The moving system is not an inertial frame in 1905 Relativity
in [Relativity]
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From: PD on 8 Jul 2010 16:27 On Jul 8, 12:46 pm, va...(a)icmf.inf.cu wrote: > On 8 jul, 10:31, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Jul 8, 8:38 am, va...(a)icmf.inf.cu wrote: > > > > On 7 jul, 17:46, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Jul 7, 5:05 pm, va...(a)icmf.inf.cu wrote: > > > > > > On 6 jul, 09:33, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > 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. > > > > > > Once you have the unique centre of mass inertial frame corresponding > > > > > to some determined body set, what denote you by the system? For me, > > > > > the centre of mass inertial frame and the system is one and the same > > > > > thing. > > > > > No, a system is a collection of interacting physical entities. A > > > > reference frame is the coordinate system in which the coordinates of > > > > those entities have a particular values. > > > > > For example, a physical system may include a proton, a neutron and an > > > > electron, interacting with each other by various interactions. That > > > > system may be viewed by any number of reference frames, and in each > > > > reference frame, the coordinates as a function of time of each of the > > > > bodies in the system will have values that are unique to that frame.. > > > > The coordinates are not part of the system, nor is the reference > > > > frame. > > > > > For example, this system can be viewed from the inertial reference > > > > frame where the center of mass of these objects is zero. This very > > > > same system can be viewed from an inertial reference system where the > > > > center of mass of these objects is moving at 12,323 m/s along the z > > > > axis of the first reference frame. The laws of physics will be > > > > identical in both those reference frames. > > > > > This is all FRESHMAN stuff, on what constitutes a physical system and > > > > what a reference frame is. If this is all new to you, then please > > > > revisit some freshman materials. > > > > Remember that the topic in this thread is 1905 Relativity. I will > > > answer your post on that historical context. > > > In the Newtonian view exists a primary unique absolute inertial frame, > > > the one with absolute space and time. From that frame, relative > > > inertial frames can be derived, moving with all possible uniform > > > velocities with respect to the absolute one. This covers all possible > > > inertial frames, all of them without any relation at all with massive > > > bodies. > > > In 1905 Relativity the things are completely different, the theory > > > starts putting out the absolute frame (and with it then also all the > > > other depending on it), remaining then only the massive bodies > > > themselves to determine inertial frames. > > > And that is wrong, as a NUMBER of people have pointed out to you. You > > have refused to let go of that misapprehension. Since you've done > > that, there's no real point to continue. > > The topic of this thread is very narrow, practically a single physics > paper (30Jun1905 Einsteins one). It is then very easy to support any > assertion in the debate, making the adequate reference to the 1905 > text. I will put here again the literal 1905 text supporting what I am > saying about 1905 Relativity. > Almost at the end of the introduction (between [ ]): [The theory to be > developed is based like all electrodynamics- on the kinematics of the > rigid body, since the assertions of any such theory have to do with > the relationships between rigid bodies (systems of co-ordinates), > clocks, and electromagnetic processes.] Kinematics refers to the motion of bodies in a physical system, where that motion is defined in terms of coordinates that are particular to a reference frame. Note that I have distinguished for you a physical system from a reference frame. The rigid bodies in a physical system are referenced by coordinates appropriate to a reference frame that does not belong to the physical system itself. This is where you are misreading the text of the article. > Specify then in what bodies are you supporting your system of co- > ordinates in which you put the c-o-m at a velocity of 12,323 m/s. There are no bodies needed to support a system of coordinates. A system of coordinates exists independent of a collection of bodies. > If > you cant do that, contact the NUMBER of people that you refer to > help you. I will be very patient waiting for your answer. > > RVHG (Rafael Valls Hidalgo-Gato)- Hide quoted text - > > - Show quoted text -
From: glird on 8 Jul 2010 17:43 On Jul 8, 4:27 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > There are no bodies needed to support a system of > coordinates. A system of coordinates exists independent > of a collection of bodies. A co-ordinate system is an artifice invented by man. In order to use one, is origin (the imaginary point where its three imaginary lines intersect each other) has to be findable. In order to find it, it HAS TO BE attached to a visible referent; where "visable" can use any method at all to locate the referent object. Once the referent is given, it can be taken as "stationary"; and becomes the referent for an imaginary "frame of reference" to which the co-ordinate system )cs) is attached. Regardless of the state of rest or motion of the referent, the frame of reference and the attached cs can be aken as stationary. In terms of such an infiniely extending cs, any differently moving object is then given a velocity v = dxyz/dt; where x, y, and z are co-ordinate values of that cs and t is its time. Be it noted that other than the findable referent body, all of that is purely imaginary. Indeed, too much of present Physics is limited to imaginary devices; most of them being quantities of nobody-knows- what, as measured in a given frame of reference.
