Speed of gravity
in [Relativity]
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From: BURT on 4 Mar 2010 13:29 On Mar 4, 9:50 am, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > 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]- Hide quoted text - > > - Show quoted text - Light moves through space at C. Matter moves through space below C. You can get ahead or behind light. Mitch Raemsch
From: "Juan R." González-Álvarez on 4 Mar 2010 13:39 Uncle Al wrote on Thu, 04 Mar 2010 08:25:48 -0800: > 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. Troll :-D
From: "Juan R." González-Álvarez on 4 Mar 2010 13:47 eric gisse wrote on Thu, 04 Mar 2010 09:50:02 -0800: > 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 Your ad hominem is rather laugdable Eric, because you are the only poster that still maintain that c has not units of speed, in despite of being taugh elementary dimensional analysis and SR and GR, the last weeks, on three different nws (sci.physics, sci.physics.relativity, and sci.physics.research) :-D -- http://www.canonicalscience.org/ BLOG: http://www.canonicalscience.org/publications/canonicalsciencetoday/canonicalsciencetoday.html
From: "Juan R." González-Álvarez on 4 Mar 2010 14:09 G. L. Bradford wrote on Thu, 04 Mar 2010 11:24:21 -0500: > "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 (...) My goal was not to write a detailed post naming all the mistakes and over-simplifications that Steve is doing :-D In the several dozens of references cited in the four links contained in my original message, *links that you sniped now*, he can find the experimental stuff, the rigorous theorems, and the extra info :-D -- http://www.canonicalscience.org/ BLOG: http://www.canonicalscience.org/publications/canonicalsciencetoday/canonicalsciencetoday.html
From: BURT on 4 Mar 2010 14:18
On Mar 4, 9:50 am, eric gisse <jowr.pi.nos...(a)gmail.com> wrote: > 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]- Hide quoted text - > > - Show quoted text - The coordinate speed of light would be its space frame motion. Mitch Raemsch |