Re: The Fundamental Flaw of SR

From: kenseto (kenseto_at_erinet.com)
Date: 08/06/04 

Date: Fri, 6 Aug 2004 10:31:07 -0400

"Gregory L. Hansen" <glhansen@steel.ucs.indiana.edu> wrote in message
news:ceqr51$eke$1@hood.uits.indiana.edu...
> In article <10h1lqltggnt79b@corp.supernews.com>,
> kenseto <kenseto@erinet.com> wrote:
> >
> >"Gregory L. Hansen" <glhansen@steel.ucs.indiana.edu> wrote in message
> >news:ceonn4$pvf$1@hood.uits.indiana.edu...
> >> In article <10gvjmvi90m0005@corp.supernews.com>,
> >> kenseto <kenseto@erinet.com> wrote:
> >> >
> >> >"Gregory L. Hansen" <glhansen@steel.ucs.indiana.edu> wrote in
message
> >> >news:ceoa88$kjt$1@hood.uits.indiana.edu...
> >> >> In article <10gv7d89t2ltr8a@corp.supernews.com>,
> >> >> kenseto <kenseto@erinet.com> wrote:
> >> >> >
> >> >> >"Gregory L. Hansen" <glhansen@steel.ucs.indiana.edu> wrote in
> >message
> >> >> >news:celin1$oaf$1@hood.uits.indiana.edu...
> >> >> >> In article <10gsfhdrhjoogec@corp.supernews.com>,
> >> >> >> kenseto <kenseto@erinet.com> wrote:
> >> >> >> >
> >> >> >> >"Gregory L. Hansen" <glhansen@steel.ucs.indiana.edu> wrote
in
> >> >message
> >> >> >> >news:cej7uj$u7c$1@hood.uits.indiana.edu...
> >> >> >> >> In article <10gpvs2572bktd5@corp.supernews.com>,
> >> >> >> >> kenseto <kenseto@erinet.com> wrote:
> >> >> >> >> >
> >> >> >> >> >"Gregory L. Hansen" <glhansen@steel.ucs.indiana.edu>
wrote
> >in
> >> >> >message
> >> >> >> >> >news:cehe8g$7q3$1@hood.uits.indiana.edu...
> >> >> >> >> >> In article <10gngkblsrcogc3@corp.supernews.com>,
> >> >> >> >> >> kenseto <kenseto@erinet.com> wrote:
> >> >> >> >> >> >
> >> >> >> >> >> >"Gregory L. Hansen" <glhansen@steel.ucs.indiana.edu>
> >wrote
> >> >in
> >> >> >> >message
> >> >> >> >> >> >news:cegebp$uis$1@hood.uits.indiana.edu...
> >> >> >> >> >> >> In article <10gn8mb2sdqbkb6@corp.supernews.com>,
> >> >> >> >> >> >> kenseto <kenseto@erinet.com> wrote:
> >> >> >> >> >> >> >
> >> >> >> >> >> >> >"Gregory L. Hansen"
<glhansen@steel.ucs.indiana.edu>
> >> >wrote
> >> >> >in
> >> >> >> >> >message
> >> >> >> >> >> >> >news:cedt1o$4av$1@hood.uits.indiana.edu...
> >> >> >> >> >> >> >> In article <10gkm0eko31jrc5@corp.supernews.com>,
> >> >> >> >> >> >> >> kenseto <kenseto@erinet.com> wrote:
> >> >> >> >> >> >> >> >
> >> >> >> >> >> >> >> >"Gregory L. Hansen"
> ><glhansen@steel.ucs.indiana.edu>
> >> >> >wrote
> >> >> >> >in
> >> >> >> >> >> >message
> >> >> >> >> >> >> >> >news:cec7lh$jal$1@hood.uits.indiana.edu...
> >> >> >> >> >> >> >> >> In article
<10gi006js5bu5b@corp.supernews.com>,
> >> >> >> >> >> >> >> >> kenseto <kenseto@erinet.com> wrote:
> >> L/gamma?
> >
> >"See" is being used loosely ....it has the same meaning of
calculating.
> >In real
> >life A does not "see" anything about B's rod.
> >>
> >> You got it right the first time. He sees L/gamma.
> >
> >No...he calculated that the length of B's rod is L/gamma.
> >
> >>He doesn't have to
> >> calculate the length in his frame because he *is* in his frame.
> >
> ><sigh> A calculate B's rod length in his frame.
> >
> >> The
> >> Lorentz transformations, like any set of transformation equations,
are
> >> used to transform a measurement made in one frame to another frame.
> >
> >Right...B measures his length to be L and this is transformed into
A's
> >frame
> >as L/gamma.
> >
> >>But A
> >> just has to measure the length of the rod in his own frame with any
of
> >the
> >> myriad possibilities available to him; focus camera lenses on the
> >front
> >> and back, bounce radar signals from markers on the front and back,
> >take a
> >> picture and calculate length by the perspective narrowing of the
rod
> >> towards the back, arrange contact switches and timers at rest in
his
> >> frame, whatever pleases you.
> >
> >I have no idea what you are babbling about. A's rod length as
measured
> >by A is l.
>
> I'm babbling about ways that A might have *measured* the length of B's
> rod, without having to ask B how long it is and calculating a
transformed
> length.
>
> All of those are thought measurements in a thought experiment. But
the
> rods and measurement procedures are dramatizations for the
understanding
> that the light has some trajectory x_c(t), and the ends of the rod
have
> their own trajectories x_1(t) and x_2(t).

