isaac Newton
Sue...
> When comparing the length of an object from 2
> different IRFs, one must refer to the endpoints
> of the object as locatable simultaneously.
> In fact, it seems that, this can be done only in
> one IRF at a time, i.e. in the frame where the
> object is not moving.
> For the moving frame we can not attach a
> certain time value to the L' length , can we?
> If not, then, this makes the Lorentz transformation
The problem is not insurmountable:
<<..the instantaneous Coulomb potential associated with
the charge density, which appears at first glance to
violate causality, since motions of electric charge appear
everywhere instantaneously as changes to the Coulomb
potential. This is generally explained by pointing out
that the scalar and vector potentials themselves do not
affect the motions of charges, only the combinations
of their derivatives that form the electromagnetic
field strength. Although one can compute the field
strengths explicitly in Coulomb gauge and demonstrate
that changes in them propagate at the speed of light,
it is much simpler to observe that the field strengths
are unchanged under gauge transformations and to
demonstrate causality in the manifestly covariant
Lorenz gauge described below. >>
http://en.wikipedia.org/wiki/Gauge_fixing
So the contraction moves in spacetime.
<< a general Lorentz transformation preserves the
volume of space-time. Since time is dilated by a
factor gamma in a moving frame, the volume of space-time
can only be preserved if the volume of ordinary 3-space
is reduced by the same factor. As is well-known, this
is achieved by length contraction along the direction
of motion by a factor gamma. >>
http://farside.ph.utexas.edu/teaching/em/lectures/node114.html
Remembering...
<< space-time cannot be regarded as a straightforward
generalization of Euclidian 3-space to four dimensions,
with time as the fourth dimension. The distribution of
signs in the metric ensures that the time coordinate
is not on the same footing as the three space coordinates.
Thus, space-time has a non-isotropic nature which is
quite unlike Euclidian space, with its positive
definite metric. According to the relativity principle,
all physical laws are expressible as interrelationships
between 4-tensors in space-time. >>
http://farside.ph.utexas.edu/teaching/em/lectures/node113.html
Sue...
> ;--))
>
> Regards, LL
xray4abc
SperM.hotmail.com> wrote:
> "xray4abc" <lemhen...@yahoo.ca> wrote in messagenews:246b7283-4867-46c4...@b40g2000prf.googlegroups.com...
IF !
How, as a matter of principle, can one make this
happen when measuring an unknown length object?
>
> Note that this length measuring method also works for
> non-moving objects. In that case we don't even need
> to arrange the simultaneity of the reflection events.
>
> A less practical, but still possible, way is by measuring
> the length of a moving object by putting 'fixed' clocks
> all along its path and having these clock mark the time
> when the endpoints are passing. The difference between
> any pair of such clocks that mark the same time, is the
> lenght of the moving object,
>
> > If not, then, this makes the Lorentz transformation
> > for time, in it known form, questionable, doesn't it?
> > ;--))
>
> Indeed it would. But the transformation was of course
> conceived with the above measuring methods in mind.
> After all, this is physics, remember, not philosophy.
>
> Dirk Vdm
Regards, LL
Dono
SperM.hotmail.com> wrote:
> "xray4abc" <lemhen...@yahoo.ca> wrote in messagenews:246b7283-4867-46c4...@b40g2000prf.googlegroups.com...
>
> Dirk Vdm
Dirk,
This is excellent.
I would rephrase the above a little:
>- Send signal1 at local time ts1 to endpoint1.
> - Send signal2 at local time ts2 to endpoint2.
> - Receive echo1 from signal1 at local time te1.
> - Receive echo2 from signal2 at local time te2.
> - Distance of reflection event1 on eindpoint1 = 1/2 (te1-ts1) c.
> - Distance of reflection event2 on eindpoint2 = 1/2 (te2-ts2) c.
> then length of moving object is given by
> | 1/2 (te1-ts1) c - 1/2 (te2-ts2) c |
if the endpoints of the object are marked simultaneously in the
observer frame, i.e. if the echoes are received simultaneously:
te1=te2
This can be accomplished by adjusting ts2 while keeping ts1 fixed
until the echoes arrive simultaneously.
Dono
>
> IF !
> How, as a matter of principle, can one make this
> happen when measuring an unknown length object?
this is exactly what he showed you, doofus.
xray4abc
>
> - Show quoted text -
Thanks for taking the time to answer.
I prefer a simpler approach, one similar
to Dirk's, to the issue.
It is about locating simultaneously 2 points
in 2 IRFs, like in the case of Einstein's train.
Compare the length of the train at a certain
time in IRF S with the same-train length in IRF S'.
Real train length can vary a bit during its movement.
So we need to refer to the length at a given moment.
Can be that moment expressed by a time value t in S
and a corresponding time value t' in IRF S' ?
I do not care about the length itself here.
I just want to make sure that it is possible,
as a matter of principle, to locate simultaneously
the very same endpoints in the 2 IRFs.
Regards, LL
Dirk Van de moortel
"Dono" <sa...@comcast.net> wrote in message news:506d5218-b2d9-4332...@a35g2000prf.googlegroups.com...
Surely not :-)
The (local!) echo reflection events are simultaneous if
te1 = te2,
but the (remote!) reflection events are simultaneous if
1/2 (te1+ts1) = 1/2 (te2+ts2),
or equivalently, if
te1+ts1 = te2+ts2.
In order to be sure that we measure the distances to the
(remote!) endpoints simultaneously, we need simultaneous
events taking place *on* the remote endpoints, not on
our local clock.
>
> This can be accomplished by adjusting ts2 while keeping ts1 fixed
> until the echoes arrive simultaneously.
But that does not guarantee the simultaneity of the reflection
events. Draw a spacetime diagram and you'll see :-)
Dirk Vdm
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:98940823-ac93-45c6...@j20g2000hsi.googlegroups.com...
Ah yes, of course. Otherwise you don't measure the length.
It would be a bit daft to measure the distance to the front
of a train now, and the distance to the back 15 minutes later.
> How, as a matter of principle, can one make this
> happen when measuring an unknown length object?
For instance by continuously sending signals and coding
them. When the echo1s and echo2s start arriving, decode,
calculate and use the onse that satisfy the condition.
Dirk Vdm
Dono
SperM.hotmail.com> wrote:
> "Dono" <sa...@comcast.net> wrote in messagenews:506d5218-b2d9-4332...@a35g2000prf.googlegroups.com...
Hmm, so you want to mark both ends simultaneously in the moving object
frame, not in the frame where you are doing the measurement?
Dono
SperM.hotmail.com> wrote:
> "Dono" <sa...@comcast.net> wrote in messagenews:506d5218-b2d9-4332...@a35g2000prf.googlegroups.com...
I am having some trouble with your condition, I am not quite sure how
making the AVERAGE roundtrip times coincide GUARANTEES the
simultaneity of the reflections from the two ends of the object in the
object frame. Can you explain, I am really interested in this problem.
Dirk Van de moortel
"Dono" <sa...@comcast.net> wrote in message news:2e4ff325-3a40-4f49...@e6g2000prf.googlegroups.com...
No, all times ts1, ts2, te1, te2 are locally measured on my clock.
I send signals and I get echoes.
The calculated quantities 1/2 (te1+ts1) and 1/2 (te2+ts2) are by
definition (!) the times that I attribute in my coordinate system to
the remote reflection events, so these times must be equal in order
for the defined (!) distances 1/2 (te1-ts1) c and 1/2 (te2-ts2) c
to be simultaneous (according to me) events on the remote object.
We don't use remote clocks; nothing is measured by the remote
object; we don't even need to mention a "moving object frame".
Dirk Vdm
Dirk Van de moortel
"Dono" <sa...@comcast.net> wrote in message news:2d8e46cb-8948-497e...@s19g2000prg.googlegroups.com...
Send a signal at ts.
Receive an echo at te.
The time of the reflection event is defined as 1/2 (te+ts).
The distance of the reflection event is defined as 1/2 (te-ts) c.
Dirk Vdm
Dono
SperM.hotmail.com> wrote:
> "Dono" <sa...@comcast.net> wrote in messagenews:2e4ff325-3a40-4f49...@e6g2000prf.googlegroups.com...
Dirk,
I understand that all times are local (as they were in my approach).
What I do not understand is how you tie the condition ts1+te1=ts2+te2
to the ASSUMPTION that it guarantees the simultaneity of reflections
off the measured object as seen in the object's frame. You want to
mark both ends in the object frame, I marked them in the observer
frame.
To me, the condition for marking the ends simultaneously in observer
frame (te1=te2) is very easy, how did you arrive to your condition of
simultaneity in object frame?
Dono
> The calculated quantities 1/2 (te1+ts1) and 1/2 (te2+ts2) are by
> definition (!) the times that I attribute in my coordinate system to
> the remote reflection events,
Why are you attributting the above expressions to the remote
reflection events? What entitles you to do that? This is the part I am
missing.
Josef Matz
"xray4abc" <lemh...@yahoo.ca> schrieb im Newsbeitrag
news:246b7283-4867-46c4...@b40g2000prf.googlegroups.com...
Clocks go different thats proove. The question is how, yes.
What is a proper inertial frame we can use on earth as a basis ?
And two clocks taking the same path in an inertial frame but in opposite
directions must show the same clock rate when they meet. SR says that both
are delayed with respect to the other what is not possible. Somewhere a
mistake in SR time dilation.
Since all that best proven things, would be interesting what
those guys made for assumptions for the inertial frame valid on earth.
Josef
Dono
SperM.hotmail.com> wrote:
> "Dono" <sa...@comcast.net> wrote in messagenews:2d8e46cb-8948-497e...@s19g2000prg.googlegroups.com...
> The distance of the reflection event is defined as 1/2 (te-ts) c.
>
This one is obvious
> The time of the reflection event is defined as 1/2 (te+ts).
This one isn't , this is why I am having trouble with it.
Dirk Van de moortel
"Dono" <sa...@comcast.net> wrote in message news:07371895-ae75-4079...@i12g2000prf.googlegroups.com...
There is no object frame.
*All* six time values are in my "observer frame".
Four values (for local events) are directly read on my clock.
Two values (for remote events) are calculated from these four.
Just draw a spacetime diagram, shoot a ray from your worldline
to a remote event, have it bounce back to your worldline, and
do some simple analytical geometry. You'll see the light :-)
Have you read Robert Geroch's 'General Relativity from A to B'?
If not - hurry!
If yes - read it again :-)
Dirk Vdm
Igor
Why would it make the LT questionable? Your issue is apparently with
time dilation, not the LT.
PD
Any frame is going to have clocks near the endpoints of the object
with which you can take position measurements simultaneously (in that
frame). The problem is that two frames will not agree on what's
simultaneous, and there's no way to resolve who is right. That is, if
you make simultaneous measurements in the frame in which the object is
at rest, those very same measurements will NOT be simultaneous in any
other reference frame (which is one way an observer in that frame will
argue that the measurement is not done right).
PD
xray4abc
See ?
(That was my question too! )
Regards, LL
xray4abc
That's right !
But then you have no basis in comparing the
length/distance between 2 points in 2 different IRFs,
do you?
Regards, LL
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:c94e0987-aa45-4cd1...@e6g2000prf.googlegroups.com...
And do you understand it now?
Send a radar signal to the moon at t = 10 s.
Receive the echo at t = 12 s.
Distance to the reflection event =
1/2 ( 12 s - 10 s) 300000 km/s =
300000 km
Time of the reflection event =
1/2 ( 12 s + 10 s ) =
11 s
Dirk Vdm
Dono
SperM.hotmail.com> wrote:
> "Dono" <sa...@comcast.net> wrote in messagenews:07371895-ae75-4079...@i12g2000prf.googlegroups.com...
Yes, I know.
> Two values (for remote events) are calculated from these four.
> Just draw a spacetime diagram, shoot a ray from your worldline
> to a remote event, have it bounce back to your worldline, and
> do some simple analytical geometry. You'll see the light :-)
>
Well, I don't "see the light". I think that you are missing the point,
what allows you to surmise that the reflection occured at 1/2(te+ts).
This is obvious for the case when the object that is being radar-
ranged is at rest wrt observer but it is not that obvious when it is
in motion.
> Have you read Robert Geroch's 'General Relativity from A to B'?
> If not - hurry!
> If yes - read it again :-)
Yes, I read it.
