Re: Twin paradox revisited ll

On Jul 14, 7:49 pm, "Martin Hogbin" <goatREMOVETHIS...@xxxxxxxxxx>
wrote:

Sorry, I did not see your response to my reply to your previous post
so I will respond to that now.

----------------------------------------------------------------
[cosmosco]
My question is - does the claim that the traveller does not age at the
slower rate but that his twin ages at a faster rate and only during
the ships period of acceleration following turn around still have any
support?

[Hogbin]
Your question is still not clear to me. The two twins age
differently with respect to one another. To say one ages
'at a slower rate' has no meaning unless you say with
respect to what.

The concept of the more rapid aging of the stay at home twin (but only
during acceleration following turn around) claims that his clock
physically ticks over at a faster rate than the traveler's clock
during that period of acceleration only. That the traveler does not
age at a slower rate than his twin as shown by special theory but that
the twin ages at a faster rate than the traveler.

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 not what that concept said. Its proponents insisted, in my
opinion - totally in contradiction with SR, that they would not
measure the other to be aging slower during the cruising phase of the
flight (in either direction) but that the age differential only takes
place during acceleration following turn around.

During the turn-around the situation is more complicated.
The earthbound twin remains in an (approximately) inertial
frame throughout. 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.

I fully agree but those proponents insisted that regardless of what is
observed by the inertial twin it is not the traveler's clock that runs
more slowly as the traveler accelerates to begin his return journey
but that it is the inertial twin's clock that runs faster than it did
when the ship was at a stop prior to return acceleration.

They also insisted that at the very instant the traveler stops
accelerating this variation in aging rates ceases. As I pointed out in
my responses at the time, if this were so then the traveler could
obliterate all life on this planet simply by taking his foot off the
gas pedal.

As the traveller turns round, they are not in an inertial frame.

If he comes to a stop then reverses his motors he is temporarily in
the same quasi-inertial frame as the planet. Alternatively, if he is
in the centre of the ship as it turns end over end he is neither
moving away from nor toward the earth.

As a matter of interest; what would SR say regarding one clock that is
spinning on its own axis relatively to a stationary clock?

Measurements made from non-inertial frames are weird, but
one view they might take is that time for the inertial twin
rushed forward during the turn-around. Neither the
earthbound twin nor anyone else on Earth would notice
anything odd during this time.

snip

[cosmosco]
If there was no dissent there would be no progress. Several authors
have accepted that special theory may eventually be replaced.

[Hogbin]
There is research into relativity on two basic fronts. Firstly
into the mathematics of general relativity, which is
complicated. Secondly, most current research is into
reconciling relativity with quantum mechanics.

I prefer to stick with the subject of special theory's concept of time
dilation and the resultant 'twin paradox'.

Special relativity and quantum mechanics are both related to the
solipsist notion that observation creates reality.

If this
succeeds then there may well be a theory to replace
relativity but relativity will probably still stand as an
excellent approximation in non-quantum cases, just as
Newtonian physics stands as an approximation to
relativity.

In his book 'Relativity, the Special and General Theory' (p. 76, Crown
Publishers, 1961), Einstein pointed out that whilst general theory
shows that the speed of light is affected by a gravitational field,
special theory still stands as an excellent approximation in zero-
gravity cases(that SR lives on in GR as a limiting case). To the best
of scientific knowledge there is no place in the entire universe that
is completely free from gravity ergo there is no limiting case to
which SR can be applied.

Science insists that the earth's gravitational field strength is so
weak that it can be ignored for the purpose of any related experiments
and that it has no lateral effect on any object that is being made to
move across that field but this does not take into account the effects
of gravity on a particle that has been accelerated to near light
speed.

[cosmosco]
Thanks Martin, although, as you point out, the respective ageing of
the twins during the journey has several interpretations perhaps you
could let me know of one that has been completely accepted by the
scientific community?

Preferably one that is presented in everyday language and is not
reliant on mathematical equations.

[Hogbin]
To the best of my knowledge the descriptions I have given above
represent the accepted view of how each twin will measure things.
Does this answer your question?

--
Martin Hogbin

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

Confucius stated "Knowledge is one dimensional, the proper application
of knowledge is multi dimensional. Only the extremely wise, and the
exceptionally foolish, are not prepared to change."

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.

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

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?

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.

Bill

.

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