Notices
Results 1 to 44 of 44

Thread: Gravity

  1. #1 Gravity 
    Forum Sophomore
    Join Date
    Jul 2007
    Posts
    103
    Gravity seems to me to be the primary ingrediant of exsistence, rather we are talking chemicals (bonding) or atomic structures, gravity or its cousin magnetics makes it all possible. our science seem to know very little about gravity other then to say its everywhere.

    Indeed the whole of what we know about our universe is based upon a gravitational varable. Black holes, Dark matter, Solar system anchors all have gravity at its base.


    Reply With Quote  
     

  2.  
     

  3. #2 Re: Gravity 
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by curious1
    Gravity seems to me to be the primary ingrediant of exsistence, rather we are talking chemicals (bonding) or atomic structures, gravity or its cousin magnetics makes it all possible. our science seem to know very little about gravity other then to say its everywhere.

    Indeed the whole of what we know about our universe is based upon a gravitational varable. Black holes, Dark matter, Solar system anchors all have gravity at its base.
    You should "Google" "general relativity". Gravity is better understood than you seem to think.

    If can show definitively that gravity and electromagnetism are related I can get you a Nobel Prize.


    Reply With Quote  
     

  4. #3  
    Suspended
    Join Date
    Oct 2006
    Posts
    769
    I can show that they're related.
    Reply With Quote  
     

  5. #4  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Farsight
    I can show that they're related.
    Only in your deluded mind.

    Einstein was unable to do that despite years of trying. No one has succeeded.
    Reply With Quote  
     

  6. #5  
    Forum Isotope (In)Sanity's Avatar
    Join Date
    Oct 2004
    Location
    Mesa AZ
    Posts
    2,699
    Just my opinion, but perhaps we should forget the dead old womanizer for a while and come up with new ways of looking at everything. We assume Einstein is the end all solution to everything and perhaps that is the problem, people can't look beyond that. Again, just my opinion. How about some theories that throw his work out completely and start fresh.

    What..what what...you can't do that.... There in lies the problem. New ideas will solve the mysteries of the past. Perhaps even radical ideas....gee...sound familiar.

    IS
    Pleased to meet you. Hope you guess my name
    Reply With Quote  
     

  7. #6  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by (In)Sanity
    Just my opinion, but perhaps we should forget the dead old womanizer for a while and come up with new ways of looking at everything. We assume Einstein is the end all solution to everything and perhaps that is the problem, people can't look beyond that. Again, just my opinion. How about some theories that throw his work out completely and start fresh.

    What..what what...you can't do that.... There in lies the problem. New ideas will solve the mysteries of the past. Perhaps even radical ideas....gee...sound familiar.

    IS
    There is nothing wrong with new ideas. That is what research is all about.

    But research is also a disciplined process. General relativity is supported by a mountain of empirical data, and is known to be very accurate in most cases -- it has a large established domain of validity. So any viable improved theory must agree with general relativity, to a very close approximation, in situations in which it is known to be accurate.

    Situations in which it is known not to be accurate are well inside the event horizon of black holes and very near the actual moment of the big bang. That is the reason that so much theoretical attention is being paid to those conditions.

    General relativity is known to be incompatible with quantum theory, and much research is directed toward quantum theories of gravity that would replace GR. String theory is one candidate. Loop quantum gravity is another.

    It is also known that GR does not handle intrinsic spin. This is because it assumes spacetime to be torsion free. Cartan-Einstein theory is another theory of gravitation that does not make this assumption. It is far more mathematically complicated than GR, and makes predictions that cannot be distinguished from GR experimentally with current measurement technology. But it is a viable theory of gravitation, and does not predict the same singularities as does GR.

    But one cannot throw out the baby with the bathwater, and the correspondence principle demands that any valid theory refine and extend Gr, but not overturn it where it is known to be accurate. A valid replacement may appear to be radically different, just as GR is different from Newtonian mechanics. But it must make very similar predictions in situations where GR is known to be accurate -- which is most situations.
    Reply With Quote  
     

  8. #7  
    Forum Bachelors Degree
    Join Date
    Mar 2009
    Posts
    421
    As far as relativity is concerned, the main point is to take home is that (1) physics should be coordinate-invariant, and (2) an observer should never be able to put himself into a reference frame in which a cause precedes an effect.

    If you think that physics should obey those two properties, I think you're pretty much stuck with relativity (it's possible there's another formulation of physics that would also work, but I suspect it would have to be pretty convoluted and arbitrary, whereas relativity is actually pretty simple and clean).
    Reply With Quote  
     

  9. #8  
    Forum Isotope (In)Sanity's Avatar
    Join Date
    Oct 2004
    Location
    Mesa AZ
    Posts
    2,699
    I'm just not sure it's possible for modern science to truly work with fresh new ideas. There is nothing wrong with using the knowledge of the past, so long as that knowledge is 100% perfect. The question is how can we perfectly separate the flawed ideas from the correct ideas. It's very difficult to do when we don't know the accurate final outcome. The easiest solution would be to start again with zero knowledge and work our way up, unfortunately that is also unrealistic.

    IS
    Pleased to meet you. Hope you guess my name
    Reply With Quote  
     

  10. #9  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by (In)Sanity
    I'm just not sure it's possible for modern science to truly work with fresh new ideas. There is nothing wrong with using the knowledge of the past, so long as that knowledge is 100% perfect. The question is how can we perfectly separate the flawed ideas from the correct ideas. It's very difficult to do when we don't know the accurate final outcome. The easiest solution would be to start again with zero knowledge and work our way up, unfortunately that is also unrealistic.

    IS
    All of our current physical models are imperfect. That is well known. Physics progresses and has always progressed through a series of bsuccessive approximations. Throwing out the existing models wholesale would produce nothing of value.

    But one can and usually does throw out the philosophy that lies behind the theories. Thjat is precisely whar was done when relativity and quantum theory supplanted Newtonian mechanics. That is not radical, it is the way that scientific research is done.

    The impression that researchers are stuck in the past is common but also completely wrong nothing could be farther from the truth. Scientific research requires imagination on a scale that most laymen cannot begin to understand. But it also requires discipline. Imagination is not fantasy.

