Speed of gravity
in [Relativity]
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From: Androcles on 4 Mar 2010 06:05 "Jan Panteltje" <pNaonStpealmtje(a)yahoo.com> wrote in message news:hmo3rg$jvr$1(a)news.albasani.net... > On a sunny day (Wed, 03 Mar 2010 16:55:07 -0800) it happened Uncle Al > <UncleAl0(a)hate.spam.net> wrote in <4B8F04EB.1D3009F9(a)hate.spam.net>: > >>Urion wrote: >>> >>> Gravity is invisible and dark energy is invisible. So these two could >>> be related. Both are subnuclear invisible forces. >> >>The speed of gravity is 6. As this is a unitless constant it must be >>universally true. >> >>idiot > > Was not the answer to everything '42'? > (Hitchhikers guide to the galaxy? > Maybe it was some other number? > LOL > Mainstream says 'Einstein'. > > FOTGLMAO There are seven days a week, we have gravity every day, 7 * 6 = 42.
From: "Juan R." González-Álvarez on 4 Mar 2010 06:28 carlip-nospam wrote on Mon, 01 Mar 2010 17:53:55 +0000: > Art <null(a)zilch.com> wrote: >> Has this question been settled yet? I've read that Einstein assumed >> gravity travels at c. But I've also read that certain orbits are >> iunstable unless gravity travels >> c. > > It depends what you mean by "settled." > > General relativity predicts that gravity propagates at the speed of > light, in the sense that if you change the matter configuration in some > finite region, the gravitational effects of that change don't reach > distant regions until after the light-travel time to those regions. I > wouldn't say Einstein "assumed" this -- it was not put into the > derivation of the field equations of general relativity, but is, rather, > a conclusion. There's a rigorous proof in Low, "Speed limits in general > relativity," Class. Quant. Grav. 16 (1999) 543, on line at > arxiv.org/abs/gr-qc/9812067. Right. > It's also true that if you start with *Newtonian* gravity and stick in a > finite propagation speed, orbits become dramatically unstable. Newtonian gravity is not a theory of "finite propagation speed" [1]. > This does > *not* happen in general relativity, though; in GR, there are additional > velocity-dependent interactions that almost (but not quite) cancel the > instability. Adds self-interaction, retardation, or many-body effects and the GR 'orbits' become highly unstable. Numerical relativists have never checked the general case of motion. Authors as Dr. Schieve "regarded as one of the world experts in the field of relativistic chaos" [2] know that GR fails for general case in many-body dynamics and they are using other theories of gravity to try to study those more complex motions [1] for which, I repeat, GR fails. > The lack of exact cancellation leads to slow changes in > the orbits of binary neutron stars ("gravitational radiation reaction"), > which are observed and agree very precisely with prediction. This > cancellation was, again, not put into the derivation of the field > equations of general relativity, but comes out as a conclusion. It's > discussed in my paper, "Aberration and the speed of gravity," published > in Phys. Lett. A267 (2000) 81, on line at arxiv.org/abs/gr-qc/9909087. This paper only considers simplified models, only studies some aspects of motion and make several bold claims about Newtonian gravity and other models that the author clearly dislike [1]. > As for the experimental/observational question, we have no direct > evidence. Gravity is too weak an interaction for the difference between > an infinite propagation speed and the GR prediction of a finite speed > plus velocity-dependent interactions. But a Newtonian theory with > infinite propagation speed would give the wrong results for binary > pulsars, unless some additional radiation reaction terms were stuck in > by hand. Continue doing bold claims about Newtonian theory. In particular Newtonian theory is not the c--> oo limit of a field, metric, or similar theory. This limit gives you a theory of gravity without retardation, which is not equivalent to a true AAAD theory, of course [1]. Evidently, nobody would try to use a Newtonian theory (non-relativistic theory) to explain a relativistic observation. One would use a generalized theory, which already gives the "radiation