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From: Androcles on 28 Jun 2010 08:24

<valls(a)icmf.inf.cu> wrote in message
news:9510ddde-8485-47a0-b60e-81cd189b8dd9(a)j4g2000yqh.googlegroups.com...
On 26 jun, 10:43, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote:

> Indeed, a "frame" really means a collection of rulers and clocks
> associated with
> an observer, not with any particles or objects.
>
Are not the clocks and rules massive bodies for you? They are not
�objects�? Only the absolute space and time can be measured with your
non-massive rules and clocks. And of course, in the real world you
will NEVER made a real measurement with those imaginary entities. All
your measurements will be also only imaginary ones without any
experimental value at all.
==================================================
I'm with you on that one. Roberts is babbling idiot who doesn't know a
frame of reference is a coordinate system that can be attached to any
object, independent of any observer. You've just seen a perfect example
of his complete ignorance.

From: Tom Roberts on 2 Jul 2010 00:21
valls(a)icmf.inf.cu wrote:
> On 26 jun, 10:43, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote:
>> va...(a)icmf.inf.cu wrote:
>>> 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 Newton s 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.
>> This is just plain not true. An observer can also determine an inertial frame.
>> So it is easy to discuss what (say) an observer moving with speed 0.5 c
>> (relative to the frame you mention) would measure in her inertial frame.
>>
> You write �an observer can also determine an inertial frame�. Then,
> without any doubt from my part, what you mean by �observer� is a very
> important concept for the topic we are addressing here. What is an
> �observer� for you?

In this context, the essence of an observer is a set of coordinates and the
ability to note the location in that coordinate system of any event. No human is
required, nor is any mass. But if one uses an inertial coordinate system, then
it must move with speed less than c relative to any other inertial coordinate
system.


>> Indeed, for multi-particle systems it is more common for observers to determine
>> the frame. Yes, one might well choose the c-o-m frame of the particles, but that
>> is the OBSERVER'S choice, and is not dictated by either the particles themselves
>> or by the theory.
>>
> Totally non-sense in the 1905 Einstein�s view.

How can you claim that???? He did not discuss such things at all in that paper.

But no matter, because the SR we use today is the same theory as he presented in
1905. We have learned A LOT about it, but the theory is the same (i.e. the set
of theorems has not changed, and the meanings of the symbols have not changed;
the experimental record is much more complete today than in 1905).


> The centre of mass of
> some specific massive body set can�t be moving with respect to
> nothing. It is OUR choice: to use the Newtonian view or the 1905
> Einstein�s one. In this last one the centre of mass MUST be at rest.

Nonsense. I can stand here on the earth and throw a baseball -- the c-o-m of
that baseball is not at rest relative to me. Or an astronaut can be in low earth
orbit and throw a baseball. Note the c-o-m of the earth is moving wrt that
astronaut, as is the c-o-m of earth+astronaut.


> You can�t put a centre of mass moving with respect to the absolute
> frame (or any other moving with a uniform velocity with respect to
> it).

More nonsense. First, there is no "absolute frame". Second, by throwing that
baseball I did indeed "put its centre of mass moving with respect to me".


But I see your basic point: momentum is conserved. That translates into the fact
that if the c-o-m of a set of objects is at rest in some inertial frame, then no
internal action can put the c-o-m into motion relative to that frame. But, of
course, an external action can do so. So my primary issue is with the way you
attempt to describe this, and the fact that you ignore the possibility of
external agents. I suppose you can avoid external agents in principle by
requiring the analyst to include everything in the universe when computing the
c-o-m. But that is an unreasonable requirement....


>> Also: you seem to think that "1905 Relativity" is somehow different from Special
>> Relativity today. This is also not true. We have learned a lot about the theory
>> since then, but there has been no change in the theory itself (i.e. the set of
>> theorems and the meanings of the symbols in them).
>>
> The �Special Relativity� denotation was introduced by first time by
> 1916 Einstein. He declared gravitation out of the scope of SR. In
> 1905 Relativity we have as a real example (at the end of paragraph 4
> of the 30Jun1905 text) the rotating Earth as the stationary system and
> a clock at the equator as the moving system. This one is moving
> GRAVITATIONAL centripetal accelerated in a circular path.

Yes. In 1905 Einstein did not understand gravitation and made what we now know
is a mistake here. But since it is a gedanken, it can be fixed by using a rocket
of negligible mass moving along a circular path.

To think that the theory presented in his 1905 paper includes
gravity is just plain wrong. Yes, he mentioned gravity, but
he got it wrong; it took him 11 years to fix it.