>
> Dirk Vdm
PD
Length is defined by a procedure. The procedure is that you measure
the locations of the ends of an object, and you do that simultaneously
according to clocks in your own frame of reference. Those clocks in
*your* frame determine what is simultaneous for you. This does not
guarantee that observers at rest in other frames will agree that your
positions were recorded simultaneously. But they will agree with the
procedure. Of course, if another observer follows the very same
procedure (agreed upon) and measures the locations of the ends of the
object simultaneously, according to clocks in his own frame of
reference, then you won't agree that the measurements have been done
simultaneously either.
The fact that no two relatively moving observers will ever agree on
the simultaneity of two events, is the foundation of the relativity of
length. And to compound this:
a) There is no way to resolve whether one of these observers is
correct and the others incorrect about the simultaneity of two events.
b) There is no way to define a different procedure such that two
relatively moving observers will agree on the simultaneity of two
events.
Most attempts to get around SR have stemmed from trying to find a way
around (1) or (2) above. None are successful and/or lead to
predictions that are in direct conflict with experimental evidence.
PD
xray4abc
The LT used formally for 2 points, we can have the
same time value associated with the 2 points in
ONE of the IRFs/coordinate systems but NOT in the
second one.
The LT for time gives a different value of time
for each of the considered end-points.
Then, in the second coordinate system we can not
calculate the distance of the points for a
certain time value, can we?
But, we may compare the distance of the points
in the 2 IRFs only if the distances/lengths
are defined as instantaneous quantities,
that is, L is the length in S at moment T,
and L' is the length in S' in moment T'.
Applying LT for time does not give a unique value
T', but 2 different values.
Right now this is the only aspect of SRT
for which I am interested to get an answer :
Where is the error, if any, in the above
judgement?
Regards, LL
xray4abc
>
> - Show quoted text -
I agree with you!
Yet, a question arises : What lengths are we talking about?
Length can be a variable quantity in any IRF.
So, we must refer to the length at a given moment of time.
Let say, in IRF S at moment T the distance between 2 points
of a deformable object is L.
Now what about the distance L' of the same points in IRF S'
compared to L ?
( It does not matter at this point if L' is the measured
quantity in S' or the quantity (as *seen*) attributed
by the observer from S TO S'. Dirk seems to use this
second meaning. )
For a better understanding of my point here
see the answer I gave to Igor (post 27).
Regards, LL
xray4abc
SperM.hotmail.com> wrote:
> "xray4abc" <lemhen...@yahoo.ca> wrote in messagenews:c94e0987-aa45-4cd1...@e6g2000prf.googlegroups.com...
I think, I understand.
You described a method which by definition locates
simultaneously the endpoints of a moving rigid object.
This happens when the calculated reflection times
coincide.
So you got a method to have the locating events
(which are the reflections) simultaneous in one
of the reference frames.
Still, these events might not be simultaneous in
a frame in which the object is at rest.
Actually, acording to the LT they are not simultaneous
in the latter frame.
My question was: What would be the time value,
associated with the length in the OTHER frame ?
You have described how to get ONE set of time and length.
What can you tell me about the OTHER set?
(After all, the question is about how to apply the
LT when it comes to lengths.If they can not be applied,
then something is, probably, wrong with them.
That's why the title of this thread.)
Regards, LL
xray4abc
> "xray4abc" <lemhen...@yahoo.ca> schrieb im Newsbeitragnews:246b7283-4867-46c4...@b40g2000prf.googlegroups.com...
Sorry, Josef, you misunderstood my question.
Regards, LL
Dirk Van de moortel
"Dono" <sa...@comcast.net> wrote in message news:d077e41a-abd5-4f68...@s36g2000prg.googlegroups.com...
> On Dec 1, 9:46 am, "Dirk Van de moortel" <dirkvandemoor...@ThankS-NO-
> SperM.hotmail.com> wrote:
>> "Dono" <sa...@comcast.net> wrote in messagenews:07371895-ae75-4079...@i12g2000prf.googlegroups.com...
>> > On Dec 1, 9:26 am, "Dirk Van de moortel" <dirkvandemoor...@ThankS-NO-
>> > SperM.hotmail.com> wrote:
>> >> "Dono" <sa...@comcast.net> wrote in messagenews:2e4ff325-3a40-4f49...@e6g2000prf.googlegroups.com...
[snip]
>> > I understand that all times are local (as they were in my approach).
>> > What I do not understand is how you tie the condition ts1+te1=ts2+te2
>> > to the ASSUMPTION that it guarantees the simultaneity of reflections
>> > off the measured object as seen in the object's frame. You want to
>> > mark both ends in the object frame, I marked them in the observer
>> > frame.
>> > To me, the condition for marking the ends simultaneously in observer
>> > frame (te1=te2) is very easy, how did you arrive to your condition of
>> > simultaneity in object frame?
>>
>> There is no object frame.
>> *All* six time values are in my "observer frame".
>> Four values (for local events) are directly read on my clock.
>
> Yes, I know.
>
>> Two values (for remote events) are calculated from these four.
>> Just draw a spacetime diagram, shoot a ray from your worldline
>> to a remote event, have it bounce back to your worldline, and
>> do some simple analytical geometry. You'll see the light :-)
>>
>
> Well, I don't "see the light". I think that you are missing the point,
> what allows you to surmise that the reflection occured at 1/2(te+ts).
What else could it be?
> This is obvious for the case when the object that is being radar-
> ranged is at rest wrt observer but it is not that obvious when it is
> in motion.
Ha, here you go :-)
A reflection *event* is not in motion. It is just a single event.
That it happens *on* an object in motion, can only affect
the wavelenght of the reflected light, not the speed of the
light. Nobody cares what the object did or does before or
after that single event. We're talking about the time coordinate
of one single event.
>
>> Have you read Robert Geroch's 'General Relativity from A to B'?
>> If not - hurry!
>> If yes - read it again :-)
>
> Yes, I read it.
Ok, then review the part where he defines the interval
pages 81 and 82. Take fig. 38.
He's going to define the interval between events p and q.
He send a signal at event r and gets the echo at event s.
Then he defines
t1 as the elapsed time from p to s: t1 = T(s) - T(p)
t2 as the elapsed time from r to p: t2 = T(p) - T(r)
when T(x) is the clock reading at local event x.
With these definitions we can translate to my notation above.
We have
T(p) = 0 being the zero event of my clock,
ts = -T(r) being my clock reading when I send the signal,
te = T(s) being my clock reading when I get the echo.
so we have
t1 = te
t2 = -ts
(Also look at fig 42 (A) page 88, where event p is 'under'
and therefore 'before' r and s, but t2 < 0, and so ts > 0 so
this works out)
Now, jump to page 96 where he defines "the apparent
spatial distance" and the "apparent elapsed time" between
the events p and r:
Dx = c/2 ( t1 + t2 )
Dt = 1/2 ( t1 - t2 )
(but note that there is little typo, at least in my edition):
Finally, translating to my notation, since the event p is
my coordinate origin with x = 0 and t = 0:
x = c/2 ( te - ts )
t = 1/2 ( te + ts )
and there you go :-)
Dirk Vdm
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:39208e1c-dbfc-48b9...@s19g2000prg.googlegroups.com...
Indeed, and therefor the measured depends depens
on the frame. That is the whole idea.
> Actually, acording to the LT they are not simultaneous
> in the latter frame.
> My question was: What would be the time value,
> associated with the length in the OTHER frame ?
What would be the time of what?
> You have described how to get ONE set of time and length.
> What can you tell me about the OTHER set?
> (After all, the question is about how to apply the
> LT when it comes to lengths.
The LT says
Dx' = g ( Dx - v Dt ).
If you want to measure the lenght, make sure that you measure
the distances at the same time, in other words, make sure that
Dt = 0,
With this choise we are using the coordinates x and t to measure
places and times of events. Someone riding with the object uses
coordinates x' and t' to mark events.
So we would measure Dx for the length of the object, and a
person riding with the object would measure Dx' for that lenght.
So with
{ Dx' = g ( Dx - v Dt )
{ Dt = 0
you have
Dx = 1/g Dx'
which means that we measure the object to be shorter than
someone riding with the object measures it.
Dirk Vdm
PD
There's a bit of a language issue I want to be rigorous about, and
you'll see why in a moment. Let's say, in IRF S at moment T, the
distance between two *events* -- one corresponding to one point of a
deformable object at time T, the other corresponding to another point
of a deformable object at time T -- is L.
> Now what about the distance L' of the same points in IRF S'
> compared to L ?
This observer would come up with the same value of L, but he would not
consider it to be appropriately called the length of the object,
because those two *events* would now occur at different times, T and
T'. Now, you know perfectly well that measuring the location of the
back of a flying javelin at one time T and measuring the location of
the front of the javelin at another time T' would not correspond to
the javelin's length.
If the observer in IRF S' wanted to measure the length between two
points of the object, he'd want to do it at the same moment T'. If he
did that, he'd come up with a length L' that is different than L.
Of course, the observer in IRF S would not agree that this measurement
was done at the same moment T', but rather at two different moments T'
and T", and so should not be considered a length.
Note: If they both follow the *same* procedure, they get different
results. Of course, by following the *same* procedure, they'd use
different pairs of events to correspond to the length, and there's no
way to determine which pair of events is the correct one.
Dono
OK, thank you for the explanation. Not that obvious.
Sue...
<< if the amplitude and phase of the signal returning from a
given piece of ground are recorded, and if the aircraft emits
a series of pulses as it travels, then the results from these
pulses can be combined. Effectively, the series of observations
can be combined just as if they had all been made simultaneously
from a very large antenna; this process creates a synthetic
aperture much larger than the length of the antenna (and
in fact much longer than the aircraft itself). >>
http://en.wikipedia.org/wiki/Synthetic_aperture_radar
Sue...
Dirk Van de moortel
"Dono" <sa...@comcast.net> wrote in message news:4e24f1e2-06cc-4622...@s8g2000prg.googlegroups.com...
> On Dec 2, 3:53 am, "Dirk Van de moortel"
>>
>> Ok, then review the part where he defines the interval
>> pages 81 and 82. Take fig. 38.
>> He's going to define the interval between events p and q.
>> He send a signal at event r and gets the echo at event s.
>> Then he defines
>> t1 as the elapsed time from p to s: t1 = T(s) - T(p)
>> t2 as the elapsed time from r to p: t2 = T(p) - T(r)
>> when T(x) is the clock reading at local event x.
>>
>> With these definitions we can translate to my notation above.
>> We have
>> T(p) = 0 being the zero event of my clock,
>> ts = -T(r) being my clock reading when I send the signal,
Oops, typo. remove the minus-sign:
ts = T(r) being my clock reading when I send the signal
>> te = T(s) being my clock reading when I get the echo.
>> so we have
>> t1 = te
>> t2 = -ts
>> (Also look at fig 42 (A) page 88, where event p is 'under'
>> and therefore 'before' r and s, but t2 < 0, and so ts > 0 so
>> this works out)
>>
>> Now, jump to page 96 where he defines "the apparent
>> spatial distance" and the "apparent elapsed time" between
>> the events p and r:
>> Dx = c/2 ( t1 + t2 )
>> Dt = 1/2 ( t1 - t2 )
>> (but note that there is little typo, at least in my edition):
>>
>> Finally, translating to my notation, since the event p is
>> my coordinate origin with x = 0 and t = 0:
>> x = c/2 ( te - ts )
>> t = 1/2 ( te + ts )
>> and there you go :-)
>>
>> Dirk Vdm
>
> OK, thank you for the explanation. Not that obvious.
No problem.
The link between Geroch's notation and mine is indeed
not that obvious.
But I do think that the definitions
t = 1/2 ( te + ts )
x = 1/2 ( te - ts ) c
are pretty straightforward per se, *provided* one lets go
of the erroneous notion of the "moving event". I think that
was the culprit :-)
Dirk Vdm
Dirk Van de moortel
"Dirk Van de moortel" <dirkvand...@ThankS-NO-SperM.hotmail.com> wrote in message
news:l1x4j.235623$HA5.12...@phobos.telenet-ops.be...
Typo. The minus-sign shoulb be removed:
ts = T(r) being my clock reading when I send the signal
Igor
But that has absolutely nothing to do with the LT itself. You claimed
it did. It's an issue involving measurement after the LT has been
applied. Time dilation is a consequence of the LT, but additional
assumptions must be made that have nothing to do with the LT. That's
what I trying to point out.
xray4abc
SperM.hotmail.com> wrote:
> "xray4abc" <lemhen...@yahoo.ca> wrote in messagenews:39208e1c-dbfc-48b9...@s19g2000prg.googlegroups.com...
OK.