reaction terms" from first principles. > It's also worth noting that the same issue occurs in electromagnetism. > Almost everyone accepts that the electromagnetic force travels at the > speed of light. You continue doing very bold claims Steve. The Lorentzian electromagnetic force (associated to the field model of electromagnetic interactions) "travels at the speed of light". But that is not true in more advanced models of electromagnetism. E.g. the generalized electromagnetic forces obtained from the theory studied by Dr. Schieve and many other people to study relativistic chaos, dissipation, and other advanced topics are instantaneous and cannot be obtained from electromagnetic field theory, which (as is well-known to actual experts) gives the wrong results [3]. There exists a quote from Schieve monograph "Classical Relativistic Many-Body Dynamics" [3] which is reproduced in [4] about the failure of field theory: "Of course, the most interesting results derivable from the many-body theory are for systems for which field theory is not capable of producing the equations of motion." In [4] it is showed that the theory discussed in the above monograph reduces exactly to Newtonian theory plus Coulomb interactions, whereas Maxwell-Lorentz fails. [4] also discusses some of the mistakes in your wrong PLA paper. [1] http://www.canonicalscience.org/publications/canonicalsciencereports/20092.html [2] http://order.ph.utexas.edu/research/glimpse.html [3] http://order.ph.utexas.edu/people/Schieve.htm [4] http://www.canonicalscience.org/publications/canonicalsciencereports/20093.html -- http://www.canonicalscience.org/ BLOG: http://www.canonicalscience.org/publications/canonicalsciencetoday/canonicalsciencetoday.html
From: G. L. Bradford on 4 Mar 2010 11:24 "Juan R. González-Álvarez" <nowhere(a)canonicalscience.com> wrote in message news:pan.2010.03.04.11.32.22(a)canonicalscience.com... > carlip-nospam wrote on Mon, 01 Mar 2010 17:53:55 +0000: > >> Art <null(a)zilch.com> wrote: >>> Has this question been settled yet? I've read that Einstein assumed >>> gravity travels at c. But I've also read that certain orbits are >>> iunstable unless gravity travels >> c. >> >> It depends what you mean by "settled." >> >> General relativity predicts that gravity propagates at the speed of >> light, in the sense that if you change the matter configuration in some >> finite region, the gravitational effects of that change don't reach >> distant regions until after the light-travel time to those regions. I >> wouldn't say Einstein "assumed" this -- it was not put into the >> derivation of the field equations of general relativity, but is, rather, >> a conclusion. There's a rigorous proof in Low, "Speed limits in general >> relativity," Class. Quant. Grav. 16 (1999) 543, on line at >> arxiv.org/abs/gr-qc/9812067. > > Right. > >> It's also true that if you start with *Newtonian* gravity and stick in a >> finite propagation speed, orbits become dramatically unstable. > > Newtonian gravity is not a theory of "finite propagation speed" [1]. > >> This does >> *not* happen in general relativity, though; in GR, there are additional >> velocity-dependent interactions that almost (but not quite) cancel the >> instability. > > Adds self-interaction, retardation, or many-body effects and the GR > 'orbits' > become highly unstable. > > Numerical relativists have never checked the general case of motion. > > Authors as Dr. Schieve "regarded as one of the world experts in the field > of relativistic chaos" [2] know that GR fails for general case in > many-body > dynamics and they are using other theories of gravity to try to study > those > more complex motions [1] for which, I repeat, GR fails. > >> The lack of exact cancellation leads to slow changes in >> the orbits of binary neutron stars ("gravitational radiation reaction"), >> which are observed and agree very precisely with prediction. This >> cancellation was, again, not put into the derivation of the field >> equations of general relativity, but comes out as a conclusion. It's >> discussed in my paper, "Aberration and the speed of gravity," published >> in Phys. Lett. A267 (2000) 81, on line at arxiv.org/abs/gr-qc/9909087. > > This paper only considers simplified models, only studies some aspects of > motion and make several bold claims about Newtonian gravity and other > models > that the author clearly dislike [1]. > >> As for the experimental/observational question, we have no direct >> evidence. Gravity is too weak an interaction for the difference between >> an infinite propagation speed and the GR prediction of a finite speed >> plus velocity-dependent interactions. But a Newtonian theory with >> infinite propagation speed would give the wrong results for binary >> pulsars, unless some additional radiation reaction terms were stuck in >> by hand. > > Continue doing bold claims about Newtonian theory. In particular > Newtonian theory is not the c--> oo limit of a field, metric, or similar > theory. This limit gives you a theory of gravity without retardation, > which is not equivalent to a true AAAD theory, of course [1]. > > Evidently, nobody would try to use a Newtonian theory (non-relativistic > theory) to explain a relativistic observation. One would use a generalized > theory, which already gives the "radiation reaction terms" from first > principles. > >> It's also worth noting that the same issue occurs in electromagnetism. >> Almost everyone accepts that the electromagnetic force travels at the >> speed of light. > > You continue doing very bold claims Steve. > > The Lorentzian electromagnetic force (associated to the field model > of electromagnetic interactions) "travels at the speed of light". But that > is not true in more advanced models of electromagnetism. > > E.g. the generalized electromagnetic forces obtained from the theory > studied by Dr. Schieve and many other people to study relativistic > chaos, dissipation, and other advanced topics are instantaneous and > cannot be obtained from electromagnetic field theory, which (as is > well-known to actual experts) gives the wrong results [3]. > > There exists a quote from Schieve monograph "Classical Relativistic > Many-Body Dynamics" [3] which is reproduced in [4] about the failure of > field theory: > > "Of course, the most interesting results derivable from the many-body > theory are for systems for which field theory is not capable of > producing the equations of motion." > > In [4] it is showed that the theory discussed in the above monograph > reduces exactly to Newtonian theory plus Coulomb interactions, whereas > Maxwell-Lorentz fails. [4] also discusses some of the mistakes in your > wrong PLA paper. > ============================= Just for the heck of it, too bad you did not mention the Lagrange points, the stable and the unstable, regarding the overlapping and crossing fields in the multiple body system. GLB =============================
From: Uncle Al on 4 Mar 2010 11:25 Inertial wrote: > > "Uncle Al" <UncleAl0(a)hate.spam.net> wrote in message > news:4B8F04EB.1D3009F9(a)hate.spam.net... > > Urion wrote: > >> > >> Gravity is invisible and dark energy is invisible. So these two could > >> be related. Both are subnuclear invisible forces. > > > > The speed of gravity is 6. As this is a unitless constant it must be > > universally true. > > I thought it would have been 42 :):) > Gravity is much weaker than 42. Since 1 is god, 2 is man, and 3 is woman... 6 must be gravitation. It is necessary and sufficient. There is a quantum correction to 6.0023193043622, but only by heretics who must be destroyed. -- Uncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) http://www.mazepath.com/uncleal/qz4.htm
From: eric gisse on 4 Mar 2010 12:50
Ken S. Tucker wrote: > On Mar 3, 4:55 pm, Uncle Al <Uncle...(a)hate.spam.net> wrote: >> The speed of gravity is 6. As this is a unitless constant it must be >> universally true. > > I suppose we might begin with c described in GR by, > > 0 = ds^2 = g_uv dx^uv , > > and then it's derivative, > > g_uv,w dx^uv = -g_uv dx^uv,w , (A) > > is an 'explicit' relationship in GR. > > Using w = time, the term dx^uv,w is sometimes called the > coordinate speed of light, that Shapiro & team measured, > to be retarded in g-fields. > (It's detailed but I think you get the over-all picture). No, Ken, that's not the coordinate speed of light. http://www.ncbi.nlm.nih.gov/pubmed/10626367 [snip] |