Gravity And Electromagnetism As Spacetime Structure Disturbances

[pogono]

Hi. Checked, and with no doubt gravity propagates with the light speed.

 

Cheers.

[Aethelwulf]

Hi. Checked, and with no doubt gravity propagates with the light speed.

 

Cheers.

 

 

 

Hey, if I knew this was a question I would have been able to tell you this. Consider a vacuum perturbation [math]h_{\mu \nu}[/math], the wave equations satisfy [math]\Box h_{\mu \nu} = 0[/math] for a velocity [math]c[/math]... or something like that. There are some heavy graviton theories.

Edited September 3, 2013 by Aethelwulf

[Andrex]

I cannot make any calculation of the level needed but if you allow me, I can make a small suggestion that you could evaluate afterward. Naturally, everyone of you knows the facts of the follwing description; but it might just be a different way to look at things.

 

Curvature around a mass is not the complete reality

 

To “see” the exact situation we have to consider the nature of a black hole

 

From what I know, a Black hole is the maximal deformation of the geometry of a certain volume of space-time.

 

That deformation of the volume of space-time extends way down to its center of gravity. 

 

Which seems to mean that the deformation in question is the result of something acting on the center of gravity itself. 

 

And that means that de deformation is not, at all, caused by the presence of a "ball of matter" floating in space, like a bowling ball placed on a mattress. If you look, for example, at the M31 galaxy (Andromeda) where there is a black hole in its center, the galaxy doesn't have the form of a funnel. You can get in the Black hole from either side of the galaxy. And you certainly won’t get through and emerge on the other side.

 

The first consideration we must do is accept that; if it’s not the quantity of matter that deforms space-time it has to be the next best bet: the mass energy of that quantity of matter. And we can had that, the "mass energy" directs itself toward the center of gravity of that quantity of matter. To support this view, just think that the mass of a proton consist of its three internal quarks for 1% and its inner energy for 99%.

 

So what kind of space-time deformation are we talking about?

 

The only possibility is that the deformation is in the fabric of space-time itself and not at all in the fabric of matter. The reason might be that matter doesn't replace space-time; it only occupies it. The volume of matter is space-time in itself and that space doesn't disappear when matter appears.

 

First of all, the deformation of space-time is not in a downward direction; so the name Black "hole" is physically inappropriate. It is not a "hole". Instead, we should talk about a "Black ball"; because the circular event horizon of a Black hole doesn't represent a flat surface; it represents a volume of space-time: a "ball".

 

So, again, what can we say about the fabric of space-time?

 

We can only say that it has a metric. And, it's easy to understand that the expansion of the universe is exactly the progressive growth of that metric. But what does that mean? What does it looks like?

 

To find out, let’s say we choose a metric (a length) of one foot. The continuous growth of that metric will result in the fact that our foot will gradually become a foot that measures 13 inches-> 14 inches -> 15 inches and so on, but will still be "a foot". That is the expansion of the metric of the universe. The whole thing started when the universe had a diameter of 10^-35 meter; and the date was: 10^-43 sec after time = zero. And the universe of that epoch is still de same universe today (plus its entropy).

 

So what happens if we choose one precise point of the fabric of the universe and we block the growth "movement" at that point?

 

I'd say that the expansion of space-time will stop for that point and a deformation will occur around it because the surroundings of the point will continue to expand.

 

Let’s say that we stopped the expansion of our chosen point at the moment where our metric had grown to the size of two feet. In stopping its growth, we have obtained a metric of space-time that is now "stable". That part of space-time doesn't change its metric anymore; even though the rest of the universe still expands. 

 

That is exactly the situation in which we observe our space-time from the level of the galaxies down to the level of the atoms. We live in a volume of space-time where its metric is stabilized (with a margin of déformations here and there). That volume of stable space-time is our galaxy. 

 

Now; let’s choose a deformation of space that is occupied by a great big star in our galaxy. The point "center of gravity" of that deformation is blocked like the rest of the galaxy where this star is located; and the "mass energy" of the star is what stabilises its own volume, gives its form etc.

 

What we now are going to do is add "mass energy" to that star. To do so, all we have to do is accumulate matter particles, containing mass energy, on the surface of the star so that the energy of those particles joins the mass energy of the star. Adding mass energy increases the “action” on the centre of gravity of the deformation of its space-time. So gradually, our point "center of gravity" start to "back up" in its metric. This is called "collapsing".