I am interested in learning about t', associated
with the same events happening at the endpoints of the
object already discussed as having associated
a t=(te1 + ts1)/2 value to them.
My current understanding is that there is not
a unique value t', as simultaneous events from one IRF
do not have corresponding simultaneous events in other IRF.
At least this is what results from a formal application
of LT.
> So we would measure Dx for the length of the object, and a
> person riding with the object would measure Dx' for that lenght.
> So with
> { Dx' = g ( Dx - v Dt )
> { Dt = 0
> you have
> Dx = 1/g Dx'
> which means that we measure the object to be shorter than
> someone riding with the object measures it.
>
> Dirk Vdm- Hide quoted text -
>
> - Show quoted text -
Regards, LL
xray4abc
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
And, if things are changing in the meantime..? :-)
Regards, LL
mL
>> When comparing the length of an object from 2
>> different IRFs, one must refer to the endpoints
>> of the object as locatable simultaneously.
>> In fact, it seems that, this can be done only in
>> one IRF at a time, i.e. in the frame where the
>> object is not moving.
>> For the moving frame we can not attach a
>> certain time value to the L' length , can we?
>
> object and arrange things in such a way that the reflection
> events of the signals occor simultaneously. By timing the
> signals and their echos we get the distances to these
> endpoints. The difference between these distances is
> the lenght of the moving object.
>
> Operational procedure:
> - Send signal1 at local time ts1 to endpoint1.
> - Send signal2 at local time ts2 to endpoint2.
> - Receive echo1 from signal1 at local time te1.
> - Receive echo2 from signal2 at local time te2.
> - Time of reflection event1 on eindpoint1 = 1/2 (te1+ts1).
> - Time of reflection event2 on eindpoint2 = 1/2 (te2+ts2).
> - Distance of reflection event1 on eindpoint1 = 1/2 (te1-ts1) c.
> - Distance of reflection event2 on eindpoint2 = 1/2 (te2-ts2) c.
> - If times are equal, i.o.w. if
> 1/2 (te1+ts1) = 1/2 (te2+ts2),
> then length of moving object is given by
> | 1/2 (te1-ts1) c - 1/2 (te2-ts2) c |
>
> non-moving objects. In that case we don't even need
> to arrange the simultaneity of the reflection events.
>
> A less practical, but still possible, way is by measuring
> the length of a moving object by putting 'fixed' clocks
> all along its path and having these clock mark the time
> when the endpoints are passing. The difference between
> any pair of such clocks that mark the same time, is the
> lenght of the moving object,
>
>> If not, then, this makes the Lorentz transformation
>> for time, in it known form, questionable, doesn't it?
>> ;--))
>
> conceived with the above measuring methods in mind.
> After all, this is physics, remember, not philosophy.
>
> Dirk Vdm
another approach ..
If the velocity v of a moving rod is known,
simply use a stopwatch to measure the time T
it takes for the rod to pass a chosen point O.
Then,
length of moving rod = v*T
In the general case, you must, of course, provide
a method to measure v (using light signals for
example).
/mel
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:1dddd183-c746-468b...@f3g2000hsg.googlegroups.com...
Indeed, these two measurements are not simultaneous
in the frame in which the object is at rest, but does
not matter, since the object is going nowhere to begin
with, so you can safely take the difference of the distances
to the endpoints to calculate the 'real' aka 'proper' lenght of it.
See below for an additional remark...
>
>> So we would measure Dx for the length of the object, and a
>> person riding with the object would measure Dx' for that lenght.
>> So with
>> { Dx' = g ( Dx - v Dt )
>> { Dt = 0
>> you have
>> Dx = 1/g Dx'
>> which means that we measure the object to be shorter than
>> someone riding with the object measures it.
Using the other part of the LT
Dt' = g ( Dt - v/c^2 Dx ),
you see that this Dt' is indeed not zero, but it doesn't have to
be zero, since the object is at rest in that frame.
Dirk Vdm
Dirk Van de moortel
"mL" <mL.b...@elsewhere.xxx> wrote in message news:TRC4j.1205$R_4...@newsb.telia.net...
Of course, and with the radar method that again would
require 2 measurments.
Dirk Vdm
xray4abc
SperM.hotmail.com> wrote:
> "xray4abc" <lemhen...@yahoo.ca> wrote in messagenews:1dddd183-c746-468b...@f3g2000hsg.googlegroups.com...
>
> - Show quoted text -
The object is at rest, but its length could vary, in a
finite time interval, due to some physical process (unimportant here).
So the requirement of simultaneity is not a negligible one.
I am not asking the impossible, that is simultaneity in 2 different
IRFs, as it appears.
Yet, you have a length L and a time T in one frame, and a time T'
and and length L' in the other frame associated with the same
endpoints
of an object which could be have after all variable dimensions in
time.
It is very clear, from what you have showed several times, how you
get
measured L and T.
Now, how you get the other set ( L', T') ?
In fact you showed what would be the relation between the lengths.
I just need the same thing be done for the time values : T and T' !
Of course, if there is any . If not, then I want to have clearly
stated
that there is not such a relation, to avoid further sterile
discussions.
I hope you do not mind for bugging you on the issue !
These things , kind of, got lost in the physics literature, and you
seem to be well informed and liking the subject. :-)
Best regards, LL
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:280a57fe-d766-4953...@j20g2000hsi.googlegroups.com...
It is irrelevant, as long as we were talking about an object with a
fixed length. If you have a varying object in mind it is up to you to
to specify the way in which the object is varying and to define
your concept of "length".
> I am not asking the impossible, that is simultaneity in 2 different
> IRFs, as it appears.
> Yet, you have a length L and a time T in one frame, and a time T'
> and and length L' in the other frame associated with the same
> endpoints
> of an object which could be have after all variable dimensions in
> time.
> It is very clear, from what you have showed several times, how you
> get
> measured L and T.
> Now, how you get the other set ( L', T') ?
Do I really have to write the equations? Again?
Ok, here you go:
L' = g ( L - v T )
T' = g ( T - v/c^2 L )
> In fact you showed what would be the relation between the lengths.
> I just need the same thing be done for the time values : T and T' !
Can't you do the algebra???
Use the equations. Keeping the same situation as before,
the object is at rest in the primed (x',t')-system and has proper
lenght L'. It is measured using two simultaneous events
according to the unprimed (x,t)-system, so T = 0.
So you have
L' = g L
T' = - g v/c^2 L
and therefore
L' = g L
meaning that the proper length L' is longer than the length
L which is measured in the unprimed (x,t)-system in which the
object is moving, and
T' = - v/c^2 L'
meaning that the two reflection events (caused by the light
signals of the unprimed (x,t)-system) are not sumultaneous
in the primed (x',t')-system.
> Of course, if there is any . If not, then I want to have clearly
> stated
> that there is not such a relation, to avoid further sterile
> discussions.
> I hope you do not mind for bugging you on the issue !
> These things , kind of, got lost in the physics literature, and you
> seem to be well informed and liking the subject. :-)
Frankly, the thing that seems to be lost, is your failure to
understand the physical meanings of the variables in the
equations.
> Best regards, LL
I hope that all this helps a bit - but I remain pessimistic.
Keep in mind that the physics literature was created by
and for physicists - not for laymen. You can't just dive
into an advanced topic of physics if you really weren't
properly introduced to the basics of physics to begin
with, at least not without risking to get hurt in the process.
Dirk Vdm
xray4abc
SperM.hotmail.com> wrote:
> "xray4abc" <lemhen...@yahoo.ca> wrote in messagenews:280a57fe-d766-4953...@j20g2000hsi.googlegroups.com...
One thing is sure for me! SRT is not a finished
theory! This is shown by the difficulty in understanding
it, among other things. Some people THINK they do
understand SRT, and pose like that, taking advantage
of other's honesty in admitting not understanding at
all or not fully.
I admit not understanding it fully, because,
I say, it can not be understood after all.
(I am not talking about the math of SRT or
General Relativity. That is OK.)
I consider LT for time as the weakest point
of SRT. I got my own ideas about it.
I just needed the things stated by someone who is
on the official line of interpreting SRT and is
a knowledgeable person.
I can do the math, be sure, and even more than that.
I have studied thoroughly SRT, with some
I would say, interesting results.
I will present my results on the internet,
in the near future, and you will be one of the invitees
to "proofread" it.
Regards, lL
PD
>
> That was not nice, Dirk !
> One thing is sure for me! SRT is not a finished
> theory! This is shown by the difficulty in understanding
> it, among other things. Some people THINK they do
> understand SRT, and pose like that, taking advantage
> of other's honesty in admitting not understanding at
> all or not fully.
> I admit not understanding it fully, because,
> I say, it can not be understood after all.
> (I am not talking about the math of SRT or
> General Relativity. That is OK.)
The above speaks volumes. It is the cry of the frustrated aspirant.
When a novice finds that they cannot understand special relativity,
then they rationalize by saying there's something wrong with it, that
it can't be understood. Then they further complain that if the novice
cannot be illumined on a newsgroup, then the others on the newsgroup
must be fooling themselves when they say they understand it.
Otherwise, the novice complains, he would have understood it by now.
> I consider LT for time as the weakest point
> of SRT. I got my own ideas about it.
> I just needed the things stated by someone who is
> on the official line of interpreting SRT and is
> a knowledgeable person.
> I can do the math, be sure, and even more than that.
> I have studied thoroughly SRT, with some
> I would say, interesting results.
> I will present my results on the internet,
> in the near future, and you will be one of the invitees
> to "proofread" it.
>
> Regards, lL- Hide quoted text -
Sue...
> On Dec 3, 10:02 pm, xray4abc <lemhen...@yahoo.ca> wrote:
>
>
>
> > That was not nice, Dirk !
> > One thing is sure for me! SRT is not a finished
> > theory! This is shown by the difficulty in understanding
> > it, among other things. Some people THINK they do
> > understand SRT, and pose like that, taking advantage
> > of other's honesty in admitting not understanding at
> > all or not fully.
> > I admit not understanding it fully, because,
> > I say, it can not be understood after all.
> > (I am not talking about the math of SRT or
> > General Relativity. That is OK.)
>
> The above speaks volumes. It is the cry of the frustrated aspirant.
> When a novice finds that they cannot understand special relativity,
> then they rationalize by saying there's something wrong with it, that
> it can't be understood. Then they further complain that if the novice
> cannot be illumined on a newsgroup, then the others on the newsgroup
> must be fooling themselves when they say they understand it.
> Otherwise, the novice complains, he would have understood it by now.
Half the graduate programs embrace one interprtation, Half the
other. Are graduate level professors of physics, "Novices" ?
On the Interpretation of the Redshift in a Static Gravitational Field
http://arxiv.org/abs/physics/9907017 --Okun
Sue...
PD
Read the paper you cite, where they insist that their point is a
*pedagogical* one (that is, what is the more effective way to *teach*
it?), not about what the underlying physical reality is.
>
>
>
>
> > > I consider LT for time as the weakest point
> > > of SRT. I got my own ideas about it.
> > > I just needed the things stated by someone who is
> > > on the official line of interpreting SRT and is
> > > a knowledgeable person.
> > > I can do the math, be sure, and even more than that.
> > > I have studied thoroughly SRT, with some
> > > I would say, interesting results.
> > > I will present my results on the internet,
> > > in the near future, and you will be one of the invitees
> > > to "proofread" it.
>
> > > Regards, lL-- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
xray4abc
>
> - Show quoted text -
Look!
And how would you qualify phenomena like
"time dilatation" "time contraction"
"Length contraction due to IRF change",
"length dilatation due to IRF change" ?
Do you consider them "physical reality"
or just simply different views of the same reality
as I do?
Time dilatation or contraction per se is a
non sense.
So, when someone comes with this kind of ideas, he/she
must bring something more than " as it could be seen
on the moving clock" or other childish things
like that.
When I will present my results on special relativity
you will see that, theoretically, there are 2
completely different ways of interpreting the LT.
(and this results going exactly on Einstein's steps,
and not from some crazy ideas of a "novice" or "aspirant" )
LL
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:8cb59d84-60b8-464e...@w34g2000hsg.googlegroups.com...
[snip]
>> I hope that all this helps a bit - but I remain pessimistic.
>> Keep in mind that the physics literature was created by
>> and for physicists - not for laymen. You can't just dive
>> into an advanced topic of physics if you really weren't
>> properly introduced to the basics of physics to begin
>> with, at least not without risking to get hurt in the process.
>>
>> Dirk Vdm
>>
> That was not nice, Dirk !
