Re: Twin paradox revisited ll


"bill" <cosmosco@xxxxxxxxxxxxxxx> wrote in message
news:1185497595.555218.10920@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
: On Jul 27, 6:48 am, "Martin Hogbin" <goatREMOVETHIS...@xxxxxxxxxx>
: wrote:
: > "bill" <cosmo...@xxxxxxxxxxxxxxx> wrote in
messagenews:1185416809.446909.24230@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
: > > Martin Hogbin wrote:
: > > > "bill" <cosmo...@xxxxxxxxxxxxxxx> wrote in
messagenews:1185339722.394291.34610@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
: >
: > > > > If something that happens cannot be described in everyday language
: > > > > then in my opinion that 'thing' or 'event' does not take place. If
it
: > > > > can only be 'described' in mathematical 'language' or propositions
I
: > > > > agree with Einstein that it has no place in the real world.
: >
: > > > Experiment indicates otherwise.
: >
: > > Please provide an example of an event or a 'thing' that can be
: > > experimentally tested but which cannot, of itself, be explained in
: > > everyday language.
: >
: > The results of all the experiments that confirm relativity
: >
: In other words - in your opinion - the results of the Michelson-Morley
: experiment *cannot* be explained in everyday language.
:
: In your opinion - the results of the Hafele-Keating experiment cannot
: be explained in everyday language? I refer you to Clifford M Will's
: book 'Was Einstein Right?' in which he (p.54, Oxford University Press,
: 1986) clearly explains, *in everyday language*, the results of those
: experiments.
:
: In your opinion - the results of particle acceleration experiments
: *cannot* be explained in everyday language?
: >
: > > > > > In SR, a clock made to travel on a circular path is not in an
inertial
: > > > > > frame. Making measurements from a non-inertial frame is
: > > > > > complex and bizarre. Even in Newtonian mechanics, measurements
: > > > > > from non-inertial frames are significantly more complicated.
: >
: > > > > The Hafele-Keating experiment as well as information garnered from
: > > > > global positioning satellites and from particle acceleration
: > > > > experiments have *all* involved non-inertial frames yet they are
*all*
: > > > > cited as providing confirmation of SR.
: >
: > > > None of what you say negates what I have said above.
: >
: > > I did not suggest that my comments *negate* SR just that they are
: > > examples of *your* comment that "a clock made to travel on a circular
: > > path is not in an inertial frame."
: >
: > > > SR is a special case of GR. SR is generally taken to include
everything
: > > > in GR except gravitation.
: >
: > > In 'Relativity (the Special and General Theory)' Einstein wrote (p.76,
: > > Crown, 1961) that
: > > special theory *only* applies to *zero* gravity locations.
: >
: > As I said,SR does not include gravitation and strictly speaking should
: > not be used when gravity is involved. My point was that gravity
: > can play a relatively minor or even insignificant role. Ultimately
: > every experiment should be analysed using GR but is many cases
: > SR is sufficient in practice. I would agree with you that the GPS
: > should not be quoted as evidence of SR since gravitation plays
: > a small but significant role.
: >
: > > > The experiments you quote confirm relativity.
: >
: > > On the basis (of what I understand is a primary tenet of physics) that
: > > no experiment can *prove* a theory only *dis*prove a theory those
: > > experiments do *not* as some people insist *prove* SR but merely
: > > appear to confirm its concepts.
: >
: > That is what I said.
: >
: > > > > A version of the traveler's journey whereby he does not take a
: > > > > straight out and return journey but travels in a circular path
: > > > > provides the same argument as the former example but - as you
point
: > > > > out - this is *not* an 'inertial frame' journey.
: >
: > > > > > > He *can* say that the stationary clock *IS* ticking over at a
faster
: > > > > > > rate than his clock but to insist that this has *physically*
occurred
: > > > > > > - that the rate of operation of the stationary clock has
*physically*
: > > > > > > increased rather than the fact that the rate of operation of
*his*
: > > > > > > clock - as the result of its rate of travel with respect to
the
: > > > > > > stationary clock - has decreased, is solipsist nonsense!
: >
: > > > > > You really must try to understand the point I am making about
: > > > > > use of the English language. You _must_ define exactly what you
: > > > > > mean by each of your emphasised words.
: >
: > > > I note that you decline to do this.