 

When we will have added enough mass energy to our star, its metric will collapse with all the matter it contains (passing through opposite reactions encountered) back to the size of the original metric it started from : The one which has (or had) the size of 10^-35 meter. 

 

We have now obtained a "Black hole" with its singularity that everybody cannot describe.

 

We can even make a parallel between the photon liberation at 380,000 years after Big bang and the horizon of a Black hole where we find the limit of "free" photons approaching a Black hole.

 

With these information, we can now start again breaking our brain on problems created by Black holes. 

 

Our actual description, above, is that the production of a Black hole is exactly the reverse process of the production (or the evolution) of the universe. So whatever mathematics says that doesn't correspond to the evolution of the universe since 13, 7 billion years has great chances to be wrong, to my point of vue.

 

André Lefebvre

[Pmb]

Andre' - I'd like to comment on some of what you said above.

 

What do you mean by, and where did you hear, the phrase "Curvature around mass is not the complete reality."

 

What is it you mean by "curvature"?"  Matter causes spacetime to curve, not simply space. Wherever there is matter there is spacetime curvature. However that doesn't mean that there is spacetime curvature near all matter. For example; if you have a spherically symmetric distribution of mass and carve out a spherical cavity whose center is offset from the center of the sphere. Inside the cavity there will be a uniform gravitational field whose strength is proportional to the distance of the cavities center to the sphere's center. Being uniform there will be no spacetime curvature inside the cavity (i.e. the region of space inside the cavity for all time). It's easy to prove this using Newtonian gravity so if you'd like to see the proof let me know.

 

Regarding your comment of the "deformation in question is the result of something acting on the center of gravity itself", I disagree. The point mass is where the singularity is. You get the same thing using Newtonian gravity. I.e. the gravitational field is given by G = GM/r² which explodes at r = 0. The closer you get to r = 0 the stronger the gravitational field and as such the stronger the gravitational tidal forces (i.e. spacetime curvature).

 

Question: Since I don't know you I'd like to ask you a question so that I know whether we're on the same page or not. Do you understand that spacetime curvature is just a fancy mathematical way of saying tidal gradients/tidal forces?

 

So the mass at r = 0 is what causes the spacetime curvature and not the other way around. This is implicit in Einstein's equations.

 

Regarding that "bowling ball on a mattress" comment. I assume that arises from all the diagrams such as the one at the Wikipedia website for general relativity where the earth appears to be sitting on a rubber sheet and deforms the sheet as a result. That diagram is not really a diagram which is meant to demonstrate spacetime curvature. That's a common misinterpretation. It's an embedding diagram which shows the spatial geometry only and not the spacetime geometry. See: http://jila.colorado.edu/~ajsh/astr2030_11/schwembed.pdf

 

Regarding the source of gravity: the term used to describe the mathematical quantity which is used to describe the source is the stress-energy-momentum tensor. The name is what it is because each of those terms is a source of gravity. Not only does mass (and thus energy) but also stress (and therefore pressure and tension) are also sources of gravity. In fact they're also sources of inertia as a result. There's a paper at the arXiv.org archive on this called the "Inertia of stress". It's an article that was published in the American Journal of Physics.

 

Regarding the term black hole itself. You believe it's inappropriate. It was John Wheeler who coined the term. He did so because a hole is something that things fall into they can't come back out. That made him think of a hole in space. That's all there was to it.

 

Regarding the term "metric" - From what you wrote it's not clear to me that you know what a metric is. A metric is an abstraction of a "distance" in a space. In the case of relativity the notion of distance is replaced by "interval" since it measures spacetime intervals and not physical distances. The mathematical quantity used in relativity to define the metric is the metric tensor. You can read about this on Wikipedia.

 

I'd comment on a lot more but not being able to paste anything here is making it difficult to write these posts.

[Andrex]

 

 

where did you hear, the phrase "Curvature around mass is not the complete reality."

I didn't hear it; I wrote it.

 

 

 

What is it you mean by "curvature"?"  Matter causes spacetime to curve, not simply space.

There's no such thing as "space"; all there is is space-time. So when you read the word space, it's talking about space-time. As for "curvature of space-time"; it can be used for two things: 1) a non-curved space-time (universe) and 2) the geodesic of space-time where we have gravity..

