Speed of Time
in [Relativity]
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From: Inertial on 28 Dec 2009 01:10 "Sue..." <suzysewnshow(a)yahoo.com.au> wrote in message news:7c5de113-b2fb-4654-85e0-7d921368b3c8(a)a21g2000yqc.googlegroups.com... > On Dec 24, 3:51 pm, Ste <ste_ro...(a)hotmail.com> wrote: >> I was just wondering, can anyone tell me at what rate time advances on >> earth? > > Know thy enemy. What enemy? > =====================================================\ > > http://en.wikipedia.org/wiki/Lorentz_ether_theory#Later_activity_and_Current_Status > > > ======================================================/ Do you think LET is an enemy? And how is that link relevant .. silly question, of course its not. Now Sue copy and pastest the same old collection of quotes as always in the hope they are relevant to the thread and to make herself look knowledgeable [snip em]
From: Dirk Van de moortel on 28 Dec 2009 06:03 Ste <ste_rose0(a)hotmail.com> wrote in message a35de26f-5383-4b5f-86b5-0c0c3b43bbe5(a)26g2000yqo.googlegroups.com > On 27 Dec, 11:19, "Dirk Van de moortel" > <dirkvandemoor...(a)nospAm.hotmail.com> wrote: >> Ste <ste_ro...(a)hotmail.com> wrote in message >> >> 82a2de5c-1a2e-48e4-a7e4-76287acb8...(a)j19g2000yqk.googlegroups.com >> >> >> >> >> >>> On 26 Dec, 23:32, "Dirk Van de moortel" >>> <dirkvandemoor...(a)nospAm.hotmail.com> wrote: >>>> Ste <ste_ro...(a)hotmail.com> wrote in message >> >>>> c6d4ea67-9711-4b79-b35f-7bc54e086...(a)n35g2000yqm.googlegroups.com >> >>>>> On 26 Dec, 00:30, "Androcles" <Headmas...(a)Hogwarts.physics_q> wrote: >> >>>>>> You should read Dork's twin paradox analysis. He can >>>>>> pick up the origin of frame of reference and move it, >>>>>> so if you go from London to New York you can do it >>>>>> twice without ever going from New York to London. >> >>>>>> He says >>>>>> quote/ >>>>>> "We use 3 inertial reference frames. >>>>>> S: The frame of the "stay at home" twin. >>>>>> S': The frame of the "outbound part of the trip". >>>>>> S": The frame of the "inbound part of the trip". >>>>>> http://users.telenet.be/vdmoortel/dirk/Physics/TwinsEvents.html >> >>>>>> So if T = 5 years and v = 0.8c, then the stay at home twin will >>>>>> have aged 10 years while his travelling twin sister will have aged >>>>>> 6 years. >>>>>> /unquote >> >>>>> I'm afraid I don't understand how he arrives at that conclusion. I >> >>>> You see how I arrived at it by looking at >>>> http://users.telenet.be/vdmoortel/dirk/Physics/TwinsEvents.html >>>> If there is anything unclear about it, let me know - perhaps I >>>> can explain. >>>> Or if there's a mistake, I can correct it. >> >>> There is indeed a mistake. >> >> I assume you understood everything about it, so, in which >> line do you find the first mistake? > > The mistake is with this "changing frame of reference" business. It's > not the frame of reference that changes, the time-lag is on account of > the fact that the astronaut accelerates more than the Earth, within a > reference frame that encompasses the Earth, the astronaut, and the > whole journey. Sure, if you like, you can use equations where no more than the proper accelerations of both twins are used: See for instance http://arxiv.org/PS_cache/physics/pdf/0411/0411233v1.pdf and http://en.wikipedia.org/wiki/Twin_paradox#Difference_in_elapsed_times:_how_to_calculate_it_from_the_ship In this case however, a simplified *calculation* can be used, with simple Lorentz transformations in simple inertial reference frames. In order to be able to use the transformations, we use three of them. (Of course we ignore the fact that the stay at home twin is not *really* inertial, since he is on the surface of a rotating planet. It can be shown however that the effect of this can be ignored, and of course we can just as well put the stay at home twin somewhere freely floating in space). The twin who takes the trip can't possible stay in one inertial reference frame, but in order to make the calculations, we can use two different inertial frames to model the trip in the most simplified case. If you look at the PDF (1st paragraph of section A), you will find a way to use the "proper-acceleration-way" to model the simplified situation. It gives the same result as the two-frame-jump way. Don't you agree? Dirk Vdm
From: Dirk Van de moortel on 28 Dec 2009 06:17 Ste <ste_rose0(a)hotmail.com> wrote in message ec506642-8744-4fbe-82e0-3937e9e35394(a)m38g2000yqd.googlegroups.com > On 26 Dec, 23:02, "Dirk Van de moortel" > <dirkvandemoor...(a)nospAm.hotmail.com> wrote: >> Ste <ste_ro...(a)hotmail.com> wrote in message >> >> e2b39ba1-e151-4bd3-8adb-b5f35af59...(a)j4g2000yqe.googlegroups.com >> >> >> >> >> >>> On 26 Dec, 09:09, ..@..(Henry Wilson DSc) wrote: >>>> On Sat, 26 Dec 2009 14:28:03 +1100, "Inertial" <relativ...(a)rest.com> wrote: >>>>> "Ste" <ste_ro...(a)hotmail.com> wrote in message >>>>> news:ee5c4ca0-faf6-46a8-8565-c830f685d3b9(a)m16g2000yqc.googlegroups.com... >>>>>> I was just wondering, can anyone tell me at what rate time advances on >>>>>> earth? >> >>>>> There is no such thing as a rate of time, as 'rate' implies change over >>>>> time. That is a problem with the English language (and I suspect most if >>>>> not all human languages). >> >>>>> But one can compare the rates of ticking of clocks (which measures time) and >>>>> compare the rates in different locations or at different relative >>>>> velocities. >> >>>>> There is no absolute measure of 'rate' of time (whatever that means) >> >>>> Time flows at 1 second (t1) per second (t2) >> >>> So in other words, time can only be expressed as a factor relative to >>> some other frame. In other words, it is *impossible* to prove a >>> forward flow of time - the forward flow of time is an axiom of the >>> human mind, not a measurable quality of the physical world. > > Just to clarify, the above text is not mine, even though you attribute > it to me. (this was cleared this up in the previous exchange) > > > >> In physics and in engineering (and in fact in every day life), >> time is defined as what is read on clocks, as you can see in >> http://physics.nist.gov/cuu/Units/second.html >> Armchair philosophers might have different ideas, but this is >> a physics newsgroup. > > I'm an engineer to my very core. If you can't explain physics to me, > then there is probably a shortfall in your understanding of the world. > > > >> Since counting events is what happens in a clock, our clocks >> are designed to run forward, so time is defined to run forward. >> So indeed "the forward flow of time is an axiom of the human >> mind", if you wish. >> But it *is* a measurable quality of the physical world - by >> definition. > > I never said time isn't a measurable quantity But I did not say that you said that. You said: "The forward flow of time is [...] not a measurable quality of the physical world" and I merely said that the forwardness of the flow of time is solidly baked in in our definition of time: time is something we *count*, and we cannot "uncount". See http://physics.nist.gov/cuu/Units/second.html Don't you agree that, at least for physicists and engineers, given this definition, there is no other way than a "forward flow" of time? Dirk Vdm
From: Ste on 28 Dec 2009 06:33 On 28 Dec, 05:47, "Inertial" <relativ...(a)rest.com> wrote: > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > news:0ee9d1e6-4eeb-40ff-907a-722c351315e7(a)r5g2000yqb.googlegroups.com... > > > > > > > On 28 Dec, 03:27, "Inertial" <relativ...(a)rest.com> wrote: > >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >>news:483e2fe2-a490-4f59-846e-1a7abf63fa86(a)26g2000yqo.googlegroups.com.... > > >> > On 27 Dec, 11:25, "Inertial" <relativ...(a)rest.com> wrote: > >> >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >> >>news:82a2de5c-1a2e-48e4-a7e4-76287acb88c2(a)j19g2000yqk.googlegroups.com... > > >> >> > On 26 Dec, 23:32, "Dirk Van de moortel" > >> >> > <dirkvandemoor...(a)nospAm.hotmail.com> wrote: > >> >> >> Ste <ste_ro...(a)hotmail.com> wrote in message > > >> >> >> c6d4ea67-9711-4b79-b35f-7bc54e086...(a)n35g2000yqm.googlegroups.com > > >> >> >> > On 26 Dec, 00:30, "Androcles" <Headmas...(a)Hogwarts.physics_q> > >> >> >> > wrote: > > >> >> >> >> You should read Dork's twin paradox analysis. He can > >> >> >> >> pick up the origin of frame of reference and move it, > >> >> >> >> so if you go from London to New York you can do it > >> >> >> >> twice without ever going from New York to London. > > >> >> >> >> He says > >> >> >> >> quote/ > >> >> >> >> "We use 3 inertial reference frames. > >> >> >> >> S: The frame of the "stay at home" twin. > >> >> >> >> S': The frame of the "outbound part of the trip". > >> >> >> >> S": The frame of the "inbound part of the trip". > >> >> >> >>http://users.telenet.be/vdmoortel/dirk/Physics/TwinsEvents.html > > >> >> >> >> So if T = 5 years and v = 0.8c, then the stay at home twin will > >> >> >> >> have aged 10 years while his travelling twin sister will have > >> >> >> >> aged > >> >> >> >> 6 years. > >> >> >> >> /unquote > > >> >> >> > I'm afraid I don't understand how he arrives at that conclusion. > >> >> >> > I > > >> >> >> You see how I arrived at it by looking at > >> >> >> http://users.telenet.be/vdmoortel/dirk/Physics/TwinsEvents.html > >> >> >> If there is anything unclear about it, let me know - perhaps I > >> >> >> can explain. > >> >> >> Or if there's a mistake, I can correct it. > > >> >> > There is indeed a mistake. > > >> >> Nope > > >> >> > You disproved relativity; because > >> >> > relativity says that no matter what the frame of reference, the > >> >> > effects will be the same. > > >> >> That's right .. in every frame, one twin is younger than the other > > >> > And isn't that a contradiction? > > >> No. > > > Dear me. > > Dear me what? Every frame will agree that one of the twins is younger than > the other .. ie that less time has elapsed for the 'travelling' twin as > opposed to that of the 'stay-at-home' twin. There is nothing contradictory > about that I should clarify. The explanations I've seen so far, about "changing reference frames", I find quite inadequate and they contradict SR, which says that an observer in any reference frame should perceive the same effects. If one twin ends up younger, then there is clearly some factor that applies differently to the astronaut than the homebody, and I'm afraid I don't accept the explanation that it is because the astronaut changes direction (because by definition in relativity, it may as well be the earth that changes direction as far as the astronaut is concerned).
From: Ste on 28 Dec 2009 06:43
On 28 Dec, 05:59, "Inertial" <relativ...(a)rest.com> wrote: > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > news:55e687f7-b47e-4325-aedc-9584f0234270(a)b2g2000yqi.googlegroups.com... > > > On 28 Dec, 03:55, "Inertial" <relativ...(a)rest.com> wrote: > >> "Androcles" <Headmas...(a)Hogwarts.physics_q> wrote in message > > >> >> People are so bitter here! > > >> > It's not a question of emotion, it's a question of teaching arrogant > >> > lunatics like you the basics. You forgot to adjust the speed of lunacy. > > >> Androcles described himself nicely .. an arrogant lunatic. Though he > >> forgot > >> to add "blatant liar" to his self-description > > > Indeed. Why is this place so feral? > > Crackpots who have enormous egos, usually accompanied by a hatred for > Einstein. > > Usually they are fail physics students who, rather than accept that they > failed physics, think physics must be wrong, and become convinced of that > fact. > > Others think they are intelligent and yet they have not achieved the fame > the Einstein has (usually for good reason) and so therefore Einstein must be > some sort of con artist or charlatan .. and so therefore SR (as it was > something einstein was involved in) must (by association) be wrong. So which did you say you were? > Of course, all physicists must be part of a cult or conspiracy to keep this > 'truth' hidden. Anyone who disagrees with them if obviously one of the > runts of the Einsteinian religion. I actually think Einstein was on the right track. If he was wrong at all, then he wasn't that wrong. > In order to maintain these delusions, they deny the existence of all the > experiments that support SR, except those that also happen to not refute > their particular pet theory. They will make ridiculous claims about what > they mistakenly think SR says in order to 'prove' it wrong (and instead show > why it is they failed physics) and go on a character assassination vendetta > against Einstein. I claim to have solved the paradox within the terms of SR. The fact is, the homebody does *not* accelerate as much as the astronaut, no matter what reference frame you choose. > Of course, this means each of them thinks they are the lone voice of reason > in a world that is out to get them and silence their voice. > > Also those who DO understand physics (SR in particular) will point out the > mistaken ideas of the crackpots, and that truth makes the resent just about > everyone. PD, Eric, Tom (and myself) are amongst the few who understand SR > well. Perhaps. But then no one doubts that theologians know their subject. |