Question about gravity
in [Physics]
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From: mathematician on 19 Mar 2010 01:49 On 17 maalis, 10:13, mathematician <hapor...(a)luukku.com> wrote: > On 16 maalis, 13:40, mathematician <hapor...(a)luukku.com> wrote: > > > > > On 15 maalis, 08:42, MicroTech <henry.ko.nor...(a)gmail.com> wrote: > > > > Can someone in this forum please help me sort out a confusing issue? > > > > Many scientists (including Einstein) claim that gravity is not a > > > force, but the effect of mass on the "fabric of spacetime". Many other > > > scientists refer to gravity as one of the four fundamental > > > interactions (three, if one considers the unification of the weak and > > > electromagnetic interactions, the "electroweak" force). > > > > Adding to the confusion, some scientists use both concepts with no > > > apparent difficulty: > > > Stephen Hawking (in his "A Brief History Of Time") first says that > > > gravity is not a force, but "simply" the effect of mass on the > > > "spacetime fabric" (making it "curve"). However, later in the book, he > > > refers to gravity as a fundamental force, carried by the graviton. > > > > So what is gravity, "really"? Does anybody really know? Or do we just > > > know its effects? > > > > Is it an attractive force "mutually pulling" the Earth towards the Sun > > > (and vice versa), "causing" the Earth to "fall" towards the Sun? And > > > due to the "forward motion" of the Earth, exactly matching the > > > "gravitational pull", it stays in orbit (just like any other > > > satellite, man-made or not); OR > > > > Is it the mass of the Sun that "curves spacetime", so no force is > > > interacting with the Earth, it is just moving in a "straight line" > > > along a "curved spacetime" geodesic? > > > > At my current level of understanding, gravity should be one or the > > > other, and not both... > > > > If Einstein's concept of "curved spacetime" is "correct," where does > > > the (hypothetical?) "graviton" (and/or "gravitino") enter the picture? > > > > References to published papers (accessible online) would be much > > > appreciated! > > > > Henry Norman > > > I have thought one possibility that origin of gravitational > > interaction could be > > > "oscillation of size of neutrino´s signal periphery" > > > What you think about this possibility? > > > (Neutrinos are described as colored black holes in this H-M´s > > picture.) > > > Best Regards, > > > Hannu Poropudas > > I would expect that different kind of "light particles" would > be produced due oscillation of size of neutrino´s signal periphery. > > I would expect also that these "light particles" would also > correspond different kind of waves. > > Please take a look my summary from year 1992 to 2009. > Address of this more than 1500 ASCII text pages can be > found from my profile page. > > (Question here is not ordinary photon and corresponding > ordinary electromagnetic waves.) > > Hannu I would also expect that these light particles are not Higg´s particles W+- , Z0, H0 due these are composite in H-M´s picture. They are something presently unknown ? Hannu
From: kenseto on 19 Mar 2010 09:27 On Mar 18, 9:50 am, PD <thedraperfam...(a)gmail.com> wrote: > On Mar 18, 6:29 am, kenseto <kens...(a)erinet.com> wrote: > > > > > > > On Mar 17, 2:59 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Mar 17, 1:57 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Mar 17, 12:31 pm, kenseto <kens...(a)erinet.com> wrote: > > > > > > On Mar 17, 10:01 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > On Mar 17, 8:49 am, kenseto <kens...(a)erinet.com> wrote: > > > > > > > > On Mar 17, 9:14 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > > On Mar 16, 5:08 pm, kenseto <kens...(a)erinet.com> wrote: > > > > > > > > > > On Mar 15, 2:57 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > > > > On Mar 15, 1:43 pm, kenseto <kens...(a)erinet.com> wrote: > > > > > > > > > > > > On Mar 15, 2:27 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > > > > > > On Mar 15, 1:25 pm, "kens...(a)erinet.com" <kens...(a)erinet.com> wrote: > > > > > > > > > > > > > > On Mar 15, 10:08 am, Huang <huangxienc...(a)yahoo..com> wrote: > > > > > > > > > > > > > > > On Mar 15, 9:04 am, kenseto <kens...