 

 

 

Wherever there is matter there is spacetime curvature.

Because matter contains mass energy. That mass energy is responsible of "pressure" in a space-time deformation.

 

 

 

Being uniform there will be no spacetime curvature inside the cavity

So if you get to that kind of cavity inside the Earth, and you jump in, you'll probably float in that space-time instead of falling toward the earth's center of gravity. Right?

 

 

 

 Do you understand that spacetime curvature is just a fancy mathematical way of saying tidal gradients/tidal forces?

No. What I understand is that "tidal forces" are a consequence of two space-time deformations either touching each other or a smaller space-time deformation inside a bigger one. Like real tidal force on oceans of Earth are consequences of the Moon's deformation and the Sun's deformation.

 

 

 

See: http://jila.colorado...1/schwembed.pdf

That link shows the same thing as the ball on a mattress. Space-time deformation is a collapsing (sagging) of the metric of space-time compared to where "flat space-time" is expanding. And a black hole is a volume of space-time whose metric has collapse; not a hole in space-time.

 

 

 

 is the stress-energy-momentum tensor. The name is what it is because each of those terms is a source of gravity.

Gravity is a consequence of the deformation of space-time geometry. Nothing else. And the cause of that deformation is mass energy. Einstein's equation is clear: E = Mc².

I agree that M is "at rest" in the equation; but you have to give it "light speed square" to make it equal to E. So E is kinetic energy and M "with that speed" is mass energy.

 

 

 

 In fact they're also sources of inertia as a result.

 

Inertia is what opposes a "mass" to go from "at rest" to "in movement"; or to "acceleration". In a proton, you have three quarks that count for 1% of the proton's mass; the rest of it (99%) is the energy "inside" de proton. And the total is the inertia of the proton.

 

 

 

 A metric is an abstraction of a "distance" in a space.

 A metric is a way to "see" the fabric of the universe expanding. Hubble's constant has a "metric" of one megaparsec. You can chose any length of "metric" you want, to describe the expansion of the universe. or its collapsing for that matter.

 

 

 

In the case of relativity the notion of distance is replaced by "interval" since it measures spacetime intervals and not physical distances

What size are the intervals?

 

 

 

I'd comment on a lot more but not being able to paste anything here is making it difficult to write these posts.

I agree; but it's just as difficult for me. 

Edited July 3, 2015 by Andrex

[Andrex]

But then, maybe not.

 

Here’s what causes the tidal effect you spoke of:

We will start by giving a V shape to space-time deformation (in reality it's a decreasing metric of space-time). In fact, I’ll propose a toast with two different sizes of glass wine. The smaller glass wine representing the smaller deformation inside a bigger one. For the purpose of the experience, we will say that the small glass is empty and the big one is full. And I will ask you to imagine what would happen if the glasses, when “toasted” to one another, merged their edges to get a mutual edge. So here is the drawing of that toast:

 

 

As you can see the merging of both edges results in a lower mutual edge and the wine in the big glass will flow in the small glass. Furthermore, the merging of edges also has another important effect: the two bases of the glasses get closer to each other. Which means that both centers of gravity draw closer together and stop coinciding with the center of each volume of matter contained inside each deformations. That's why Jupiters mass energy, for example, displaces the center of gravity of the solar system.

 

Now let’s have a look at a real “tidal effect” seeing it from above:

 

 

The blue/green line is the sea level. The incurved black line is the Earth space-time deformation and the outcurve black line is the moon space-time deformation. The two points touching is the "lower" merged edge of both deformation (like the merge glass edges we just saw). That edge of both deformation being “lower” than de rest of both edges (represented by both triangles); the sea water tends to flow toward the lowering (the drop). This effect happens where Earth’s oceans are in line with the Moon and when they’re in line with the sun.

 

That’s what explains the seemingly “attraction” resulting from deformation of space-time geometry.

 

(Sorry for the poor quality of the drawing (I did my best) and the French terms on it (it was done for a French article).

Edited July 2, 2015 by Andrex

[sanctus]

Admin question: could both of you send me a pm telling which OS and browser you use? Because on Ubuntu and firefox I have no problems to paste both in the linux-way (middle mouse) as well as in the win-way (C-C C-V) .

 

To the thread:

How can the hubble constant have a metric of 1 megaparsec associated to it? I mean a metric is about computing distances in space-time, not about scales...