    Starting with zero knowledge simply will not work. Remember Newtons words "If I have seen further it is only by standing on the shoulders of giants."


    BTW the PhD is awarded for discovery and imagination, not for accumulated knowledge.
    Reply With Quote  
     

  11. #10  
    Forum Isotope
    Join Date
    Feb 2009
    Location
    Transient
    Posts
    2,914
    IS, I think you're kidding and being sarcastic, but it's very hard to tell right now.
    Wise men speak because they have something to say; Fools, because they have to say something.
    -Plato

    Reply With Quote  
     

  12. #11  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Arcane_Mathematician
    IS, I think you're kidding and being sarcastic, but it's very hard to tell right now.
    If you are talking to me, you are wrong.

    I am 100% serious.
    Reply With Quote  
     

  13. #12  
    Guest
    IS = In(sanity)
    Reply With Quote  
     

  14. #13  
    Forum Professor
    Join Date
    Apr 2007
    Location
    In the circuitous haze of my mind
    Posts
    1,028
    What is the objective basis for wanting to unify electromagnetism with gravity again? I constantly hear, "It would be an elegant solution". You're a fool and arrogant at that if you think such arbitrary emotions can with 100% accuracy solve objective problems. Ignoring such comments....I can see a desire to simplify a system; often times the simpler answer is the correct one, but that is only a generalization and not always true. We HAVE (sort of) unified electromagnetism and the weak force; I do not entirely agree with that idea, nor do I entirely disagree. That would again create a desire to unify more forces, but come on, we only unified two once, its not like there are 100 natural forces and we've unified 98 of them, leaving only gravity and electromagnetism left. Looking less probabilistically at the problem, are there any hard scientific reasons for trying to unify the two? Does the math ever naturally attempt to lead to unification? Does unification naturally solve a tremendous number of links? Do the two forces share their origin, or effects in any way? In other words, does any causality occur between the two?

    I for one, see no reason to unify the two.
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

    "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

    "Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence"

    -Einstein

    http://boinc.berkeley.edu/download.php

    Use your computing strength for science!
    Reply With Quote  
     

  15. #14  
    Forum Isotope (In)Sanity's Avatar
    Join Date
    Oct 2004
    Location
    Mesa AZ
    Posts
    2,699
    Quote Originally Posted by Arcane_Mathematician
    IS, I think you're kidding and being sarcastic, but it's very hard to tell right now.
    lol, it's all in the name
    Pleased to meet you. Hope you guess my name
    Reply With Quote  
     

  16. #15  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Cold Fusion
    What is the objective basis for wanting to unify electromagnetism with gravity again? I constantly hear, "It would be an elegant solution". You're a fool and arrogant at that if you think such arbitrary emotions can with 100% accuracy solve objective problems. Ignoring such comments....I can see a desire to simplify a system; often times the simpler answer is the correct one, but that is only a generalization and not always true. We HAVE (sort of) unified electromagnetism and the weak force; I do not entirely agree with that idea, nor do I entirely disagree. That would again create a desire to unify more forces, but come on, we only unified two once, its not like there are 100 natural forces and we've unified 98 of them, leaving only gravity and electromagnetism left. Looking less probabilistically at the problem, are there any hard scientific reasons for trying to unify the two? Does the math ever naturally attempt to lead to unification? Does unification naturally solve a tremendous number of links? Do the two forces share their origin, or effects in any way? In other words, does any causality occur between the two?

    I for one, see no reason to unify the two.
    The first notable unification was of the theories of the electric and magnetic fields, Radio and television were results of that unification

    Currently we have three major physical theories -- the electroweak theory, quantum chromodynamics (the strong interaction) and general relativity (gravitation).

    The electroweak and quantum chromodynamic theories are perturbation theories of quantum fields, inherently stochastic. The application requires renormalization, which is only partially understood to eliminate infinities and produce good predictions.

    General relativity is a non-perturbative completely deterministic theory. It is incompatible with quantum theory. It also predicts singularities that are probably not physical for black holes and for the big bang.

    When quantum field theory is used to predict the energy of the vacuum, using typical renormalization techniques, it produces an overestimation of the cosmological constant used in relativistic models for cosmology that is in error by about 120 orders of magnitude -- the worst prediction in all of physics.

    There is good reason to believe that a unified theory of the electroweak, strong and gravitational forces would produce a non-perturbative theory with no infinities and no need for renormalization. That would mark a profound increase in our understanding of nature.

    Scientific understanding usually precedes engineering applications. It was quantum mechanics that lead to solid state circuits and the computer that you are using.
    Reply With Quote  
     

  17. #16  
    Suspended
    Join Date
    Oct 2006
    Posts
    769
    Quote Originally Posted by DrRocket
    It was quantum mechanics that lead to solid state circuits and the computer that you are using.
    I'd say that's debateable, Doc. One could say it was hands-on electronics that led to modern computers. See the history of the transistor. Also see Ehrenberg and Siday's The Refractive Index in Electron Optics and the Principles of Dynamics. That's the classical paper that predicted what is now known as the Aharanov-Bohm effect.

    Quote Originally Posted by Insanity
    How about some theories that throw his work out completely and start fresh.
    I'd say that's the wrong approach, and that the right approach is to go back to Einstein's work, plus work by Maxwell and others, and look at it afresh with no preconceptions.

    Quote Originally Posted by Cold Fusion
    What is the objective basis for wanting to unify electromagnetism with gravity again?
    People want to understand how the universe works. And they want to generate an artificial gravitational field.

    Quote Originally Posted by ColdFusion
    Do the two forces share their origin, or effects in any way? In other words, does any causality occur between the two?
    Yes and no. There are two forces in electromagnetism already. Gravity is caused by a concentration of energy above and beyond the background energy density. This concentration of energy might be configured as say an electron with mass and charge, or say a massless photon which exhibits a field variation rather than a standing field. Either way the electromagnetic field is involved, and either way the particle's energy causes gravity. But the neutrino is different again, and it would be wrong to say that gravity causes electromagnetism or vice versa.

    Quote Originally Posted by (In)Sanity
    I'm just not sure it's possible for modern science to truly work with fresh new ideas.
    There's usually a lot of resistance to new ideas. And old ideas too. People who consider themselves to be an expert in a field tend to be hostile to anything that threatens their standing. Hence the saying "science advances one death at a time".