> Why can 1905
> Einstein consider the clock at the pole at rest? Because all the
> rotating axis is at rest. The stationary system is the centre of mass
> inertial system corresponding to all the massive bodies involved, the
> UNIQUE possible alternative.

In SR one could analyze this from any inertial frame, not just the ECI.


> That system is the today denoted GPS ECI.
> To use an imaginary inertial system moving at a uniform velocity with
> respect to the ECI is a total absurd.

No, it is not absurd. It is what would happen if a rocket passed by the earth.
There's no reason to expect the theory cannot model such a case.


> You NEVER can make a real
> measurement in that totally imaginary system that has no value at all.

You are confusing gedanken land with the real world. In gedanken land one can do
whatever one wishes; not so in the real world. In gedanken land we can consider
arbitrary coordinate systems and reference events to them; in the real world it
takes measurement instruments to make measurements.


> 1905 Relativity is NOT Special Relativity.

Not true. You attempt to make a distinction without a difference.


> And 1905 Relativity has all
> the huge experimental evidence of today GPS.

Again not true. OUTRAGEOUSLY not true.


> Try to describe the Sun�s trajectory in the ECI to see how many
> contradictions and absurdities arise.

Nobody who understood the basics of GR would attempt such a thing. In GR the ECI
is a LOCALLY-inertial frame, and its region of validity does not extend to the
sun for more than a few seconds. This has NOTHING to do with SR or Einstein's
1905 paper.


Tom Roberts
From: BURT on 2 Jul 2010 13:43
On Jul 1, 9:21 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote:
> va...(a)icmf.inf.cu wrote:
> > On 26 jun, 10:43, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote:
> >> va...(a)icmf.inf.cu wrote:
> >>> 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 Newton s 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.
> >> This is just plain not true. An observer can also determine an inertial frame.
> >> So it is easy to discuss what (say) an observer moving with speed 0.5 c
> >> (relative to the frame you mention) would measure in her inertial frame.
>
> > You write an observer can also determine an inertial frame . Then,
> > without any doubt from my part, what you mean by   observer is a very
> > important concept for the topic we are addressing here. What is an
> > observer for you?
>
> In this context, the essence of an observer is a set of coordinates and the
> ability to note the location in that coordinate system of any event. No human is
> required, nor is any mass. But if one uses an inertial coordinate system, then
> it must move with speed less than c relative to any other inertial coordinate
> system.
>
> >> Indeed, for multi-particle systems it is more common for observers to determine
> >> the frame. Yes, one might well choose the c-o-m frame of the particles, but that
> >> is the OBSERVER'S choice, and is not dictated by either the particles themselves
> >> or by the theory.
>
> > Totally non-sense in the 1905 Einstein s view.
>
> How can you claim that???? He did not discuss such things at all in that paper.
>
> But no matter, because the SR we use today is the same theory as he presented in
> 1905. We have learned A LOT about it, but the theory is the same (i.e. the set
> of theorems has not changed, and the meanings of the symbols have not changed;
> the experimental record is much more complete today than in 1905).
>
> > The centre of mass of
> > some specific massive body set can t be moving with respect to
> > nothing. It is OUR choice: to use the Newtonian view or the 1905
> > Einstein s one. In this last one the centre of mass MUST be at rest.
>
> Nonsense. I can stand here on the earth and throw a baseball -- the c-o-m of
> that baseball is not at rest relative to me. Or an astronaut can be in low earth