From: PD on 8 Jul 2010 18:15 On Jul 8, 4:43 pm, glird <gl...(a)aol.com> wrote: > On Jul 8, 4:27 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > There are no bodies needed to support a system of > > coordinates. A system of coordinates exists independent > > of a collection of bodies. > > A co-ordinate system is an artifice invented by man. Yes. So are coordinates. > In order to > use one, is origin (the imaginary point where its three imaginary > lines intersect each other) has to be findable. Not really. It has to be DEFINABLE. > In order to find it, > it HAS TO BE attached to a visible referent; where "visable" can use > any method at all to locate the referent object. No. This is the most boneheaded thing I've heard you say. You are claiming that you cannot define a coordinate system unless there is some material anchor at the origin of that coordinate system??? REALLY???? > Once the referent is given, it can be taken as "stationary"; and > becomes the referent for an imaginary "frame of reference" to which > the co-ordinate system )cs) is attached. > Regardless of the state of rest or motion of the referent, the frame > of reference and the attached cs can be aken as stationary. In terms > of such an infiniely extending cs, any differently moving object is > then given a velocity v = dxyz/dt; where x, y, and z are co-ordinate > values of that cs and t is its time. > > Be it noted that other than the findable referent body, all of that > is purely imaginary. Indeed, too much of present Physics is limited > to imaginary devices; most of them being quantities of nobody-knows- > what, as measured in a given frame of reference.
From: valls on 9 Jul 2010 12:31 On 8 jul, 15:27, PD <thedraperfam...(a)gmail.com> wrote: > On Jul 8, 12:46 pm, va...(a)icmf.inf.cu wrote: > > > > > > > On 8 jul, 10:31, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Jul 8, 8:38 am, va...(a)icmf.inf.cu wrote: > > > > > On 7 jul, 17:46, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > On Jul 7, 5:05 pm, va...(a)icmf.inf.cu wrote: > > > > > > > On 6 jul, 09:33, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > 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. > > > > > > > Once you have the unique centre of mass inertial frame corresponding > > > > > > to some determined body set, what denote you by the system? For me, > > > > > > the centre of mass inertial frame and the system is one and the same > > > > > > thing. > > > > > > No, a system is a collection of interacting physical entities. A > > > > > reference frame is the coordinate system in which the coordinates of > > > > > those entities have a particular values. > > > > > > For example, a physical system may include a proton, a neutron and an > > > > > electron, interacting with each other by various interactions. That > > > > > system may be viewed by any number of reference frames, and in each > > > > > reference frame, the coordinates as a function of time of each of the > > > > > bodies in the system will have values that are unique to that frame. > > > > > The coordinates are not part of the system, nor is the reference > > > > > frame. > > > > > > For example, this system can be viewed from the inertial reference > > > > > frame where the center of mass of these objects is zero. This very > > > > > same system can be viewed from an inertial reference system where the > > > > > center of mass of these objects is moving at 12,323 m/s along the z > > > > > axis of the first reference frame. The laws of physics will be > > > > > identical in both those reference frames. > > > > > > This is all FRESHMAN stuff, on what constitutes a physical system and > > > > > what a reference frame is. If this is all new to you, then please > > > > > revisit some freshman materials. > > > > > Remember that the topic in this thread is 1905 Relativity. I will > > > > answer your post on that historical context. > > > > In the Newtonian view exists a primary unique absolute inertial frame, > > > > the one with absolute space and time. From that frame, relative > > > > inertial frames can be derived, moving with all possible uniform > > > > velocities with respect to the absolute one. This covers all possible > > > > inertial frames, all of them without any relation at all with massive > > > > bodies. > > > > In 1905 Relativity the things are completely different, the theory > > > > starts putting out the absolute frame (and with it then also all the > > > > other depending on it), remaining then only the massive bodies > > > > themselves to determine inertial frames. > > > > And that is wrong, as a NUMBER of people have pointed out to you. You > > > have refused to let go of that misapprehension. Since you've done > > > that, there's no real point to continue. > > > The topic of this thread is very narrow, practically a single physics > > paper (30Jun1905 Einsteins one). It is then very easy to support any > > assertion in the debate, making the adequate reference to the 1905 > > text. I will put here again the literal 1905 text supporting what I am > > saying about 1905 