Why two mass attracts each other?

Discussion in 'Physics & Math' started by hansda, Mar 19, 2013.

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  1. hansda Valued Senior Member

    My basic question was to explain "gravitational force between the Sun and the Earth in terms of GR".

    Instead you are explaining gravitational force between the Earth and an electron in terms of GR. I guess you consider behavior of an electron like that of a photon.

    Do you think 'the way light curves around the Earth', same way 'our Earth also bends around the Sun'?
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  3. OnlyMe Valued Senior Member

    The gravitational interaction between the earth and a neutron has been experimentally confirmed to be consistent with GR. the same is not true for electrons, protons or other charged subatomic particles. That does not mean there is no gravitational interaction or that it is not consistent with GR, is just means that there are other forces active that prevent accurate measurement. One of which is the particle's charge and electromagnetic interactions.

    Electrons and neutrons are not equivalent electromagnetically, or kinetically. Neutrons are observed to naturally occur with relativistic velocities. Electrons are not.

    Here you begin once again to intermingle quantum issues with the macroscopic gravitational issues of GR. Where is your model of Quantum Gravity? .... Your references relate to the theoretical. You present them as if they were proven fact.

    Radium Salts? Think how does radium decay? And did Einstein know the mechanism?

    When Einstein made many of the statements he did, he did not have all of the facts that are available to us today. You seem to quote, as if those you quote had all the answers. Even GR as it is understood today, would be unreconizable to Einstein, in the early 1900's. Quoting him or Newton, without considering the context and limitaions of information, of the time in which their comments were made, lacks credibility. It is almost as if you are attempting to invoke a name, as support for your obvious misunderstanding.

    Perhaps you should re-read it, first setting aside your preconceptions and with some understanding of the limitations within which they were presented. (The decay mechanisms of radium salts being just one.)

    You can certainly say it, and it may be a fact.., but that does not raise it from theory to proven....!

    The results of those references are subject to interpretation. Carbon molecules are not electromagnetically neutral and any Difraction mechanisms cannot be assumed to represent and equivalent diffraction process as is seen with photons. You could fire bearings through a magnetic field and also see a pattern develope that resembles a diffraction pattern seen with light. That does not mean the molecule exists macroscopically as a wave. Just as an old TV tube does not require an electron to be a wave for the electron to be deflected by the involved magnetic field.

    My original comment was directed at your attempt to divert the question from one of an interaction between masses by suggesting a hypothetical gravitational interation between a free electron and the earth. You raise several independently reasonable citations, and then try to connect them without doing any of the fundamental ground work required to support the connections.
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  5. OnlyMe Valued Senior Member


    There is an orbital earth and sun gravitational interaction, while there is not similar orbital interaction between light and the earth. It is not even clear that a black hole traps light in an orbital relationship.

    There is a great deal of difference in the momentum involved, when comparring any massive "object" and light or photons. While theoretically both light and planets (in stable orbits), follow the curvature of spacetime, the curvature for each cannot be equivalent. Photons donot orbit the earth or the sun, while planets do orbit the sun and the moon does orbit the earth.
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  7. Farsight Valued Senior Member

    Sorry hansda, maybe I missed something. Your OP referred to Newton, to charges and magnets attracting one another, and then gave these questions:

    Why two mass attract each other and not repel each other? and

    Does a mass also have some kind of polarity?

    I chimed in on page 3 giving information about chirality, and how Minkowski and Maxwell talking about the "screw" nature of electromagnetism, Maxwell also referring to vortices. I hope that helped with the charges and the magnets. Gravity is different to electromagnetism. It doesn't have this vortex-screw nature. However gravitomagnetism does, check out this NASA page on gravity probe B: "Einstein was right again. There is a space-time vortex around Earth, and its shape precisely matches the predictions of Einstein's theory of gravity".