(a)erinet.com> wrote: > > > > > > > > > > > > > > > > On Mar 15, 6:43 am, "Peter Webb" > > > > > > > > > > > > > > > > <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > > > > > > > > > > > > > > > > Not a whole lot to add to what Inertial in particular said. > > > > > > > > > > > > > > > > > In GR, gravity is a virtual force in a similar way to centrifugal force in > > > > > > > > > > > > > > > > Newton. In both cases its really an acceleration, and the force is just the > > > > > > > > > > > > > > > > product (literally) of this acceleration and the mass of the object. > > > > > > > > > > > > > > > > > Einstein in GR gave a geometric interpretation of what gravity is. This is > > > > > > > > > > > > > > > > very appealing, because it provides a mechanism for force at a distance. > > > > > > > > > > > > > > > > Wrong it provides no such physical mechanism. It merely assumes the > > > > > > > > > > > > > > > existence of a physical entity caLLED the fabric of spacetime for the > > > > > > > > > > > > > > > interacting object to follow. The problem with such assumption is: > > > > > > > > > > > > > > > What is the fabric of spacetime physically? This question is relevant > > > > > > > > > > > > > > > because SR/GR deny the existence of physical space. > > > > > > > > > > > > > > > > Ken Seto > > > > > > > > > > > > > > > What ? ".... SR/GR deny the existence of physical space......" > > > > > > > > > > > > > > > What the devil are you saying man ????? > > > > > > > > > > > > > > > The theory of relativity says that gravity IS deformation of space. > > > > > > > > > > > > > > How can this same theory deny the existence of space ??? Better visit > > > > > > > > > > > > > > your optometrist really, really soon. > > > > > > > > > > > > > > Sigh...How can you deform space when space is defined by Einstein as > > > > > > > > > > > > > "empty space".???? > > > > > > > > > > > > > Being empty means it has no matter in it. Having no matter in it does > > > > > > > > > > > > not mean that space cannot have physical properties.. Physical > > > > > > > > > > > > properties are not limited to matter. > > > > > > > > > > > > Bullshit. fields are stresses in a solid medium occupying space > > > > > > > > > > > according to steven weinberg > > > > > > > > > > > Solid medium? He said nothing about an electric field being a stress > > > > > > > > > > in a solid medium. > > > > > > > > > > Do you just make this stuff up as you go along? > > > > > > > > > > On page 25 he said A field like an electric field or a magnetic field > > > > > > > > > is a sort of stress in space, something like the various sorts of > > > > > > > > > stress possible within a soild body, but a field is a stress in space > > > > > > > > > itself. > > > > > > > > > Note what Weinberg actually said: "...something LIKE the various sorts > > > > > > > > of stress possible within a solid body, but a field is a stress IN > > > > > > > > SPACE ITSELF." He does not say that stress only happens in solid > > > > > > > > bodies. He says that stress happens in solid bodies AND in empty > > > > > > > > space, and the stress in empty space is something like the stress in > > > > > > > > solid bodies. This does NOT mean that empty space is a solid body. > > > > > > > > No stress can exit in liquid or gas. Stress can exist only in solid. > > > > > > > This is an incorrect statement, Ken. It is just flat wrong. > > > > > > What I said is 100% correct. Stress exsts only in solids. I suggest > > > > > that you go to your freskman physics book and look it up. > > > > > Sure. I have the one you have. Please cite in your freshman physics > > > > text where it says that stress exists only in solids. > > > Please point out in your freshman book where it said that stresses can > > occur in liquid or gas. > > Or in space. > > In liquids, you can look up in the index shear modulus, which induces > a shear in the liquid. That's not stress in liquid. > > Are you thinking that the only things that physics deals with are > solids, liquids, and gases, and nothing else? Why would you think > that? See the index item permittivity of empty space. So empty space is not empty. It is a new entity (medium or aether) that can have stress and permittivity. So what is your point? Ken Seto > > > > > > > > > Otherwise, as you say Ken, assertion is not an argument. > > > > > > > When you add your mistake to a correct statement that Weinberg makes, > > > > > > this is only going to make your conclusion wrong. > > > > > > Wienberg compare stress in space to stresses in solid. So my > > > > > conclusion is 100%correct. > > > > If I tell you that a cat has four legs like a lizard, but is a mammal, > > > you should not draw the conclusion that mammals are lizards or that > > > cats are lizards. > > > > Weinberg said that the electric field is LIKE a stress in a solid, but > > > is a stress in