: >
: > > Because I am of the opinion that it is a waste of effort to explain
: > > what I mean by 'can' and 'is' and 'physically' and 'his'. If you can't
: > > understand what I am saying then I would be wasting my time trying to
: > > explain it. There is *no* _must_ about it.
: >
: > But this is what physics is about. How can I tell if something
'physically'
: > happens? If there is no objective way to tell, it is not physics just
your
: > personal feelings.
:
: And the concept that the earth bound twin physically ages at the
: faster rate and only during acceleration following turn around is
: *not* physics but is just the personal feelings of the traveller.
:
: > > > > Thank you, that's precisely my point. A traveler who insists that
the
: > > > > earth's axial spin decreases or increases on the basis that what
he
: > > > > sees is, from his point of view reality, would also insist that
Hafele
: > > > > or Keating *would* have concluded that it was the planet's axial
spin
: > > > > that had slowed down.
: >
: > > > I am not sure what you mean here. Are H and K on a plane with
: > > > one of the clocks or on the Earth's surface.
:
: > > The latter. Having returned to the laboratory at the end of the second
: > > journey they determine the time differences between the clocks. They
: > > could either conclude that their clocks ticked over at the faster rate
: > > *or* that the laboratory clocks ticked over at a slower rate which
: > > would mean that the earth's axial spin had also decreased.
: >
: > No, you are continuing to think of time as being absolute. In a
: > relatively moving frame the Earths rotation does indeed slow down.
: >
: Pardon the pun but you keep going round in circles.
:
: The earth's rotation does *not* slow down - this is merely the
: personal feelings of the traveller.
: >
: > > > > We could move the HKX to the abovementioned off-earth circular
: > > > > trajectory journey where the astronaut commences his trip from a
: > > > > geostationary location. This is precisely the same as Einstein's
: > > > > reference to a clock that is made to travel in a circular path
around
: > > > > another clock but the traveler's course (clock's path) is
eccentric to
: > > > > the earth (Einstein's central clock).
: >
: > > > > For that astronaut to insist that during his trip the earth's
axial
: > > > > spin alternately increased and decreased is just as nonsensical as
: > > > > Hafele or Keating insisting that the earth's axial spin physically
: > > > > decreased during the first part of the experiment and that it
: > > > > increased during the second part of their experiment.
: >
: > > > As I have said before, to attempt to describe what is observed
: > > > from a non-inertial frame is difficult - but possible.
: >
: > > > > I am of the opinion that at least *some* of the world's physicists
: > > > > might agree with Hafele and Keating that the laboratory clocks did
: > > > > *not* tick over at a faster rate than their own clock during the
first
: > > > > leg of the experiment because for this to take place they would
also
: > > > > have to believe that the earth's axial spin had increased and that
the
: > > > > earth's axial spin decreased during the second leg of that
experiment.
: > > > > Seemingly you do not believe that either Hafele or Keating would
have
: > > > > insisted that this actually took place.
: >
: > > > From any relatively moving reference frame, the Earth's rotation
: > > > does indeed slow down.
: >
: > > So *now* you are suggesting that Hafele and Keating *should* have been
: > > of the opinion that the earth's rotation *was* affected by *their*
: > > location in a "relatively moving reference frame." That's *not* what
: > > you said before.
: >
: > I was not sure where they were supposed to be. In a relatively moving
: > frame the Earth's rotation does slow down. We, of course, notice
nothing
: > because we are on the Earth.
:
: The concept that 'the earth's rotation does slow down' is merely the
: personal feelings of the traveler.
:
: > > > > I assume that you mean that *all* of the world's physicists would
say
: > > > > that a clock that is moving past another clock would physically
tick
: > > > > over at slower rate than the latter and that the latter would
: > > > > physically tick over at a slower rate than the former
: >
: > > > As ever, you have not defined what you mean by 'physically'.
: >
: > > As distinct from 'seemingly' as a result of a visual illusion as per
: > > the steel rod in a tank of water example.
: >
: > In that case, yes. See my other post.
: >
: > > > > which is *not*
: > > > > what Einstein wrote in his 1918 article where he insisted that it
is
: > > > > *only* the clock that experiences the force of acceleration as it
: > > > > moves to the other clock's location *which is the one that has
: > > > > incurred time dilation*. Of course, all the world's physicists
might
: > > > > not agree with Einstein.
: >
: > > > Overall, it is the non-inertial twin whose clock runs slower. That
: > > > is the point that Einstein was making in his 1918 article.