    Yes, you start with the photon, then take the simplest example of matter, which is the electron, because Einstein talked about electrons quite a lot. After that you move on up to the hydrogen atom, then a test particle in the gravitational field of a large mass, then two large masses, and so on.

    They're related. Light hardly curves at all when it goes past the Earth. And it only curves a little when it goes past the Sun. If you could throw the Earth past the Sun extremely fast, its path would only curve a little. In similar vein a ball is made up of electrons etc, and when you throw it across the room it follows an arc. If you throw the ball really fast the arc is much flatter. If you could throw it at something close to the speed of light, its arc would even flatter than the way light bends, because light is deflected twice as much as matter. See this article where you can read this:

    "Newtonian mechanics predicts that a particle traveling at the speed of light which just grazes the edge of the Sun will be deflected by 0.875 seconds of arc...

    ...Before Einstein developed the full theory of General Relativity he also predicted a deflection of 0.875 arcseconds in 1913, and asked astronomers to look for it. But World War I intervened, and during the war Einstein changed his prediction to 1.75 arcseconds, which is twice the Newtonian deflection."

    Also check out On the gravitational deflection of light and particles by C S Unnikrishnan. He refers to "matter waves" which I'm not fond of myself, and he talks GR down a bit, but it's an interesting read anyhow.

    Edit: I see OnlyMe said "no" and not much else to your question about the behaviour of light and matter in a gravitational field. I recommend you take his answers with a pinch of salt, because he doesn't know much physics.
  8. eram Sciengineer Valued Senior Member

    To sidetrack, I think the buckyball diffraction experiment was quite convincing.
  9. Farsight Valued Senior Member

  10. OnlyMe Valued Senior Member

    Frame dragging or the Lense-Thirring effect, was not an original prediction of Einstein's. That is way it is called the Lense-Thirring effect. And yes it did emerge from Einstein's earlier work.... GR. The NASA quote you referenced was misleading in ascribing the prediction to Einstein (circa 1915 and his publication of GR) rather than Lense and Thirring, in 1918.

    Also to be clear for those who do not have the background, "gravitomagnetism" suggests only a similarity Or analogy between Maxwell's equations of electromagnetism and GR equations for gravity, not that there is any connection or associating between electromagnetism and gravitation. In a way this lies at the heart of my original point, your argument is mixing aspects of physics which at present do not have a common theoretical origin.

    I never said they (light and planets) were not both affected by graviation. I said they are not affected in the same way. The question was are they (light and the earth) affected in the same way. The answer remains no..., not in the same way.

    You keep throwing out examples that are not within the context of reality. You cannt "throw" the earth past the sun in a manner similar to the way a photon passes the sun at close range. It is not even certain that matter as in atom's can remain intact at relativistic velocities. Note, we do see ionized atoms, protons and bare nuclei, even some neutrons with relativistic velocities, but those do not represent intact atoms.
  11. OnlyMe Valued Senior Member

    It was not the Difraction pattern that I was questioning, it is the mechanism that results in the pattern. Buckyballs are conductive and thus must be thought of as charged "objects". As charged objects their proximity to the edges of the slits in the diffraction grate could very easily deflect their trajectory in a pattern that mirrors the diffraction pattern of light.., without the mechanism of that "diffraction" being the same as with light.

    With light there are a number of different ways to demonstrate interference patterns, which support the wave nature of light, that cannot be reproduced with buckyballs or other "objects". The fact that we can construct mechanisms that will duplicate the diffraction pattern of light with "objects" does not in and of itself prove that those objects are waves. An example is the classic Michaelson & Morley interferometer, which works well with light but would not work with buckyballs.., or even with electrons for that matter. We just cannot separate a stream of "objects" into two paths and then reunite them, they way you can with light.