> orbit and throw a baseball. Note the c-o-m of the earth is moving wrt that
> astronaut, as is the c-o-m of earth+astronaut.
>
> > You can t put a centre of mass moving with respect to the absolute
> > frame (or any other moving with a uniform velocity with respect to
> > it).
>
> More nonsense. First, there is no "absolute frame". Second, by throwing that
> baseball I did indeed "put its centre of mass moving with respect to me".
>
> But I see your basic point: momentum is conserved. That translates into the fact
> that if the c-o-m of a set of objects is at rest in some inertial frame, then no
> internal action can put the c-o-m into motion relative to that frame. But, of
> course, an external action can do so. So my primary issue is with the way you
> attempt to describe this, and the fact that you ignore the possibility of
> external agents. I suppose you can avoid external agents in principle by
> requiring the analyst to include everything in the universe when computing the
> c-o-m. But that is an unreasonable requirement....
>
> >> Also: you seem to think that "1905 Relativity" is somehow different from Special
> >> Relativity today. This is also not true. We have learned a lot about the theory
> >> since then, but there has been no change in the theory itself (i.e. the set of
> >> theorems and the meanings of the symbols in them).
>
> > The Special Relativity denotation was introduced by first time by
> > 1916 Einstein. He declared gravitation out of the scope of  SR. In
> > 1905 Relativity we have as a real example (at the end of paragraph 4
> > of the 30Jun1905 text) the rotating Earth as the stationary system and
> > a clock at the equator as the moving system. This one is moving
> > GRAVITATIONAL centripetal accelerated in a circular path.
>
> Yes. In 1905 Einstein did not understand gravitation and made what we now know
> is a mistake here. But since it is a gedanken, it can be fixed by using a rocket
> of negligible mass moving along a circular path.
>
>         To think that the theory presented in his 1905 paper includes
>         gravity is just plain wrong. Yes, he mentioned gravity, but
>         he got it wrong; it took him 11 years to fix it.
>
> > Why can 1905
> > Einstein consider the clock at the pole at rest? Because all the
> > rotating axis is at rest. The stationary system is the centre of mass
> > inertial system corresponding to all the massive bodies involved, the
> > UNIQUE possible alternative.
>
> In SR one could analyze this from any inertial frame, not just the ECI.
>
> > That system is the today denoted GPS ECI.
> > To use an imaginary inertial system moving at a uniform velocity with
> > respect to the ECI is a total absurd.
>
> No, it is not absurd. It is what would happen if a rocket passed by the earth.
> There's no reason to expect the theory cannot model such a case.
>
> > You NEVER can make a real
> > measurement in that totally imaginary system that has no value at all.
>
> You are confusing gedanken land with the real world. In gedanken land one can do
> whatever one wishes; not so in the real world. In gedanken land we can consider
> arbitrary coordinate systems and reference events to them; in the real world it
> takes measurement instruments to make measurements.
>
> > 1905 Relativity is NOT Special Relativity.
>
> Not true. You attempt to make a distinction without a difference.
>
> > And 1905 Relativity has all
> > the huge experimental evidence of today GPS.
>
> Again not true. OUTRAGEOUSLY not true.
>
> > Try to describe the Sun s trajectory in the ECI to see how many
> > contradictions and absurdities arise.
>
> Nobody who understood the basics of GR would attempt such a thing. In GR the ECI
> is a LOCALLY-inertial frame, and its region of validity does not extend to the
> sun for more than a few seconds. This has NOTHING to do with SR or Einstein's
> 1905 paper.
>
> Tom Roberts- Hide quoted text -
>
> - Show quoted text -

