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Every one know that Einstein was the creator of the General relativity,yes I know too, But after I have read this article ...sorry, you cannot view external links. To see them, please REGISTER or LOGIN that was written by Peter M Brown who was the member here too. I also confused with this articles very much. This article said that Einstein did not create the real General relativity he didn,t think that gravity was the space time curvature but I have read many book and almost of it said that Einstein create the General relativity of space time curvature. Who can explain me and tell me that who is Peter M brown does he was the professor of any university ??

I think that I have read your article clearly, Your article try to proof that there are two version of The General relativity the Einstein version and The modern version.You try to proof that Einstein did not determine the gravity as the space time curvature.

...Tesla criticize Einstein general relativity ...sorry, you cannot view external links. To see them, please REGISTER or LOGIN by Percy Hammond and see where he says "We conclude that the field describes the curvature that characterizes the electromagnetic interaction".What Peter says is true. There are some differences between relativity as described by Einstein and relativity as it's taught today. I think it's something of an issue actually. It causes problems.

Quote from: parakorn on 29/08/2014 13:39:58 I think that I have read your article clearly, Your article try to proof that there are two version of The General relativity the Einstein version and The modern version.You try to proof that Einstein did not determine the gravity as the space time curvature. Then you read it wrong. The article only refers to the interpretation of how the term "gravitational field" is defined. Einstein defined it one way and others defined it another way. I know that's what the author means because I'm the author. Anything else is your interpretation. If you claim that I said otherwise then please post the page number and the sentence in which you claim I said it.

But in truth there are many time that Einstein said that gravity is the curvature of space time.

Quote from: parakornBut in truth there are many time that Einstein said that gravity is the curvature of space time.No there isn't. If you beg to differ, give a few reference where he did say that.

first page that you wrote that "Einstein identified the existence of gravity with the inertial motion of accelerating bodies (i.e. bodies in free-fall) whereas contemporary physicists identify the existence of gravity with space-time curvature (i.e. tidal forces). The interpretation of gravity as a curvature in space-time is an interpretation Einstein didnot agree with"

In the fourth page that you wrote Did Einstein actually hold the view that gravity is a curvature in space-time? At this point let us whet your appetite. No. Einstein never said nor implied in anyway that gravity is a curvature in space-time.

This apparent disparity is a result of a change of interpretation.

In page 9 that you wrote In the year following the completion and publication of the general theory of relativity Einstein published the review article The Foundation of the General Theory of Relativity in 1916 3. The statement It will be seen from these reflections that in pursuing the general theory of relativity we shall be led to a theory of gravitation, since we are able to “produce” a gravitational field merely by changing the system of coordinates. identifying gravity with non-inertial systems, wholly reflects Einstein’s interpretation of gravity, the existence of which depends on the observer’s frameof reference.

This view is made possible for us by the teaching of experience as to the existence of a field of force, namely, the gravitational field, which possesses the remarkable property of imparting the same acceleration to all bodies. The mechanical behavior of bodies relatively to K' is the same as presents itself to experience in the case of systems which we are wont to regard as "stationary" or as "privileged." Therefore, from the physical standpoint, the assumption readily suggests itself that the systems K and K' may both with equal right be looked upon as "stationary" that is to say, they have an equal title as systems of reference for the physical description of phenomena. It will be seen from these reflexions that in pursuing the general theory of relativity we shall be led to a theory of gravitation, since we are able to "produce" a gravitational field merely by changing the system of co-ordinates. It will also be obvious that the principle of the constancy of the velocity of light in vacuo must be modified, since we easily recognize that the path of a ray of light with respect to K' must in general be curvilinear, if with respect to K light is propagated in a straight line with a definite constant velocity.

But in truth there are many time that Einstein said that gravity is the curvature of space time

... what characterizes the existence of a gravitational field from the empirical standpoint is the non-vanishing of the components of the affine connection], not the vanishing of the [components of the Riemann tensor]. If one does not think in such intuitive (anschaulich) ways, one cannot grasp why something like curvature should have anything at all to do with gravitation. In any case, no rational person would have hit upon anything otherwise. The key to the understanding of the equality of gravitational mass and inertial mass would have been missing.