    So, I would say the buckyball experiment is interesting, but not compellingly convincing.
  12. arauca Banned Banned

    they attract each other because the spin of the masses who create a magnetic field and the central body spins in opposite direction ?????
  13. OnlyMe Valued Senior Member

    Hansda, to be clear, GR "describes" gravitation. It describes the dynamics, or mechanics, or kinetics of how objects interact due to gravitation... It does not explain it... It does not say why two objects attract gravitationally, only how the presence of each affects the other, in space over time. It is that in space over time that gives us spacetime.

    There is some work on quantum gravity that may lead to an answer to the question of the origin of the "force" of gravitation. Personnally I am currently most interested in Induced Inertia and Gravity, with an emphasis on how gravitation might emerge from Induced Inertia... But then I tend to stray a bit from the mainstream in how that may workout. (Keep in mind that I do not work in the field. I am retired and have the luxury of indulging my imagination.)

    See papers by Puthof, Rueda & Haisch for more information on induced inertia and gravity.
  14. Farsight Valued Senior Member

    Yes, it was somewhat misleading, but Einstein included shear stress in the EFEs, which is why the Lense-Thirring effect emerges from Einstein's earlier work. But having said that, it would have been less misleading if it had mentioned Oliver Heaviside, see below.

    This is misleading. Gravitomagnetism was developed by Oliver Heaviside. Whilst he used the word analogy in his original 1893 paper, don't forget that it was Heaviside who reformulated Maxwell's equations into vector form. That's why the equations are known as the "Maxwell-Heaviside equations". Oliver Heaviside is the connection between electromagnetism and gravitomagnetism. And like I said, they aren't all that different. That's why the NASA article referred to a vortex, and Maxwell's page heading was The Theory of Molecular Vortices. And why both he and Minkowski referred to a screw. Look at the picture on the NASA page. Then remember what I said about grabbing the rubber sheet and twisting it round.

    I gave a reference to a bona-fide website that made it clear that the faster a matter particle moves, the more lightlike its deflection, but that in the limit the deflection is half that of light. Now go and read it, go and learn some physics, and stop playing the ignorant naysayer who dismisses Newton, Maxwell, Einstein, Minkowski, and all the hard scientific evidence that's out there.
  15. OnlyMe Valued Senior Member

    Could you post that link again, it is sometimes difficult to search back through a discussion for a specific link on a mobile device... And clarify whether this was a "bona-fide" theoretical paper or a practical proof. Does "matter particle" refer to a sub atomic particle, i.e. a proton, neutron etc., or an "object"? Are you suggesting that matter as in an "object" composed of atom's and molecules can be naturally accelerated to relativistic velocities.., without ionization occurring? If so where is the observational proof?

    Re: The gravitomagnetism issue, I don't see how your reaching back to a reference of Heaviside, changes the point I was attempting to make. "Gravitomagnetism" does not suggest that gravitation and magnetism or electromagnetism are in any way unified or even emergent from one another. It only emphasizes the similarities in the field equations, describing the two... There is no issue with the use of the word, except within a lay context where that subtle distinction, may be misunderstood. Even NASA assumes too much in some of their lay oriented releases and publications. Notice that the Wiki page begins with, "Gravitoelectromagnetism, abbreviated GEM, refers to a set of formal analogies between the equations for electromagnetism and relativistic gravitation;", an attempt to clarify the "analogy".., or similarity, before detailed discussion.
  16. hansda Valued Senior Member

    I think papers by Puthof, Rueda & Haisch and induced inertia for gravitational force are quite different.
  17. Farsight Valued Senior Member

    Neither are right I'm afraid, hansda. Einstein was right with his Does the Inertia of a Body Depend upon its Energy-Content? You just have to know what he was on about with a radiating body loses mass and radiation conveys inertia. It's simple, but you have to know about things like Compton scattering to know just how simple it is. Remember what I was saying on the other thread. You can't make a photon slow down or speed up, so mass doesn't apply. It's massless. But you can "accelerate" the photon by changing its direction. That's what happens in Compton scattering. The photon changes direction and loses energy, and the electron gets a "kick" of linear acceleration and gains energy. There's also Inverse Compton scattering where the electron loses energy to the photon.