space. You should not draw the conclusion that space is > > > a solid or that electric fields are stresses in a solid. > > > So what he said implies that space is a solid. You are so stupid. > > > Ken Seto > > > > > > Ken Seto > > > > > > > > So if stress exits in space as weinberg claimed then space must be a > > > > > > > solid. Your ranting and parsing of words is irrelevant. > > > > > > > Sorry, Ken, but pointing out a mistake of yours is not irrelevant. > > > > > > When you can learn to acknowledge mistakes, then you will start to > > > > > > make progress. But since you always claim that remarks by others about > > > > > > your mistakes are irrelevant, you will never get off square one.. > > > > > > > You have to get over your personality defects before you will be able > > > > > > to do science. > > > > > > It will help also to learn some basic physics, like what is taught in > > > > > > your freshman textbook. > > > > > > > > Ken Seto > > > > > > > > > > > Physical properties are not limited to matter. > > > > > > > > > > > You know that there is a permittivity of EMPTY SPACE? You know there > > > > > > > > > > is a permeability of EMPTY SPACE? You know there is an impedance of > > > > > > > > > > EMPTY SPACE? You know there is a gravitational potential in EMPTY > > > > > > > > > > SPACE?- Hide quoted text - > > > > > > > > > > > - Show quoted text -- Hide quoted text - > > > > > > > > > - Show quoted text -- Hide quoted text - > > > > > > > > > - Show quoted text -- Hide quoted text - > > > > > > > - Show quoted text -- Hide quoted text - > > > > > > > - Show quoted text -- Hide quoted text - > > > > - Show quoted text -- Hide quoted text - > > > > - Show quoted text -- Hide quoted text - > > - Show quoted text -- Hide quoted text - > > - Show quoted text -
From: bert on 19 Mar 2010 09:41 On Mar 15, 1:22 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Mar 15, 1:42 am, MicroTech <henry.ko.nor...(a)gmail.com> wrote: > > > > > > > Can someone in this forum please help me sort out a confusing issue? > > > Many scientists (including Einstein) claim that gravity is not a > > force, but the effect of mass on the "fabric of spacetime". Many other > > scientists refer to gravity as one of the four fundamental > > interactions (three, if one considers the unification of the weak and > > electromagnetic interactions, the "electroweak" force). > > > Adding to the confusion, some scientists use both concepts with no > > apparent difficulty: > > Stephen Hawking (in his "A Brief History Of Time") first says that > > gravity is not a force, but "simply" the effect of mass on the > > "spacetime fabric" (making it "curve"). However, later in the book, he > > refers to gravity as a fundamental force, carried by the graviton. > > > So what is gravity, "really"? Does anybody really know? Or do we just > > know its effects? > > > Is it an attractive force "mutually pulling" the Earth towards the Sun > > (and vice versa), "causing" the Earth to "fall" towards the Sun? And > > due to the "forward motion" of the Earth, exactly matching the > > "gravitational pull", it stays in orbit (just like any other > > satellite, man-made or not); OR > > > Is it the mass of the Sun that "curves spacetime", so no force is > > interacting with the Earth, it is just moving in a "straight line" > > along a "curved spacetime" geodesic? > > > At my current level of understanding, gravity should be one or the > > other, and not both... > > > If Einstein's concept of "curved spacetime" is "correct," where does > > the (hypothetical?) "graviton" (and/or "gravitino") enter the picture? > > > References to published papers (accessible online) would be much > > appreciated! > > > Henry Norman > > It's definitely a different kind of animal. > Part of the issue is understanding better what it is the particle > represents. > For example, in electromagnetism, the classical picture is a field in > the background of space and time. The particle is a quantization of > disturbances in that field in the background of space and time. > Here, the field IS space and time itself, not in a background of space > and time. And the particle would be a quantization of a disturbance in > space and time itself, not a disturbance of a field in the background > of space and time. > The naive (but appealing) view of the electromagnetic quantum is > something that moves *through* the background of time and space. > The gravitational quantum isn't quite like that, as it is not really > moving *through* the background of time and space, but is more closely > tied