    Quote Originally Posted by DrRocket
    Only in your deluded mind.
    See above, and where would you like to start? How about with Einstein's 1920 Leyden Address where he said this:

    "Of course it would be a great advance if we could succeed in comprehending the gravitational field and the electromagnetic field together as one unified conformation. Then for the first time the epoch of theoretical physics founded by Faraday and Maxwell would reach a satisfactory conclusion".

    Or how about Minkowski’s Space and Time from 1908, where we see this little paragraph two pages from the back:

    "Then in the description of the field produced by the electron we see that the separation of the field into electric and magnetic force is a relative one with regard to the underlying time axis; the most perspicious way of describing the two forces together is on a certain analogy with the wrench in mechanics, though the analogy is not complete".

    I really can show that electromagnetism and gravity are related. It isn't rocket science, it's simple. But as you can imagine, rocket scientists won't be too chuffed about it.
    Reply With Quote  
     

  18. #17  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Farsight
    Quote Originally Posted by DrRocket
    Only in your deluded mind.
    See above, and where would you like to start? How about with Einstein's 1920 Leyden Address where he said this:

    "Of course it would be a great advance if we could succeed in comprehending the gravitational field and the electromagnetic field together as one unified conformation. Then for the first time the epoch of theoretical physics founded by Faraday and Maxwell would reach a satisfactory conclusion".
    Yes it would be a great advance. Note the future tense. Einstein tried for years, unsuccessfully, to produce such a unified theory. It would still be a huge accomplishment. It is one of the goals of string theory.

    The point is not that it is a worthy goal, but that your clain to be able to do this, with zero evidence, is just ridiculous. If you can indeed produce such a theory then do so, and step forward to claim your Nobel Prize.


    Quote Originally Posted by Farsight
    Or how about Minkowski’s Space and Time from 1908, where we see this little paragraph two pages from the back:

    "Then in the description of the field produced by the electron we see that the separation of the field into electric and magnetic force is a relative one with regard to the underlying time axis; the most perspicious way of describing the two forces together is on a certain analogy with the wrench in mechanics, though the analogy is not complete".
    This is standard aspecial relativity. The electromagnetic field is invariant, but the decomposition into electric and magnetic components is observer-dependent. This has absolutely nothing to do with a unification of electromagnetism and gravity.

    Quote Originally Posted by Farsight
    I really can show that electromagnetism and gravity are related. It isn't rocket science, it's simple. But as you can imagine, rocket scientists won't be too chuffed about it.
    If you can produce such a theory then do so. Show me the math. Hollow claims are the hallmark of a crank.
    Reply With Quote  
     

  19. #18  
    Forum Sophomore
    Join Date
    Jul 2007
    Posts
    103
    In Physics not one, i repeat, not one composition, force, material, or chemical stands alone seperate from all other forces, material etc etc.

    So the connection between electromagnitsm and gravity do have a point of kinship i would think, somewhere in the (as of this second) undiscovered.

    And i agree that reliance totally on the worthy of our historical dogma, should not exclude our travel down another road.


    Science must start always start as a question.
    Reply With Quote  
     

  20. #19  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by curious1
    In Physics not one, i repeat, not one composition, force, material, or chemical stands alone seperate from all other forces, material etc etc.
    Probably, but not yet firmly established. In fact only the electromagnetic and weak forces are currently explained with a single theory.

    Quote Originally Posted by curious1
    So the connection between electromagnitsm and gravity do have a point of kinship i would think, somewhere in the (as of this second) undiscovered.
    Thinking so is quite different from being able to prove that it is correct and knowing so.

    There is a tremendous amount of research directed towards converting what most physicists think (that all the fundamental forces can be ubified in a single theory) into a fact in the form of a well-formulated theory.

    Before this research program is ultimately successful there will be several major breakthroughs and attendant Nobel Prizes -- there have been quite a few already.

    Quote Originally Posted by curious1
    And i agree that reliance totally on the worthy of our historical dogma, should not exclude our travel down another road.


    Science must start always start as a question.
    Scientific research is all about shattering dogma. But you don't do that by throwing out the baby with the bath water.

    Nobel Prizes and Fields Medals are awarded for imagination -- imagination bolstered by discipline and scientific rigor. It is the constraints of data, logic andrigor that make scientific research challenging and valuable. If fantasy were enough, Nobel Prizes would go to science fiction writers.
    Reply With Quote  
     

  21. #20  
    Suspended
    Join Date
    Oct 2006
    Posts
    769
    You know what, curious? I've followed the trail and I'm going down that road. And what's quite plain, is that other people have gone before me. It isn't some new, other, road. It's an old road, and it takes you places.

    Quote Originally Posted by DrRocket
    The point is not that it is a worthy goal, but that your clain to be able to do this, with zero evidence, is just ridiculous. If you can indeed produce such a theory then do so, and step forward to claim your Nobel Prize.
    I can offer evidence, and it's very powerful. But all this isn't all my own work, it would be unfair for me to claim otherwise and attempt to claim credit and prizes. Now, do you want to see that evidence, or would you prefer to remain firmly convinced that there isn't any?
    Reply With Quote  
     

  22. #21  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Farsight
    You know what, curious? I've followed the trail and I'm going down that road. And what's quite plain, is that other people have gone before me. It isn't some new, other, road. It's an old road, and it takes you places.

    Quote Originally Posted by DrRocket
    The point is not that it is a worthy goal, but that your clain to be able to do this, with zero evidence, is just ridiculous. If you can indeed produce such a theory then do so, and step forward to claim your Nobel Prize.
    I can offer evidence, and it's very powerful. But all this isn't all my own work, it would be unfair for me to claim otherwise and attempt to claim credit and prizes. Now, do you want to see that evidence, or would you prefer to remain firmly convinced that there isn't any?
    You have been challenged to back up your assertion several times already. Put up or shut up. Show me the math.
    Reply With Quote  
     

  23. #22  
    Forum Professor
    Join Date
    Apr 2007
    Location
    In the circuitous haze of my mind
    Posts
    1,028
    I do not see the magnetic and electric field as independent 'forces' really; they seem to only be the same thing at different 'levels'. When I first became aware of both, I naturally thought they were essentially one 'force' of sort, and simply different versions of each other. In this way....you could misinterpret any number of devices, claim them to initially be separate, and then 'unify' them into what they have every right to be, even though it was only your misinterpretation that made you separate them to begin with. I suppose this distorts my statement about 98/100 forces since you can create an infinite number of 'unifications' if you so wished, hence clouding such statistics.