    If that photon is going round and round inside a gedanken mirror-box, then when you open the box, it's a radiating body that loses mass. If you then catch the photon in another box, the box is a body that gains it. Hence radiation conveys inertia. Even though it's massless, the photon increases the mass of the body, because the inertia of a body depends upon its energy content. The reason for this is simply that to move the box, you have to "accelerate" the photon inside it by changing its direction. Draw the photon as light going round a square path. Then repeat, but this time with your eyes closed while pulling the paper from right to left. When you look at the "square" you drew it now looks like this: \_/‾. It isn't a square any more. See Light is Heavy for more. The 't hooft isn't the Nobel prizewinner, it's some other Dutch guy
  18. Farsight Valued Senior Member

    Here it is: http://www.astro.ucla.edu/~wright/deflection-delay.html . It isn't a paper, it's a tutorial or part of an online course by Ned Wright, a physics/astronomy professor from Harvard/MIT/UCLA.

    Ned Wright just says "particle". I inserted "matter" to make a distinction between the photon and the electron we'd been talking about. The important thing to appreciate is that the faster it goes, the less it's deflected by gravity. Ned Wright's exact words were "Newtonian mechanics predicts that a particle traveling at the speed of light which just grazes the edge of the Sun will be deflected by 0.875 seconds of arc.". We all know that we can't accelerate an electron to the speed of light, but that's the limit we tend towards.

    You don't understand the relationship because you've never read and never been taught the original Maxwell. He talked about vortices and referred to the screw nature of electromagnetism. Even Minkowski referred to the screw nature of electromagnetism. You just have to appreciate what electron magnetic moment and spinors and curl and the Einstein-de Haas effect are all about. It really isn't all that different to the frame-dragging of gravitomagnetism. That's why Heaviside, who knew a thing or two about electromagnetism, was able to work out that a big spinning body like the Earth should have a field that was in some respects like the electromagnetic field. It's like you assemble a bunch of electrons and protons, and spin them bodily. It's a different kind of spin to the electron "intrinsic" spin, and the resultant field is temendously weak, but it's there just like the electromagnetic field is there. Heaviside was smart enough to see it. Sadly he wasn't smart enough to avoid screwing up Maxwell's electromagnetism. The vector notation replaced what the field is with what field interactions do. Nowadays too many people think E and B are fields instead of linear and rotational forces on particles undergoing electromagnetic field interaction. Again, see what Minkowski said towards the bottom of Space and Time next to figures 3 and 4 on wikisource. I've bolded a couple of bits:

    "In the description of the field caused by the electron itself, then it will appear that the division of the field into electric and magnetic forces is a relative one with respect to the time-axis assumed; the two forces considered together can most vividly be described by a certain analogy to the force-screw in mechanics; the analogy is, however, imperfect."

    Gotta go. Do your own research.
  19. OnlyMe Valued Senior Member

    Your claim, "I gave a reference to a bona-fide website that made it clear that the faster a matter particle moves, the more lightlike its deflection,...", is what I was asking for the link to. At least int he context of direct discussion, the above links refer to light, not matter, as in atoms and molecules. Remember I asked for a reference that supported some documented or experimental proof, not just the theoretical extensions...

    I think I have been overly clear in stating atoms, molecules, "objects", perhaps even complex matter, as opposed to "particles" ..., or subatomic particles. What happens to light has not been the issue I was raising. What I have been raising is presenting the extension of what we know, in the case of light and theory, to "objects" you know rocks and baseballs or as you initially mentioned, throwing the earth past the sun at relativistic velocities (paraphrased).

    Here you begin to go down the toilet, by interjecting personal comments, and assuming you know anyone's background or what they have or have not read or been exposed to. You seem to do this often when faced with anyone who does not interpret historical data in the same way you do.

