Doppler shift vs second postulate (redux)

---{continuation of prior thread "Doppler shift vs second
postulate"}---

On Jun 24, 6:00 pm, Martin Hogbin <goatNOSP...@xxxxxxxxxx> wrote:
ron_ai...@xxxxxxxxxxx wrote:
<<<<snip>>>>
Is the "second postulate" physics or mere convention?

The clue is in the name - 'postulate'. As Einstein
made clear, the second postulate is a free choice or
something that is taken to be true, an axiom, if you
like. It is a convention.

Martin, you are confused re postulates and conventions; the latter
are essentially meaningless (as far as the laws of physics are
concerned), whereas the former are - as you said - assumed to be
true as a basis for further physical advancement.

Convention: The inch equals 3 barleycorn laid end-to-end

Postulate: The American theorists Murray Gell-Mann & George Zweig
independently postulated the existence of quarks

All scientific postulates must be experimentally testable.

All scientific postulates must say pertain to the nature
of nature.

A scientific postulate is a guess, a supposition, a
hunch, or a hypothesis about the nature of nature.

One does not assume a convention to be a physical truth. One merely
dictates a convention as a matter of convenience.

Convention: In order to have some sort of clock "synchronization,"
clocks can be adjusted to get the same travel time each way for
one-way light rays. (Nickname: "standard synchronization" What it
is NOT: absolute synchronization)

Postulate: Nature will not allow us to absolutely synchronize our
clocks in order to measure the one-way light speed anisotropy (that
certainly exists since light's speed through space never changes).


... if you know of a way to absolutely synchronize clocks
you can proove us all wrong by telling us how to do it.

See my latest post to Dr. David.

Is that in this thread or another? You seem rather
reluctant to propagate your world shattereing
discovery. Why not post it here? Are you afraid of
raucous laughter?

Have you never heard of "the invention being stolen"?
I gave Dr. David some dead-on hints, but he merely got
more confused. Maybe you can take the hints and figure
it out?

What are 'slowed clocks' and 'contracted rulers' and
how can I tell if I have got one?

Here's one answer:
They are exactly what YOU need to show on paper the
round-trip invariance (the null result).

(Yes, I am saying that you cannot show the null result
on paper without using a slowed clock and a shrunken
ruler.)

Of course I can. Just draw a diagram showing what
happens in one inertial reference frame. Now, in a
different inertial frame the same diagram applies
exactly, no lengths are changed, no clocks slowed, and
the speed of light is the same in both cases. Null result.

No, you cannot show two inertial frames getting round-trip
light speed invariance without showing at least one frame's
ruler physically contracting and its clock physically slowing.
Merely stating that you can does not make it so.

Here's another answer:
If Triplets Timmy and Tommy move rapidly apart after
meeting in passing when their ages match, then the third
Triplet Tony meets Tommy in passing, and their ages also
match, and then Tommy and Timmy meet in passing, we will
find that their ages DO NOT match; this is called "time
dilation" or "clock slowing," and it is very easy to tell
if you have it by looking at Tommy and Timmy when they
meet. One will be much older than the other. (Hint: look
for wrinkles and gray hairvssmooth skin and black hair!)

As you well know, each triplet will measure the others'
clocks to be running slowly. How can we decide which
one is really slowed?

Did you not read the above?

The clock that is really slowed is the one that the younger
twin carried.

Any more questions?

Yes, well actually it is the same one because you have
not anwered it propery. I have a watch in my wrist.
How can I tell if it is a 'slowed clock'?

By measuring its speed through space. Just as the twin who
moves faster thru space ages less, the clock that moves
faster thru space runs slower. (Of course, the only way to
measure a clock's speed thru space is by measuring your
speed relative to Nature's absolute frame, any passing ray
of light. Light is an absolute frame because its speed thru
space is both unchanging and known.)

I have a ruler on my desk, is it a contracted ruler?

Martin Hogbin

Odds are, it is. But, see above.

***RA***
.

Relevant Pages

  • Re: Das 3. Postulat der Relativitätstheorie (Clock Hypothesis)
    ... "The Clock Hypothesis states that the tick rate of a clock when ... its acceleration, doesn't that mean the Equivalence Principle ... result of acceleration: changing speeds! ... "So the clock postulate says that the rate of an accelerated clock doesn't ...
    (de.sci.physik)
  • Re: What happened between Newton and Einstein?
    ... From this postulate was directly derived the Lorentz ... The Lorentz transforms in turn implied that a clock ... or absolute motion through space, ... is the only possible cause of the age differences ...
    (sci.physics.relativity)
  • Re: What happened between Newton and Einstein?
    ... From this postulate was directly derived the Lorentz ... a greater time elapsed between two events than a clock ... or absolute motion through space, ... I don't see how absolute motion is the *only* possible ...
    (sci.physics.relativity)
  • Re: GPS CLOCK PARADOX
    ... | According to relativity, ... | The GPS clock paradox is a variation of the twin paradox, ... The paradox resides in the third postulate. ... using the Lorentz. ...
    (sci.physics.relativity)
  • Re: Analysis of gas mode MM interferometer operation using standard SR formulae.
    ... |>| Define variables for light speeds relative to the interferometer frame ... |>| for the equivalent speeds relative to the 3-space frame as follows. ... | The postulates of special relativity only ...
    (sci.physics.relativity)