[Andrex]

Hubble's constant is 68,7 km per sec per megaparsec. A megaparsec is a "distance" so it can be seen like a metric of the universe.

 

As for your first question, I can't answer.

[Pmb]

Andrex - Since you didn't hear it then you must have originated the phrase. What justification do you have for "Curvature around mass is not the complete reality"?

 

Re - There's no such thing as space; all there is is space-time"

 

That is somewhat common misconception. There is very much such a thing as space. I can explain why in all the detail one would like but an acquaintance of mine is a well-known GRist who wrote the following on space: http://user.wfu.edu/brehme/space.htm

 

Basically space is the three-dimensional extent in which all objects have a position r = (x, y, z). On the other hand spacetime is a mathematical model that combines space and time. Or put another way, spacetime is the collection of all events in which an event is defined as a position and an time X = (t, x, y, z). Please look these up in Wikipedia and an SR or GR textbook and learn what each is and why there is actually a real thing called "space" and not merely spacetime.

[Andrex]

 

 

Andrex - Since you didn't hear it then you must have originated the phrase. What justification do you have for "Curvature around mass is not the complete reality"?

That is the TITLE of the whole message; you don't want me to repeat it here do you?

 

 

 

Please look these up in Wikipedia and an SR or GR textbook and learn what each is and why there is actually a real thing called "space" and not merely spacetime.

 Geez! I don't live in mathematical model; I live in a "space" where time is "ever" present.

 

But then, I guess that that's all that is important in the message I posted since that's all you want to talk about. So we have "space" and then we have "space-time". It suits me fine. I don't have any objections. Furthermore, I think I finally understood your point. Thanks.

Edited July 3, 2015 by Andrex

[Pmb]

I know that you live in a space. That's why I said that space exists and why you're wrong for claiming otherwise. Your comment "I don't live in mathematical model" is a comment which confuses math with what the math describes. There is real thing such a speed. However you can't hammer a nail into it, you can't grab onto it and you can't touch it. But it exists nonetheless. Its defined mathematically but it doesn't mean that it doesn't have a real phenomena attached to it. In this case time and space, each of which has an independent existence, as they must, are merged together into a four-dimensional continuum which we call spacetime. But you're assertion that space doesn't exist is  wrong. You never even made an attempt to justify your assertion. But even if you did it would be wrong because all relativists in the physics community understand this to be the way it is.

 

Now, if we add the following metric to spacetime

 

ds² =  (cdt)² - dx² - dy² - dz²

 

where ds² is called the spacetime interval between two closely spaced events then the then the spacetime is called Minkowski Spacetime.

 

And no. That was not all that I wanted to talk about. Since I don't know you I first wanted to see how you reacted to my response. If you turned out to be a outrageous jerk then I wouldn't want to talk about anything else with you and I didn't want to waste more time addressing more of your comments for that reason. Also this problem with cutting and pasting is a pain in the butt. It makes discussions difficult. There are plenty of articles online which explain the same things I'd explain but I wouldn't have to take all the time to type it all out. I can just cut and paste. It's much easier for me. I have a problem with my back so I can't sit in a chair too long.

 

But you've made some serious errors above such as your claim that mass-energy, i.e. E = mc² is the sole source of gravity when its well know that it isn't. It's also not true that mass is not the sole source of  of either. That means that E = mc² is not always true. It's only true under certain conditions. E.g. for elementary particles or closed systems, i.e. when an object is not subjected to external forces, its true. Otherwise one has to take into account stress and pressure. If you had ever read a decent text on this you'd know it. E.g. Tolman's or Moller's texts on relativity are good examples as is the paper called The inertia of stress that I pointed out above but which you ignored.

 

Anyway, those are the kinds of errors you made. A real good relativist wouldn't have made those errors.

[Andrex]

 

 

I know that you live in a space. That's why I said that space exists and why you're wrong for claiming otherwise.

 

It's not reaaly that I'm wrong; it's that I consider time is not somethig that's exists whitout space.

 

 

 

 is a comment which confuses math with what the math describes.

 Math can be "confusing" more than my comment; realy. Let's say for example that math tells you there are minus three apples in a bag; how much would you pay for that bag of apples. I'wouldn't event think of bying it.

