If Einstien's view of gravity is that it is an effect of curved spacetime, and objects move in a gravitational field according to the local "geometry" of spacetime, then how do gravitons fit into the scheme of things? Are they required by theories of quantum gravity? And if they are the exchange particles of the gravitational force, is there any reason to believe that they could be manipulated or blocked (sort of like shielding against electromagnetic fields)?
I think this would probably lead to violation of the law of conservation of energy.. Block gravity, lift up a weight, unblock, let the falling weight do work. Ofcourse if the blocking would consume more energy then the lifting of the weight in normal conditions, then I suppose there is a possibility. But I'm just thinking out loud, not that I knew anything about it.
I dont think there is a possibility to find a substance of some sort, that canceles out gravitation, as it passes through it, weakening the gravity on the other side of it. But possibly some sort of field, that needs some amount of energy to be in existence. I remember reading somewhere, that a test had been made where a body was measured to be lighter above a rotating disc. Don't know if its correct and if its got to do anything with actually weakening the gravitational field, but still if anyone else has heard about it, then maybe you could post some links.
Gravitons are not included in General Relativity. They are particles postulated by String Theory to carry gravity.
The modern physics are screwed up because scientists don't care to research more about magnetism. Magnetism is the only force...
Lucas, does this your assertion mean that GRT does not lead to the possibility of the existence of the gravitational waves?
I understand that. So what does this do to the notion of "curved" spacetime as the explanation for the origin of gravity (if gravitons are actually detected)?
Hmm, gravitation shield, interesting. You can imagine gravity as a constant stream of gravitons pointed toward the Earth, coming from all directions. if there was some way to produce gravitons in the opposite to the gravity direction, something like a gravitons generator, the both streams of graviton will compensate and you will have exactly the same - A Super Power Anti-Gravitational Engine, which will bring you up to the stars... Please Register or Log in to view the hidden image! Anyway, i think that a shiled that do not permits gravitons to pass, something like gravity isolator is impossible because gravitons are produced in gigantic quantities all around us and they are a basic property of the vacuum. There is bothing that can stop gravitons. I think that GG /Gravitons Generator/ is the only way. But before a proper and complete theory about gravity (or micro-gravity) is nessary ...
Yuriy, gravitational waves are a prediction of GR, but they don't have any relation with gravitons. They are simply ripples of spacetime If gravitons are detected (i don't think because I don't believe in their existence) it will mean the GR is dead wrong. But actually Einstein can rest happy, there's no way to detect the damned particle
Light can be considered as a wave too, but that doesn't prohibit viewing it as a flow of particles also.
But that's quantum mechanics and here we are talking about classical GR, a classical theory, thus quantization of waves is not included
Lucas, Imagine that we went into Museum wearing the red glasses. We can passionate discuss colors of things there, and we will be amazed that some of them totally absent there. We will try to create appropriate theory of that phenomena, dispute on validity of our old theories predicted a full spectrum of colors in Nature, create and challenge specific postulates to explain what we see, etc, etc. But all what it needs to be done is that …we should take off our glasses! The same situation is with your response: Simply take off artificial restriction (glasses) “we are talking about classical GR” and you will see another World!
1 - Would you agree that GR (like Newton) gravitational strength is calculated as a function from the bodies center of mass? 2 - Would you find any test which showed gravity was not based on center of mass required a different view of gravity?
Dear superL You said: Actually there are two huge “themes” in your post: 1. The theme of ties of Gravity and space-time, and 2. The theme of Antigravitational Sield. My advice is to separate these two themes in different threads. If you do that I will discuss both of them with you. It is not my caprice – it is a necessity: visitors should know what they will find in each thread, when they read the name of thread. (Believe me, our crank-Museum members will put in any of your thread so many junks that there is no need for us to create more difficulties for readers above that one…) But both themes are very good and we should not lose any of them...
Both topic are undividable. They will lead to similar kind of answers. It is better all the staff to be neatly collected in one thread.
MacM, there's not such a thing as gravitational force in GR. Objects in GR follow geodesics. A geodesic is a curve whose tangent vector is parallel propagated along itself
If the force of gravity extemnds inversely to the distance squared from a mass center the force of gravity coult not possibly extend very far from the planet earth for instance. To assume the earth is subject to a rain of gravity particles summed over the entire mass of the universe is specious. The contribution of gravity forces from the nearest galaxy tot he planet earth is immeasurable and is only counted in the graphite marks made by theoretical heiroglyphics (sic). All teh gravity models discussed in this thread after I performed a rapid scan of posts shows one implicit common attribute which is the vopid in inserting nonlocal forces expressely in the model. If we are all led to believe in the quantum and classical models as related functionally but so far indescribable process including local and nonmlocal force exchanges all those models void in local/nonlocal exchanges is grossly incomplete. In an exchange with Lucas a few post above, Yuriy makes a curious comment: Of course Yuriy is correct, but is he suggesting an analysis of GR absent QM imperatives will lead to some useful result? I read Lucas as suggesting the simultaneous analysis using QM and GR. Either one discussed without the functional inclusion of the other is a waste of time and energy. For those familiar with JS Bell, it is he who remarked that QM modles expressly void in nonlocal forces was incomplete. Bell, always the gentleman was did not wemphacize the statement, which taken on the clear meaning of the word incomplete aka useless. Geistkiesel