: >
: > > That is *precisely* the point I am trying to make!
: >
: > > According to *Einstein* it is the non-inertial clock that ticks over
: > > at the slower rate than the inertial clock and anyone who insists
: > > that the inertial clock ticks over at the slower rate on the basis
: > > that this is what the non-inertial twin observes is contradicting
: > > Einstein. According to that article, Einstein was of the opinion that
: > > it is *only* the non-inertial clock that, in *reality* physically,
: > > really, actually, incurs time dilation.
: >
: > No, you are misunderstanding him.
:
: Did he, or did he not insist in that article that it is the clock
: that experiences the force of acceleration which is the one that
: incurs time dilation?
:
: You wrote, above, "Overall, it is the non-inertial twin whose clock
: runs slower. That is the point that Einstein was making in his 1918
: article."yet when *I* write that my understanding of that article is
: that 'it is the non-inertial twin whose clock runs slower' you insist
: that I am misunderstanding him!
:
: > Inertial frames are special and making measurements in makes
: > life easy. which is why it is fairly easy to calculate the elapsed time
: > of the traveller from the Earth's reverence frame.
: >
: > Calculating the elapsed time for the earthbound twin from the
: > frame of the traveller is much harder, but possible.
: >
: > > > To make life a little easier let us assume the journey takes place
: > > > in three stages. We assume a flying start and finish in which the
: > > > traveller passes by Earth at speed and when very close to his
: > > > twin they compare clocks (and photographs of one another).
: >
: > > In his 1918 article Einstein insisted that the *only* way that the
: > > rates of operation of the clocks can *physically* be compared is when
: > > they are *stationary* alongside each other i.e. located in the *same*
: > > inertial reference frame.
: >
: > No he did not. Obviously clocks can be compared when
: > they are in motion, provided that they are in the same place.
:
: I am of the opinion that your denial that this is what Einstein wrote
: in that article is erroneous.
:
: > Of course you cannot compare the rates of two clocks by
: > this method because, if they are in relative motion, they will
: > only be at the same place for an instant
:
: You are going round in circles again. You wrote "Obviously clocks
: *can* be compared when they are in motion" and now you state "you
: *cannot* compare the rates of two clocks by this method...."
:
: You wrote "...if they are in relative motion, they will only be at the
: same place for an instant.."
:
: I suggest that *the rates of operation* of the clocks *cannot* be
: determined *in an instant* nor can their rates of operation be
: compared by looking at photographs of same.
:
: > > > During the cruise phases each twin measures the other's
: > > > clock to be running more slowly than his own. Neither
: > > > has any special claim to considered 'correct'.
:
: > > And it seems to me that this paradox is *precisely* what Einstein
: > > sought to overcome.
: >
: > Absolutely not. Which one would you say is correct?
:
: I'm not talking about which one *I* would say is correct but what
: *Einstein* 'said' in that article.
:
: > > > During the turnaround the earthbound twin measures the
: > > > traveller's clock to be running more slowly, dependent only
: > > > on the traveller's relative velocity.
:
: > > Having come to a stop the traveler's clock is in the same reference
: > > frame as the earth clock hence it is ticking over at the same rate as
: > > his twin's clock. He flips his ship end over end and during this turn
: > > around period - on the assumption that he and his clock are at the
: > > centre of his ship - he has *no* relative velocity other than the fact
: > > that, during the few minutes that it takes to flip the ship over, he
: > > is *not* moving toward, or away from, his twin. If he, having come to
: > > a stop, simply reverses his motors he has absolutely *no* velocity
: > > relatively to his twin so how can the latter measure his twin's clock
: > > to be 'running more slowly'?
: >
: > That is what I said. The clock is measured to be running slowly
: > when it is moving to and from the Earth. When it is stationary
: > with respect to the Earth it is measured to run at the same speed
: > as you quite rightly say.
:
: No that is *not* what you said. You wrote that "*During the
: turnaround* the earthbound twin measures the traveller's clock to be
: running more slowly." You did *not*, in that sentence, say that "The
: clock is measured to be running slowly *when it is moving to and from
: the Earth.*"
:
: > > > During the turnaround the travelling twin measures some
: > > > very strange things such as the earthbound twin's clock
: > > > running backwards! Note however that he is making his
: > > > measurements in a non-inertial frame.
