Re: Circular motion in SR

On Mar 23, 10:53 am, PD <TheDraperFam...@xxxxxxxxx> wrote:
On Mar 22, 10:50 am, rbwinn <rbwi...@xxxxxxxx> wrote:

On Mar 22, 7:27�am, PD <TheDraperFam...@xxxxxxxxx> wrote:

But the rotation of the sun is not the standard. The standard is
defined in terms of reproducible physical processes that can be
replicated locally.

Well, The Galilean transformation equations can be referenced to the
rotation of the sun, but not to reproducible physical processes
replicated locally.

By choosing some distant reference, one can *always* impose an
absolute time, sacrificing all locally consistent behavior. That,
however, is not an obviously superior position. It leaves you with the
situation that, in terms of rotations of the sun, an observer at rest
can measure radioactive half-lives, the growth of trees, the
population of bacteria, an AC-circuit resonance period; but as soon as
you go to a frame in which the sun is moving, then you need to *first*
redefine seconds to be in terms of that distant sun's rotation, and
then after doing so you note that all your local radioactive half-
lives, the growth of the trees, the population of bacteria, and the AC-
circuit resonance period have all changed in terms of the new second.
Seems rather stupid, just to preserve the rotation rate of the distant
sun and to preserve a Galilean transformation.

If you make this change just to preserve the Galilean transformation,
and as a result you find that all local physical phenomena now have
different rates, then this *normally* would be an indication that the
Galilean transformation is not a good one to insist on. And in fact,
the Galilean transformation was thought to have value when it was
believed that you would not *have to* do the goofy redefinition of the
second you propose. When it was found out that you'd have to, most
reasonable people began to look for a better transformation than the
Galilean one. You on the other hand, want to preserve the Galilean
transformation, even though it would mean that all local physical
processes would now have different rates. Why you think that's better
is beyond me.

I think that local physical processes having different rates is
reality,

But there is no evidence for it. Note that all the local physical
processes would have to have their local rates affected by *exactly*
the same amount, even though they are completely different processes.

Well, something you do not seem to have considered is that what you
are calling the speed of light is the rate at which the elements react
with each other at a certain place and time.

and if they are affected by velocity,

They are NOT affected by velocity. I already tried to address this
with you. The differential aging of the twins does NOT have to do with
the speed of one of the twins.

Well, you try to claim the twin is going through some kind of time
warp or something. I think the twins are the same age, whatever one
twin might have been put through by science because they were born at
the same time.

I believe that there
may be other factors which also affect local physical processes.  What
I cannot understand is the position of scientists.  Scientific time is
the only measurement of time allowed.  OK, so what about your twin
theory?  How do they ever get back together according to scientific
time?
If they do, then obviously, there is some measurement of time that
includes the separation of the twins and their reuniting, which could
be calculated in either frame of reference.

No, sir. There is only frame-dependent time. There is no single time
measurement that both both twins would agree on. (You also mention
"either frame of reference" as though there were two. There are not
two. There are at least three.

Right. If you can't answer something, try to make it more
complicated. Really there are at least 7,238. You say there is only
frame-dependent time, but anyone can determine for themselves that the
same event can be observed from two different frames of reference and
used to measure time in both frames of reference, just as the Galilean
transformation equations show.

  So, as the Galilean
transformation equations show, there is not a different number of
separatings and reunitings in one frame of reference as compared to
the other.

OK

 And the twin does not leave and return in one frame of
reference and then wait until he finishes returning in the other.

OK

 If
time is measured by separatings and reunitings in each frame of
reference,

But it's not.

OK, so you refuse to consider the separating and reuniting of the
twins. That does not mean it does not happen.

It's measured according to the number of seconds
elapsed, and the number of seconds elapsed is determined by a standard
second that is defined in terms of local physical standard, and
against which it is verified that all physical processes behave the
same in every inertial reference frame. (That is, trees grow in the
same way, thorium samples decay in the same way, bacteria multiply at
the same rate, hair grays at the same rate, etc.) And by those
standards, the interval of time between the separating and reuniting
of the twins is *different* between the two twins.

Well, if we are not allowed to count time any other way, I guess a lot
of people are going to be criminals by your standard. There are still
people who count days by the rising and setting of the sun.

then t'=t, just as the Galilean transformation equations
show.  The difference in clock rates will not affect how many times
the twin leaves and returns.  But you would have to decide which clock
has the more meaningful time in describing what took place.

No, you don't. You don't have to say, "Well, we have to choose one to
be more correct and the other less correct." Likewise, when I tell you
that your speed right now is either zero or 850 mph, depending on
whether you are looking at a frame tied to the earth or one that isn't
rotating with the earth, there is no need to say one is more "right"
than the other. Your speed is simply a frame-dependent quantity, as is
your kinetic energy, as is your momentum, and is a whole host of other
completely useful and completely frame-dependent physical quantities.

I did not say one was more correct than the other, I said one was more
meaningful than the other. If you want to measure everything by
transitions of a cesium atom, it seems to me that you are free to do
it. Just don't try to tell me that you are more intelligent than
everyone else because that is what you decided to do.

Robert B. Winn
.

Relevant Pages

  • Re: Circular motion in SR
    ... defined in terms of reproducible physical processes that can be ... Galilean transformation is not a good one to insist on. ... the speed of one of the twins. ... be calculated in either frame of reference. ...
    (sci.physics.relativity)
  • Re: Circular motion in SR
    ... defined in terms of reproducible physical processes that can be ... the speed of one of the twins. ... be calculated in either frame of reference. ... "either frame of reference" as though there were two. ...
    (sci.physics.relativity)
  • Re: Circular motion in SR
    ... defined in terms of reproducible physical processes that can be ... the speed of one of the twins. ... be calculated in either frame of reference. ... "either frame of reference" as though there were two. ...
    (sci.physics.relativity)
  • Re: Circular motion in SR
    ... defined in terms of reproducible physical processes that can be ... the speed of one of the twins. ... be calculated in either frame of reference. ... whether you are looking at a frame tied to the earth or one that isn't ...
    (sci.physics.relativity)
  • Re: Circular motion in SR
    ... defined in terms of reproducible physical processes that can be ... Galilean transformation is not a good one to insist on. ... the only measurement of time allowed. ... be calculated in either frame of reference. ...
    (sci.physics.relativity)