It was not my intention to be 'not nice', nor nice, but
sometimes some people really benefit from someone
kicking their bottom to make them realize something.
> One thing is sure for me! SRT is not a finished
> theory! This is shown by the difficulty in understanding
> it, among other things. Some people THINK they do
> understand SRT, and pose like that, taking advantage
> of other's honesty in admitting not understanding at
> all or not fully.
> I admit not understanding it fully, because,
> I say, it can not be understood after all.
Yes, my pessimism was ad rem.
O yes.
> (I am not talking about the math of SRT or
> General Relativity. That is OK.)
> I consider LT for time as the weakest point
> of SRT. I got my own ideas about it.
> I just needed the things stated by someone who is
> on the official line of interpreting SRT and is
> a knowledgeable person.
> I can do the math, be sure, and even more than that.
I surely hope so. Any 12 years old school kid can do the
math of SRT. It is the most trivial piece of math in the book.
That is precisely the reason - and arguably the only reason -
why there are so many crackpots (ranging from 13 years
old school kids to 80 years old retired engineers) around
who think that they *should* understand the theory.
Trust me, It Is Hopeless. This newsgroup is the living proof.
> I have studied thoroughly SRT, with some
> I would say, interesting results.
> I will present my results on the internet,
> in the near future, and you will be one of the invitees
> to "proofread" it.
I will repeat what I said yesterday, but I will cast it into
advice format:
I you want to run a marathon, learn how to crawl first.
If you don't want to get hurt, don't dive into an advanced
topic of physics unless you really are properly introduced
to the basics of physics.
>
> Regards, lL
Since nothing will help a bit, still pessimistic,
Dirk Vdm
PD
Yes indeed. But you and I have different views of what physical
reality entails. I gather that you believe that if an object is seen
to exhibit length contraction, then the reality of that contraction
would demand that something has happened to the object. I disagree.
There are lots of *physically real* quantities, like velocity and
kinetic energy and electric field and so on that depend on the frame
of reference, and in none of those cases does something physical
happen to the object.
If I'm riding on a plane, I can *measure* the kinetic energy of the
magazine in the seat-back in front of me to be zero, and that is a
real measurement. But to someone in a car on the road below me, the
magazine has a totally different kinetic energy. And there was not a
thing physical that happened to that magazine to effect that change.
> or just simply different views of the same reality
> as I do?
> Time dilatation or contraction per se is a
> non sense.
That's because you've attributed false assumptions that you think you
need in order for it to make sense. What you need to do is let go of
some assumptions and notice that it still makes sense -- in fact, it
makes better sense.
> So, when someone comes with this kind of ideas, he/she
> must bring something more than " as it could be seen
> on the moving clock" or other childish things
> like that.
> When I will present my results on special relativity
> you will see that, theoretically, there are 2
> completely different ways of interpreting the LT.
> (and this results going exactly on Einstein's steps,
> and not from some crazy ideas of a "novice" or "aspirant" )
> LL- Hide quoted text -
xray4abc
Honestly, I do no t expect you or anybody else to rally
to some new ideas.
As Max von Laue has said, new ideas need new people.
There were scientists who never accepted Quantum Mechanics
until they died, for example.
(So, some of us are off the list, just not having the necessary
mobility/elasticity of their mind)
New ideas can ( my opinion) win much faster if......
you can transform them in ....dollars( lots of them).
This can not be done, for now, with any improvements
of SRT.
I am not interested to make money from SRT, but I am
interested to solve the problem I can see here.
I can see information *distortion* due to a limited
speed of interaction transmission, retardation and
....things like that, instead of time or space
contraction. I am trying to approach SRT and
not only, with these ideas in my mind.
You, and many others, obviously do not see any
problem to solve regarding SRT.
That is OK. You can live with that and I can live
with that.
Though you showed yourself very knowledgeable
regarding the question I have asked on purpose,
you did not dare to give me a straight answer as
Dirk did. ( Regarding the time at which a length
in the moving frame should be considered).
You just circled around the issue, as .....you
felt that.....it is not that obvious, what
the answer should be !
Should I tell you that, this tells me volumes?
I could, but I am not interested.
Regards, LL
PD
Well, if you'll look, this is precisely what I was encouraging you to
do. The "new idea" that you seem to have problems with is that there
are physical variables that vary from frame to frame for the *same*
object, without any physical process being required to act on the
object. Because you cannot deal with that "new idea", you perceive
problems with SRT. Others who precede you have managed to grasp the
"new idea" you cannot, and then it is you who say that they cannot
rally to your new ideas.
PD
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:19e04864-72f7-4467...@i12g2000prf.googlegroups.com...
[snip]
> Honestly, I do no t expect you or anybody else to rally
> to some new ideas.
> As Max von Laue has said, new ideas need new people.
> There were scientists who never accepted Quantum Mechanics
> until they died, for example.
> (So, some of us are off the list, just not having the necessary
> mobility/elasticity of their mind)
> New ideas can ( my opinion) win much faster if......
> you can transform them in ....dollars( lots of them).
> This can not be done, for now, with any improvements
> of SRT.
> I am not interested to make money from SRT, but I am
> interested to solve the problem I can see here.
> I can see information *distortion* due to a limited
> speed of interaction transmission, retardation and
> ....things like that, instead of time or space
> contraction. I am trying to approach SRT and
> not only, with these ideas in my mind.
> You, and many others, obviously do not see any
> problem to solve regarding SRT.
The only problem *I* see regarding SRT, is how to
persuade a certain class of people who clearly are
not equipped to deal with it, to stay away from it as
far as they possibly can - just to prevent them from
getting sick with frustration.
> That is OK. You can live with that and I can live
> with that.
> Though you showed yourself very knowledgeable
> regarding the question I have asked on purpose,
> you did not dare to give me a straight answer as
> Dirk did. ( Regarding the time at which a length
> in the moving frame should be considered).
If you had payed attention you should realize that
I never said *anything* "regarding the time at which
a length in the moving frame should be considered".
Dirk Vdm
Dono
SperM.hotmail.com> wrote:
> "Dono" <sa...@comcast.net> wrote in messagenews:4e24f1e2-06cc-4622...@s8g2000prg.googlegroups.com...
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
Dirk,
I think that you may have misunderstood, I do not refer to a "moving
even", I referred to the fact that the reflection time of a moving
object is DIFFERENT from the one from a stationary object. So, I did
the calculations (I can send them to you) and the correct formula is
indeed:
t_reflection=((c+v)te+(c-v)ts)/2c
For v00 one recovers your formula.
Dirk Van de moortel
"Dono" <sa...@comcast.net> wrote in message news:b503f5ac-a46a-4297...@l16g2000hsf.googlegroups.com...
> object is DIFFERENT from the one from a stationary object.
But it is *not* different.
The only thing that could possibly be different, is the frequency of
the reflected light. The speed of the light is c, remember?
You said:
| ... what allows you to surmise that the reflection occured at 1/2(te+ts)?
| This is obvious for the case when the object that is being radar-
| ranged is at rest wrt observer but it is not that obvious when it is
| in motion.
It does not matter whether the light ray bounces on an approaching,
or still or receding mirror, the speed of the returning signal is c.
Just try to *forget* about the object. Concentrate on the light
signals and the reflection event.
Okay, time for a drawing :-)
Just have a look at
http://users.telenet.be/vdmoortel/dirk/Stuff/RemoteEventTime.png
On the left it is drawn with the axes perpendicular.
On the right we look at the same situation but from another 'moving
frame' so to speak.
Note that there is only one single clock here.
You see one reflection event for 3 kinds of mirrors.
- Signal is sent on local event with clock reading ts.
- Signal bounces at event R.
- Echo is received on local event with clock reading te.
- The local event halfway between the local ts and te events
takes place at local time t = 1/2 (te+ts)
- This local event is simultaneous with the remote event R
Verify that the line between these events is parallel to the
x-axis, so these events are simultaneous - i.o.w. the remote
vent R happens at t = 1/2 (te+ts).
This is elementary analytical geometry, you now...
See the light? :-)
Dirk Vdm
Dirk Van de moortel
If/when (and only if/when) you see it, here's the measurement
of the length of the moving object:
http://users.telenet.be/vdmoortel/dirk/Stuff/MovingObjectLength.png
Dirk Vdm
scratch
SperM.hotmail.com> wrote:
> "Dono" <sa...@comcast.net> wrote in messagenews:b503f5ac-a46a-4297...@l16g2000hsf.googlegroups.com...
than whay not puttin this moron in your fumbles
tha man is a naked proven moron,
he cant be your friend, again
xray4abc
SperM.hotmail.com> wrote:
> "xray4abc" <lemhen...@yahoo.ca> wrote in messagenews:19e04864-72f7-4467...@i12g2000prf.googlegroups.com...
And I see a mixture of legends and science, where
nobody seems to be able to tell you which is which.
>
> > That is OK. You can live with that and I can live
> > with that.
> > Though you showed yourself very knowledgeable
> > regarding the question I have asked on purpose,
> > you did not dare to give me a straight answer as
> > Dirk did. ( Regarding the time at which a length
> > in the moving frame should be considered).
>
> If you had payed attention you should realize that
> I never said *anything* "regarding the time at which
> a length in the moving frame should be considered".
You did not say it and did not deny it either.
You just placed there T' and said nothing (?):
"the object is at rest in the primed (x',t')-system.."
>
> Dirk Vdm
>
>
>
> > You just circled around the issue, as .....you
> > felt that.....it is not that obvious, what
> > the answer should be !
> > Should I tell you that, this tells me volumes?
> > I could, but I am not interested.
> > Regards, LL- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
Let's come back to your algebra!
You could do the algebra, but not much good
resulted from of it.
You have* already* associated the time (te1+ts1)/2 with
the endpoints of the moving object.
Then you came up with another time value T=o,
which is the time difference of locating the endpoints
in the IRF where the signals are emitted.
A similar difference T' you consider for the moving frame.
So to speak, you simply forgot everything you have said
and just simply went on to apply the formal LT to get T and T'.
In other words, you just spent some time and proved nothing.
We are back at square one now, at Einstein's train example.
When you say that the endpoints are not met
simultaneously in the object-frame does this mean,
by your opinion : 1. a reality of the frame where the
object is moving ?
2. a reality of the "object" frame ?.
...................
(My bet is nr 1, by the way. )
Regards, LL
xray4abc
I understand that idea.
Yet, a see it a bit more complicated.
The parameters are different from one frame to other,
because they reflect a different view of reality either.
On the other hand, when doing coordinate transformation
for example, actually what you get is NOT something that
correspondes to the view from the *other* IRF but
something else, which actually correspondes again
to *your* view.
That is why we talk about the twin-paradox etc.
Or a better example, I think, regarding LT :
X=1m and X'=1m COULD be the coordinates of the
same point in 2 IRFs, but to x'=1m corresponds
in the other frame X<>1m and to X=1m in the latter
corresponds X'<>1m.
Simply said, the x,x' pairs corresponding to a
*given* point CAN be different.
This, shows a change of parameters from one
coordinate system to the other which IS NOT
BIUNIVOCAL !
Now, excuse me, do I see the change of the value of physical
parameters, when changing the reference frame?
> > Regards, LL- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
Regards, LL
Dono
SperM.hotmail.com> wrote:
> "Dono" <sa...@comcast.net> wrote in messagenews:b503f5ac-a46a-4297...@l16g2000hsf.googlegroups.com...
Thank you, I will look at it.
My calculations show otherwise (and yes, I am uing constant c :-))
I think you might be missing the closing speed, I´ll email you the
complete set of calculations.
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:376c2e94-c3e0-4dd7...@w56g2000hsf.googlegroups.com...
Yes, since you have not idea what it is about, and since you
just don't seem to have what it takes, you are probably
doomed to continue seeng what you see.
I don't think there is way out for you.
>>
>> > That is OK. You can live with that and I can live
>> > with that.
>> > Though you showed yourself very knowledgeable
>> > regarding the question I have asked on purpose,
>> > you did not dare to give me a straight answer as
>> > Dirk did. ( Regarding the time at which a length
>> > in the moving frame should be considered).
>>
>> If you had payed attention you should realize that
>> I never said *anything* "regarding the time at which
>> a length in the moving frame should be considered".
>
> You did not say it and did not deny it either.
I also did not say or deny that the moon is made of green cheese.
> You just placed there T' and said nothing (?):
> "the object is at rest in the primed (x',t')-system.."
Before we can continue I want you to realize and clearly
express why your statement
| "... you did not dare to give me a straight answer as
| Dirk did. ( Regarding the time at which a length
| in the moving frame should be considered)."
is wrong.