Gravity is energy center generating a geometry radiating outward.

Mitch Raemsch
From: valls on 5 Jul 2010 19:48
On 1 jul, 23:21, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote:
> va...(a)icmf.inf.cu wrote:
> > On 26 jun, 10:43, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote:
> >> va...(a)icmf.inf.cu wrote:
> >>> 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 Newton s 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.
> >> This is just plain not true. An observer can also determine an inertial frame.
> >> So it is easy to discuss what (say) an observer moving with speed 0.5 c
> >> (relative to the frame you mention) would measure in her inertial frame.
>
> > You write “an observer can also determine an inertial frame”. Then,
> > without any doubt from my part, what you mean by  “observer” is a very
> > important concept for the topic we are addressing here. What is an
> > “observer” for you?
>
> In this context, the essence of an observer is a set of coordinates and the
> ability to note the location in that coordinate system of any event. No human is
> required, nor is any mass. But if one uses an inertial coordinate system, then
> it must move with speed less than c relative to any other inertial coordinate
> system.
>
A system of coordinates is identified by 1905 Einstein with a rigid
body, with more detail, with three rigid material lines. If you say
now that “nor is any mass”, we have a disagreement here. Only the
imaginary inertial frames rejected by 1905 Einstein are massless ones
(the absolute frame and all the other derived ones moving with all
possible uniform velocities with respect to it). I don’t care if what
you say corresponds or not to the Special Relativity introduced by
1916 Einstein.
> >> Indeed, for multi-particle systems it is more common for observers to determine
> >> the frame. Yes, one might well choose the c-o-m frame of the particles, but that
> >> is the OBSERVER'S choice, and is not dictated by either the particles themselves
> >> or by the theory.
>
> > Totally non-sense in the 1905 Einstein’s view.
>
> How can you claim that???? He did not discuss such things at all in that paper.
>
It is a well-established fact of the Newtonian mechanics that given
any body set, there exists a UNIQUE centre of mass inertial frame
corresponding to it, determined ONLY by the bodies themselves. If you
refer now to an OBSERVER’S choice, you are re-introducing the human
being that seemed put out previously. The use of this UNIQUE c-o-m
inertial frame IS determined by the bodies themselves and by the
theory that starts putting out all Newtonian imaginary massless
frames. An inertial frame moving with a uniform velocity with respect
to the c-o-m one is nothing more that one of the massless ones
considered already out by the 1905 Relativity theory (I don’t care if
that massless frames are present or not in Special Relativity). 1905
Einstein is very clear putting out all Newtonian massless inertial
frames.
> But no matter, because the SR we use today is the same theory as he presented in
> 1905. We have learned A LOT about it, but the theory is the same (i.e. the set
> of theorems has not changed, and the meanings of the symbols have not changed;
> the experimental record is much more complete today than in 1905).
>
Your interpretation of 1905 Relativity is anti-historical, and then
false. You put in 1905 Relativity a lot of things developed after
1905.
> > The centre of mass of
> > some specific massive body set can’t be moving with respect to
> > nothing. It is OUR choice: to use the Newtonian view or the 1905
> > Einstein’s one. In this last one the centre of mass MUST be at rest.
>
> Nonsense. I can stand here on the earth and throw a baseball -- the c-o-m of
> that baseball is not at rest relative to me. Or an astronaut can be in low earth
> orbit and throw a baseball. Note the c-o-m of the earth is moving wrt that
> astronaut, as is the c-o-m of earth+astronaut.
>
No matter what interaction can you conceive between the bodies of some
c-o-m inertial frame, the c-o-m will remain always at rest. A whole
can never be moving with respect to some of its parts. And a part can
only be moving with respect to its whole. All this is simple Newtonian
mechanics. By the way, a c-o-m inertial frame can never be used to say
something about some body not belonging to its body set.
> > You can’t put a centre of mass moving with respect to the absolute
> > frame (or any other moving with a uniform velocity with respect to
> > it).
>
> More nonsense. First, there is no "absolute frame". Second, by throwing that
> baseball I did indeed "put its centre of mass moving with respect to me".
>
Of course that the absolute frame doesn’t exist at all (as all the
other non-massive derived ones moving with all possible uniform
velocities with respect to it). This is precisely the starting point
of 1905 Relativity. If both you and a baseball belong to some c-o-m
inertial frame, neither you or the ball can be used as an inertial
frame to describe the movement of the other.
> But I see your basic point: momentum is conserved. That translates into the fact
> that if the c-o-m of a set of objects is at rest in some inertial frame, then no
> internal action can put the c-o-m into motion relative to that frame. But, of
> course, an external action can do so. So my primary issue is with the way you
> attempt to describe this, and the fact that you ignore the possibility of
> external agents. I suppose you can avoid external agents in principle by
> requiring the analyst to include everything in the universe when computing the
> c-o-m. But that is an unreasonable requirement....
>
Good! You seem now starting an understanding of which my point is
managing centre of mass inertial frames. But you are still confused
mixing it with the imaginary non-massive inertial frames of Special
Relativity, that don’t exist at all in 1905 Relativity.
No, the c-o-m of a set of objects can’t be at rest in some inertial
frame. The objects themselves determine a UNIQUE inertial frame, the c-
o-m one, which must be always at rest (as a whole entity modelled by a
material point in its c-o-m) with respect to all its parts, the
starting body set.
You are very right pointing that the relationship with an EXTERNAL
agent is the primary issue here. To describe it I need to introduce a
new concept, denoted by me Hierarchical Inertial System (HIS) (this is
not the first time I talk about it in this group). A HIS is simply the
c-o-m inertial frame corresponding to some body set in which each one
of the bodies is modelled by a HIS of low hierarchy, all of them
interacting by all Nature forces that can be present. The INTERIOR of
a high hierarchy HIS is a rest c-o-m inertial frame where lower
hierarchy HIS are interacting among them. The EXTERIOR of a low
hierarchy HIS is the INTERIOR of the high hierarchy HIS it belong as a
moving interacting part.
A very important detail is missing. To be considered a HIS, the
EXTERNAL world of a HIS must provokes a sufficiently almost equal
ACCELERATION in all its parts. The ECI moving in the Solar System is
my preferred example (more clear with an ECI extended by the Moon
presence).
Yes, we are in agreement about that modelling the whole universe with
a single HIS is an unreasonable requirement, but it leave us to an
interesting return of the Newtonian absolute frame as a limit for an
(maybe infinite) HIS structure.