    The original question was, to paraphrase again, whether gravity affected light (photons) in the same way it affects the earth.

    My objection was that your substitution of an electron for the earth or light was misleading and raised issues other than gravity... Specifically issues involving electromagnetism and QM which have not been reconciled with GR and gravitation. The question having been about graviation.

    The only references I asked for you those you claimed to have already supplied supporting your interpretations. The way I read what you have supplied is that you have a unique and sometimes imaginative way of interpreting, the references you do supply... Which does not to me seem to represent a consensus view of the science community.

    One question just to clear my own mind.

    Do you really believe that when NASA or Stanford, in connection with the Gravity Probe B experiment, used or uses the word "Gravitomagnetism", they were or are referring to some hybrid of gravity and magnetism or electromagnetism? If so read the full GP-B final report and see how far they went to exclude magnetic and electromagnetic interactions from the raw data on the gravitomagnetic or frame dragging, the experiment was designed to isolate and measure.
  20. OnlyMe Valued Senior Member

    I was perhaps a bit vague in just saying induced inertia and gravity, there has been and remains more than one approach that would fall under that umbrella. As I mentioned I, lately have been most interested in induced inertia and a rather non-traditional application toward gravitation.

    There have been many papers by a number of different researchers, starting with Sakharov 1967 and Puthoff beginning around 1988. Probably others in between and certainly many others later.

    Some of the following links may be redirected to updated or newer papers or even be completely dead. This is only a sampling of the available work directly or indirectly related to the inertia issue I mentioned...

    Vacuum Quantum Fluctuations in Curved Space and the Theory of Gravitation, Sakharov (1967), http://www.math.uwaterloo.ca/~akempf/sakharov.pdf

    Radiation pressure from the vacuum: Physical interpretation of the Casimir force, Milonni (1988), http://www.dtic.mil/dtic/tr/fulltext/u2/a199899.pdf

    Source of electromagnetic zero-point energy, Puthoff (1989), http://www.earthtech.org/publications/PRAv40_4857.pdf

    Inertia as a zero-point-field Lorentz force, Hairsh (1994), http://www.calphysics.org/articles/PRA94.pdf

    Electromagnetic Zero Point Field as Active Energy Source in the Intergalactic Medium, Rueda & Haisch (1999), http://arxiv.org/abs/gr-qc/9906067

    Vacuum Generated - Inertia Reaction Force, Rueda-Haisch (2001), link seems to be dead
  21. hansda Valued Senior Member

    Most of these papers are suggesting a link between "gravity" and "EM field".
  22. OnlyMe Valued Senior Member

    Yes, but I would say between inertia/gravity and zero-point energy or the ZPF, rather than an or the EM field.

    I listed several papers, because they are somewhat related and/or build on one another.., and since my own ideas stray from what appears to be a limited consensus view, I did not want to just jump into an "Alternate" interpretation of some of the work.

    As I mentioned I am most interested in inertia, as emergent from the interaction of an object (or particle/Parton, as described in most cases), and an inherent momentum or resistence associated with ZPF. However, my own ideas on the issue of gravity, are more an adaptation of the work on on inertia, than an extension of those papers dealing with gravity. In a way something like the association of acceleration and graviation via the equivalence principle.

    By the way, to head off any nay saying I don't see any of this as in conflict with GR, though I do see potential for gravity and GR to emerge from mechanism(s) involving quantum dynamics.
  23. PhysBang Valued Senior Member

    But Minkowski doesn't refer to a screw. In the text you cite the translation is "force-screw". Other translators use "wrench in mechanics" or other phrases. He originally used German words that refer to a feature of mechanics where a combination of forces can be broken down into a (somewhat) arbitrary decomposition.

    This is one example of one reason why textual analysis of translations should not be used in the place of actual physics.
    Indeed, you take one translation, you studiously avoid studying physics, and you claim yourself the authority of physics.
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