Again, I did *not* give an answer "regarding the time at
which a length in the moving frame should be considered."
I gave an answer regarding something else.
Regarding what?
Dirk Vdm
Dirk Van de moortel
"Dono" <sa...@comcast.net> wrote in message news:33556838-baa1-403c...@j44g2000hsj.googlegroups.com...
Forget about closing speed.
Define events, attribute equations to worldlines and
light rays, and use analytic geometry:
- Signal is sent on local event with clock reading ts.
(t,x) = (ts,0)
- Outward light ray:
x - 0 = c ( t - ts )
- Mirror worldline:
x = v t + k (for some arbitrary v and k - you took k=0)
- Reflection event:
{ x - 0 = c ( t - ts )
{ x = v t + k
gives you some
(t,x) = (tR,xR) = ( (c ts + k)/(c-v) , c (v ts + k)/(c-v) )
- Reflected light ray:
x - xR = -c ( t - tR )
- Echo reception event:
{ x = 0
{ x - xR = -c ( t - tR )
gives you
(t,x) = ( tR + xR/c , 0 )
Since this event is also given by
(t,x) = ( te , 0 )
you get the condition:
te = tR + xR/c
Now eliminate k from the equations
{ tR = (c ts + k)/(c-v)
{ xR = c (v ts + k)/(c-v)
{ te = tR + xR/c
and you'll get
tR = 1/2 ( te + ts )
xR = 1/2 ( te - ts ) c
QED.
The proof should not be necessary.
Just look at the pictures.
Exercise: in stead of using
x = v t + k ,
use
x = f(t)
for an arbitrary locally invertible function f.
Dirk Vdm
Dono
SperM.hotmail.com> wrote:
> "Dono" <sa...@comcast.net> wrote in messagenews:33556838-baa1-403c...@j44g2000hsj.googlegroups.com...
You can´t "forget about closing speed", it comes up in the first
equation
Say that the mirror is a distantance x0 from the observer at ts.
Then, the light signal emmitted at ts reaches the mirror at
ct10x0?vt1 , so t1=x0/(c-v)
The reflected signal needs t2 to get back at the obsever:
ct2=x0+ct1=x0 c/(c-v)
Therefore t2=t1=x0/(c-v)
The reflection time tR satisfies the equations:
ts+t1=tR=te-t2
So, eliminating x0 from the above we obtain indeed tR=0.5(ts+te)
Dirk Van de moortel
"Dono" <sa...@comcast.net> wrote in message news:412f1057-ce49-4b53...@j20g2000hsi.googlegroups.com...
[snip - you are using a strange format. I don't get the quoting chars (">") ]
> You can´t "forget about closing speed", it comes up in the first
> equation
If you want to go that way to prove the result, yes of course,
but I prefer the geometric way.
I just suggested to forget it, since you obviously obtained the
wrong result with your
t_reflection=((c+v)te+(c-v)ts)/2c
You see, it just *cannot* possibly depend on v :-)
>
> Say that the mirror is a distantance x0 from the observer at ts.
> Then, the light signal emmitted at ts reaches the mirror at
>
> ct10x0?vt1 , so t1=x0/(c-v)
I can't read this. Strange posting format you are using :-(
>
> The reflected signal needs t2 to get back at the obsever:
>
> ct2=x0+ct1=x0 c/(c-v)
>
> Therefore t2=t1=x0/(c-v)
>
> The reflection time tR satisfies the equations:
>
> ts+t1=tR=te-t2
>
> So, eliminating x0 from the above we obtain indeed tR=0.5(ts+te)
Anyway, here comes the Sun!
Good :-)
Dirk Vdm
Dono
SperM.hotmail.com> wrote:
> "Dono" <sa...@comcast.net> wrote in messagenews:412f1057-ce49-4b53...@j20g2000hsi.googlegroups.com...
Sorry:
c.t1=x0+v.t1 , so t1=x0/(c-v)
I am using a foreign keyboard :-(
The point was that the Geroch formula was unobvious
xray4abc
SperM.hotmail.com> wrote:
> "xray4abc" <lemhen...@yahoo.ca> wrote in messagenews:376c2e94-c3e0-4dd7...@w56g2000hsf.googlegroups.com...
>
> - Show quoted text -
You tell me, I know what my question was!
I had the impression, until now, that you, seemed ...sometime..
to interpret the coordinate transformation in similar
way as I do. It is now obvious that it is not the case!
When I refer to LT, every (x', t') set can have *for
me* 2 possible meanings:
- the set as measured in the S' frame : (X', T') of S'
- the set as *attributed* TO the moving frame, S', by the observer
from
frame S : (X' , T')of S
The 2 sets, as it can be shown (I can!) are not necessarily identical.
This is understandable, as after all the value of parameters can vary
from one reference frame to another.
Now, I know that the locating events, described by you, are
simultaneous in frame S and that a discussion is needed for S' :
-*as seen* by observer in frame S - the events are not
simultaneous *in* S'
- as seen/measured by the observer in S' - the events can be
simultaneous.
This means that I make distinction between measuring the value of
parameters and
*attributing* the value of parameters, generally speaking.
I guess that, this is kind of *nonsense* by your opinion, so
I just made the above statement for the *sake of record*.
The LT applies to coordinate transformation in well
defined conditions.
The spatial coordinates x, x' give distances, that's true, but
distances
from the event location TO 2 different points, which are the
O and O' reference points of the coordinate axises.
Then, if we refer to the distance of 2 *given points*, that's
a qualitatively different situation to analyze.
That is why I wanted these discussions.
Regards, LL
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:1ff99571-bf25-4561...@e1g2000hsh.googlegroups.com...
No, you tell me.
Dirk Vdm
xray4abc
SperM.hotmail.com> wrote:
> >> >> If you had payed attention you should realize that
> >> >> I never said *anything* "regarding the time at which
> >> >> a length in the moving frame should be considered".
>
> >> Before we can continue I want you to realize and clearly
> >> express why your statement
> >> | "... you did not dare to give me a straight answer as
> >> | Dirk did. ( Regarding the time at which a length
> >> | in the moving frame should be considered)."
> >> is wrong.
> >> Again, I did *not* give an answer "regarding the time at
> >> which a length in the moving frame should be considered."
> >> I gave an answer regarding something else.
> >> Regarding what?
>
> >> Dirk Vdm
Hi
I did not have time to reply earlier
to your post, and frankly I start to
think that there is not much sense either
in it, as each of us is having basically
a monologue.
You are stuck with the exact the same
knowledge of SRT as you were 3 years ago,
and I admit that at that time that was more
than was able to show.
Since then, I made big efforts, encouraged by the fact
that many scientists admitted openly that they have
doubts regarding at least the interpretation of SRT,
and I made good progress, so that I can say
I know a lot more better SRT now than
I did 3 years ago.
Now, just to give a kind of closing to this
thread, let's come back to the offence you
seem to feel, regarding my answer to PDs post:
I will reproduce, relevant parts from my posts and
your posts to illustrate it:
Dec 2 LL
You have described how to get ONE set of time and length.
> What can you tell me about the OTHER set?
> (After all, the question is about how to apply the
> LT when it comes to lengths.
Dec 2 Dirk
The LT says
Dx' = g ( Dx - v Dt ).
If you want to measure the lenght, make sure that you measure
the distances at the same time, in other words, make sure that
Dt = 0,
With this choise we are using the coordinates x and t to measure
places and times of events. Someone riding with the object uses
coordinates x' and t' to mark events.
So we would measure Dx for the length of the object, and a
person riding with the object would measure Dx' for that lenght.
So with
{ Dx' = g ( Dx - v Dt )
{ Dt = 0
you have
Dx = 1/g Dx'
which means that we measure the object to be shorter than
someone riding with the object measures it.
Dirk Vdm
Dec 2, LL
OK.
I am interested in learning about t', associated
with the same events happening at the endpoints of the
object already discussed as having associated
a t=(te1 + ts1)/2 value to them.
My current understanding is that there is not
a unique value t', as simultaneous events from one IRF
do not have corresponding simultaneous events in other IRF.
At least this is what results from a formal application
of LT.
Dec 2 Dirk
Indeed, these two measurements are not simultaneous
in the frame in which the object is at rest, but does
not matter, since the object is going nowhere to begin
with, so you can safely take the difference of the distances
to the endpoints to calculate the 'real' aka 'proper' lenght of it.
See below for an additional remark...
Using the other part of the LT
Dt' = g ( Dt - v/c^2 Dx ),
you see that this Dt' is indeed not zero, but it doesn't have to
be zero, since the object is at rest in that frame.
Dirk Vdm
Dec 2 LL
It is very clear, from what you have showed several times, how you
get
measured L and T.
Now, how you get the other set ( L', T') ?
In fact you showed what would be the relation between the lengths.
I just need the same thing be done for the time values : T and T' !
Now, how you get the other set ( L', T') ?
Dec 3, Dirk
Do I really have to write the equations? Again?
Ok, here you go:
L' = g ( L - v T )
T' = g ( T - v/c^2 L )
In fact you showed what would be the relation between the lengths.
> I just need the same thing be done for the time values : T and T' !
Can't you do the algebra???
Use the equations. Keeping the same situation as before,
the object is at rest in the primed (x',t')-system and has proper
lenght L'. It is measured using two simultaneous events
according to the unprimed (x,t)-system, so T = 0.
So you have
L' = g L
T' = - g v/c^2 L
and therefore
L' = g L
meaning that the proper length L' is longer than the length
L which is measured in the unprimed (x,t)-system in which the
object is moving, and
T' = - v/c^2 L'
meaning that the two reflection events (caused by the light
signals of the unprimed (x,t)-system) are not sumultaneous
in the primed (x',t')-system.
Dec 7, Dirk
Before
we can continue I want you to realize and clearly
express why your statement
| "... you did not dare to give me a straight answer as
| Dirk did. ( Regarding the time at which a length
| in the moving frame should be considered)."
is wrong.
Again, I did *not* give an answer "regarding the time at
which a length in the moving frame should be considered."
I gave an answer regarding something else.
Regarding what?
Dirk Vdm
-------------
A good point for you, from my part, is that
you realized that your answer could be interpreted
as a straight answer to my question, which
obviously was not.
It was not possible as, a matter of fact, the LT
does not apply , in its known form, for the
"official " time of the 2 IRFs considered but
only for intervals.
Anyway, my question was all along the same, even
if its form was changed a bit from one post to another.
So, for anybody would appear that you have answered
THAT question.
OK, one of the forms of my question was, the relation
between T and T', which could have been understood
as a different question ( which was not in my
intention) !
And, yes, you have answered *that* question.
My intention was to lead you to the point
where you were supposed to admit that LT can
not be applied for the official time of the IRFs,
at least not in their classical form.
Does this answer satisfy you?
Regards, LL
Sue...
> On Nov 30, 10:45 pm, xray4abc <lemhen...@yahoo.ca> wrote:
>
> > When comparing the length of an object from 2
> > different IRFs, one must refer to the endpoints
> > of the object as locatable simultaneously.
> > In fact, it seems that, this can be done only in
> > one IRF at a time, i.e. in the frame where the
> > object is not moving.
> > For the moving frame we can not attach a
> > certain time value to the L' length , can we?
> > If not, then, this makes the Lorentz transformation
> > for time, in it known form, questionable, doesn't it?
> > ;--))
>
> > Regards, LL
>
> Any frame is going to have clocks near the endpoints of the object
> with which you can take position measurements simultaneously (in that
> frame). The problem is that two frames will not agree on what's
> simultaneous, and there's no way to resolve who is right.
There certainly is a way.
If a bullet wearing a watch slams into a bucket of
water sitting on a clock, then the indications
on the clocks, at the instant of impact is *real*.
http://www.bartleby.com/173/15.html
What the clocks indicate prior to impact is
*imaginary*.
<< It is to be found rather in the fact of his
recognition that the four-dimensional space-time
continuum of the theory of relativity, in its
most essential formal properties, shows a pronounced
relationship to the three-dimensional continuum of
Euclidean geometrical space. 1 In order to give due
prominence to this relationship, however, we must
replace the usual time co-ordinate t by an
imaginary magnitude
sqrt(-1)
ct proportional to it. Under these conditions,
the natural laws satisfying the demands of the
(special) theory of relativity assume mathematical
forms, in which the time co-ordinate plays
exactly the same rôle as the three space
co-ordinates. >>
http://www.bartleby.com/173/17.html
You will think this irrelevant unless you
are familiar with Oliver Heaviside's work
with reactance and know how to apply it
to an electromagnetic coupling structure.
