Re: Twin paradox revisited ll

On Jul 15, 7:10 pm, "Martin Hogbin" <goatREMOVETHIS...@xxxxxxxxxx>
wrote:
<cosmo...@xxxxxxxxxxxxxxx> wrote in messagenews:1184459344.132792.294170@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Jul 14, 7:49 pm, "Martin Hogbin" <goatREMOVETHIS...@xxxxxxxxxx>
wrote:
You wrote that...

Why not place your response directly under my text to
save you having to repeat it?

I'm still a newbie and don't understand what you mean by that.

...if each twin were to measure the aging of the other,
making allowance for the transit time of light or radio or whatever
measurement medium they used, they would each measure the other to be
aging slower during the cruise phase of the flight.

This is, of course, based on the doppler effect

No, it has little to do with the Doppler effect.

As the traveler moves away from the earth at a uniform velocity is his
image (or the radio messages that he sends) not red shifted from his
twin's point of view and is this effect not known as the Dopler
effect and is this not the information obtained by the twin that
causes him to conclude that the traveler is aging at the slower rate?

What else is it, other than the red shift of the light from the
traveler or of the radio messgaes that he transmits that causes his
twin to assume that the traveler is aging at the slower rate?

If it is not the Doppler shift of the light or the radio signals
emitted from the earth that causes the traveler to insist that his
twin is aging at the faster rate what else is it that generates this
phenomenon?

You wrote 'it has little to do with the Doppler effect' so I assume
that it has something to do with that effect.

whereby those messages
are blue shifted from both points of view and is related to the above
mentioned concept that observation creates reality. The question is,
are they both physically aging slower than each other during the
cruise phase of the flight

Yes, they are.

or is this nothing more than a visual
illusion created by changing perspectives?

No.

After so many years of discussion on this subject I think it should be
unecessary for me to repeat the question but if they are both aging at
(presumably identical) slower rates than each other aren't they aging
at the same rate as each other?

I'm sorry, but a simple 'no' doesn't impart a great deal of
information.

In his book 'An Introduction to the Special Theory of Relativity'
Professor Robert Katz wrote that according to physics, reality is
determined by what has been measured i.e. that observation
(determination) creates reality.

Agreed.

Whilst both observers measure (or determine) that the other person is
aging at a slower rate than themselves this obviously cannot represent
reality. They cannot both be aging at the same slower rate than each
other

Why not?

otherwise they are aging at the same rate as each in other...

No, they each measure the other to be aging more slowly.

And there we have it, the traveler, obviously grossly ignorant of
special theory and Einstein's 1918 article assumes, on the basis of
the red shift of the light emitted by the earth clock, that his twin
is physically aging at a slower rate than he is.

Einstein pointed out in his 1918 article that it is the clock (or
twin) that physically experiences the force of accelration which is
the one that incurs time dilation however our intrepid traveler,
having experienced that force of acceleration, pointedly ignores
Einstein's suggestion and insists that it is the earth, and the rest
of the universe, that is now moving relatively to him.

The traveler can only assume that a force that is greater than the
infinite mass of the universe has caused it to start accelerating.

...words
- the twin paradox.
You also wrote that as the traveller turns around, the inertial twin
would measure the travelling twin's time to return to normal as the
traveller came to a stop and then run more slowly again as the
traveller accelerated to begin their return journey.

So although the inertial twin now sees blue shift of the ship's image
he is still of the opinion that the traveler's clock is ticking over
at a slower rate than his own clock irrespective of the fact that he
previously arrived at the same conclusion on the basis of the red
shift of the departing ship's image/radio messages.

Blue and red shift have nothing to do with it. They are what the
inertial twin _sees_.

How can he determine slow running of the traveler's clock on the basis
of the red shift of that image and on the basis of the blue shift of
that image?

By knowing what the cause of Doppler shift is and making the
necessary corrections.

Having made the necessary corrections and if 'blue and red shift have
nothing to do with it' - what other information does the inertial twin
receive which gives him the impression that the traveler is
alternately aging at slower and faster rates than himself?

Whilst you have answered my question regarding an interpretation that
has been completely accepted by the scientific community that
interpretation does not, in my opinion, make sense.

That is because you choose to believe your own preconceptions,
based on everyday experience,

What preconceptions? Please detail same.

I have no everyday experience in relation to a space traveler moving
away from or toward this planet at relativistic velocities.

Perhaps you could describe it as a preconception but I do not believe
that the traveler could be of the opinion that as the result of his
relativistic rate of travel toward us the earth is physically orbiting
the sun at close to the speed of light or that, whilst on the outward
bound trip, the earth's rate of travel around the sun had physically
decreased from 30,000m-s to a sluggish 1m-s irrespective of the fact
that this is what he would 'see'.

rather than the experimental
evidence.

--
Martin Hogbin

What experimental evidence, other than that dealing with the Doppler
effect, shows that the inertial twin will determine that the traveler
is alternately aging at a slower then faster rate than he is?

Particle acceleration experiments show that when muons are made to
travel at rapid velocity they 'live longer' than those which are
comparitively at rest in the laboratory however the claim that, from
the muons point of view, it is the laboratory clocks that are ticking
over at the faster rate is merely an assumption. Muons don't have
points of view - at least none that have been 'observed' or
'determined.'

I get the feeling that you are deliberately going around in circles in
order to obfuscate this discussion.

.

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