Question about gravity
in [Physics]
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From: mpc755 on 15 Mar 2010 13:40 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 The interactions of the quanta is the interaction of the aether with the matter. If you need to allow your head to hurt a little less you can conceptualize the aether as consisting of photon particles where the photons are the quanta. I prefer Einstein's concept of the aether as not consisting of particles which can be separately tracked through time which means it cannot be known if the aether consists of quanta or if the aether is a one something but since you are conceptually deficient you may need to conceptualize the aether as quanta in order to make any progress whatsoever in terms of understanding the physics of nature. There is no such thing as a graviton. In terms you may have the slightest chance of understanding, gravity is the pressure associated with the displacement of the quanta by the matter. The quanta are not at rest when displaced and 'displace back'. How do we know the quanta 'displace back'? Because light from distant stars reaches us from where Jupiter was in its orbit (i.e. Jupiter does not leave a void in its wake). The pressure associated with the quanta exerted towards the matter which is the massive object doing the displacing is gravity.
From: BURT on 15 Mar 2010 14:01 On Mar 15, 10:40 am, mpc755 <mpc...(a)gmail.com> wrote: > 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 > > The interactions of the quanta is the interaction of the aether with > the matter. If you need to allow your head to hurt a little less you > can conceptualize the aether as consisting of photon particles where > the photons are the quanta. > > I prefer Einstein's concept of the aether as not consisting of > particles which can be separately tracked through time which means it > cannot be known if the aether consists of quanta or if the aether is a > one something but since you are conceptually deficient you may need to > conceptualize the aether as quanta in order to make any progress > whatsoever in terms of understanding the physics of nature. > > There is no such thing as a graviton. In terms you may have the > slightest chance of understanding, gravity is the pressure associated > with the displacement of the quanta by the matter. The quanta are not > at rest when displaced and 'displace back'. How do we know the quanta > 'displace back'? Because light from distant stars reaches us from > where Jupiter was in its orbit (i.e. Jupiter does not leave a void in > its wake). The pressure associated with the quanta exerted towards the > matter which is the massive object doing the displacing is gravity.- Hide quoted text - > > - Show quoted text - Gravity particles get in the way. Einstein's Gravity Continuum is correct. Mitch Raemsch
From: dlzc on 15 Mar 2010 14:11 Dear "Juan R." González-Álvarez: On Mar 15, 8:03 am, "Juan R." González-Álvarez <nowh...(a)canonicalscience.com> wrote: > dlzc wrote on Mon, 15 Mar 2010 07:08:28 -0700: > > On Mar 14, 11:42 pm, MicroTech <henry.ko.nor...(a)gmail.com> wrote: > >> Can someone in this forum please help me sort > >> out a confusing issue? > > > As usual, you have received some pearls and some > > jokers so far. > > > Let's just add that with "reasonable" > > simplifications, Einstein's Relativity > > (gravity =/= force) reduces to Newton's > > gravitation (gravity = force). > > Nope. > > First, recent research shows that GR does > not reduces to NG, with textbooks claims > about this being wrong. > > Second, even if we ignore this point the > approx geodesic equation > > a = -@phi/@x > > obtained from GR cannot be interpreted as > describing gravity as a force. Wald does > beatiful remarks about this in his textbook in GR. Thank you for a very informative response. It will help the OP and posterity. Not that I agree with you, depending on the simplifications considered, but not important here. David A. Smith
From: BURT on 15 Mar 2010 14:13 On Mar 15, 11:11 am, dlzc <dl...(a)cox.net> wrote: > Dear "Juan R." González-Álvarez: > > On Mar 15, 8:03 am, "Juan R." González-Álvarez > > > > > > <nowh...(a)canonicalscience.com> wrote: > > dlzc wrote on Mon, 15 Mar 2010 07:08:28 -0700: > > > On Mar 14, 11:42 pm, MicroTech <henry.ko.nor...(a)gmail.com> wrote: > > >> Can someone in this forum please help me sort > > >> out a confusing issue? > > > > As usual, you have received some pearls and some > > > jokers so far. > > > > Let's just add that with "reasonable" > > > simplifications, Einstein's Relativity > > > (gravity =/= force) reduces to Newton's > > > gravitation (gravity = force). > > > Nope. > > > First, recent research shows that GR does > > not reduces to NG, with textbooks claims > > about this being wrong. > > > Second, even if we ignore this point the > > approx geodesic equation > > > a = -@phi/@x > > > obtained from GR cannot be interpreted as > > describing gravity as a force. Wald does > > beatiful remarks about this in his textbook in GR. > > Thank you for a very informative response. It will help the OP and > posterity. Not that I agree with you, depending on the > simplifications considered, but not important here. > > David A. Smith- Hide quoted text - > > - Show quoted text - Einstein's theory of gravity is incomplete. The strength of gravity comes from a different source than the curve alone. Mitch Raemsch
From: kenseto on 15 Mar 2010 14:25
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".???? Ken Seto |