    I think the need for renormalization is a clear marker that something is severely wrong with QM.

    So, they are trying to make up for the blunder of renormalization by synthesizing QM/electrodynamics with relativity? Isn't that just putting a bandaid over the problem instead of actually healing it? I am fairly sure this is a bad approach. We should learn more about nature before attempting such a unification. What we are doing now is akin to a caveman trying to build a lightbulb as opposed to just using fire and going from there.
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

    "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

    "Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence"

    -Einstein

    http://boinc.berkeley.edu/download.php

    Use your computing strength for science!
    Reply With Quote  
     

  24. #23  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Cold Fusion
    I think the need for renormalization is a clear marker that something is severely wrong with QM.

    So, they are trying to make up for the blunder of renormalization by synthesizing QM/electrodynamics with relativity? Isn't that just putting a bandaid over the problem instead of actually healing it? I am fairly sure this is a bad approach. We should learn more about nature before attempting such a unification. What we are doing now is akin to a caveman trying to build a lightbulb as opposed to just using fire and going from there.
    Renormalization is a feature of quantum field theories. Quantum field theories are what you get when you formulate quantum theories that include special relativity. So QED is the quantum theory of electromagnetism that includes special relativity.

    The problem with quantum field theories is that they tend to predict that things are infinite -- until one renormalizes. So renormalization is more than just a band aid. But once renormalization is used, most QED predictions are as accurate as experiment has been able to measure, so there is something to renormalization.

    Nevertheless, renormalization is not totally satisfying and a theory that would not require it and that would not be perturbative would be preferable. Unfortunately we don't have one yet.

    QED is generally so accurate that it is a bit hard to argue with success, so I can't agree with your caveman analogy. But great deal of research is devoted to finding something better -- and that would be a unified theory of all of the known forces.
    Reply With Quote  
     

  25. #24  
    Forum Sophomore
    Join Date
    Jul 2007
    Posts
    103
    To my untrained eye the unified theroy of all things QM or i should say down to plain old biology is a given since " all matter, force, energy etc etc has it's beginnings in the material of what we do know i..e.. All that is, spurs from the same source.

    I suspect in finding the unification point is a matter of the devil being in the detail, but to suggest that it dont exsist, would be to say 2 has no connection to 1.
    Reply With Quote  
     

  26. #25  
    Forum Sophomore
    Join Date
    Jul 2007
    Posts
    103
    To my untrained eye the unified theroy of all things QM or i should say down to plain old biology is a given since " all matter, force, energy etc etc has it's beginnings in the material of what we do know i..e.. All that is, spurs from the same source.

    I suspect in finding the unification point is a matter of the devil being in the detail, but to suggest that it dont exsist, would be to say 2 has no connection to 1.
    Reply With Quote  
     

  27. #26  
    Forum Professor
    Join Date
    Apr 2007
    Location
    In the circuitous haze of my mind
    Posts
    1,028
    What I meant to say is that we should first increase our knowledge before haphazardly attempting something more advanced than we can currently handle, but that's just my opinion.
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

    "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

    "Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence"

    -Einstein

    http://boinc.berkeley.edu/download.php

    Use your computing strength for science!
    Reply With Quote  
     

  28. #27  
    Suspended
    Join Date
    Oct 2006
    Posts
    769
    Quote Originally Posted by DrRocket
    Put up or shut up. Show me the math.
    You said you wanted evidence, and that has to come first. So here's something to be going on with. A plane-polarized electromagnetic wave is usually drawn as a sinusoidal field variation like this:



    In an electromagnetic wave, no charged particle is present, but the electromagnetic field varies, so a form of current is present. This is obviously not the conduction current associated with the motion of a charged particle. So what sort of current is it? It's displacement current, and it's alternating. Here's a depiction of ordinary alternating current, note the similarity:



    Consider one wavelength of an electromagnetic wave, starting from the far left. The displacement current is orthogonal to the direction of wave propagation, moving "up" in the polarization plane. It starts slowly and increases to a positive peak rate of displacement, then continues positive and upwards but slowing as the sinusoidal waveform returns to the midway zero. The displacement current then reverses and changes direction, so now it's negative and going back down. The rate of this reaches a peak at the sinusoidal negative before slowing on the final return to zero.



    Go back to Maxwell and take this displacement at face value. Think of it as something like the spatial distortion LIGO hopes to find due to gravitational waves. In this context the sinusoidal electromagnetic waveform is the derivative of a pulse of displacement or photon wavefunction. The displacement is at a maximum midway along the sinusoidal waveform. Here the electromagnetic field variation is zero, but there's still something there. Just as there is in the Aharonov-Bohm effect, first predicted by Ehrenberg and Siday in 1948. Hence the peak displacement represents the four-potential, which is "more fundamental" than the electromagnetic field. It also represents h-bar, but we'll come back to that another time along with Maxwell's screw and elasticity. For now what's important is vacuum permittivity ε0 and permeability μ0. These combine as vacuum impedance Z0=√(μ0/ε0), impedance being resistance to alternating current. They also combine as c=√(1/ε0μ0), this expression being akin to the mechanics expression v = √(G/ρ) where ρ is density.

    Whilst formulating general relativity, Einstein said "I arrived at the result that the velocity of light is not to be regarded as independent of the gravitational potential" and "a curvature of rays of light can only take place when the velocity of propagation of light varies with position.". People usually see the word velocity and take this to be a vector quantity. But what he actually said was "die Ausbreitungs-geschwindigkeit des Lichtes mit dem Orte variiert" which translates into the speed of light varies with the locality. This is similar to Newton's Opticks query 20: "Doth not this aethereal medium in passing out of water, glass, crystal, and other compact and dense bodies in empty spaces, grow denser and denser by degrees, and by that means refract the rays of light not in a point, but by bending them gradually in curve lines?" Newton wasn't interested in light for nothing.

