<BLOCKQUOTE id=quote><font size=2 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>"... You may want to contact Eric Adelberger at the University of Washington or Riley Newman at the university of Santa Cruz since these guys do this for a living....<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
The people who published the current state of the "speed of gravity" debate also do this for a living. Neither Adelberger nor Newman has made any comment of substance concerning that debate.
<BLOCKQUOTE id=quote><font size=2 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>"...[You must] design an experiment that carefully guards against possible sources of systematic errors that will fool the experimenter. The reputable gravity experimenters that do this are few and far between but they are the only ones whose results I tend to take seriously. Most of the others I find simply do some weird experiment and then get some weird result....<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
I've never heard of any weird experiments getting weird results. Citations, please. Any scientist worthy of the label knows to guard against sources of systematic error, and is unlikely to get published in reputable journals if that were not done. Does the writer have any problems with any of the six published experiments?
<BLOCKQUOTE id=quote><font size=2 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>"...Finally, I disagree with your conclusion that NASA does not take relativity into account. I have worked on Ashby’s program of calculating orbits using the Post-Newtonian Parameterized Metric when I was a graduate student, and general relativity was definitely important in these calculations. General relativity is used in GPS calculations as well."<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
Read “What the Global Positioning System tells us about relativity”, in “Open Questions in Relativistic Physics”, F. Selleri, ed., Apeiron, Montreal, pp. 81-90 (1998). Also available at <
metaresearch.org
>, “cosmology” tab, “gravity” sub-tab. This explains exactly how relativity is, and is not, included in the GPS.
But isn't this irrelevant to the "speed of gravity" issue?
<BLOCKQUOTE id=quote><font size=2 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote> I know there are lots of people wanting to measure the speed of gravity ... The fact of the matter is that it would be very difficult to believe that there is anything wrong with the way gravity is calculated because we would measure large deviations with gravimeters, planets would collide, and space travel (even the amount we have already done) would not be possible. Even GPS would not work as well as it does. There is no need to make a bad measurement of the speed of gravity. It is doubtful that it is interesting to make a high precision measurement of the speed of gravity and as you point out it is difficult.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
This writer is very confused. There <i>isn't</i> anything wrong with the way gravity is calculated, and no one is saying otherwise. But those calculations involve instantaneous interactions. The propagation delay between and source mass and the acceleration it induces on a target body at any distance is zero in GR. If any computer program capable of computing orbits allows force-propagation delays as large as the light-time, the system flies apart, generally in under 1000 revolutions for even the most stable configurations.
<BLOCKQUOTE id=quote><font size=2 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>[JBailey]: I seek a simple way to initiate a conversation that doesn’t get these kinds of reactions. I thought the orbit calculations and the direction of sun’s gravity would pique some interest but instead he fixated on my GR and GPS comment. Does anyone know how to substantiate or refer someone to the results of the U.S. Naval Observatory or to the Development Ephemerides of the Jet Propulsion Laboratory that show the non-alignment of sun gravity and light? I understand the procedure from the topmost posts in this thread but I don’t know a reference for the original work.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>
If you continue to argue the technical merits of your position, you will likely continue to get back technical objections, ad infinitum. Why are you talking to these gentlemen in the first place? What is to be gained by convincing them that the speed of gravity has not yet been bounded on the high side? Your goal will determine the best strategic approach.
The 1998 PLA paper has the best general description of the planetary radar ranging experiment. I have never expounded further on the details because the result (an angle of 20 arc seconds between the direction of Earth's acceleration and the direction of the Sun's arriving photons) is well known and undisputed by anyone in the know. Of course, most such persons will dispute the interpretation placed on this fact, but not the fact of the angular difference existing. -|Tom|-
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