Relativity. > > Almost at the end of the introduction (between [ ]): [The theory to be > > developed is based like all electrodynamics- on the kinematics of the > > rigid body, since the assertions of any such theory have to do with > > the relationships between rigid bodies (systems of co-ordinates), > > clocks, and electromagnetic processes.] > > Kinematics refers to the motion of bodies in a physical system, where > that motion is defined in terms of coordinates that are particular to > a reference frame. > > Note that I have distinguished for you a physical system from a > reference frame. > > The rigid bodies in a physical system are referenced by coordinates > appropriate to a reference frame that does not belong to the physical > system itself. This is where you are misreading the text of the > article. > A reference frame (with a particular system of coordinates) independent from the referenced bodies (physical system) cant exist at all in 1905 Relativity. Those reference frames, with no relation at all with physical (massive) bodies, are precisely the ones put out by 1905 Einstein when starting his theory: the absolute frame and the relative ones depending on it. This is why 1905 Einstein identifies rigid bodies with systems of coordinates (by the way, the rigid character is really not necessary, see the example at the end of paragraph 4 where a rotating non-rigid Earth is more than sufficient to determine a centre of mass stationary system, and where the reference frame and the referenced physical bodies are one and the same thing). The involved massive bodies themselves are the ones determining a unique inertial reference frame, the centre of mass one. When you put the c-o-m with the velocity 12,323 m/s, you select ANY velocity. Dont you see clearly that you are using precisely the inertial reference frames put out by 1905 Einstein? You are considering (surely without realizing it) the c-o-m inertial frame as the absolute one, and the other inertial frame (where you put the c-o- m with velocity 12,323 m/s) as any of the relative ones moving with respect to the absolute frame with all possible uniform velocities. You are putting a non-massive (imaginary) inertial frame at rest with a massive (real) one moving with respect to it at the total arbitrary uniform velocity that you want. Following that procedure you can put for example our real Earth (ECI frame) moving uniformly at 0.999c with respect to some imaginary frame, a model without any value at all to represent our real Universe, that is the goal of any science. > > Specify then in what bodies are you supporting your system of co- > > ordinates in which you put the c-o-m at a velocity of 12,323 m/s. > > There are no bodies needed to support a system of coordinates. A > system of coordinates exists independent of a collection of bodies. > Only in the Newtonian view based in the primary absolute frame rejected by 1905 Einstein. What you say has nothing to do with 1905 Relativity, the topic of this thread. In my last comment I addressed already this in all detail. > RVHG (Rafael Valls Hidalgo-Gato)
From: PD on 12 Jul 2010 17:11
On Jul 9, 11:31 am, va...(a)icmf.inf.cu wrote: > On 8 jul, 15:27, PD <thedraperfam...(a)gmail.com> wrote:> On Jul 8, 12:46 pm, va...(a)icmf.inf.cu wrote: > > > > On 8 jul, 10:31, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Jul 8, 8:38 am, va...(a)icmf.inf.cu wrote: > > > > > > On 7 jul, 17:46, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > On Jul 7, 5:05 pm, va...(a)icmf.inf.cu wrote: > > > > > > > > On 6 jul, 09:33, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > > 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. > > > > > > > > Once you have the unique centre of mass inertial frame corresponding > > > > > > > to some determined body set, what denote you by the system? For me, > > > > > > > the centre of mass inertial frame and the system is one and the same > > > > > > > thing. > > > > > > > No, a system is a collection of interacting physical entities. A > > > > > > reference frame is the coordinate system in which the coordinates of > > > > > > those entities have a particular values. > > > > > > > For example, a physical system may include a proton, a neutron and an > > > > > > electron, interacting with each other by various interactions. That > > > > > > system may be viewed by any number of reference frames, and in each > > > > > > reference frame, the coordinates as a function of time of each of the > > > > > > bodies in the system will have values that are unique to that frame. > > > > > > The coordinates are not part of the system, nor is the reference > > > > > > frame. > > > > > > > For example, this system can be viewed from the inertial reference > > > > > > frame where the center of mass of these objects is zero. This very > > > > > > same system can be viewed from an inertial reference system where the > > > > > > center of mass of these objects is moving at 12,323 m/s along the z > > > > > > axis of the first reference frame. The laws of physics will be > > > > > > identical in both those reference frames. > > > > > > > This is all FRESHMAN stuff, on what constitutes a physical system and > > > > > > what a reference frame is. If this is all new to you, then please > > > > > > revisit some freshman materials. > > > > > > Remember that the topic in this thread is 1905 Relativity. I will > > > > > answer your post on that historical context. > > > > > In the Newtonian view exists a primary unique absolute inertial frame, > > > > > the one with absolute space and time. From that frame, relative > > > > > inertial frames can be derived, moving with all possible uniform > > > > > velocities with respect to the absolute one. This covers all possible > > > > > inertial frames, all of them without any relation at all with massive > > > > > bodies. > > > > > In 1905 Relativity the things are completely different, the theory > > > > > starts putting out the absolute frame (and with it then also all the > > > > > other depending on it), remaining then only the massive bodies > > > > > themselves to determine inertial frames. > > > > > And that is wrong, as a NUMBER of people have pointed out to you. You > > > > have refused to let go of that misapprehension. Since you've done > > > > that, there's no real point to continue. > > > > The topic of this thread is very narrow, practically a single physics > > > paper (30Jun1905 Einsteins one). It is then very easy to support any > > > assertion in the debate, making the adequate reference to the 1905 > > > text. I will put here again the literal 1905 text supporting what I am > > > saying about 1905 Relativity. > > > Almost at the end of the introduction (between [ ]): [The theory to be > > > developed is based like all electrodynamics- on the kinematics of the > > > rigid body, since the assertions of any such theory have to do with > > > the relationships between rigid bodies (systems of co-ordinates), > > > clocks, and electromagnetic processes.] > > > Kinematics refers to the motion of bodies in a physical system, where > > that motion is defined in terms of coordinates that are particular to > > a reference frame. > > > Note that I have distinguished for you a physical system from a > > reference frame. > > > The rigid bodies in a physical system are referenced by coordinates > > appropriate to a reference frame that does not belong to the physical > > system itself. This is where you are misreading the text of the > > article. > > A reference frame (with a particular system of coordinates) > independent from the referenced bodies (physical system) cant exist > at all in 1905 Relativity. And as I've repeated told you (and will tell you no more), this is just plain hogwash. > Those reference frames, with no relation at > all with physical (massive) bodies, are precisely the ones put out by > 1905 Einstein when starting his theory: the absolute frame and the > relative ones depending on it. This is why 1905 Einstein identifies > rigid bodies with systems of coordinates He does NOT. He identifies rigid bodies IN systems of coordinates. You repeatedly misread this. I've corrected you a number of times. Since you still cannot read correctly, there's nothing more to say. > (by the way, the rigid > character is really not necessary, see the example at the end of > paragraph 4 where a rotating non-rigid Earth is more than sufficient > to determine a centre of mass stationary system, and where the > reference frame and the referenced physical bodies are one and the > same thing). The involved massive bodies themselves are the ones > determining a unique inertial reference frame, the centre of mass > one. > When you put the c-o-m with the velocity 12,323 m/s, you select ANY > velocity. Dont you see clearly that you are using precisely the > inertial reference frames put out by 1905 Einstein? You are > considering (surely without realizing it) the c-o-m inertial frame as > the absolute one, and the other inertial frame (where you put the c-o- > m with velocity 12,323 m/s) as any of the relative ones moving with > respect to the absolute frame with all possible uniform velocities. > You are putting a non-massive (imaginary) inertial frame at rest with > a massive (real) one moving with respect to it at the total arbitrary > uniform velocity that you want. Following that procedure you can put > for example our real Earth (ECI frame) moving uniformly at 0.999c with > respect to some imaginary frame, a model without any value at all to > represent our real Universe, that is the goal of any science. > > > > Specify then in what bodies are you supporting your system of co- > > > ordinates in which you put the c-o-m at a velocity of 12,323 m/s. > > > There are no bodies needed to support a system of coordinates. A > > system of coordinates exists independent of a collection of bodies. > > Only in the Newtonian view based in the primary absolute frame > rejected by 1905 Einstein. What you say has nothing to do with 1905 > Relativity, the topic of this thread. In my last comment I addressed > already this in all detail. > > > > RVHG (Rafael Valls Hidalgo-Gato) |