    But don't take Einstein and Newton's word for it. Monitor two identical light clocks at different altitudes, and watch them lose synchronisation. The lower light-clock will run slower. This clock is clocking up the motion of light. So when it runs slower, take it at face value: the light goes slower. That's scientific evidence, and it's solid. Thus since c=√(1/ε0μ0) and Z0=√(μ0/ε0), gravitational time dilation is direct evidence for a gradient in the impedance of space. The speed of light varies, just like Einstein said it did, and it causes light to curve like a car veers when the near-side wheels encounter mud at the side of the road.
    Reply With Quote  
     

  29. #28  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Farsight
    Quote Originally Posted by DrRocket
    Put up or shut up. Show me the math.
    You said you wanted evidence, and that has to come first. So here's something to be going on with. A plane-polarized electromagnetic wave is usually drawn as a sinusoidal field variation like this:



    In an electromagnetic wave, no charged particle is present, but the electromagnetic field varies, so a form of current is present. This is obviously not the conduction current associated with the motion of a charged particle. So what sort of current is it? It's displacement current, and it's alternating.
    Maxwell's third equation, Ampere's law :


    is the displacement current, which does NOT represent moving charge. J is the current density. The terminology stems from the situation that occurs in charging a capacitor, where the D-field in the dilectric stores energy as the plates are charged and charge one one plate displaces charge on the other plate.


    Quote Originally Posted by Farsight
    Here's a depiction of ordinary alternating current, note the similarity:



    Consider one wavelength of an electromagnetic wave, starting from the far left. The displacement current is orthogonal to the direction of wave propagation, moving "up" in the polarization plane.
    This is only because in the case of the propagating plane wave is sinusoidal anmd hence so is , just out-of-phase with . You have said nothing important and clearly don't understand what is going on.


    Quote Originally Posted by Farsight
    It starts slowly and increases to a positive peak rate of displacement, then continues positive and upwards but slowing as the sinusoidal waveform returns to the midway zero. The displacement current then reverses and changes direction, so now it's negative and going back down. The rate of this reaches a peak at the sinusoidal negative before slowing on the final return to zero.

    More drivel relating the obvious and irrelevant.

    You cannot baffle me with buzz words. You don't understand this stuff, but I do.


    Quote Originally Posted by Farsight
    Go back to Maxwell and take this displacement at face value. Think of it as something like the spatial distortion LIGO hopes to find due to gravitational waves. In this context the sinusoidal electromagnetic waveform is the derivative of a pulse of displacement or photon wavefunction.
    Displacement has no "face value". You have just demonstrated that you have no idea what displacement current is.

    The electromagnetic wave has nothing whatever to do with gravitational waves.

    Your assertion, " In this context the sinusoidal electromagnetic waveform is the derivative of a pulse of displacement or photon wavefunction." is a meaningless juxtaposition of buzz words -- total nonsense.

    Once again, you cannot baffle me with bullshit. I understand this stuff.


    Quote Originally Posted by Farsight
    The displacement is at a maximum midway along the sinusoidal waveform. Here the electromagnetic field variation is zero, but there's still something there.
    This makes no sense. You are fixated on your cartoon, but that cartoon represents a traveling wave and so is not stationary in space.



    Quote Originally Posted by Farsight
    Just as there is in the Aharonov-Bohm effect, first predicted by Ehrenberg and Siday in 1948. Hence the peak displacement represents the four-potential, which is "more fundamental" than the electromagnetic field. It also represents h-bar, but we'll come back to that another time along with Maxwell's screw and elasticity.
    The Aharonov-Bohm effect has nothing to do with either the propagation of electromagnetic waves or with gravitational waves.

    The 4-potential is just a convenient way of handling the usual vector potentials for the electric and magneticv fields. It is most certainly not represented by the peak of the displacement.

    More futile attempt bto baffle with bullshit. It won't work.

    Quote Originally Posted by Farsight
    For now what's important is vacuum permittivity ε0 and permeability μ0. These combine as vacuum impedance Z0=√(μ0/ε0), impedance being resistance to alternating current. They also combine as c=√(1/ε0μ0), this expression being akin to the mechanics expression v = √(G/ρ) where ρ is density.
    Not quite. Impedance is a complex quantity that is analogous to resistance in DC circuits, but is applied not to the time-domain but in this case to the Fourier btransforms of thev fields of interest.

    You are once again trying to use concepts that you don't understand to "snow" someone who does understand. It won't work.

    Quote Originally Posted by Farsight
    Whilst formulating general relativity, Einstein said "I arrived at the result that the velocity of light is not to be regarded as independent of the gravitational potential" and "a curvature of rays of light can only take place when the velocity of propagation of light varies with position.". People usually see the word velocity and take this to be a vector quantity. But what he actually said was "die Ausbreitungs-geschwindigkeit des Lichtes mit dem Orte variiert" which translates into the speed of light varies with the locality.
    We have been through this before. This is total nonsense. The speed of light does not vary with position. Coordinate speed is not nspeed. Coordinate time is not time.

    Also, once again you will find that Einstein quote properly addressed here http://www.webcitation.org/5lLQD61qh

    You are completely wrong and are again proving that you completely fail to understand relativity. If any further proof the self-published (I am not surprised that a mainstream publisher would not print such junk) book that you champion is proof positive.

    http://www.toequest.com/forum/physic...verything.html

    http://www.waterstones.com/waterston...ty+2b/6591195/

    http://www.scienceforums.net/topic/2...entific-paper/


    http://www.facebook.com/group.php?gid=72445616847 (complete with contact info no less)

    Quote Originally Posted by farsight
    This is similar to Newton's Opticks query 20: "Doth not this aethereal medium in passing out of water, glass, crystal, and other compact and dense bodies in empty spaces, grow denser and denser by degrees, and by that means refract the rays of light not in a point, but by bending them gradually in curve lines?" Newton wasn't interested in light for nothing.
    What in the hell do you think refraction of light has to do with any of what we are talking about ?

    Clearly another attempt to baffle with bullshit.


