Is temporal sign ambiguity inherent in Einstein's general relativistic field equation?

Mathematically speaking, Einstein's general relativistic field
equation admits two possibilities for the speed of propagation of
gravitational fields/waves, + or - the speed of light (c) (i.e.
propagation forwards or backwards in the dimension of time).

Would I be correct in therefore concluding that the planetary orbits
predicted by this field equation remain the same, irrespective of this
mathematical sign ambiguity? If so, it appears to me that this might
provide a conceptually simpler/alternative explanation as to why such
orbits remain stable, to that given in the physics faq. (although
clearly, the real reason for this stability is that Einstein derived
the equation from the axiomatic foundations of the theory, under the
constraints of energy and impulse conservation)

If the answer to my first question is yes, then does this same level of
pure mathematical sign ambiguity extend to the predictions of this
field equation on the galactic and intergalactic scales?

If the answer to both of the above questions is yes, then, taking this
line of enquiry to its logical conclusion, when we discount the obvious
experimental physics option of directly observing when a test body
moves in response to a major gravitational event (such as the detection
of a gravitational wave from a supernova), is there anything in the
cosmological application of this field equation to suggest any
observable difference between the mathematical effects of positive and
negative gravitational propagation speeds?

(In the case of the decay of binary pulsars, it appears to me at
present, that the emission of negative energy gravitational waves with
negative propagation speed should be mathematically equivalent to the
emission of positive energy waves, with a positive propagation speed)

Bell

On Sun, "John Bell" wrote:

[snip]
(In the case of the decay of binary pulsars, it appears to me at
present, that the emission of negative energy gravitational waves with
negative propagation speed should be mathematically equivalent to the
emission of positive energy waves, with a positive propagation speed)
Bell

Merging binary stars (not decay) are thought to be a possible source of
gravity waves, and I suppose the "shaking" of the detector arm should
result (according some interpretations of the theory).

So how could negative waves be detected, shaking is shaking.

I would like to state how I think LIGO should have been tested from the
beginning.

A perfectly level rail line should have been built running toward and
away from the end of the arm, and a rail car propelled by rockets used
to accelerate a large mass ~10E+6 kg, back and forth as rapidly as
possible.

Then using the results from that calculate just what kind of signal to
expect from distant merging stars.

I have no idea why black holes or neutron stars are talked about,
ordinary binary stars would seem to merge at least as easy as any other
because of their size and atmospheric drag, plus ordinary stars should
flex and transfer material easier than dense stars.

A heavy mass pushed back and forth by rockets should provide many times
the shaking as very distant stars.

Joe Fischer

In sci.physics.research Joe Fischer wrote:
I would like to state how I think LIGO should have been tested from the
beginning.

A perfectly level rail line should have been built running toward and
away from the end of the arm, and a rail car propelled by rockets used
to accelerate a large mass ~10E+6 kg, back and forth as rapidly as
possible.

Unfortunately, this would
(a) produce large ground vibrations which might well interfere with
LIGO's operation,
(b) produce large *Newtonian* gravitational effects which would
interfere with LIGO's operation, and
(c) produce a gravitational-wave signal which is *vastly* too small
for LIGO to detect. A rough approximation to the emitted
gravitation-wave power is
P_GW = P_internal^2 / P_0
where P_0 = 4e52 Watts = (2e5 solar masses*c^2)/second
and P_internal = the non-spherically-symmetric power flow in the
emitting system
If you work it out, you'll see that this is WAY below LIGO's
sensitivity.


I have no idea why black holes or neutron stars are talked about,
ordinary binary stars would seem to merge at least as easy as any other
because of their size and atmospheric drag, plus ordinary stars should
flex and transfer material easier than dense stars.