 

 

 

There is real thing such a speed. However you can't hammer a nail into it, you can't grab onto it and you can't touch it. But it exists nonetheless. Its defined mathematically 

 I'm not saying that math doesn't define reality; I'm saying that it can just as much define irreality. You have to be cautious with maths.

 

 

 

In this case time and space, each of which has an independent existence

Not that much independent since they both are the product of movement. Further away you look, further back in time you see. Distances and time are made by slower movement than light speed. 

 

 

 

are merged together into a four-dimensional continuum which we call spacetime.

 

In reality, distance and time are the two sides of the same thing which is produced by movement.

 

 

 

But you're assertion that space doesn't exist is  wrong.

 

You'll have to find me space where there's no time involved; then I'll say you're right and I'm wrong; no problem.

 

 

 

You never even made an attempt to justify your assertion.

 

Sorry; I didn't think that someone could imagine a space without time involved. That's probably because I don't live in a math universe. :-)

 

 

 

But even if you did it would be wrong because all relativists in the physics community understand this to be the way it is.

 Is this what you consider being a satisfactory reason? Everybody says so, so I've got to say it too? Ask them how long sunset really happened before we saw it set yesterday evening. They'll answer 8 minutes before.

 

 

 

where ds² is called the spacetime interval between two closely spaced events then the then the spacetime is called Minkowski Spacetime.

 

So, you know; and .., what then?

 

 

 

Since I don't know you I first wanted to see how you reacted to my response. If you turned out to be a outrageous jerk then I wouldn't want to talk about anything else with you

Same with me; glad to meet you. :-)

 

 

 

There are plenty of articles online which explain the same things I'd explain but I wouldn't have to take all the time to type it all out.

 

Don't I know them and they all say almost the same things, Read my posts it's going to make a change. To my point of view the work involved to exchange opinions with you is worth it.

 

 

 

I have a problem with my back so I can't sit in a chair too long.

 

I'm sorry.

 

 

 

But you've made some serious errors above such as your claim that mass-energy, i.e. E = mc² is the sole source of gravity when its well know that it isn't.

 

It all depends on what mass really is. Is it matter? Is it weight? Is it energy? To me E=Mc2 means it's energy. Furthermore, if you ask a physicist where mass comes from, he might say that it's not the job of physic to find where it comes from, physics job is to find how it works. I don't agree with that opinion. The origin could change the understanding of the way it works.

 

 

 

That means that E = mc² is not always true. It's only true under certain conditions

 

How can an equation representing General Relativity be true only in certain conditions?

 

 

 

Otherwise one has to take into account stress and pressure

 

Stress and pressure are cause by gravity; either around atoms or around stars. Gravity is the only "opposition" existing in the universe; and stress and pressure cannot appear if there's not "opposition" involved.

 

 

 

The inertia of stress that I pointed out above but which you ignored.

 

By definition stress is not a particle so it cannot have inertia. Inertia is a consequence of mass. Like I told you before; maths are dangerous to let go free.

 

 

 

Anyway, those are the kinds of errors you made. A real good relativist wouldn't have made those errors.

 

Probably; but then a good relativist wouldn't take observations as facts, as I do; he would interpretate it with preceding opinions.

 

If ever you decide to read all I posted. I hope you'll come back to me.

 

Thank you for your time.

 

[Pmb]

re - It's not really that I'm wrong; it's that I consider time is not something that exists without space.

 

But you're assertion was There's no such thing as "space"; all there is is space-time. So when you read the word space it's really about spacetime. That is not at all true. Being a physicist I've never written spacetime when I've meant space. In no document about relativity has the author ever meant spacetime when he/she wrote space. So your assertion is quite false. You're making statements about the way physicists (i.e. relativists) think when in fact its not true. Being a relativist this is something I know a great deal about too. I've read several textbooks on relativity and none of them mean what you claim they mean. I proof read a popular textbook on relativity known as Exploring Black Holes by Taylor and Wheeler. I even wrote the glossary of terms and that's not how I defined spacetime. Again, space and spacetime are defined differently. Space is the 3-dimensional continuum of points r = (x, y, z) while spacetime is the 4-dimensional continuum of points X = (ct, x, y, z)

 

Back to your comment; I could say the same thing about the electric field too; wherever there is a region of space where there is an electric field present then there is also energy in that region of space. But that doesn't mean that when you read the phrase electric field its wrong to say There is no such thing as an electric field; all there is is electric field-energy.