    Quote Originally Posted by farsight
    But don't take Einstein and Newton's word for it. Monitor two identical light clocks at different altitudes, and watch them lose synchronisation. The lower light-clock will run slower. This clock is clocking up the motion of light. So when it runs slower, take it at face value: the light goes slower. That's scientific evidence, and it's solid. Thus since c=√(1/ε0μ0) and Z0=√(μ0/ε0), gravitational time dilation is direct evidence for a gradient in the impedance of space. The speed of light varies, just like Einstein said it did, and it causes light to curve like a car veers when the near-side wheels encounter mud at the side of the road.
    Utter nonsense.

    All that you have done in this post is prove conclusively that you are a crank without the slightest understanding of basic physics. A glib crank who spews buzz words with no understanding. A menace to neophytes on the board.

    Do you really think that you can invoke well-known concepts, even though profoundly misunderstood by you, and wave your hands to effect a unification of gravity and electromagnetism that eluded Einstein from his announcement of general relativity in 1915 until his death in 1955, not to mention all physicists since then ? That is irrational. But then, you are irrational.

    This crap belongs in Pseudoscience, or better yet, the Trash.
    Reply With Quote  
     

  30. #29  
    Forum Professor
    Join Date
    Apr 2007
    Location
    In the circuitous haze of my mind
    Posts
    1,028
    Hey, I think he gave an honest attempt. But no, I do not agree with it either.
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

    "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

    "Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence"

    -Einstein

    http://boinc.berkeley.edu/download.php

    Use your computing strength for science!
    Reply With Quote  
     

  31. #30  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Cold Fusion
    Hey, I think he gave an honest attempt. But no, I do not agree with it either.
    This guy is a well-known internet charlatan. Take a look at some of those links.

    He may well actually believe the nonsense that he is spouting, and in that sense, and only in that sense, could the response be considered honest.

    There is zero real science in his post.
    Reply With Quote  
     

  32. #31  
    Suspended
    Join Date
    Oct 2006
    Posts
    769
    Dismissal and denial, Doc, propped up by your usual outraged torrent of ad-hominems. I've got Einstein and Newton on my side, and the patent scientific evidence. So let's take it one step at a time and hold your nose to the grindstone of real science:

    You referred to a capacitor. That involves electrons. Electrons can be created from electromagnetic waves via pair production. And displacement current is a "time-varying electric field". So, when an electromagnetic wave passes you by, what do you detect?
    Reply With Quote  
     

  33. #32  
    Veracity Vigilante inow's Avatar
    Join Date
    Oct 2009
    Location
    Austin, TX
    Posts
    3,499
    Quote Originally Posted by Farsight
    what do you detect?
    A lack of mathematics.
    Reply With Quote  
     

  34. #33  
    Suspended
    Join Date
    Oct 2006
    Posts
    769
    What you detect is a time-varying electric field. So it is displacement current. And because the field-variation is sinusoidal, it's alternating. Hence vacuum impedance Z0=√(μ0/ε0) applies.

    Note that you can perform pair production to turn that electromagnetic wave into an electron and a positron. Then, when you move that electron, you've got conduction current. Move that electron back and forth, and it's alternating. You now have an alternating field-variation again. It's all pretty simple once it clicks. A key piece of evidence with all this is the Einstein-de Haas effect which "demonstrates that spin angular momentum is indeed of the same nature as the angular momentum of rotating bodies as conceived in classical mechanics". Understand the meaning of this, and you appreciate why gravity affects light twice as much as matter.
    Reply With Quote  
     

  35. #34  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Farsight
    What you detect is a time-varying electric field. So it is displacement current. And because the field-variation is sinusoidal, it's alternating. Hence vacuum impedance Z0=√(μ0/ε0) applies.

    Note that you can perform pair production to turn that electromagnetic wave into an electron and a positron. Then, when you move that electron, you've got conduction current. Move that electron back and forth, and it's alternating. You now have an alternating field-variation again. It's all pretty simple once it clicks. A key piece of evidence with all this is the Einstein-de Haas effect which "demonstrates that spin angular momentum is indeed of the same nature as the angular momentum of rotating bodies as conceived in classical mechanics". Understand the meaning of this, and you appreciate why gravity affects light twice as much as matter.
    This is ridiculous. You are delusional.

    Photon nucleus pair production requires a miminum photon energy of 1.022Mev -- gamma rays. Under your scenario what you would detect, aka see, would be high-energy gamma rays. That would leave you blind in the usual visual spectrum.

    Your crap does not belong in a legitimate physics forum. Crank
    Reply With Quote  
     

  36. #35 Re: Gravity 
    Suspended
    Join Date
    Oct 2006
    Posts
    769
    Gamma rays are electromagnetic waves. An electromagnetic wave is a time-varying electric field, vacuum impedance Z0=√(μ0/ε0) is no delusion. Pair production happens, and the Einstein-de Haas effect has been around for nearly a hundred years. The scientific evidence is there.
    Reply With Quote  
     

  37. #36 Re: Gravity 
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Farsight
    Gamma rays are electromagnetic waves. An electromagnetic wave is a time-varying electric field, vacuum impedance Z0=√(μ0/ε0) is no delusion. Pair production happens, and the Einstein-de Haas effect has been around for nearly a hundred years. The scientific evidence is there.
    Not only is an electromagnetic wave time-varying, it is also spatially varying, what is called a traveling wave. So what ? Every undergraduate physics and engineering student knows that.

    All of which has absolutely nothing to do with the topic at hand or your initial assertion as to how electromagnetic waves are sensed.

    All you have proved is that you know a lot of buzz words associated with physics about which you have not the slightest clue.