That's the problem. Your thought measurements are based on Galilean
relativity
which we know it to be bogus. you assumed that the leading edge of a
light
beam will hit the target. In real life the leading edge of a light beam
will not
hit the target. Why? Because if it does that would mean that you would
know
the velocity and position of the leading photon. That is a clear
violation of
the uncertainty principle.
>
> In B's frame they would also have trajectories, x'_c(t'), x'_1(t'),
> x'_2(t'). But we're focusing on A.

Again these thought measurements are based on Galilean Relativity and
they are bogus.
>
> When you ask how long it takes the light o traverse the rod, we ask
what
> the time interval, in A's frame, is between the two events: light
touches
> end 1, light touches end 2.

Again bogus thought measurements.

>An event has a time and a position. And we
> can determine times and positions in any frame. The light beam was
here
> at x1, at time t1. The left end of the rod was here at x1, at time
t1.
> The light beam was there at x2, at time t2. The end of the rod was
there
> at x2, at time t2. The path of the light doesn't affect where the bar
> was, the velocity of the bar doesn't change the path of the light.
It's
> amazingly simple.

Again bogus thought measurements.
>
> If a second observer, say B with velocity w relative to A (w needn't
equal
> v unless we specify B is at rest with respect to the rod), then the
> Lorentz transforms must be used to determine how A's measurements
relate
> to B's frame. But if we stick to one frame, we don't tranform.
> Transformation equations relate quantities in one frame to another
frame;
> if we don't transform to another frame, we don't use the
transformation
> equations.

The only true way to determine the transit time for light to traverse B'
s rod is
by using the LT to tranform B's rod into A's frame and then divide the
transform length with c to deterimne the correct transit time in all
directions.
>
> >>
> >> >This calculated length
> >> >will
> >> >have the same transit time in all directions in his frame.
> >>
> >> You haven't demonstrated that.
> >
> >Yes I have. The tranform length is not directional sensitive.
> >>
> >> This is really nothing more mysterious than if you roll a golf ball
> >past a
> >> skateboard. If the skateboard is moving in the direction of the
golf
> >> ball, it will take longer to go from the back to the front. If the
> >> skateboard is moving in the direction of the ball, and very nearly
as
> >fast
> >> as the ball, it could take a long time for the golf ball to
traverse
> >it.
> >
> >This is a poor example and it has no connection to how light move to
> >traverse
> >the length of a rod. In SR we know that you can't add velocities as
you
> >stated above.
> >>
> >> I assume you can agree with the skateboard and golf ball. So what
do
> >you
> >> think changes when it becomes a rod and a beam of light?
> >
> >NO...with light it is different. Remenber that the speed of light is
> >independent of the relative motion of the source or the receiver.
>
> In SR you can't *transform* velocities by adding the velocity of the
rod
> in one frame to the velocity of the second observer. BUT NO
> TRANSFORMATION WAS PERFORMED! No transformation needed to be
performed,
> because no second observer in a different frame was involved. The
> velocity of the skateboard was defined in frame A, the velocity of
> the golf ball was defined in frame A, the observer was in frame A, the
> positions and times and interval he determines are positions and times
> and an interval in frame A. No transformation is to be used unless
you
> make a measurement in one frame and need to know what that same
> measurement would look like in a different frame.

You can use the Galilean Relativity with skateboard and golf ball. But
you
can't use Galilean Relativity how light traverse B's rod in A's frame..
>
> There was nothing wrong with the skateboard example I gave above, and
it's
> entirely analogous to the rod and light beam example. It's valid in
the
> Newtonian picture, it's valid in special relativity. And it's valid
when
> you have a beam of light instead of a golf ball.

Everything is wrong with your example.

Ken Seto

Relevant Pages

  • Re: Frame dependent distances in relativity?
    ... Since SR predicts that length measurements are frame-dependent, ... invariance was a result of special relativitys clocks and rulers). ... The postulates aren't "depending upon a transformation". ... measurements are not "rigid", but frame dependent. ...
    (sci.physics.relativity)
  • Re: The Fundamental Flaw of SR
    ... >No...he calculated that the length of B's rod is L/gamma. ... >> used to transform a measurement made in one frame to another frame. ... Transformation equations relate quantities in one frame to another frame; ... it could take a long time for the golf ball to traverse ...
    (sci.physics)
  • Re: Is there length contraction in SRT, uncle Ben?
    ... length of the rod, setting up measurements at their will, ... manner, each in his frame. ... and L is the measured (and at the same time the proper) length ... it doesn't matter whether the measurements ...
    (sci.physics.relativity)
  • Re: Frame dependent distances in relativity?
    ... Since SR predicts that length measurements are frame-dependent, ... invariance was a result of special relativitys clocks and rulers). ... The postulates aren't "depending upon a transformation". ... measurements are not "rigid", but frame dependent. ...
    (sci.physics.relativity)
  • Re: Frame dependent distances in relativity?
    ... Since SR predicts that length measurements are frame-dependent, ... invariance was a result of special relativitys clocks and rulers). ... The postulates aren't "depending upon a transformation". ... measurements are not "rigid", but frame dependent. ...
    (sci.physics.relativity)