Quote from: JohnDuffield on 29/08/2014 16:06:38Quote from: parakornBut in truth there are many time that Einstein said that gravity is the curvature of space time.No there isn't. If you beg to differ, give a few reference where he did say that. for example ...sorry, you cannot view external links. To see them, please REGISTER or LOGIN section 23-section 27 and section 31-32

Quote from: JohnDuffield on 29/08/2014 16:06:38Quote from: parakornBut in truth there are many time that Einstein said that gravity is the curvature of space time.No there isn't. If you beg to differ, give a few reference where he did say that. He certainly realized that the mathematics of his theory describing gravitation also describe curvature in space-time(...sorry, you cannot view external links. To see them, please REGISTER or LOGIN which aren't even there though!!!!

He certainly realized that the mathematics of his theory describing gravitation also describe curvature in space-time (...sorry, you cannot view external links. To see them, please REGISTER or LOGIN).

Curvature of any sort will only happen when the gravitational radiation is emitted from a curved surface and is a result of the geometry. An enormous flat slab would radiate a generally flat field. The geometry of the field would vary at the corners.

Quote from: jeffreyH on 29/08/2014 20:09:47Curvature of any sort will only happen when the gravitational radiation is emitted from a curved surface and is a result of the geometry. An enormous flat slab would radiate a generally flat field. The geometry of the field would vary at the corners.That's quite incorrect. Gravitational radiation is in no way required for the presence of spacetime curvature. Where did you ever get that idea from?

OK then Pete. What is required? This is of particular interest to me.

Quote from: jeffreyHOK then Pete. What is required? This is of particular interest to me.Let's use the Newtonian description since most people are used to that terminology. Mass generates gravitational forces, right? When the distribution of matter is such that the tidal force tensor is non-zero then there are tidal forces present. That means that the gravitational force varies from one place to another. See ...sorry, you cannot view external links. To see them, please REGISTER or LOGIN

In order for there to be a tidal force a mass has to radiate force carriers, surely!

Those virtual particles are virtual, Jeffrey. They aren't real particles. Hydrogen atoms don't twinkle, magnets don't shine, and there are no gravitons pouring out of a black hole. Have a read of ...sorry, you cannot view external links. To see them, please REGISTER or LOGIN. Note this bit: "The best way to approach this concept, I believe, is to forget you ever saw the word “particle” in the term. A virtual particle is not a particle at all. It refers precisely to a disturbance in a field that is not a particle at all". Virtual particles are "field quanta". It's like you divide the field up into little distorted squares, and say each one is a virtual particle.

Well quantum gravity is the ultimate goal....sorry, you cannot view external links. To see them, please REGISTER or LOGIN

Curvature of any sort will only happen when the gravitational radiation is emitted from a curved surface and is a result of the geometry.

I'm afraid some of what you read about is just rubbish, Jeffrey.

May be we had out from our first topic of this discussion so I think that we should back to our topic about Einstein and his Gravitational theory. PMB you want me to find the evidence about Einstein theory of space time curvature I will show youmy evidence ..

Here we put\Gamma_{im}^{l}=-\left\{ {im\atop l}\right\} (4) which magnitudes we will denote as the "components" of the gravitational field.

If you said that Einstein version of general relativity wasn't relate with space time curvature I think you are wrong ...

I haven't seen in any paper of Einstein general relativity that he write about tidal force

Thus, Einstein and Newton, with their very different viewpoints on the nature of space and time, give different names to the agent that causes the crossing. Einstein calls it spacetime curvature; Newton called it tidal gravity. But there is just one agent acting. Therefore, spacetime curvature and tidal gravity must be precisely the same thing, expressed in different languages.

OK may be I didn't understand your paper or I didn't read your article clearly.May be you can to simplify about the different between Einstein General Relativity and Modern General Relativity in the easy word for me. Sorry for I didn't read your article clearly and sorry if this reply disturb you. Thank you

In the year following the completion and publication of the general theory of relativity Einstein published the review article The Foundation of the General Theory of Relativity in 1916. The statement "It will be seen from these reflections that in pursuing the general theory of relativity we shall be led to a theory of gravitation, since we are able to “produce” a gravitational field merely by changing the system of coordinates."