> >> Also: you seem to think that "1905 Relativity" is somehow different from Special
> >> Relativity today. This is also not true. We have learned a lot about the theory
> >> since then, but there has been no change in the theory itself (i.e. the set of
> >> theorems and the meanings of the symbols in them).
>
> > The “Special Relativity” denotation was introduced by first time by
> > 1916 Einstein. He declared gravitation out of the scope of  SR. In
> > 1905 Relativity we have as a real example (at the end of paragraph 4
> > of the 30Jun1905 text) the rotating Earth as the stationary system and
> > a clock at the equator as the moving system. This one is moving
> > GRAVITATIONAL centripetal accelerated in a circular path.
>
> Yes. In 1905 Einstein did not understand gravitation and made what we now know
> is a mistake here. But since it is a gedanken, it can be fixed by using a rocket
> of negligible mass moving along a circular path.
>
Perhaps you will be interested some day to know how 1905 Relativity
can be used to manage gravity (among many other things). I can assure
you that it is very more simple than the introduction of your
imaginary rocket violating Newton’s laws.
>         To think that the theory presented in his 1905 paper includes
>         gravity is just plain wrong. Yes, he mentioned gravity, but
>         he got it wrong; it took him 11 years to fix it.
>
I have very different opinions. To convince you that gravity is
present in 1905 Relativity, answer the questions I make in the
following thread:
Potential energy in 1905 Relativity
http://groups.google.com.cu/group/sci.physics.relativity/browse_frm/thread/584f67f39bbb3237/40c66d38b6b7a650?hl=es#40c66d38b6b7a650
Almost sure you will be the first one answering them.

> > Why can 1905
> > Einstein consider the clock at the pole at rest? Because all the
> > rotating axis is at rest. The stationary system is the centre of mass
> > inertial system corresponding to all the massive bodies involved, the
> > UNIQUE possible alternative.
>
> In SR one could analyze this from any inertial frame, not just the ECI.
>
Any non-massive inertial frame moving with a uniform velocity with
respect to the ECI is just an imaginary one already rejected by 1905
Einstein.
> > That system is the today denoted GPS ECI.
> > To use an imaginary inertial system moving at a uniform velocity with
> > respect to the ECI is a total absurd.
>
> No, it is not absurd. It is what would happen if a rocket passed by the earth.
> There's no reason to expect the theory cannot model such a case.
>
The goal of any theory is to model the real Universe. If a rocket
exists, you can include it in the model. The Moon can be included in
the ECI if the need arises. The absurd is not to include a real
object. The absurd is to include a totally useless imaginary object.
> > You NEVER can make a real
> > measurement in that totally imaginary system that has no value at all.
>
> You are confusing gedanken land with the real world. In gedanken land one can do
> whatever one wishes; not so in the real world. In gedanken land we can consider
> arbitrary coordinate systems and reference events to them; in the real world it
> takes measurement instruments to make measurements.
>
All the real bodies are already in the ECI, and you can extend the set
if needed. Why to make a totally useless gedanken with an imaginary
inertial frame?
> > 1905 Relativity is NOT Special Relativity.
>
> Not true. You attempt to make a distinction without a difference.
>
Gravity is out from Special Relativity. Go to the link I give you to
verify that gravity IS in 1905 Relativity. Why to be involved in a
pure scholastic debate?
> > And 1905 Relativity has all
> > the huge experimental evidence of today GPS.
>
> Again not true. OUTRAGEOUSLY not true.
>
Then it will be very easy to you to give me a SINGLE 1905 Relativity
topic not supported right by today GPS.
> > Try to describe the Sun’s trajectory in the ECI to see how many
> > contradictions and absurdities arise.
>
> Nobody who understood the basics of GR would attempt such a thing. In GR the ECI
> is a LOCALLY-inertial frame, and its region of validity does not extend to the
> sun for more than a few seconds. This has NOTHING to do with SR or Einstein's
> 1905 paper.
>
In 1905 Relativity the ECI is simply a c-o-m inertial frame, with a
very well determined application scope. I don’t care about your
problems in GR trying to determine which is the application scope of a
local inertial frame. By the way, don’t you see that the GPS is a
direct experimental evidence about the presence of a gravitational
field in an inertial frame? And remember that an atomic clock
behaviour in a gravitational field can be explained using only 1905
Relativity.
> Tom Roberts

RVHG (Rafael Valls Hidalgo-Gato)
From: Dono. on 5 Jul 2010 23:17
On Jul 5, 4:48 pm, va...(a)icmf.inf.cu wrote:
>
> No matter what interaction can you conceive between the bodies of some
> c-o-m inertial frame, the c-o-m will remain always at rest.

"At rest" with respect to what frame, old fart?
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