<< Figure 3: The wave impedance measures
the relative strength of electric and magnetic
fields. It is a function of source [absorber] structure. >>
Formerly: ht tp://www.conformity.com/0102reflections.html
http://www.sm.luth.se/~urban/master/Theory/3.html
<< where μ is the magnetic permeability, ε is
the electric permittivity and σ is the conductivity
of the material the wave is travelling through.
In the equation, j is the imaginary unit, and ω
is the angular frequency of the wave. >>
http://en.wikipedia.org/wiki/Wave_impedance
IOW... If you know something about light propagtion
you can *see* if an *imagined* trajectory will result
in a *real* collision.
In certain circles this comes as no surprise.
http://en.wikipedia.org/wiki/Heat_seeking_missile
Sue...
> That is, if
> you make simultaneous measurements in the frame in which the object is
> at rest, those very same measurements will NOT be simultaneous in any
> other reference frame (which is one way an observer in that frame will
> argue that the measurement is not done right).
>
> PD
PD
> On Dec 1, 2:00 pm, PD <TheDraperFam...@gmail.com> wrote:
>
>
>
>
>
> > On Nov 30, 10:45 pm, xray4abc <lemhen...@yahoo.ca> wrote:
>
> > > When comparing the length of an object from 2
> > > different IRFs, one must refer to the endpoints
> > > of the object as locatable simultaneously.
> > > In fact, it seems that, this can be done only in
> > > one IRF at a time, i.e. in the frame where the
> > > object is not moving.
> > > For the moving frame we can not attach a
> > > certain time value to the L' length , can we?
> > > If not, then, this makes the Lorentz transformation
> > > for time, in it known form, questionable, doesn't it?
> > > ;--))
>
> > > Regards, LL
>
> > Any frame is going to have clocks near the endpoints of the object
> > with which you can take position measurements simultaneously (in that
> > frame). The problem is that two frames will not agree on what's
> > simultaneous, and there's no way to resolve who is right.
>
> There certainly is a way.
>
> If a bullet wearing a watch slams into a bucket of
> water sitting on a clock, then the indications
> on the clocks, at the instant of impact is *real*.http://www.bartleby.com/173/15.html
>
Those two clocks are at the same location. Spatially separated clocks
that are synchronized in one frame will not satisfy the same
synchronization rule in another frame.
> What the clocks indicate prior to impact is
> *imaginary*.
You get so easily diverted by this "imaginary time" that has led you
astray. Using "imaginary time" is in no way indicative of real
physics. It is merely a mathematical stunt to make the metric (which
is decidedly non-Euclidean) appear Euclidean. You have taken it to
mean something real, and have gotten hopelessly muddled ever since.
>
> << It is to be found rather in the fact of his
> recognition that the four-dimensional space-time
> continuum of the theory of relativity, in its
> most essential formal properties, shows a pronounced
> relationship to the three-dimensional continuum of
> Euclidean geometrical space. 1 In order to give due
> prominence to this relationship, however, we must
> replace the usual time co-ordinate t by an
> imaginary magnitude
>
> sqrt(-1)
>
> ct proportional to it. Under these conditions,
> the natural laws satisfying the demands of the
> (special) theory of relativity assume mathematical
> forms, in which the time co-ordinate plays
> exactly the same rôle as the three space
> co-ordinates. >>http://www.bartleby.com/173/17.html
>
> You will think this irrelevant unless you
> are familiar with Oliver Heaviside's work
> with reactance and know how to apply it
> to an electromagnetic coupling structure.
>
> << Figure 3: The wave impedance measures
> the relative strength of electric and magnetic
> fields. It is a function of source [absorber] structure. >>
> Formerly: ht tp://www.conformity.com/0102reflections.htmlhttp://www.sm.luth.se/~urban/master/Theory/3.html
>
> << where μ is the magnetic permeability, ε is
> the electric permittivity and σ is the conductivity
> of the material the wave is travelling through.
> In the equation, j is the imaginary unit, and ω
> is the angular frequency of the wave. >>http://en.wikipedia.org/wiki/Wave_impedance
>
> IOW... If you know something about light propagtion
> you can *see* if an *imagined* trajectory will result
> in a *real* collision.
>
> In certain circles this comes as no surprise.http://en.wikipedia.org/wiki/Heat_seeking_missile
>
> Sue...
>
>
>
> > That is, if
> > you make simultaneous measurements in the frame in which the object is
> > at rest, those very same measurements will NOT be simultaneous in any
> > other reference frame (which is one way an observer in that frame will
> > argue that the measurement is not done right).
>
> > PD- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
Sue...
I believe Einstein establishes the ability to cause
a midpoint collision as "the rule".
I think you may be using something from Newton's
mechanics, which does not apply to light.
>
> > What the clocks indicate prior to impact is
> > *imaginary*.
>
> You get so easily diverted by this "imaginary time" that has led you
> astray. Using "imaginary time" is in no way indicative of real
> physics. It is merely a mathematical stunt to make the metric (which
> is decidedly non-Euclidean) appear Euclidean. You have taken it to
> mean something real, and have gotten hopelessly muddled ever since.
Neither light nor projectiles pay any attention to grid lines
nor clocks. It completly appropriate to apply imaginary
operators to mathematical constructions, particularly where
they preseve equations that can have real interpretations.
Credit for the practice is not due to me but to those who
apply the theory rigourously:
<< if you know about complex numbers you will notice
that the space part enters as if it were imaginary
R2 = (ct)2 + (ix)2 + (iy)2 + (iz)2 = (ct)2 + (ir)2
where i^2 = -1 as usual. This turns out to be the
essence of the fabric (or metric) of spacetime
geometry - that space enters in with the imaginary
factor i relative to time. >>
http://www.nrao.edu/~smyers/courses/astro12/speedoflight.html
Sue...
>
>
>
>
>
> > << It is to be found rather in the fact of his
> > recognition that the four-dimensional space-time
> > continuum of the theory of relativity, in its
> > most essential formal properties, shows a pronounced
> > relationship to the three-dimensional continuum of
> > Euclidean geometrical space. 1 In order to give due
> > prominence to this relationship, however, we must
> > replace the usual time co-ordinate t by an
> > imaginary magnitude
>
> > sqrt(-1)
>
> > ct proportional to it. Under these conditions,
> > the natural laws satisfying the demands of the
> > (special) theory of relativity assume mathematical
> > forms, in which the time co-ordinate plays
> > exactly the same rôle as the three space
> > co-ordinates. >>http://www.bartleby.com/173/17.html
>
> > You will think this irrelevant unless you
> > are familiar with Oliver Heaviside's work
> > with reactance and know how to apply it
> > to an electromagnetic coupling structure.
>
> > << Figure 3: The wave impedance measures
> > the relative strength of electric and magnetic
> > fields. It is a function of source [absorber] structure. >>
> > Formerly: ht tp://www.conformity.com/0102reflections.htmlhttp://www.sm.luth.se/~urban/m...
PD
Uh, no.
>
> I think you may be using something from Newton's
> mechanics, which does not apply to light.
Uh, no.
>
>
>
> > > What the clocks indicate prior to impact is
> > > *imaginary*.
>
> > You get so easily diverted by this "imaginary time" that has led you
> > astray. Using "imaginary time" is in no way indicative of real
> > physics. It is merely a mathematical stunt to make the metric (which
> > is decidedly non-Euclidean) appear Euclidean. You have taken it to
> > mean something real, and have gotten hopelessly muddled ever since.
>
> Neither light nor projectiles pay any attention to grid lines
> nor clocks. It completly appropriate to apply imaginary
> operators to mathematical constructions, particularly where
> they preseve equations that can have real interpretations.
>
> Credit for the practice is not due to me but to those who
> apply the theory rigourously:
>
> << if you know about complex numbers you will notice
> that the space part enters as if it were imaginary
>
> R2 = (ct)2 + (ix)2 + (iy)2 + (iz)2 = (ct)2 + (ir)2
> where i^2 = -1 as usual. This turns out to be the
> essence of the fabric (or metric) of spacetime
> geometry - that space enters in with the imaginary
> factor i relative to time. >>http://www.nrao.edu/~smyers/courses/astro12/speedoflight.html
Well, as I said, this little mathematical device, which is frequently
used in a *pedagogical* intent to establish a conceptual bridge with
Euclidean geometry, has nothing to do with the physical geometry of
spacetime.
However, everytime you see it, and apparently every time you see
complex numbers in any mathematical treatment whatsoever (such as in
electrical circuit theory or diffusion equations), it throws you into
a minor tizzy.
It might help you to relax to see how all of this can be done
*without* the mathematical stunt of complex numbers, no matter how
convenient they are for computational purposes.
PD
>
> Sue...
>
Sue...
S<< I believe Einstein establishes the ability to cause
a midpoint collision as "the rule". >>
>
<< Uh, no. >>
Uh Yes:
<< 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. >>
http://www.bartleby.com/173/9.html
>
>
> > I think you may be using something from Newton's
> > mechanics, which does not apply to light.
>
> Uh, no.
Then I don't know what you are using. A Ouji board perhaps.
>
>
>
>
>
>
>
> > > > What the clocks indicate prior to impact is
> > > > *imaginary*.
>
> > > You get so easily diverted by this "imaginary time" that has led you
> > > astray. Using "imaginary time" is in no way indicative of real
> > > physics. It is merely a mathematical stunt to make the metric (which
> > > is decidedly non-Euclidean) appear Euclidean. You have taken it to
> > > mean something real, and have gotten hopelessly muddled ever since.
>
> > Neither light nor projectiles pay any attention to grid lines
> > nor clocks. It completly appropriate to apply imaginary
> > operators to mathematical constructions, particularly where
> > they preseve equations that can have real interpretations.
>
> > Credit for the practice is not due to me but to those who
> > apply the theory rigourously:
>
> > << if you know about complex numbers you will notice
> > that the space part enters as if it were imaginary
>
> > R2 = (ct)2 + (ix)2 + (iy)2 + (iz)2 = (ct)2 + (ir)2
> > where i^2 = -1 as usual. This turns out to be the
> > essence of the fabric (or metric) of spacetime
> > geometry - that space enters in with the imaginary
> > factor i relative to time. >>http://www.nrao.edu/~smyers/courses/astro12/speedoflight.html
>
> Well, as I said, this little mathematical device, which is frequently
> used in a *pedagogical* intent to establish a conceptual bridge with
> Euclidean geometry, has nothing to do with the physical geometry of
> spacetime.
It isn't a *physical" geometry. But it has some mathematical
properties that can relate a volume to electromagnetic enegry
and therby to kinetic energy and inertia.
Yes... it is all to frequently used to show light conforming
or not conforming to 300 year old rules of mechanics.
>
> However, everytime you see it, and apparently every time you see
> complex numbers in any mathematical treatment whatsoever (such as in
> electrical circuit theory or diffusion equations), it throws you into
> a minor tizzy.
No... When the imaginary operator is omitted I don't
hesitate to point it out. Useful equaions get
broken if the rigour is not followed.
>
> It might help you to relax to see how all of this can be done
> *without* the mathematical stunt of complex numbers, no matter how
> convenient they are for computational purposes.
Well yes... we could relax, tolerate some sloppy accounting
practices and enjoy watching the bellhop make dollars vanish
in his pocket if entertainment is the purpose.
I prefer the story about the siblings. One is a liar and
the other always tells the truth. :-)
Sue...
>
> PD
>
>
>
>
>
> > Sue...-
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:40b65341-d9e2-4c5a...@w56g2000hsf.googlegroups.com...
> On Dec 8, 4:44 am, "Dirk Van de moortel"
> > >> >> If you had payed attention you should realize that
> > >> >> I never said *anything* "regarding the time at which
> > >> >> a length in the moving frame should be considered".
> >
> > >> Before we can continue I want you to realize and clearly
> > >> express why your statement
> > >> | "... you did not dare to give me a straight answer as
> > >> | Dirk did. ( Regarding the time at which a length
> > >> | in the moving frame should be considered)."
> > >> is wrong.
> > >> Again, I did *not* give an answer "regarding the time at
> > >> which a length in the moving frame should be considered."
> > >> I gave an answer regarding something else.
> > >> Regarding what?
> >
> > >> Dirk Vdm
>
> Hi
> I did not have time to reply earlier
> to your post, and frankly I start to
> think that there is not much sense either
> in it, as each of us is having basically
> a monologue.