: >
: > > He measures (sees, determines, observes) that his twin's clock is
: > > running backwards in contradiction of the respective laws of physics
: > > as they apply to the physical operation of clocks and measures (sees,
: > > determines, observes) his twin's beard *reducing* in length or his
: > > twin coming back out of his grave and he *believes* that this is
: > > *physically* (really, actually) taking place? *Very* strange things
: > > *indeed*.
: >
: > Yes, that is why we do not make measurements from non-inertial
: > frames.
: >
: > > The idea that the traveler 'can' see his twin arising from the grave
: > > or the earth spinning backwards on its axis or its orbit of the sun
: > > reversed are prime examples of the type of solipsist nonsense - on
: > > behalf of the *traveler* of course - that I believe should *not* be
: > > applied to physics.
: >
: > You can believe what you like but physicists believe the
: > results of experiment.
:
: I note your reference to 'physicists' rather than you previous
: reference to *all* physicists.
:
: If I were talking to a physicist who truly believed, as apparently do
: you, that the earth bound twin's casket disinters itself and that the
: twin comes back to life I would tend to walk away from that
: discussion.
:
: > > > When the two twins meet, they both agree that the traveller
: > > > has aged less. The earthbound twin puts this down to the
: > > > fact that the other twin's clock has run slower that his own
: > > > during the journey.
: >
: > > > The traveller's explanation is that the earthbound twin's clock
: > > > went wild during the turnaround.
: >
: > > The earth bound twin's clock went wild or the traveler's mind went
: > > wild?
: >
: > > > Neither twin noticed anything odd going on with their own
: > > > clock although the travelling twin was able to detect that
: > > > he was not in inertial motion during the turnaround.
: >
: > > Having been of the opinion that during the first stage of the event it
: > > was the earth clocks that were ticking over at the slower rate - the
: > > traveler, in order to comply with Einstein's insistence that the
: > > *only* way that the rates of operation of the respective clocks can be
: > > *physically* (actually, really) compared, bring his ship to a stop,
: > > turns it around and *accelerates* to the earth's location and, having
: > > learned Einstein's 1918 concept, that it is *him* and *his* clock,
: > > having experienced that force of acceleration, which incurs time
: > > dilation thus that whilst he is of the opinion that the rate of
: > > operation of his clock has remained constant he *must* conclude that
: > > in *reality*, i.e. as insisted upon by Einstein, his clock was ticking
: > > over at the slower rate.
: >
: > Why does the traveller not conclude that the Earth based
: > clocks have run fast?
: >
: He does *not* believe that the earth based clocks have run fast on the
: assumption that he is aware of and accepts Einstein's 1918 article
: concept that his is the non-inertial reference fame.
:
: > > > > Although the Hafele-Keating experiment did not involve SR's
required
: > > > > inertial reference frames I presume that *some* of the world's
: > > > > physicists would agree that the flying clocks ticked over at a
slower
: > > > > rate than the laboratory clocks during the first leg of the
experiment
: > > > > thus that they agree with Hafele and Keating's (assumed) decision
that
: > > > > the earth's axial spin did not slow down.
: >
: > > > Are you talking about earthbound physicists or the ones who
travelled
: > > > with the clocks?
: >
: > > Are you *now* contradicting your previous comment that Hafele and
: > > Keating would *not* have been of the opinion that the earth's axial
: > > spin decreased or increased as the result of their rate of travel with
: > > respect to the laboratory clocks.
: >
: > > I am talking about *both* sets of physicists.
: >
: > They would conclude different things.
: >
: > > Obviously Einstein's accomplishment meant *nothing* to people who
: > > effectively suggest that the earth bound twin can arise from his
grave.
: >
: > > > > > > In 1989 I read an article in a local newspaper supposedly
quoting
: > > > > > > David Mermin from Cornwell University as stating that the moon
: > > > > > > physically ceases to exist if nobody looks at it. The author
continued
: > > > > > > that it is the actual act of looking at the moon that creates
its
: > > > > > > reality and that this is the belief held by some of the
world's best
: > > > > > > physicists.
: >
: > > > > > Such points may be relevant to a discussion about quantum
: > > > > > mechanics but they are not relevant to SR.