Black holes or neutron stars are 'talked about' because they are
much stronger gravitational-wave sources than ordinary binary stars.
This is because they are (or can be) moving much faster, in much
closer-together orbits. I think the gravitational-wave signal
grows as the 5th power of the orbital frequency, so a neutron star
or black hole binary shortly before merger, with an orbital frequency
of 100 Hz or more, produces a LOT more gravitational-wave signal
than a classical binary star (with an orbital frequency of 0.0001 Hz
or lower).

ciao,

--
-- "Jonathan Thornburg -- remove -animal to reply"
Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut),
Golm, Germany, "Old Europe" http://www.aei.mpg.de/~jthorn/home.html
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
-- quote by Freire / poster by Oxfam

Jonathan Thornburg -- remove -animal to reply wrote:

Unfortunately, this would

(b) produce large *Newtonian* gravitational effects which would
interfere with LIGO's operation, and

Interesting point. I presume, if you are answering in the context of
the original question, that we wish to shield from *Newtonian*
gravitational effects because they appear to travel at infinite speed
as do their Einsteinian equivalent.

(c) produce a gravitational-wave signal which is *vastly* too small
for LIGO to detect. A rough approximation to the emitted
gravitation-wave power is
P_GW = P_internal^2 / P_0
where P_0 = 4e52 Watts = (2e5 solar masses*c^2)/second
and P_internal = the non-spherically-symmetric power flow in the
emitting system
If you work it out, you'll see that this is WAY below LIGO's
sensitivity.

You appear to have missed the point here. The sensitivity of a
gravitational wave detector does not depend on the strength of the
source. It depends solely on the resultant strength of the signal at
the location of the detector. Consequently, although Joe Fischer's
suggestion has serious defects in practice, it does not appear to have
such defects in principle. Consequently, I suggest that it makes
perfect sense to test the theory more elegantly (and economically) by
placing a viable gravitational wave source and compatible gravitational
wave detector as close together as possible, provided that we:

(a) include means to isolate from the effects of vibration
(b) include means to isolate from atmospheric acoustic coupling
(c) include means to isolate from the detection of *Newtonian*
gravitational effects and their Einsteinian equivalent.

This is not mere idle speculation, as we performed such an experiment
over 20 years ago whilst the relevant applied technology was under
British State Secrecy Classification.
The irony of that situation is that the US government has subsequently
committed millions of dollars in taxpayers money to investigate a far
less efficient test of the theory.

John Bell

John Bell wrote:
Mathematically speaking, Einstein's general relativistic field
equation admits two possibilities for the speed of propagation of
gravitational fields/waves, + or - the speed of light (c) (i.e.
propagation forwards or backwards in the dimension of time).

Would I be correct in therefore concluding that the planetary orbits
predicted by this field equation remain the same, irrespective of this
mathematical sign ambiguity? If so, it appears to me that this might
provide a conceptually simpler/alternative explanation as to why such
orbits remain stable, to that given in the physics faq. (although
clearly, the real reason for this stability is that Einstein derived
the equation from the axiomatic foundations of the theory, under the
constraints of energy and impulse conservation)

[snip]

Orbits in multi-body systems aren't stable, I have no idea why you
would think that they were. They are stable over human and geologic
timescales, but forever.

I would love to see your justification for thinking a sign change in c
would manifest itself in altering the stability of orbits, because as
it stands what you said is absurd.

Also, energy conservation is less than well-defined in general
relativity - energy is not an invariant, though there are ways to
define energy but not when formulating the theory.

Furthermore, there is no such thing as "impulse conservation" unless
you are referring to conservation of momentum - which isn't needed to
formulate theory, but is needed to make predictions using it.

On Sat, 21 "John Bell" wrote:

Jonathan Thornburg -- remove -animal to reply wrote:
Unfortunately, this would
(b) produce large *Newtonian* gravitational effects which would
interfere with LIGO's operation, and

Interesting point. I presume, if you are answering in the context of
the original question, that we wish to shield from *Newtonian*
gravitational effects because they appear to travel at infinite speed
as do their Einsteinian equivalent.