Repeat:
I did not give an answer "regarding the time at which a
length in the moving frame should be considered."
I gave an answer regarding something else.
Regarding what?
I you can't properly answer to this question in less than
50 words, then *don't* bother.
Take it as an opportunity to prove that you have payed
attention.
If you can't do that, I see no point in trying to help you
any further.
Dirk Vdm
xray4abc
SperM.hotmail.com> wrote:
> "xray4abc" <lemhen...@yahoo.ca> wrote in messagenews:40b65341-d9e2-4c5a...@w56g2000hsf.googlegroups.com...
>
> - Show quoted text -
You answered a/the question regarding the time
intervals involved in a length measurement
in 2 relatively moving IRFs.
..............
( Which was not my question !)
(L'=gL Lorentz-Fitzgerald contraction of a bar
moving parallel to its length
T'= - vL/c^2 the time delay of signals in S' for
getting 2 simultaneous events in S, T=Dt=0 at the endpoints of
the bar.
And this is there in every physics book regarding SRT.
............
I am pursuing a different thing:
How come that the LT which initially was seen as a
single-event set of relations, is being applied for
multiple-point events without any alteration?
Or...
Why the emission of 2 or more signals in different
initial conditions does not ask for a modified
LT?
Regards, LL
Jeckyl
As I understand (and if I understand what you're asking), the LT applies to
ALL space/time events wrt two inertial frames. If you have the same pair of
inertial frames, then ALL events undergo the same transform .. because it is
a transform between inertial frames that applies to the events .. not per
individual event.
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:61b5c14f-00c2-4d3a...@q3g2000hsg.googlegroups.com...
> intervals involved in a length measurement
> in 2 relatively moving IRFs.
You didn't pay attention.
Dirk Vdm
xray4abc
> "xray4abc" <lemhen...@yahoo.ca> wrote in message
>
> - Show quoted text -
I see it like this :
Case 1
Formally, the LT can be easyly obtained from
x^2+ y^2+z^2 = c^2 * t^2
and the similar condition for x', y' z', t' .
Here the r=ct applies, which in one spatial
dimension corresponds to x=c*t.
This associates to one value of t only one value
of x and one value of x' and t', meaning that
we have only one event considered.
Case 2
From x^2+y^2+z^2 - c^2*t^2 = const. and the
same for 2 IRFs, where the constant is not necessarily =0
any more, the LT can be obtained again, and
here r can be <>c*t.
Then the LT, obtained formally, applies for
arbitrary spatial points at arbitrary moments of time.
One price paid is the elimination of the
notion of the *time of the IRF*.
( 2 events simultaneous in one frame are not
*they say* in the other frame).
I can see physical explanation for the first
case but not really for the second one,anyway
not without some kind of alteration of the LT.
I got serious doubts, not regarding the LT
themselves, but their interpretation even for case 1.
And this is, in a very short and maybe not
sufficiently relevant manner :Given the limited
speed of information transmission, no real time
data can be collected regarding moving objects.
In my view, this makes our image/description of the physical
states, quantities be different from what really
could be obtained IN the frame moving with the object.
More simpler: We do not make transformation between
our reference frame and the second/moving frame !!!!!
We make transformation between our frame and an
image (the image we create) of the second frame!!!!
Or..... :
Length of a standard metre-rod, duration
of a second can be perfectly the same in all IRFs.
Even the clocks could indicate the same universal value.
Changes occur only when we start measuring things,
*formal changes* induced by our measurements.
Our picture only, looks different from different
IRFs.
From this view, x' means one thing/value for
the observer from frame S and another thing/value
for the observer from frame S'.
The same thing applies for other coordinates.
In my use, I notate sometimes
Xs and Xs' to highlight the difference.
( I am trying now to connect these ideas to
the known results of SRT.... .
The discussions with the guys in this group
does not seem to help a lot.
The inertia of mind is so huge that even I, myself, am
falling back to the learned theory and have to rethink
my own ideas from time to time.)
Regards, LL
xray4abc
SperM.hotmail.com> wrote:
> "xray4abc" <lemhen...@yahoo.ca> wrote in messagenews:61b5c14f-00c2-4d3a...@q3g2000hsg.googlegroups.com...
>
> - Show quoted text -
So be it!
LL
Jeckyl
> On Dec 16, 7:16 pm, "Jeckyl" <no...@nowhere.com> wrote:
> I see it like this :
> Case 1
> Formally, the LT can be easyly obtained from
> x^2+ y^2+z^2 = c^2 * t^2
> and the similar condition for x', y' z', t' .
> Here the r=ct applies, which in one spatial
> dimension corresponds to x=c*t.
> This associates to one value of t only one value
> of x and one value of x' and t', meaning that
> we have only one event considered.
> Case 2
> From x^2+y^2+z^2 - c^2*t^2 = const. and the
> same for 2 IRFs, where the constant is not necessarily =0
> any more, the LT can be obtained again, and
> here r can be <>c*t.
> Then the LT, obtained formally, applies for
> arbitrary spatial points at arbitrary moments of time.
> One price paid is the elimination of the
> notion of the *time of the IRF*.
> ( 2 events simultaneous in one frame are not
> *they say* in the other frame).
The LT is the same for EVERY value of x, y, z, t .. that's why they are
pronumerals .. any value can go in there and you get the right answers.
Dirk Van de moortel
"Jeckyl" <no...@nowhere.com> wrote in message news:13meipk...@corp.supernews.com...
Don't try to explain. He doesn't understand basic high school
linear algebra or analytic geometry.
Essentially Hopeless.
Dirk Vdm
xray4abc
> "xray4abc" <lemhen...@yahoo.ca> wrote in message
>
> - Show quoted text -
Wasn't my post in English?
I did not say that LT is not the same for every value of x,y,z,t !
It is not about mathematics.
I presented a different WAY of looking at the issues.
Read it carefully, if you have the time and the patience.
Regards, LL
xray4abc
SperM.hotmail.com> wrote:
> "Jeckyl" <no...@nowhere.com> wrote in messagenews:13meipk...@corp.supernews.com...
> > "xray4abc" <lemhen...@yahoo.ca> wrote in messagenews:7dc0dd40-2306-4e15...@t1g2000pra.googlegroups.com...
>
> - Show quoted text -
You are being mean and cheap.
It took me 3 years , starting from *your kind* of view,
to get to my present view of SRT, a much more realistic one.
To respond in your manner:
With your speed of evolution it could take.....let
say,... 30 years ?
One that does not know the limits of a theory,
can not be sure that he knows it!
See, for example the Berkeley Physics Course
on SRT. They state clearly that, there is no physical
contraction or dilatation involved in relativity effects.
They are results only of the measurement process and the
oddity of constant "light"-speed in all IRFs.
Then, physically or mathematically, the primed values
in S IRF are just a *representation* of what exists in
the S' IRF, and vice-versa.
If, in your representation, 2 events are simultaneous
in one IRF and not in the other one, this is possibly
NOT a physical fact but a representation issue!
But, why I bother explaining it to you ?
This is almost philosophy.
Go back to your upper and lower indexes/indices
and have fun !
LL
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:7cc319b0-4ba6-4d7d...@s8g2000prg.googlegroups.com...
Mean and Cheap, my middle names.
Dirk Vdm
Jeckyl
Not terribly clear english, apparently.
> I did not say that LT is not the same for every value of x,y,z,t !
You said it only applied for a single event
> It is not about mathematics.
> I presented a different WAY of looking at the issues.
What issues?
> Read it carefully, if you have the time and the patience.
I did.
Jeckyl
So how is yours different to what everyone else's view is. You seem to now
be saying that the LT applies and that you get relativits of simultaneity,
all things that SR says.
Do you have a question or a point ot make .. or are you just trying to show
how 'clever' you are .. I'm not sure.
> See, for example the Berkeley Physics Course
> on SRT. They state clearly that, there is no physical
> contraction or dilatation involved in relativity effects.
> They are results only of the measurement process and the
> oddity of constant "light"-speed in all IRFs.
That is because it is space and time that is contracted and dilated. SR has
always said that the length of an object is the same in every iFoR in which
it is a rest. As far as any object is concerned, it doesn't amtter if it is
moving relative to something else .. there is no physical change. That is
not only SR, but common sense.
That, however, in some other frame of reference the object is physically
shorter .. it takes up less physical space.
It really depends on what you mean by 'physically'.
> Then, physically or mathematically, the primed values
> in S IRF are just a *representation* of what exists in
> the S' IRF, and vice-versa.
> If, in your representation, 2 events are simultaneous
> in one IRF and not in the other one, this is possibly
> NOT a physical fact but a representation issue!
No .. its a physical fact.
> But, why I bother explaining it to you ?
> This is almost philosophy.
> Go back to your upper and lower indexes/indices
> and have fun !
Fine .. I guess that means you are not interested in listening to what
others have to say. That's your loss, not ours.
xray4abc
> "xray4abc" <lemhen...@yahoo.ca> wrote in message
>
> - Show quoted text -
Hi
I am not interested in showing myself clever or else.
I am not flooding the Internet with my posts.
I was trying to make a point, which in my view makes
SRT more graspable for everyone interested in the
subject.
I am puzzled by the fact that I could not
make myself understood to you, guys, knowledgeable in
SRT and relativity in general.
I will try it again, but you need to listen
with your mind and not with your heart or prejudices !
It is stated in SRT that LT are the
relations between spatial coordinates and time
of an event in 2 IR frames : (x,y,z,t) in frame S
and (x',y',z',t') in frame S'.
The general understanding of this statement
seems to be that,
*one* observer in frame S gets the (x,y,z,t) set of data
while *another* observer in frame S' gets the (x',y',z',t')
set of data.
( Correct me if I am wrong, but this is what I have
learnt in my university studies and seem to say most
of the text- and other physics books.
Of course I can not possibly know all books on
the subject, so it might be a wrong perception.)
Then according to the same perception
LT make the liaison between the the 2 sets of data.
What *I* was saying to you, was different from
the "general understanding" as mentioned above.
In *your* reference frame, let say S, you attribute, generally
speaking, other values to physical quantities than
the ones attributed by me in *my* frame S' which is
moving at constant velocity relative to your's.
Now let say that in question are the following
physical quantities: x,y,z,t concerning a given event
in frame S.
(Treat them like any other physical quantities!)
Looking at them like this, I think that you
realize too, that I, the observer from frame S',
will not have the same values for them (like you have),
but *different* values, though I will use the same
notations like you do, that is x,y,z,t.(Because
we are referring to the same thing after all, the values
of parameters x,y,z,t attributed *in* your frame!)
Typically, in discussions regarding this
issue, they used to say things somewhat equivalent
to the ones above, like :"The observer from S' *sees*
the clock from frame S as ticking differently.." meaning
that he has his own perception of the *t* value, which
is different from the *other* t value, measured directly
by the observer of IRF S.
So, what I am bringing here is, at the *very least*,
a more accurate formulation than the one they use.
Regards, LL
Jeckyl
> Hi
> I am not interested in showing myself clever or else.
Good .. if so, it is not working :)
> I am not flooding the Internet with my posts.
> I was trying to make a point, which in my view makes
> SRT more graspable for everyone interested in the
> subject.
I don't think it really helps .. but if it helps you (and as long as you
havne't gotten lost along the way and ended up with some ideas that raren't
erally what SR says) then that's fine
> I am puzzled by the fact that I could not
> make myself understood to you, guys, knowledgeable in
> SRT and relativity in general.
Maybe we couldn't see the point of your post, or you failed to express it
clearly.
> I will try it again, but you need to listen
> with your mind and not with your heart or prejudices !
What prejudices are they?
> It is stated in SRT that LT are the
> relations between spatial coordinates and time
> of an event in 2 IR frames : (x,y,z,t) in frame S
> and (x',y',z',t') in frame S'.
Yeup .. that's what you end up with from the basic assumptinos of the
principle of relativity andthe constancuy of the speed of light in all
inertial frames. Its actually not too difficult to derive.
> The general understanding of this statement
> seems to be that,
> *one* observer in frame S gets the (x,y,z,t) set of data
> while *another* observer in frame S' gets the (x',y',z',t')
> set of data.
For the same location in space and time .. yes. Each observer sees things
slightly differently. It is similar to non-SR physics .. if you sit in a
train and throw a ball up in the air and catch it, to you it has moved
directly up and down to the same position .. to someone on the ground
outside the train, the ball has travelled a parabolic path and the start and
end positions are different. Both people are correct in what they see in
their own frames of reference.