    Crank. The evidence is here, and abundantly clear.
    Reply With Quote  
     

  38. #37  
    Suspended
    Join Date
    Oct 2006
    Posts
    769
    Quote Originally Posted by DrRocket
    So what?
    That time-varying field that you detect as the electromagnetic wave goes by is displacement current, it's alternating, impedance is resistance to alternating current, vacuum impedance is Z0=√(μ0/ε0), the speed of light c=√(1/ε0μ0), and Einstein said light curves because the speed of light varies with the locality. A light clock at a lower altitude runs slower than an identical clock at higher altitude. The Shapiro delay is evidence that the light goes slower in a region of low gμv gravitational potential. Then there's the GPS clock adjustment. So a gradient in gravitational potential is also a gradient in vacuum impedance. The scientific evidence is there, cut and dried. Howls of outrage and ad-hominem abuse because your so-called expertise is called into question, is no substitute for discussion of that evidence.
    Reply With Quote  
     

  39. #38  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Farsight
    Quote Originally Posted by DrRocket
    So what?
    That time-varying field that you detect as the electromagnetic wave goes by is displacement current, it's alternating, impedance is resistance to alternating current, vacuum impedance is Z0=√(μ0/ε0), the speed of light c=√(1/ε0μ0), and Einstein said light curves because the speed of light varies with the locality. A light clock at a lower altitude runs slower than an identical clock at higher altitude. The Shapiro delay is evidence that the light goes slower in a region of low gμv gravitational potential. Then there's the GPS clock adjustment. So a gradient in gravitational potential is also a gradient in vacuum impedance. The scientific evidence is there, cut and dried. Howls of outrage and ad-hominem abuse because your so-called expertise is called into question, is no substitute for discussion of that evidence.
    This is total bullshit. Buzz word after buzz word with no content.

    You undoubtedly will claim otherwise, but you are delusional.

    The only way you can prove otherwise is to produce supporting theory, complete with the necessary mathematics, or specific references (to the page) to the legitimate scientific literature. But that sort of reference simply does not, indeed cannot, exist.

    BTW the Shapiro delay deals with coordinate time, not local time, and absolutely does not imply that the local speed of light is anything other than the constant c.
    A you have been told innumerable times, proper time is recorded by clocks. Coordinate time is not, except in flat space when coordinate time is proper time.

    http://en.wikipedia.org/wiki/Coordinate_time :"But the coordinate time is not a time that could be measured by a clock located at the place that nominally defines the reference frame, e.g. a clock located at the solar system barycenter would not measure the coordinate time of the barycentric reference frame, and a clock located at the geocenter would not measure the coordinate time of a geocentric reference frame.[4] The coordinate times cannot be measured, but only computed from the (proper-time) readings of real clocks with the aid of the time dilation relationship shown in equation (2) (or some alternative or refined form of it)."



    http://en.wikipedia.org/wiki/Shapiro_delay

    Crank
    Reply With Quote  
     

  40. #39  
    Suspended
    Join Date
    Oct 2006
    Posts
    769
    You know Doc, you remind me of a frightened witchdoctor howling and raging when a pharmacologist turns up. You still don't get this scientific evidence thing do you?

    Quote Originally Posted by DrRocket
    BTW the Shapiro delay deals with coordinate time, not local time, and absolutely does not imply that the local speed of light is anything other than the constant c.
    The local speed of light is always measured to be constant because we use the motion of light to define our second and our metre, which we use to measure the motion of light. We can make electrons (and positrons) out of light, we can annihilate protons (and antiprotons) to yield light, so anything that affects the light affects us and our rods and clocks. Clocks like the NIST caesium fountain clock referred to in the definition of the second:

    "Since 1967, the second has been defined to be the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom. This definition refers to a caesium atom at rest at a temperature of 0 K (absolute zero), and with appropriate corrections for gravitational time dilation."

    Like I was saying, lasers and a microwave cavity are employed to cause hyperfine transitions, electron spin-flips. They're electromagnetic. They emit microwaves. They're electromagnetic too. A detector finds the peak frequency. But frequency is measured in Hertz, which is defined as cycles per second, and this clock is being used to define the second. Thus the detectors are counting incoming microwave peaks. When they get to 9,192,631,770, that's a second, and the frequency is 9,192,631,770 Hertz by definition. Then you define the metre, then you measure the speed of light at 299,792,458 m/s. Then you take this clock and place it in a region of low gravitational potential, where all electromagnetic processes and propagation occur at a slower rate. The detectors get to 9,192,631,770, and that's a second. Then you define the metre again and use the second and the metre to measure the speed of light again. Guess what you're going to come up with? 299,792,458 m/s again. But those two speeds aren't the same, because the seconds aren't the same, because the motion of light isn't the same. QED, the speed of light varies, just like Einstein said. I can't make it any simpler.
    Reply With Quote  
     

  41. #40  
    . DrRocket's Avatar
    Join Date
    Aug 2008
    Posts
    5,486
    Quote Originally Posted by Farsight
    You know Doc, you remind me of a frightened witchdoctor howling and raging when a pharmacologist turns up. You still don't get this scientific evidence thing do you?

    Quote Originally Posted by DrRocket
    BTW the Shapiro delay deals with coordinate time, not local time, and absolutely does not imply that the local speed of light is anything other than the constant c.
    The local speed of light is always measured to be constant because we use the motion of light to define our second and our metre, which we use to measure the motion of light. We can make electrons (and positrons) out of light, we can annihilate protons (and antiprotons) to yield light, so anything that affects the light affects us and our rods and clocks. Clocks like the NIST caesium fountain clock referred to in the definition of the second:

    "Since 1967, the second has been defined to be the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom. This definition refers to a caesium atom at rest at a temperature of 0 K (absolute zero), and with appropriate corrections for gravitational time dilation."

    Like I was saying, lasers and a microwave cavity are employed to cause hyperfine transitions, electron spin-flips. They're electromagnetic. They emit microwaves. They're electromagnetic too. A detector finds the peak frequency. But frequency is measured in Hertz, which is defined as cycles per second, and this clock is being used to define the second. Thus the detectors are counting incoming microwave peaks. When they get to 9,192,631,770, that's a second, and the frequency is 9,192,631,770 Hertz by definition. Then you define the metre, then you measure the speed of light at 299,792,458 m/s. Then you take this clock and place it in a region of low gravitational potential, where all electromagnetic processes and propagation occur at a slower rate. The detectors get to 9,192,631,770, and that's a second. Then you define the metre again and use the second and the metre to measure the speed of light again. Guess what you're going to come up with? 299,792,458 m/s again. But those two speeds aren't the same, because the seconds aren't the same, because the motion of light isn't the same. QED, the speed of light varies, just like Einstein said. I can't make it any simpler.
    You remind me of a paranoid schizophrenic. Better take your meds.