One of the problems of all large detectors is the
dependence on effects other than ordinary gravitational
changes in motion.
And this can only result from a gross assumption
that there is radiation of some sort other than plain old
change in motion due to gravity.
The assumption that the "energy" of this hypothetical
radiation increases with the frequency of the changes in
accelerations of objects. There is even a problem in
concept here if orbiting objects do not accelerate, but
are in inertial motion.
The increase in "signal strength" being a function
of frequency (as in em) appears to be purely a hypothetical.

(c) produce a gravitational-wave signal which is *vastly* too small
for LIGO to detect. A rough approximation to the emitted
gravitation-wave power is
P_GW = P_internal^2 / P_0
where P_0 = 4e52 Watts = (2e5 solar masses*c^2)/second
and P_internal = the non-spherically-symmetric power flow in the
emitting system
If you work it out, you'll see that this is WAY below LIGO's
sensitivity.

You appear to have missed the point here.

I didn't comment on that at the time it was written
because I am not able to think of 2e5 solar masses, let
alone a "per second" anything involving those masses.
Most stars have less than 25 times the mass of
the sun.

The sensitivity of a
gravitational wave detector does not depend on the strength of the
source. It depends solely on the resultant strength of the signal at
the location of the detector. Consequently, although Joe Fischer's
suggestion has serious defects in practice, it does not appear to have
such defects in principle. Consequently, I suggest that it makes
perfect sense to test the theory more elegantly (and economically) by
placing a viable gravitational wave source and compatible gravitational
wave detector as close together as possible, provided that we:

Yes, even if it does interfere with the detector,
provided the interference can be filtered.

(a) include means to isolate from the effects of vibration
(b) include means to isolate from atmospheric acoustic coupling
(c) include means to isolate from the detection of *Newtonian*
gravitational effects and their Einsteinian equivalent.

The last one may be hard to do, since apparently
the reasons that Weber and others had no repeatable
success is because the "equivalent" is speculative.

This is not mere idle speculation, as we performed such an experiment
over 20 years ago [snip]
John Bell

Did it show there is an Einsteinian equivalent?

I tracked the original papers I could find and
some of them were developed as class lecture notes,
apparently without a formal presentation, and that
makes me leary of the whole premise.

I may be following a foolish path, but I do
not believe in any propagated energy where gravity
is concerned, there should only be geometric changes
in distances of separation with the center of masses
of all free objects being in inertial motion.

Things appear to change motion due to gravity,
and that is all I can appreciate with my poor understanding
of General Relativity.

Joe Fischer

Eric Gisse wrote:
John Bell wrote:
Mathematically speaking, Einstein's general relativistic field
equation admits two possibilities for the speed of propagation of
gravitational fields/waves, + or - the speed of light (c) (i.e.
propagation forwards or backwards in the dimension of time).

Would I be correct in therefore concluding that the planetary orbits
predicted by this field equation remain the same, irrespective of this
mathematical sign ambiguity? If so, it appears to me that this might
provide a conceptually simpler/alternative explanation as to why such
orbits remain stable, to that given in the physics faq. (although
clearly, the real reason for this stability is that Einstein derived
the equation from the axiomatic foundations of the theory, under the
constraints of energy and impulse conservation)

[snip]

Orbits in multi-body systems aren't stable, I have no idea why you
would think that they were. They are stable over human and geologic
timescales, but forever.

Obviously, if you meant here *but NOT forever* . I was referring to
relative stability as in the context of the physics FAQ, and expected
that the readers would have the intelligence to appreciate this, and
the generosity of spirit to grant me the same intelligence.

I would love to see your justification for thinking a sign change in c
would manifest itself in altering the stability of orbits, because as
it stands what you said is absurd.

Read the posting more carefully. I repeat:
Would I be correct in therefore concluding that the planetary orbits
predicted by this field equation remain the same, irrespective of this
mathematical sign ambiguity?
The reason for the question was that somebody else had made the
opposite *absurd* assertion, at sci.physics.relativity, and I didn't
trust that assertion.

Also, energy conservation is less than well-defined in general
relativity - energy is not an invariant, though there are ways to
define energy but not when formulating the theory.