> ( Correct me if I am wrong, but this is what I have
> learnt in my university studies and seem to say most
> of the text- and other physics books.
> Of course I can not possibly know all books on
> the subject, so it might be a wrong perception.)
> Then according to the same perception
> LT make the liaison between the the 2 sets of data.
You could say that .. yes.
> What *I* was saying to you, was different from
> the "general understanding" as mentioned above.
> In *your* reference frame, let say S, you attribute, generally
> speaking, other values to physical quantities than
> the ones attributed by me in *my* frame S' which is
> moving at constant velocity relative to your's.
Yes .. so far you're saying the same thing
> Now let say that in question are the following
> physical quantities: x,y,z,t concerning a given event
> in frame S.
> (Treat them like any other physical quantities!)
> Looking at them like this, I think that you
> realize too, that I, the observer from frame S',
> will not have the same values for them (like you have),
> but *different* values, though I will use the same
> notations like you do, that is x,y,z,t.(Because
> we are referring to the same thing after all, the values
> of parameters x,y,z,t attributed *in* your frame!)
It seems you are stuffing things up by using the same names for the
coordinates in S (x,y,z,t) and the coordinates in S' (x,y,z,t). That is not
making it any simpler
> Typically, in discussions regarding this
> issue, they used to say things somewhat equivalent
> to the ones above, like :"The observer from S' *sees*
> the clock from frame S as ticking differently.." meaning
> that he has his own perception of the *t* value, which
> is different from the *other* t value, measured directly
> by the observer of IRF S.
That's simply a limitation of the English language (and perhaps others).
Anything that is relative to an observer in a given frame, in English, we
talk about as 'seeing'. But it does mean what is 'real' (don't get started
into metaphysics about what reality is) in that frame and what it is that is
being measured (or 'seen') by the observer. Of course, what he physically
sees with his eyes is going to be affected by things like doppler shift, and
that's another kettle of fish altogether.
> So, what I am bringing here is, at the *very least*,
> a more accurate formulation than the one they use.
> Regards, LL
So far I don't see what you've done that is more accurate. You've so far
said the same thing .. only stuffed up the naming of coordinates to make it
more confusing. Perhaps if you can continue your explanation?
xray4abc
>
> - Show quoted text -
Again, to make my statement clearer
For a given event we will get :
In IRF S : coordinates x, y, z, t as measured
x',y',z',t' as attributed/calculated from
LT
In IRF S' : coordinates X,,Y, Z, T as attributed/calculated from LT
X',Y',Z',T' as measured
The 2 pairs of data-sets do not coincide necessarily.
If they coincide, we are back at the "classical" SRT.
If not, the case is still compatible with LT, a thing which I have
to stress again.
But then a new way to explore opens regarding SRT.
You may have doubts regarding the correctness of the
above statements,
which is OK for now, as I have not posted any demonstration or at
least an attempt of it.
Right now I just want to make sure that you really have the idea
understood.
Regards, LL
Jeckyl
[snip]
>Again, to make my statement clearer
> For a given event we will get :
>
> In IRF S : coordinates x, y, z, t as measured
> x',y',z',t' as attributed/calculated from LT
You're wrong there .. the LT tells you the coordinates in some other frame
.. not still in S
It seems you're confused about the basics.
So not much point going further until you are de-confused.
Dirk Van de moortel
"Jeckyl" <no...@nowhere.com> wrote in message news:13mpaob...@corp.supernews.com...
What did I tell you?
Dirk Vdm
xray4abc
> "xray4abc" <lemhen...@yahoo.ca> wrote in message
You still did not understand.
See Einstein's judgement on simultaneity for
example. Hope, you won't say he was confused.:-)
( The 2 lightnings ARE simultaneous in each IRF
considered separately. They are not simultaneous
when the observer is *referring to the other frame*,
that is how, he thinks , things *should* happen
in the other frame. Einstein uses a parenthesis to
specify, that is about seeing things happening in
the other frame, *from the reality of the observer's frame*.)
AS a matter of principle YOU DO NOT HAVE ACCESS to
the data from other (moving) frame.
You COULD if the communication speed could be infinite.
But it is not! There is qualitative difference here
compared to the Galilei transformations , it is not just
math.
There....you can actually get the data from a
moving frame.
Here, not!
Here you just can get data that *refer * to the
other frame, as *seen* from the reality of your frame.
Coming back to your objection, in frame S
you have YOUR measured data :x,y,z,t for an event
and YOU calculate x',y',z',t' which YOU consider that
apply for frame S' and NOT THE OBSERVER FROM FRAME S'.
Remember, his reality is different from yours!
The 2 of you will never agree on certain issues,
like the simultaneity of 2 events, mentioned above, etc.
On his turn, the observer from frame S' will
have a similar situation.
At least, as I have said earlier, this is a
situation to be considered (and which IS compatible with the L
before discarding it as wrong.
(To answer some malicious observations,
I do not expect guys with inflexible mind, like
Dirk, to ever understand this.):-)
Regards, LL
Dirk Van de moortel
"xray4abc" <lemh...@yahoo.ca> wrote in message news:dd411043-a238-4402...@j20g2000hsi.googlegroups.com...
> On Dec 22, 1:13 am, "Jeckyl" <no...@nowhere.com> wrote:
> > "xray4abc" <lemhen...@yahoo.ca> wrote in message
> >
> > news:990108a6-c1e7-40d7...@x76g2000hsf.googlegroups.com...
> > [snip]
> >
> > >Again, to make my statement clearer
> > > For a given event we will get :
> > >
> > > In IRF S : coordinates x, y, z, t as measured
> > > x',y',z',t' as attributed/calculated from LT
> >
> > You're wrong there .. the LT tells you the coordinates in some other frame
> > .. not still in S
> >
> > It seems you're confused about the basics.
> >
> > So not much point going further until you are de-confused.
>
> You still did not understand.
And what did I tell *you*?
Dirk Vdm
Jeckyl
>On Dec 22, 1:13 am, "Jeckyl" <no...@nowhere.com> wrote:
>> "xray4abc" <lemhen...@yahoo.ca> wrote in message
>>
>> news:990108a6-c1e7-40d7...@x76g2000hsf.googlegroups.com...
>> [snip]
>>
>> >Again, to make my statement clearer
>> > For a given event we will get :
>> > In IRF S : coordinates x, y, z, t as measured
>> > x',y',z',t' as attributed/calculated from LT
>> You're wrong there .. the LT tells you the coordinates in some other
>> frame
>> .. not still in S
>> It seems you're confused about the basics.
>> So not much point going further until you are de-confused.
> You still did not understand.
I understand just fine .. whether you do is the issue
> See Einstein's judgement on simultaneity for
> example. Hope, you won't say he was confused.:-)
> ( The 2 lightnings ARE simultaneous in each IRF
>considered separately.
No
If you are talking about the lightning striking the train .. that is
incorrect
It is only simultaneous in one frame, not the other
> They are not simultaneous
>when the observer is *referring to the other frame*,
You are defintiely confused
>that is how, he thinks , things *should* happen
>in the other frame.
No .. it how they DO happenin the other frame.
>Einstein uses a parenthesis to
>specify, that is about seeing things happening in
>the other frame, *from the reality of the observer's frame*.)
> AS a matter of principle YOU DO NOT HAVE ACCESS to
> the data from other (moving) frame.
Eh? Why not? What does it matter?
> You COULD if the communication speed could be infinite.
Again .. what has that to do with it .. it s not about commmunicating
measurements to anotehr frame
> But it is not! There is qualitative difference here
>compared to the Galilei transformations , it is not just
>math.
Again .. eh?. The math models measured reality. Glilean transfomrs are
useulf appropimations at relatively low speed .. so good that we could not
effectively measure the distance at the speed we usually encounter in day to
day life
>There....you can actually get the data from a
>moving frame.
>Here, not!
Eh? Why not? What does it matter?
> Here you just can get data that *refer * to the
> other frame, as *seen* from the reality of your frame.
There is no reason why you cannot get information taken from another frame.
> Coming back to your objection, in frame S
>you have YOUR measured data :x,y,z,t for an event
> and YOU calculate x',y',z',t' which YOU consider that
> apply for frame S'
No .. it IS what the observer in frame S' would see as the coordinates of
that event
> and NOT THE OBSERVER FROM FRAME S'.
No .. it IS what the observer in frame S' would see as the coordinates of
that event
> Remember, his reality is different from yours!
No .. it is the same reality .. just a different view of it
> The 2 of you will never agree on certain issues,
Yeup .. because you are looking at the same events from different points of
view
> like the simultaneity of 2 events, mentioned above, etc.
Yeup . .because something simultaneous at different position in my frame
will not be simultaneous in any other non-co-moving frame
> On his turn, the observer from frame S' will
> have a similar situation.
Yes .. he see x',y',z',t' for the event, and can cacluate that I woudl see
it at x,y,z,t (which I do)
> At least, as I have said earlier, this is a
> situation to be considered (and which IS compatible with the L
> before discarding it as wrong.
You just seem very confused about what is going on here. x,y,z,t are
coordinates of the event in our frame S, x',y',z',t' are the coordinates of
the same event in another frame S'
> (To answer some malicious observations,
>I do not expect guys with inflexible mind, like
>Dirk, to ever understand this.):-)
First we need to ensure the YOU understand. If you really DO, then you are
expressing it VERY poorly, to the extent that it appears that you do not.
xray4abc
>
> - Show quoted text -
I remind you that I am trying to discuss not
the "classical SRT", as I referred to it earlier.
All things you have said are referring to that one,
and I got no problem with it right now.
As I said, the LT are compatible with
more than one (single) perception of the relation
between 2 IRFs.
At least this is what I think .
If you consider that this is not possible and it is
a waste of time discussing alternatives of SRT then
we stop here on this issue.
Then, I would be interested, for now, just
in finding out if, by your knowledge, the LT
was, in some textbooks or other publications,
shaped for the situation of the light-signals
emitted from an arbitrary point and in an
arbitrary moment of time (or similar).
(That is, I am interested in LT where the
initial conditions considered are not :
x=x'=o when t=t'=0)
The idea is that the LT could be slightly different
when the initial conditions are not the ones
mentioned above.
I have worked a bit in this direction
and I would like to compare my results/ideas
with the ones in the physics literature.
I could not find much so far.
Regards, LL
Jeckyl
Then WTF *ARE* you trying to discuss .. because its not relativity.
> as I referred to it earlier.
>All things you have said are referring to that one,
>and I got no problem with it right now.
I'm not convinced, but if you think you do, lets continue and see
> As I said, the LT are compatible with
>more than one (single) perception of the relation
>between 2 IRFs.
Is that supposed to mean something? LT *is* the relationship.
> At least this is what I think .
> If you consider that this is not possible and it is
> a waste of time discussing alternatives of SRT
You didn't seem to be discussing any alternatives. And any alternative will
have to predict the same resulst as SR does for the experiments so far athat
are consistent with SRT predictions.
> then
> we stop here on this issue.
> Then, I would be interested, for now, just
> in finding out if, by your knowledge, the LT
> was, in some textbooks or other publications,
> shaped for the situation of the light-signals
> emitted from an arbitrary point and in an
> arbitrary moment of time (or similar).
That's what they do .. they show the coordinates of the identical even from
another point of view (frame of reference)
> (That is, I am interested in LT where the
> initial conditions considered are not :
> x=x'=o when t=t'=0)
The thing is .. you transform your frame of reference to an equivalent one
where that is the case, apply the LT, then transform the results accordingly
in the other frame of reference.
The LT part of it is always the same.
> The idea is that the LT could be slightly different
>when the initial conditions are not the ones
>mentioned above.
No .. it is not really different in any significant way.
> I have worked a bit in this direction
>and I would like to compare my results/ideas
>with the ones in the physics literature.
>I could not find much so far.
Try wikipedia .. that's often a good place to start.
http://en.wikipedia.org/wiki/Lorentz_transformation
shuba
[snip crackpottery]
> I have worked a bit in this direction
> and I would like to compare my results/ideas
> with the ones in the physics literature.
> I could not find much so far.
Start by consideration of rotations in the x-y plane about the
origin to get an x'-y' coordinate system. The properties of
transformation groups have been studied in detail, and your
best bet is to become familiar with some of the basics.
---Tim Shuba---
Androcles
"shuba" <tim....@lycos.ScPoAmM> wrote in message
news:tim.shuba-E920A...@sn-ip.vsrv-sjc.supernews.net...
: LL wrote:
:
: [snip crackpottery]
Ok, if you insist.
[crackpottery snipped as requested]