... what characterizes the existence of a gravitational field from the empirical standpoint is the non-vanishing of the components of the affine connection], not the vanishing of the [components of the Riemann tensor]. If one doesnot think in such intuitive (anschaulich) ways, one cannot grasp why something like curvature should have anything at all to do with gravitation. In any case, no rational person would have hit upon anything otherwise. The key to the understanding of the equality of gravitational mass and inertial mass would have been missing.

Perhaps I could back that up with a simplified version? Parakorn, have a look at ...sorry, you cannot view external links. To see them, please REGISTER or LOGIN. But things don't actually fall down because of this. The force of gravity is denoted by the degree of slope, the first derivative of potential. The tidal force or Riemann curvature tensor is denoted by the change in slope, the second derivative of potential.

And of course acceleration is curved in Minkowsi diagrams and shows curvature ...

Jeffrey, imagine you're standing on a big flat board. You roll a bowling ball across it, and it goes straight. There's no curvature. But now imagine I tilt the big flat board. Now when you roll the bowling ball across it, it curves because of the slope. However the board isn't curved, it's still flat, but it's tilted. Spacetime is like the board, the path of light is like the path of the bowling ball. Once you've got that just think of the board as being tilted and curved, like something in a skateboard park.

Thanks Pete. It can be difficult to find a way to make it sound simple.

Quote from: jeffreyHAnd of course acceleration is curved in Minkowsi diagrams and shows curvature ...What do you mean by "shows curvature"? Suppose you're in a uniformly accelerating frame in flat spacetime. There's acceleration but no curvature. So how does what you say apply in that case?

Quote from: PmbPhy on 03/09/2014 04:04:06Quote from: jeffreyHAnd of course acceleration is curved in Minkowsi diagrams and shows curvature ...What do you mean by "shows curvature"? Suppose you're in a uniformly accelerating frame in flat spacetime. There's acceleration but no curvature. So how does what you say apply in that case?Have you ever plotted acceleration on a Minkowski diagram?

Quote from: jeffreyH on 04/09/2014 19:53:06Quote from: PmbPhy on 03/09/2014 04:04:06Quote from: jeffreyHAnd of course acceleration is curved in Minkowsi diagrams and shows curvature ...What do you mean by "shows curvature"? Suppose you're in a uniformly accelerating frame in flat spacetime. There's acceleration but no curvature. So how does what you say apply in that case?Have you ever plotted acceleration on a Minkowski diagram?There are two ways to address that. What are you referring to when you use the term "Minkowski diagram"? Typically that refers to spacetime diagrams for inertial frames of reference. When you plot an acceleration on such a diagram like I have in figure one here ...sorry, you cannot view external links. To see them, please REGISTER or LOGIN then that's a particle moving under a force, not in free fall and having nothing to do with gravity. However if you have in mind a spacetime diagram of a frame of reference which is accelerating uniformly and plotting the position of a particle in free-fall then that will be a curved trajectory. However the use of the term "Curvature" here refers to the worldline and not the spacetime. The spacetime is still flat. Have you been confusing the curvature of world-lines and the curvature of spacetime all this time, have you?

A fter I have come back to read the article again and again many time. In my understanding from the article are There are two version of General relativity once is einstein version and another was modern version. In Einstein version there are 2 type of gravitational field 1. uniform gravitational field that can conclude that gravitaty is the same as acceleration that we can create gravitational by changing of the coordinate there is no curvature of space time in this type of gravitational field. 2. Permanent Gravitatinal field is the space time curvature that is the same thing with tidal force. In modern view physicist confuse in 2 type of the field and conclude that uniform gravitational field is the same thing with curvature of space time.That wrong interpretation. Does I read it correctly or not

Quote from: parakorn on 10/09/2014 15:55:15A fter I have come back to read the article again and again many time. In my understanding from the article are There are two version of General relativity once is einstein version and another was modern version. In Einstein version there are 2 type of gravitational field 1. uniform gravitational field that can conclude that gravitaty is the same as acceleration that we can create gravitational by changing of the coordinate there is no curvature of space time in this type of gravitational field. 2. Permanent Gravitatinal field is the space time curvature that is the same thing with tidal force. In modern view physicist confuse in 2 type of the field and conclude that uniform gravitational field is the same thing with curvature of space time.That wrong interpretation. Does I read it correctly or not I'm so glad to see that you've got it now. It warms my heart to see that I was able to get through to someone. Thanks for your diligence!