Einstein explicitly states in the authorised English translation of his
popular exposition, that he constrained the solution to be consistent
with the laws of conservation of energy and impulse. You say he didn't?

Furthermore, there is no such thing as "impulse conservation" unless
you are referring to conservation of momentum - which isn't needed to
formulate theory, but is needed to make predictions using it.

Again, your argument is with Einstein, not me. Einstein used the term
impulse not momentum, in the passage to which I refer.

Thank you, however, for appearing to confirm that my understanding is
correct orbital invariance with sign reversal, despite your
unconventional way of doing so.

John Bell

John Bell wrote:
Eric Gisse wrote:
John Bell wrote:
Mathematically speaking, Einstein's general relativistic field
equation admits two possibilities for the speed of propagation of
gravitational fields/waves, + or - the speed of light (c) (i.e.
propagation forwards or backwards in the dimension of time).

Would I be correct in therefore concluding that the planetary orbits
predicted by this field equation remain the same, irrespective of this
mathematical sign ambiguity? If so, it appears to me that this might
provide a conceptually simpler/alternative explanation as to why such
orbits remain stable, to that given in the physics faq. (although
clearly, the real reason for this stability is that Einstein derived
the equation from the axiomatic foundations of the theory, under the
constraints of energy and impulse conservation)

[snip]

Orbits in multi-body systems aren't stable, I have no idea why you
would think that they were. They are stable over human and geologic
timescales, but forever.

Obviously, if you meant here *but NOT forever* . I was referring to
relative stability as in the context of the physics FAQ, and expected
that the readers would have the intelligence to appreciate this, and
the generosity of spirit to grant me the same intelligence.

I would love to see your justification for thinking a sign change in c
would manifest itself in altering the stability of orbits, because as
it stands what you said is absurd.

Read the posting more carefully. I repeat:
Would I be correct in therefore concluding that the planetary orbits
predicted by this field equation remain the same, irrespective of this
mathematical sign ambiguity?
The reason for the question was that somebody else had made the
opposite *absurd* assertion, at sci.physics.relativity, and I didn't
trust that assertion.

Looks like I mis-read who was saying what. Sorry.



Also, energy conservation is less than well-defined in general
relativity - energy is not an invariant, though there are ways to
define energy but not when formulating the theory.

Einstein explicitly states in the authorised English translation of his
popular exposition, that he constrained the solution to be consistent
with the laws of conservation of energy and impulse. You say he didn't?

Beats me, I haven't read his works and don't really care to. I find
them a lot harder to read than the moden expositions on the subject.
That is also where my knowledge comes from, such as it is.

This isn't specifically directed at you, but I will never understand
why people focus on Einstein so much. I'm not arguing against him on
this or anything, I just don't understand why people don't seem to be
quite capable of seperating the man from the theory.


Furthermore, there is no such thing as "impulse conservation" unless
you are referring to conservation of momentum - which isn't needed to
formulate theory, but is needed to make predictions using it.

Again, your argument is with Einstein, not me. Einstein used the term
impulse not momentum, in the passage to which I refer.

I'm going to make the guess that they are the same thing.


Thank you, however, for appearing to confirm that my understanding is
correct orbital invariance with sign reversal, despite your
unconventional way of doing so.




John Bell

Eric Gisse wrote:
John Bell wrote:
Eric Gisse wrote:
John Bell wrote:
Mathematically speaking, Einstein's general relativistic field
equation admits two possibilities for the speed of propagation of
gravitational fields/waves, + or - the speed of light (c) (i.e.
propagation forwards or backwards in the dimension of time).

Would I be correct in therefore concluding that the planetary orbits
predicted by this field equation remain the same, irrespective of this
mathematical sign ambiguity? If so, it appears to me that this might
provide a conceptually simpler/alternative explanation as to why such
orbits remain stable, to that given in the physics faq. (although
clearly, the real reason for this stability is that Einstein derived
the equation from the axiomatic foundations of the theory, under the
constraints of energy and impulse conservation)
[snip]

Furthermore, there is no such thing as "impulse conservation" unless
you are referring to conservation of momentum - which isn't needed to
formulate theory, but is needed to make predictions using it.