 

re - You'll have to find me a space where there's no time involved; then I'll say you're right and I'm wrong; No problem.

 

What?? You just contradicted yourself. How can anybody find you a space where there's no time involved when you claim there is no space to begin with? I don't respond to questions like this because they're logical fallacies. You see, I, nor anybody else, ever claimed that space doesn't exist without time. That's your mistake in implying such a thing. What I keep telling you is that space exists and just because where there is space there is also time it doesn't mean that there's no space to begin with.

 

Also, I have very little interest if you accept what I'm telling you. All I can do is explain relativity the way it really is, i.e. as understood by the relativity community, no more and no less.

 

It was your claim that there's no such thing as space and that's wrong. Just because it can be merged with time to produce spacetime doesn't mean that the components of spacetime don't exist. In relativity there are also the following quantity

 

P = (mc, p)

 

where m = mass, c = speed of light and p = 3-momentum which is known as 4-momentum. Here mass and momentum are parts of one object called 4-momentum. When physicists created this quantity they didn't think that they were doing away with either mass or 3-momentum. Then there's the quantity

 

U = dX/dT

 

where dX is an infinitesimal displacement in spacetime defined as dX = = (cdt, dr) = (cdt, dx, dy, dt) and T = proper time. Again, r represents a position in space. You simply cannot talk about a position in space if space doesn't exist as you claim. A lot of things have an existence which also implies the existence of other things but for which we don't include both names. E.g. there is such thing as a baseball. If you claimed otherwise then you'd be wrong. And that goes for any claim that baseballs don't exist; only baseball+atoms since all baseballs are made of atoms. Or that the electric field doesn't exist because its only part of one single entity called the electromagnetic field. A lot of people make that mistake.

 

re - Is that what you consider a satisfactory reason? Everybody says so, so I've got to say so too? Ask them how long sunset really happened before we saw it set yesterday evening. They'll answer it 8 minutes before.

 

Thinking like that is a misconception of the way physics works. When talking about things like this then when a physicist says that all relativists is the physics community understand it this way then we're not talking about physical phenomena since it's a logical fallacy to think that one can, in a sense, "vote" on such things, i.e. come to a common understanding. In cases like this it has to do with commonly accepted ways of perceiving nature and talking about it. E.g. It's something that is commonly understood and accepted to say that space exists. There's no debate about it. One can't prove it to be wrong for the reason you gave. And according to how its defined by the physics community it does exist. That's what I mean when I referred to the physics community, i.e. its the physics community as a whole who determine who terms in physics are defined and used. All authors of all relativity texts speak as if space exists. For example; to determine the amount of energy that a body has at one instant in time one integrates over the region of space that the body inhabits, not over the spacetime.

 

re - Read my posts and its going to make a change

 

So far that's not what I see. So far I see someone who has many misconceptions in relativity. I've been at this a very long time. If one can say that they've been a physicist since they were a freshman in college then I've been one for 36 years. Otherwise, talking into account graduate school, I've been one for 30 years. I've been a relativist for 25 years. So it's not as thought this is my first ball game. I've seen countless people make attempts to change the way that physics is understood and not one of them made any progress, i.e. all of them had serious misconceptions. And, nothing personal by the way, you're no different.

 

re - It all depends on what mass really is.

 

Mass is correctly and completely defined by a mathematical object called the Stress-Energy-Momentum (SEM) Tensor. That object can be described using matrix notation. This matrix is a 4x4 matrix. It's a symmetric tensor, meaning that the matrix associated with it is symmetric, so it has 10 independent components. Each component is a source of gravity as well as inertia. That means that pressure contributes to the gravitational field of a star. It means that stress contributes to the inertia of a capacitor and the gravitational field the capacitor generates. Both energy and momentum also contribute to the gravitational field of a moving body. So it's not just E = mc^2 that's the source of gravity. Mass-energy density is only one component of the SEM tensor.

 

re - How can an equation representing General Relativity be true only under certain circumstances?

 

I already told you where to learn about it, twice in fact. But you've chosen to ignore me. I've told you twice that there's an article in the American Journal of Physics called Inertia of stress which you should down load from http://arxiv.org/abs/physics/0609144  Read it and learn.