to space and time itself. > > It's interesting that some of the more promising candidates for > quantum gravity are "backgroundless" in that they do not assume a > space and time through which gravitons move. Instead, space and time > themselves arise from the interactions of the quanta. This makes my > head hurt a little, but it does look promising. > > PD- Hide quoted text - > > - Show quoted text - Einstein gave space a concave curve. TreBert gave space a convex curve. Einstein used cocave space so stuff falls in. TreBert gave convex curve to give reality to space inflating. Both work on accelerating motion. Accelerating relates 100% to gravity. Inertia is 100% same as gravity. They are relative to each other. TreBert
From: Yousuf Khan on 19 Mar 2010 10:24 Juan R. González-Álvarez wrote: > Yousuf Khan wrote on Mon, 15 Mar 2010 10:14:31 -0400: >> The Einstein description of gravity is the only one that's been proven >> at some level. > > This is plain wrong. All the observations verified by General relativity > are also satisfied with other theories also: > > # Reflections on Gravity 2000: arXiv:astro-ph/0006423v1. Straumann, Norbert. > > # Field Theory of Gravitation: Desire and Reality 1999: arXiv:gr-qc/9912003v1. Baryshev, Yurij, V. > > # On a possibility of scalar gravitational wave detection from the binary pulsar PSR 1913+16 1999: arXiv:gr-qc/9911081v1. Baryshev, Yurij, V. > > # A Hamiltonian approach to quantum gravity 2008: arXiv:physics/0612019v9. Stefanovich, Eugene V. > > # Nonlocal forces of inertia in cosmology 1996: Found. of Phys. 26(2), 271—283. Assis, André K. T.; Graneau, Peter. > > # Gravitational interaction in the relational approach 2008: Grav. and Cosm. 14(1), 41—52. Vladimirov, Yu. S. Yes, but many of those theories are simply derivations and/or generalizations of General Relativity. They work out to some form of General Relativity as one of their special subsets. Examples include TeVeS and f(R) Theory. TeVeS seems to have failed some observational tests recently, so it`s now probably dead. But f(R) Theory seems to have passed a recent test alongside traditional ``GR with Cosmological Constant added``. > I do not know the experimental status of teleparallelism, but my belief is > that also explains the same tests than general relativity does > > http://en.wikipedia.org/wiki/Teleparallelism Well, since it was Einstein himself who came up with Teleparallism, then it would stand to reason that it would be compatible with his own GR. >> The description of gravity as a force particle, the graviton, is part of >> a next generation theory of quantum mechanics known as Supersymmetry. > > Nonsense. Gravitons have nothing to see with speculative supersymmetry. > Your supersymmetry is "the next generation theory of quantum mechanics" is > another nonsensical statement. Don't understand where you're coming from. Gravitons were proposed by Supersymmetry theory. The Standard Model of Quantum Mechanics has no model for gravitons. The Standard Model is whatever is already known and proven. Everything else beyond, is theoretical. >> Supersymmetry is part of a larger next generation framework theory >> called Superstring Theory, and now M-Theory. > > Both build over rather standard and outdated quantum formalism. > The next generation of quantum mechanics is becoming from other camps You seem to be arguing one next-gen theory is better than another. Who cares, that's not the point here! Here we're just talking about the historical origins of certain ideas, such as gravitons. I don't care which next-gen theory you subscribe to, and neither does the OP. The OP just wants to know the background of where these ideas came from. Yousuf Khan
From: Uncle Al on 19 Mar 2010 10:26
mpc755 wrote: > > The pressure associated with the aether displaced by a massive object > is gravity. > > A moving C-60 molecule has an associated aether displacement wave. > > The pressure associated with the aether determines the rate at which > an atomic clock ticks. idiot http://arXiv.org/abs/0706.2031 Physics Today 57(7) 40 (2004) http://physicstoday.org/vol-57/iss-7/p40.shtml Phys. Rev. D8, pg 3321 (1973) Phys. Rev. D9 pg 2489 (1974) <http://cfa-www.harvard.edu/Walsworth/pdf/PT_Romalis0704.pdf> No aether <http://relativity.livingreviews.org/Articles/lrr-2005-5/index.html> Phys. Rev. D 81 022003 (2010) http://arxiv.org/abs/0801.0287 http://arxiv.org/abs/0905.1929 No Lorentz violation idiot -- Uncle Al http://www.mazepath.com/uncleal/ (Toxic URL! Unsafe for children and most mammals) http://www.mazepath.com/uncleal/qz4.htm |