Again, your argument is with Einstein, not me. Einstein used the term
impulse not momentum, in the passage to which I refer.

I'm going to make the guess that they are the same thing.

I have given this some subsequent thought. The reason for my not
wishing to make this conceptual leap in my original posting was that it
is pretty obvious that (linear) momentum is not conserved in the
presence of gravitational fields. A simple dictionary definition of
impulse is force impelling motion as well as forward motion itself.
Consequently I imagine that the Law of Impulse Conservation to which
Einstein referred could be that the Change in Momentum of a body is
equal to the Action (force x time) of the Force acting on it . However,
I must admit I am guessing too, since both Impulse and Action were much
more commonly used in Victorian physics than now.

Thank you, however, for appearing to confirm that my understanding is
correct orbital invariance with sign reversal, despite your
unconventional way of doing so.


Cheers again for your input,
Bell

Does anyone have anything further to add on any aspect of the entirety
of the original posting, or on any of the comments thus far? (some of
these comments were only posted at spr)

Joe Fischer wrote: "John Bell" wrote:
Hi again Joe.
I did respond to this posting via sci.physics.research moderation, but
my response did not get posted, so I guess the moderator thought it
added little to the discussion.

However, in addition to the comments here at sci.physics.relativity,
there is a continuation of the discussion (only) at
sci.physics.research, between T.Essel and me (under the original
title). (Essel appears to be stumped at present by my last response to
him).
John Bell.

I read the Essel response, and the only thing that
I could remark about is that he said I proposed a "railgun"
test, and that is not what I said.

Even a double ended Shuttle booster firing one way
and then the other at 200 miles altitude half way between
two of the detector locations should provide a stronger
signal than astronomical events in other galaxies.

I should study quadrapole radiation, to see if it
is know to exist in any form (tested).

The only other project that I know of offhand that
has spent such large sums of money is magnetic containment,
and in my opinion that was a mistake because in my opinion
fusion does not "release" energy, something has to "squeeze"
it out, such as gravity or inertia.

At the moment I am looking at the origination of
the Einstein Field Equations. It looks to me like the
external gravitational field should be purely geometric
--- AND --- kinematic ONLY.
The dynamic components of the field equations
should only be in the nearby matter, not in the "field",
but GR might work ok either way.

There has always been a tendency to attribute
the dynamics to a field of some kind, so Einstein would
likely have been following convention.

But if I am right, then there would be no radiation
of any kind, there would only be the geometric kinematics
of changes in motion due to gravitation, --- WITHOUT ---
any "forces" acting.

NON - contact interaction dynamics need not be
a component in the geometry, but would definitely need
to be in the field calculations in some way to relate the
results to reality and to attain a quantitative result.

So I feel that the continuum is even more of
a continuum than Einstein ever dreamed, a geometry
alone cannot be anything but continuous.

But nobody involved it gravity wave experiments
will want to hear any of this.

Joe Fischer

$$ NO m1, NO "NO-feelings".
i LOVE it when you cut the EMPTY space bull and get SPECiFiC
about your THESiS (or WHATever), howEVER, you KNOW space is FULL
of LiGHT and OTHER emissions, etc etc. So ..w.r.t "NO-feelings",
there is NO "falling" if EVERYthing is in bouyant equiblibrium:

G*M1
-- - -- = rA^2*g ..where (n=1). Newton & Einstein died on (n - 1).
(n - 1)

n = mD/m1 @ point of weightless equilibrium in equivalent ambient.
mD = DisCHARGE mass (ambient equivalent), from a sealed m1 CAViTY.
m1 = The GUESS iSS TEST mass, as per: G*M1*m1/(n - 1) = m1*rA^2*g.

TEST mass m1 isN'T UNnecessary. You NEED it to HAVE "NO-feelings".
You "feel" g because EVERYthing isN'T in a weightless equilibrium.
```Brian.