: >
: > > > > The 'observation creates reality' concept that the moon ceases to
: > > > > exist if nobody looks at it or - conversely - that it is the act
of
: > > > > observation that creates reality, *is* relevant to the idea that
if
: > > > > the traveler observes the other clock to be ticking over at a
slower
: > > > > rate than his own clock this is, in his opinion, 'reality' in the
same
: > > > > way that Hafele or Keating (hypothetically) observing the
laboratory
: > > > > clocks apparently ticking over at faster rate than their own
clocks
: > > > > could have assumed that the laboratory clocks *were* ticking over
at
: > > > > the faster rate than their own clocks thus, consequently, that the
: > > > > earth was spinning at a faster rate than it was before they took
off.
: >
: > > > Whether a moving observer chooses to observe a clock in a
: > > > different inertial frame or not it is still ticking more slowly than
: > > > his own.
: >
: > > And the traveler who, having accelerated following turn around,
: > > insists that his clock is *not* the clock referred to in Einstein's
: > > 1918 article as being the one that *is*ticking over at the slower rate
: > > is deluding himself regardless of whether or not he can *see* his
: > > twin's clock.
: >
: > > > > Einstein stated "As far as the propositions of mathematics refer
to
: > > > > reality, they are not certain; and as far as they are certain,
they do
: > > > > not refer to reality." He, of course, referred to *all* other
: > > > > propositions of mathematics *except* SR did he?
: >
: > > > Not especially.
: >
: > > That's a deliberately limp response.
: >
: > Yes, because that is a completely irrelevant quote, even if it
: > was by Einstein.
:
: The concept of relativistic 'Doppler' effect is based on the special
: theory mathematical proposition that a moving clock ticks over at a
: slower rate than a stationary clock.
:
: We are discussing Einstein's concept of time dilation therefore I am
: of the opinion that any comments made by Einstein in relation to the
: *validity* of that concept *are* relevant.
: >
: > > > You seem to be mentioning a number of diverse philosophical texts
: > > > on physics which have little to do with the subject in hand.
: >
: > > The subject on hand *is* the philosophical, solipsist attitude
: > > adopted by a traveler who, presumably being aware of Einstein's 1918
: > > attempted negation of the clock paradox, insists that his opinion
: > > takes precedence over Einstein's.
: >
: > > > > > > This refusal to accept reality, i.e. not allowing for the
transit time
: > > > > > > of light, *is* 'an obvious error' or, in my opinion, mushroom
: > > > > > > treatment.
: >
: > > > > > Yes, of course it is. If you believe that relativity does that
: > > > > > you are suffering under a serious delusion.
: >
: > > > > What gave you that impression?
: >
: > > > Because you keep mentioning it. If you agree that relativity makes
: > > > complete allowance for the transit time of light then we can drop
: > > > that subject.
: >
: > > In his book 'Fiction Stranger Than Truth' Nikolai Rudakov wrote that
: > > special theory's concept of length contraction (without which SR's
: > > concept of the constancy of light speed cannot be maintained) is
: > > determined on the basis that the observer does not allow for the
: > > transit time of light.
: > > Nikolai depicts two identical ships out in space that are at rest
: > > alongside each other. One of them (A) accelerates away from the other
: > > one (B), travels in a large circle and returns past B at near light
: > > speed.
: >
: > > An observer, located at *a specific point* on the hull of ship B sees
: > > the front end of ship A directly in line with the front end of his
: > > ship at the very same instant that he sees the rear end of ship A in
: > > line with him thus he concludes that A has contracted to a length that
: > > is equal to the distance from him to the front of his ship on the
: > > basis that he makes *no* allowance for the
: > > transit time of the message that the front ends of the ships are
: > > *seemingly* at the same location.
: >
: > > He does *not*, on the basis of philosophical solipsism, allow for the
: > > fact that in the time it has taken for that message to reach him, ship
: > > A has moved.
: >
: > I have not read the book you mention but if it indeed claims that
: > SR does not allow for the transit time of light it is wrong.
: >
: > You are now arguing about simple matters of fact. SR is a well
: > known and understood theory and any text book on the subject
: > will tell you what it is based on. I can assure you that SR is not
: > based on making measurements which ignore the transit time of
: > light.
: >
: > You have obviously studied a number of diverse writings on
: > relativity and come to some very weird conclusions. There
: > are several people on this group who could correct your
: > misunderstandings if you wish. Alternatively you could continue
: > to rant.
: >
: > --
: > Martin Hogbin
:
: Your having typically resorted to personal insult terminates our
: discussion.

Typical of all fuckheaded trolls like Pigbin. The stupid bastards
need sense knocked into them with a sledge hammer.



.