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shanesworld
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General Relativity Revisited (What if gravity actually is a force?)
I will admit a few things. First, I suppose I am posting on here because the chances of provoking some discussion, and receiving some feedback are likely better than a few other places I would try. On the other hand, I am hopful of receiving some well informed responses, if I am lucky; I'm often surprised. That aside, perhaps I'll at least have the delight of communicating some ideas, and getting some benificial feedback.
I basically understand what is meant by now when I hear about gravity not being a force. In other words General Relativity (GR) opts to model this phenomenon in terms of a curvature of the space-time fabric. I understand that this model works extremely well, and that it is, perhaps, even the best we have currently, or very close to it.
Yet, it hardly seems fair that now Gravity basically falls down into the category of a pseudo-force, while the electromagnetic interactions still get to sit on that noble pedestool of being a real force. Granted, that is a rather 'emotional' type of statement, but there is a 'reason' I have this sense of dissatisfaction with GR.
Let's talk about force. My current understanding of force is that it is, literally, is the change in mechanical momentum of a system over time. Noted, there are other forms of momentum which are not mechanical, such as those which may be stored in electromagnetic fields, but force particularly does NOT pertain to those changes, rather it purely belongs to the changes in 'Mechanical momnetum.' Are we to believe that gravity can not itself be the source of changes in the mechanical momentum of a system? The anticipated, typically educated, answer goes something like, "Well, according to the equivalence principle of GR, it cannot." In other words a body following its natural path under the influence of gravity cannot "feel" this effect.
I understand that is a nice idea. But, as romantic as it is, and as much as that makes sense 'in a way,' I am not satisfied. Why should we believe, a priori, that gravity cannot impart mechanical momentum on a body, and that this is soly up to the electromagnetc interactions? The equivalence of gravitational and inertial mass? Pshhhhhaw.
I know that the response to my 'a priori' question might go something like this. The effects of the predictions of GR have been experimentally measured through and through, and Gravitational lensing proves that the presence of mass curves the fabric of space time etc...why are you even going on? Well, for one, I have an inquisitive spirit, and I also believe that scientific theories are meant to be probed and questioned; someone like Richard Feynman might say that is the nature of the game.
More importantly, let's rewind. GR succesfully models gravitation in terms of curvature in space-time, and through some means (that few of the brightes physicist could possibly reproduce) arrives at that formulation from, well I'm not even completely certain right now, but let's just say Special Relativity, and incorperating the equivalence principle, roughly speaking. But people, THIS IS A MODEL. There are many models that make successful predictions in their appropriate realms. What if the bending of light by gravitational fields had been discovered prior to GR's creation? If I were not already biased by the beutifully compelling concept of space curvature, my conclusion would NOT be that such 'lensing' proves spacetime is curved.
I would simply take that to be definitive proof that the GRAVITATIONAL FIELD INTERACTS WITH THE ELECTROMAGNETIC FIELDS (afterall light is an electromagetic field propogatin in the form of a wave and gravity bends that, right?) The funny thing is that the converse of that statement is (and such symmetries are all to present in the the world) the Electromagnetic Field interacts with the Gravitational field. For some reason though, I never hear it put so simply. Instead we must do the space time is curved dance, never mind Occam's Razor. (Side note: I would almost expect, on such simple grounds, there to be way more research, and grants funding said research into how the Electromagnetic field interacts with the Gravitational Theorem, than I'm aware of currently, yes...with repect from the Scientific establishement and all.)
Why not entertain the idea that gravity IS a force and could hence contributes to the mechanical momentum of a system, just as electromagnetism can. Said symmetry alone to me is very intriguing. Perhaps this effect is so small we simply haven't yet measured it, but that basically makes sense considering how weak the Gravitational field is compared to the Electromagnetic field. If there is anyone that has any input or feed back on this, or is aware of current research going on that is related, please let me know. Thanks.
(BTW- I bring this up as an effort to provoke discussion on the topic, and not to claim conclusions based on any experimental knowledge, proprietary material, or sensitive information.)