    The speed of light is locally constant because the speed of light is locally constant.

    The issue at hand has nothing to do with the methods and standards used to measure time or distance, which have undergone several changes since Einsteins work of the early 1900's.

    When Einstein first formulated general relativity he did not understand tensor analysis, and made a lot of mistakes. But later he caught on. You have still not caught on and quite clearly never will.

    Crank
    Reply With Quote  
     

  42. #41  
    Moderator Moderator
    Join Date
    Jun 2005
    Posts
    1,620
    Quote Originally Posted by Farsight
    You know Doc, you remind me of a frightened witchdoctor howling and raging when a pharmacologist turns up. You still don't get this scientific evidence thing do you?
    Interesting! You are the scientist riding to the aid of those fooled by hokum-pokum merchants? Umm.

    Then you take this clock and place it in a region of low gravitational potential, where all electromagnetic processes and propagation occur at a slower rate.
    No, not in the sense you mean - clocks run slower/faster at a location with a given gravitational potential from the perspective of an observer at a location with a different gravitational potential, but all run at the same rate from the perspective of the observer co-located with them. That's why it's called relativity, and it is fact alone that gives rise to time dilation and length contraction in SR.

    If you must know, EM is a gauge theory, which GR "sort of" is, so the claim that "EM processes run slower", if it has any meaning at all, is false

    the speed of light varies, just like Einstein said.
    No, he never said that. He said that in GR the velocity of light is not a global invariant. Do you understand the difference between speed and velocity? Do you understand why it is not strictly necessary (though in my view preferable) to distinguish speed and velocity in SR, but absolutely essential to do so in GR?

    I can't make it any simpler.
    Patronizing git
    Reply With Quote  
     

  43. #42  
    Forum Ph.D. Heinsbergrelatz's Avatar
    Join Date
    Aug 2009
    Location
    Singapore
    Posts
    994
    paranoid schizophrenic
    John Nash !
    ------------------




    "Mathematicians stand on each other's shoulders."- Carl Friedrich Gauss


    -------------------
    Reply With Quote  
     

  44. #43  
    Suspended
    Join Date
    Oct 2006
    Posts
    769
    Quote Originally Posted by Guitarist
    Interesting! You are the scientist riding to the aid of those fooled by hokum-pokum merchants? Umm.
    I'm the one referring to scientific evidence here rather than the guy dismissing scientific evidence with a tirade of abuse.

    Quote Originally Posted by Guitarist
    Quote Originally Posted by Farsight
    Then you take this clock and place it in a region of low gravitational potential, where all electromagnetic processes and propagation occur at a slower rate.
    No, not in the sense you mean - clocks run slower/faster at a location with a given gravitational potential from the perspective of an observer at a location with a different gravitational potential, but all run at the same rate from the perspective of the observer co-located with them. That's why it's called relativity, and it is fact alone that gives rise to time dilation and length contraction in SR.
    A local observer is affected in the same way as a clock. That's why he doesn't see his local clock as going slower. But see this article about the guys at NIST with an optical clock so accurate you can measure a difference when you raise it a foot. Also see this re special relativity. It's pretty simple stuff. Like: you always measure wavefunction speed to be the same because you're made out of it.

    Quote Originally Posted by Guitarist
    If you must know, EM is a gauge theory, which GR "sort of" is, so the claim that "EM processes run slower", if it has any meaning at all, is false.
    The scientific evidence says it isn't false. The optical clock is counting electromagnetic processes / phenomena / events rather than "the flow of time".

    Quote Originally Posted by Guitarist
    the speed of light varies, just like Einstein said.
    No, he never said that
    He did. You still haven't translated die Ausbreitungs-geschwindigkeit des Lichtes mit dem Orte variiert. He agonised over this for years. If you don't believe me, see the Baez website on this, and read the section on general relativity:

    "Since Einstein talks of velocity (a vector quantity: speed with direction) rather than speed alone, it is not clear that he meant the speed will change, but the reference to special relativity suggests that he did mean so. This interpretation is perfectly valid and makes good physical sense, but a more modern interpretation is that the speed of light is constant in general relativity.

    Quote Originally Posted by Guitarist
    He said that in GR the velocity of light is not a global invariant.
    He said geschwindigkeit. Translate it. The standard English translation has Einstein saying A curvature of rays of light can only take place when the velocity of propagation of light varies with position. Now look at that optical clock again, and raise it a foot. You can measure a difference, and you aren't measuring a change in direction.

    Quote Originally Posted by Guitarist
    Do you understand the difference between speed and velocity? Do you understand why it is not strictly necessary (though in my view preferable) to distinguish speed and velocity in SR, but absolutely essential to do so in GR?
    Yep.
    Reply With Quote  
     

  45. #44  
    Moderator Moderator
    Join Date
    Jun 2005
    Posts
    1,620
    Quote Originally Posted by Farsight
    A local observer is affected in the same way as a clock {exactly co-located with him}. That's why he doesn't see his local clock as going slower.
    Given my add-in, yes this is true, not without it
    an optical clock so accurate you can measure a difference when you raise it a foot.
    "You" being who, exactly; you are being very imprecise. Who is doing the measuring, your foot of your hand, say? OK I know that sounds silly, but it illustrates the important point that coordinate charts in GR (in any manifold theory, really) can be made as "small" as we like, so two clocks separated in a gravity well by merely a foot will not gree on the "passage of time"
    Like: you always measure wavefunction speed to be the same because you're made out of it.
    This is gibbersh

    Quote Originally Posted by I
    He said that in GR the velocity of light is not a global invariant.
    Quote Originally Posted by you
    Einstein saying A curvature of rays of light can only take place when the velocity of propagation of light varies with position.
    Good, so now we agree, though I should point out that in your last post post you claimed that GR mandates only that the speed of light is not a global invariant.

    And since Newton has been shown the door, i.e. gravity is not a force, his first law need not apply globally so there is no contradiction in asserting the invariance of light speed while simultaneously asserting the lack of global invariance of light velocity. Gettid?

    Perhaps you forget what you said. It would not surprise me as you seem to spread yourself like Marmite over the entire web
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •