The moving system is not an inertial frame in 1905 Relativity
in [Relativity]
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From: PD on 6 Jul 2010 10:33 On Jul 5, 9:40 am, va...(a)icmf.inf.cu wrote: > On 2 jul, 09:14, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Jul 2, 6:07 am, va...(a)icmf.inf.cu wrote: > > > > On 1 jul, 10:25, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Jun 30, 3:31 pm, va...(a)icmf.inf.cu wrote: > > > > > > On 30 jun, 15:13, stevendaryl3...(a)yahoo.com (Daryl McCullough) wrote: > > > > > > > va...(a)icmf.inf.cu says... > > > > > > > >In a recent thread we established that > > > > > > > Centre of mass inertial frames are the unique ones in 1905 > > > > > > >Relativity > > > > > > > There is nothing in the development of relativity that in any > > > > > > way depends on a frame being defined by a center of mass. That's > > > > > > completely barking up the wrong tree. > > > > > > > -- > > > > > > Daryl McCullough > > > > > > Ithaca, NY > > > > > > I will answer you with the same initial post of the referred thread: > > > > > [Let be any body set with a material point modelling each one. If we > > > > > want to describe the movements of the bodies in an inertial frame, we > > > > > have a unique alternative: to use the centre of mass inertial frame > > > > > corresponding to that body set. Once the Newtons absolute frame is > > > > > rejected by 1905 Einstein (and then rejected also all the others > > > > > moving with any uniform velocity with respect to it), remain only the > > > > > bodies themselves to determine inertial frames.] > > > > > Explain to us how can you determine an inertial frame once the > > > > > absolute Newtonian one is rejected by 1905 Einstein(and with it all > > > > > the others imaginary derived ones with all possible uniform velocities > > > > > with respect to it). > > > > > > RVHG (Rafael Valls Hidalgo-Gato) > > > > > Inertial frames are *defined* by the fact that the laws of dynamics > > > > retain their form in such frames. The center of mass frame of a system > > > > of mutually interacting bodies is such an inertial frame (provided > > > > that there is no measurably significant interaction with bodies > > > > external to this system), but it is also true that ANY OTHER FRAME > > > > moving at constant velocity with respect to the center of mass frame > > > > also satisfies this requirement. > > > > If you have TWO inertial frames (real massive ones, not the imaginary > > > massless ones rejected by 1905 Einstein), then they can't be never > > > moving at a uniform velocity one with respect to the other (at least > > > some gravitational attraction must be present always). > > > Don't be ridulous. Your coffee cup and the table is sitting on have a > > uniform velocity with respect to each other (zero), even though there > > is a gravitational attraction. An elevator and the 3rd floor move at > > uniform velocity with respect to each other (nonzero), even though > > there is a gravitational attraction present. Just because there is a > > gravitational attraction present doesn't remove the presence of OTHER > > forces which can put two objects in equilibrium, either static or > > nonstatic. > > I am not rejecting at all Nature forces of any kind. The coffee cup > and the table you refer are both moving with a non-zero gravitational > centripetal acceleration in a circular path in the GPS ECI, because I > dont stay in a pole (as the clock at the equator in the example at > the end of paragraph 4 in the 30Jun1905 Einsteins paper). They cant > be considered then inertial frames. Yes, they are two entities with a > uniform zero relative velocity, but they are NOT two inertial frames. > The same remark about your elevator and floor. Only in the Newtonian > view you can derive a different inertial frame from another referring > a uniform velocity between them (the way the infinite imaginary > inertial frames moving with all possible uniform velocities with > respect to the imaginary absolute one are put in existence). In 1905 > Relativity, even if you can obtain two entities moving with a relative > uniform velocity compatible with Nature laws, they cant be inertial > frames, because even being them the unique entities considered by you, > the centre of mass inertial system of all the bodies involved continue > being the UNIQUE possible inertial frame. And as has been repeated to you over and over again, this is simply wrong. The center of mass frame is certainly unique. It just isn't the only inertial frame in the system. Since we can't seem to get past this point, and you keep circling back to the same misstatement, I don't think there's benefit in my discussing it further. > I accept that my previous explanation referring only to a > gravitational interaction between the two supposed inertial frames is > not a sufficient one. You were right rejecting it. > > > If what you said were true, then Newton's first law would be USELESS, > > and it is not. > > That the state of motion of any body without interaction with its > exterior remains constant, continue being valid in 1905 Relativity. It > allows us to understand why the centre of mass of any inertial system > must be always at rest if you want to describe in it the movement of > any body belonging to its body set. By the way, these are the UNIQUE > bodies whose movements can be described in that inertial frame.> > As a result, > > > you must consider the centre of mass inertial frame corresponding to > > > all the bodies involved. For ANY body set, you have always a UNIQUE > > > centre of mass inertial frame. > > > That is true, you do have a unique center of mass frame. However, that > > is not the only inertial reference frame in that system. It is one of > > many. > > The inertial reference frame and the system is one and the same thing. > Starting with ANY body set, you obtain a UNIQUE inertial frame, the > centre of mass one corresponding to that body set. Please, explain to > me (with a real example, if possible) which are these many inertial > reference frames that you are referring. And remember that we are > addressing 1905 Relativity (without the imaginary absolute inertial > frame and the also imaginary derived ones moving with all possible > uniform velocities with respect to it).> > I accepted the definition of inertial frame that you refer. Physics > > > laws must be always the same in all inertial frames. But I don't > > > accept that and entity moving at a uniform velocity with respect to > > > some inertial frame is also an inertial frame (at least not a real > > > existing one). > > > Then you need to demonstrate to yourself that, in a reference frame > > that is moving at uniform velocity with respect to the center of mass > > of a system of bodies, the laws of physics are still the same. Galileo > > saw that in the early 1600's, but I see you haven't figured that out > > yet. When you see this is true, then by definition this frame is an > > inertial reference frame. > > Remember the Galileo ship moving with a uniform velocity. In the > INTERIOR of the ship all things happens in the same way not depending > on the uniform velocity that the ship as a whole has with respect to > an EXTERNAL entity. But all the windows must remain closed. That is a > way to say that outside it is nothing. Let us take a more modern > example to make more clear what I am trying to say. > Consider the ECI, our Earth rotating (the stationary system in the > referred example in the 1905 text). It is a centre of mass inertial > frame. Like in the Galileos ship, you must consider existing only the > bodies in its INTERIOR, you cant use the ECI to describe the movement > of any body in its EXTERIOR (even the Moon, not to say the Sun!). Even > supposing an Earth with a uniform motion in the Solar System centre of > mass inertial frame (trying to fulfil the requirements for your > supposed inertial frame moving with a uniform velocity with respect to > a centre of mass inertial frame) , you cant describe the Suns > movement in the ECI (the same with ANY other body external to the > Earth). Yes, the laws of physics are the same in the ECI INTERIOR and > in the Solar System INTERIOR (in the INTERIOR of any centre of mass > inertial system, considering INTERIOR the set of all the bodies > involved). But I am pretty sure that when you refer to an inertial > frame moving with a uniform velocity with respect to some centre of > mass inertial system, what you have in mind is to use that uniform > moving inertial system to describe the movements of bodies in its > EXTERIOR. That is totally impossible. In the EXTERIOR of any moving > entity (with uniform velocity or not), it cant be never an inertial > system. And a moving system can be considered an inertial frame in its > INTERIOR, only if the external world provokes a sufficiently same > ACCELERATION in all its internal bodies (as is the case for the ECI > and the Solar System). > > RVHG (Rafael Valls Hidalgo-Gato)- Hide quoted text - > > - Show quoted text -
From: valls on 7 Jul 2010 06:54 On 2 jul, 08:33, "Inertial" <relativ...(a)rest.com> wrote: > wrote in messagenews:441bf1b4-1ffe-4fc8-b850-2a9f437e63dd(a)30g2000vbi.googlegroups.com... > > > > >On 1 jul, 10:25, PD <thedraperfam...(a)gmail.com> wrote: > >> Inertial frames are *defined* by the fact that the laws of dynamics > >> retain their form in such frames. The center of mass frame of a system > >> of mutually interacting bodies is such an inertial frame (provided > >> that there is no measurably significant interaction with bodies > >> external to this system), but it is also true that ANY OTHER FRAME > >> moving at constant velocity with respect to the center of mass frame > >> also satisfies this requirement. > > >If you have TWO inertial frames (real massive ones, not the imaginary > >massless ones rejected by 1905 Einstein), > > Inertial frames do not have mass. You are talking nonsense. There were no > inertial frames rejected by the 1905 paper. > > >then they can't be never > > moving at a uniform velocity one with respect to the other (at least > >some gravitational attraction must be present always). > > There is no gravitational attraction between frames of reference .. they are > not material things > > > As a result, > >you must consider the centre of mass inertial frame > > Inertial frames have no centre of mass .. they aren't material. You seem to > have NO idea at all what a frame of reference is > > [snip more nonsense] > > Please .. learn the meaning of physics terms before attempting to discuss > things further, Read in th 30Jun1905 Einstein's paper where he put out the Newtonian primary absolute inertial frame. In the Introduction: [The introduction of a luminiferous ether will prove to be superfluous inasmuch as the view to be developed will not require an absolutely stationary space ] 1905 Einstein identify systems of coordinates with rigid bodies, more specifically (beginning of paragraph 3), with three rigid material lines. You think that these things are non-massive ones? A material point is a Newtonian basic concept where a body is modelled with all its mass considered concentred in its centre of mass. RVHG (Rafael Valls Hidalgo-Gato)
From: Dono. on 7 Jul 2010 09:31 On Jul 5, 8:29 am, va...(a)icmf.inf.cu wrote: > > > I dont care at all Special Relativity, introduced by 1916 Einstein. > The rotating Earth (a centre of mass inertial frame) is the principal > example we can find in 1905R, being here the stationary system, the > same one denoted today GPS ECI, with a huge experimental evidence > supporting 1905R. The moving system is a clock at the equator, which > is very clearly not an inertial frame. > Listen, idiot None of us is denying SR, nor are you doing a good job of representing it. The equations governing the functioning of GPS are GR, not SR, old fool. The Ashby paper, that I recommended to you long ago (and where you learned about ECI) is pretty clear on this subject.
From: Tom Roberts on 7 Jul 2010 10:16 valls(a)icmf.inf.cu wrote: > 1905 Einstein identify systems of coordinates with rigid bodies, more > specifically (beginning of paragraph 3), with three rigid material > lines. So READ that paragraph and note the parenthetical after "rigid bodies" -- "(systems of coordinates)". There is no massive or material object associated with a system of coordinates. He merely requires them to be "rigid". > You think that these things are non-massive ones? A material > point is a Newtonian basic concept where a body is modelled with all > its mass considered concentred in its centre of mass. Again you are reading FAR MORE into the text than is actually written there. He makes no mention of "massive" in that paragraph. And you are wrong about considering mass to be "concentrated in its centre of mass". That can be done only for certain systems of spherically-symmetric objects. Look up "moment of inertia". Moreover, this is INTRODUCTORY MATERIAL that is explaining, describing, and motivating what follows. What follows in sections I and II are self-contained developments of the theory. In particular, the postulates are given in I.2 (not the introduction preceding section I). Tom Roberts
From: valls on 7 Jul 2010 17:46
On 7 jul, 09:16, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > va...(a)icmf.inf.cu wrote: > > 1905 Einstein identify systems of coordinates with rigid bodies, more > > specifically (beginning of paragraph 3), with three rigid material > > lines. > > So READ that paragraph and note the parenthetical after "rigid bodies" -- > "(systems of coordinates)". There is no massive or material object associated > with a system of coordinates. He merely requires them to be "rigid". > How can you conceive a rigid body without mass? Anyway, 1905 Einstein writes very clear material lines, and even a single material point has already a mass associated with it. What 1905 Einstein really needs is a space (after his rejection of the Newtonian absolute one). He doesnt realize completely that any body set is already sufficient to have a space (and also a time). This is a weak point in his theory, without any doubt. But fortunately he includes the real rotating Earth in the example at the end of paragraph 4, obtaining not only a complete Euclidean space at rest, but also parts moving at different and not uniform velocities, with the more known gravitational field of our real and very massive Earth. In resume, a centre of mass inertial frame as a stationary system where all Newtonian equations hold good, including the gravitational ones. And now you say that 1905 Einstein was wrong considering not only gravity, but also all kind of non- uniform velocities for the bodies included in the body set determining the stationary system (centre of mass inertial frame), applying relativity formulas to all of them. All 1905 Einstein assumptions were supported true by the huge experimental evidence of today GPS, a fact that you try to hide (without any success). Among them, the difference between the stationary and the moving systems, the first always at rest and the second with any kind of movement compatible with Nature laws that are always the same in any inertial frame (stationary system). > > You think that these things are non-massive ones? A material > > point is a Newtonian basic concept where a body is modelled with all > > its mass considered concentred in its centre of mass. > > Again you are reading FAR MORE into the text than is actually written there. He > makes no mention of "massive" in that paragraph. > All non-massive inertial frames are put out of the theory by 1905 Einstein at the very start when rejecting the primary non-massive absolute frame. Dont try to re-introduce them again for the support of your false Special Relativity-1905 Relativity identification. > And you are wrong about considering mass to be "concentrated in > its centre of mass". That can be done only for certain systems > of spherically-symmetric objects. Look up "moment of inertia". > Consider the Pluto-Charon system. Its centre of mass is the point running the historical Pluto orbit and where the Suns attraction is considered applied, and where the velocity of the system is put, without having here a spherical symmetry. Yes, for a space zone near to the system, the material point model fails to be accurate. Any model has quantitative application limits. > Moreover, this is INTRODUCTORY MATERIAL that is explaining, describing, and > motivating what follows. What follows in sections I and II are self-contained > developments of the theory. In particular, the postulates are given in I.2 (not > the introduction preceding section I). > You are going into secondary details. The existence of two different versions of the postulates must be analysed without taking into account in what order are them located, but considering their essential contents. > Tom Roberts RVHG (Rafael Valls Hidalgo-Gato) |