I will admit a few things. First, I suppose I am posting on here because the chances of provoking some discussion, and receiving some feedback are likely better than a few other places I would try. On the other hand, I am hopful of receiving some well informed responses, if I am lucky; I'm often surprised. That aside, perhaps I'll at least have the delight of communicating some ideas, and getting some benificial feedback.
I basically understand what is meant by now when I hear about gravity not being a force. In other words General Relativity (GR) opts to model this phenomenon in terms of a curvature of the space-time fabric. I understand that this model works extremely well, and that it is, perhaps, even the best we have currently, or very close to it.
Yet, it hardly seems fair that now Gravity basically falls down into the category of a pseudo-force, while the electromagnetic interactions still get to sit on that noble pedestool of being a real force. Granted, that is a rather 'emotional' type of statement, but there is a 'reason' I have this sense of dissatisfaction with GR.
Let's talk about force. My current understanding of force is that it is, literally, is the change in mechanical momentum of a system over time. Noted, there are other forms of momentum which are not mechanical, such as those which may be stored in electromagnetic fields, but force particularly does NOT pertain to those changes, rather it purely belongs to the changes in 'Mechanical momnetum.' Are we to believe that gravity can not itself be the source of changes in the mechanical momentum of a system? The anticipated, typically educated, answer goes something like, "Well, according to the equivalence principle of GR, it cannot." In other words a body following its natural path under the influence of gravity cannot "feel" this effect.
I understand that is a nice idea. But, as romantic as it is, and as much as that makes sense 'in a way,' I am not satisfied. Why should we believe, a priori, that gravity cannot impart mechanical momentum on a body, and that this is soly up to the electromagnetc interactions? The equivalence of gravitational and inertial mass? Pshhhhhaw.
I know that the response to my 'a priori' question might go something like this. The effects of the predictions of GR have been experimentally measured through and through, and Gravitational lensing proves that the presence of mass curves the fabric of space time etc...why are you even going on? Well, for one, I have an inquisitive spirit, and I also believe that scientific theories are meant to be probed and questioned; someone like Richard Feynman might say that is the nature of the game.
More importantly, let's rewind. GR succesfully models gravitation in terms of curvature in space-time, and through some means (that few of the brightes physicist could possibly reproduce) arrives at that formulation from, well I'm not even completely certain right now, but let's just say Special Relativity, and incorperating the equivalence principle, roughly speaking. But people, THIS IS A MODEL. There are many models that make successful predictions in their appropriate realms. What if the bending of light by gravitational fields had been discovered prior to GR's creation? If I were not already biased by the beutifully compelling concept of space curvature, my conclusion would NOT be that such 'lensing' proves spacetime is curved.
I would simply take that to be definitive proof that the GRAVITATIONAL FIELD INTERACTS WITH THE ELECTROMAGNETIC FIELDS (afterall light is an electromagetic field propogatin in the form of a wave and gravity bends that, right?) The funny thing is that the converse of that statement is (and such symmetries are all to present in the the world) the Electromagnetic Field interacts with the Gravitational field. For some reason though, I never hear it put so simply. Instead we must do the space time is curved dance, never mind Occam's Razor. (Side note: I would almost expect, on such simple grounds, there to be way more research, and grants funding said research into how the Electromagnetic field interacts with the Gravitational Theorem, than I'm aware of currently, yes...with repect from the Scientific establishement and all.)
Why not entertain the idea that gravity IS a force and could hence contributes to the mechanical momentum of a system, just as electromagnetism can. Said symmetry alone to me is very intriguing. Perhaps this effect is so small we simply haven't yet measured it, but that basically makes sense considering how weak the Gravitational field is compared to the Electromagnetic field. If there is anyone that has any input or feed back on this, or is aware of current research going on that is related, please let me know. Thanks.
(BTW- I bring this up as an effort to provoke discussion on the topic, and not to claim conclusions based on any experimental knowledge, proprietary material, or sensitive information.)
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