 

Also because E = mc^2 is not an equation representing General Relativity (GR). If you read a good text on GR, or a really good text on SR, you'd see that E = mc^2 was derived under certain conditions. When those conditions are no longer met then it no longer holds true. Many relativists know this. They simply do a poor job in explaining it. But there are also relativists that don't know it either. I think it was in 1906 that Einstein derived E = mc^2 under more general situation. I.e. he derived it for a body subjected to stress. The result he got was that the energy depended on more than just mass but also on the stress imposed on the body. His result was not E = mc^2 though.

 

re - Stress and pressure are cause by gravity...

 

Wrong yet again. They are also sources of gravity. Pick up a good text and read it. E.g. pick up Peebles text on cosmology and you'll see it in there. You'll see the expression that he has for a week gravitational field. The source is not simply the mass/energy density but also a pressure term in it. So if you held the mass density fixed and varied the pressure then the strength of the gravitational field will vary. This can be found in many GR texts. Which ones do you have?

 

You can go to http://booksos-z1.org and sign up and you can search for and download "Gravity from the ground up" by Bernhard Schutz. Turn to page 192 and the author will explain to you why pressure contributes to inertia. You can also download Peebles cosmology text too and look up "Active Gravitational Mass" and you'll see what I mean.

 

re - By definition stress is not a particle so it cannot have inertia. Inertial is a consequence of mass. Like I told you before; maths are dangerous to let go free.

 

I recommend that you at least try to keep an open mind. So far it doesn't appear that you are. I know very well what stress is and I also know very well how to derive the expression that shows that the inertia of an object (nobody ever said "particle" so you need to pay closer attention to what you're reading) or field depends on the stress in the object. Read the AJPO article I referenced about and you'll learn why.

 

By the way. It would be unwise to assume that I don't know math very well. I have a degree in math as well as physics. Right out of college I worked as a computational physicist. I know a great deal of advanced calculus, tensor calculus, differential geometry etc. So your so called "warning" about math is something you should take to heart more than I'd ever need to. Do you have a formal education in physics and/or math?

 

re - If you ever decide to read....

 

At this point it's clear to me that you're too closed minded to understand any of the corrections to your misconceptions that I post so I don't see how it would be worth my time. Especially since you never read that AJP article which makes a lot of what I said about the inertia of stress very clear. You never even chose to do a google search on pressure as a source of gravity. A friend of mine is working on a new edition of his GR text. Go to his website and read about pressure as a source of gravity. His drop site for is at

 

http://exploringblackholes.com

[Andrex]

 

 

You're making statements about the way physicists (i.e. relativists) think when in fact its not true.

I never talk about what other people think. I talk about what I think. So when I say that only space-time exists, I'm stating what I consider as a fact; not what is said by whoever.

 

 

 

Space is the 3-dimensional continuum of points r = (x, y, z) while spacetime is the 4-dimensional continuum of pointsX = (ct, x, y, z)

Which comes pretty close to what I say when I say that distances are the other face of time.

 

 

 

What?? You just contradicted yourself. How can anybody find you a space where there's no time involved when you claim there is no space to begin with?

 

What do you mean " you said there was no space to begin with" I said there was no such thing as space "only"; that there was "space-time". What would you say if I affirmed that you said there was space and then, on top of space, there was "space-time"?

 

 

 

Also, I have very little interest if you accept what I'm telling you. All I can do is explain relativity the way it really is,

 

You should add "is...interpreted officially" which would be more accurate. And I agree, that's exactly what you do. I respect it.

 

 

 

Just because it can be merged with time to produce spacetime doesn't mean that the components of spacetime don't exist. 

 

I hope you didn't think that in my mind the components of space did not exist in "space-time". That would be surprising from a physicist.

 

 

 

For example; to determine the amount of energy that a body has at one instant in time one integrates over the region of space that the body inhabits, not over the spacetime.

 

That's a perfect exemple where we can see that a body inhabits a space (volume) without involving time. Which means, to a majority, that the said body replaces the space involved. The result is that the deformation of "space-time" is considered only around that body when, in fact, all the space-time involved down to the centre of gravity of that space-time volume is deformed.  Matter doesn't "replace" space-time; it occupies it.

 

 

 

So far that's not what I see. So far I see someone who has many misconceptions in relativity.

 

That would be normal since you saw me as someone eliminating "space" by calling it "space-time". With that way of thinking, you should find a lot of misconceptions in my writings.

 

 

 

Otherwise, talking into account graduate school, I've been one for 30 years. I've been a relativist for 25 years. So it's not as thought this is my first ball game. I've seen countless people make attempts to change the way that physics is understood and not one of them made any progress, i.e. all of them had serious misconceptions. And, nothing personal by the way, you're no different.

 

Thank you; I really don't think I'm different. But whoever scientist entertains a way of seeing things for so many years, would probably have problems to catch the meanings of someone describing what he observes the way he sees it personnaly. That's understandable. Furthermore, that person would have to try to understand the way of thinking of the scientist and most of them do before talking. That's exactly why some say that the "official" way of seeing things are not exactly right. Then the "official" has to try to understand the way of thinking of that person; which most of them never accept to do, simply because, that for them, there's no other way of thinking then theirs that is correct. I don't think that this can be change. So, as you said, there's nothing personnal in what I've just said.

 

 

 

Mass is correctly and completely defined by a mathematical object called the Stress-Energy-Momentum (SEM) Tensor. That object can be described using matrix notation.

 

That object, like you said, is a mathematical "object". And so are the 10 independent components it has. Mass is, in fact, an "effect" of one single reality: energy. All we have to do is find what kind of energy we're talking about to understand what mass really is and "where it comes from" (which, by the way, is the most important part to find in order to understand what it is and how it works)..

 

 

 

Each component is a source of gravity as well as inertia.

 

Gravity is the consequence of the deformation of the geometry of space-time. Otherwise, you're saying that GR is irrelevant.

 

 

 

That means that pressure contributes to the gravitational field of a star. It means that stress contributes to the inertia of a capacitor and the gravitational field the capacitor generates.

 

No; it means that pressure and stress , inertia etc are "after effects" of deformation of space-time.

 

 

 

called Inertia of stress which you should down load from http://arxiv.org/abs/physics/0609144  Read it and learn.

 

I'll read it at the end of my present message. Maybe I'll come back to you on it.

 

 

 

Also because E = mc^2 is not an equation representing General Relativity (GR). If you read a good text on GR, or a really good text on SR, you'd see that E = mc^2 was derived under certain conditions. When those conditions are no longer met then it no longer holds true. Many relativists know this. They simply do a poor job in explaining it.

 

They sure do if that's the case. But that's very good news for me since it means that gravity is not universal but has certain conditions to answer to. In fact this means that gravity is local. Which I see and think it is.

 

 

re - Stress and pressure are cause by gravity...

 

Wrong yet again. They are also sources of gravity. Pick up a good text and read it.

 

I did read most of them. But I didn't stop there. After reading them I started thinking. And imagine my surprise when: my thoughts brought me to perceive that mass energy could simply be kenetic energy who, instead of going in "all directions", was sent toward a specific point. The one and only reason at the back of this event was the topology (direction information) imprinted in the fabric of space-time itself.So that under the "pressure" it made to that precise point, stopped it from expanding; creating thus the center of gravity of a deformation in the geometry of space-time of a definite part of its volume. Isn't that a coïncidence?

 

Naturally, I also saw that a space-time deformation was not as a "downward" event in space-time, but in a "backward" event in its expanding metric. That changes a lot in its perception.

 

 

 

I also know very well how to derive the expression that shows that the inertia of an object (nobody ever said "particle" so you need to pay closer attention to what you're reading) or field depends on the stress in the object.

. 

I try to pay attention to what I read, specially since I try to corroborate each words I see. Like, for instance, perceiving that a "particle" is an "object" which (most of them) have "mass" that creates a "gravity field" around them.

 

 

 

By the way. It would be unwise to assume that I don't know math very well.

 

Why would I assume such a thing? Do you think that I'm interested in proving you wrong and using whatever means to do it?. I don't care who is right; what I care about is finding what's really right. And so far the official way of seeing things seems to me, illogical; specially the outcome of their interpetations. There's always more questions out of them than answers.

 

 

 

I have a degree in math as well as physics. Right out of college I worked as a computational physicist. I know a great deal of advanced calculus, tensor calculus, differential geometry etc.

 

Good! Then you should look at what I wrote and try to open your mind to it and understand the differences in my way of seeing things. If you can understand, you could then find a way of explaining it with whatever existing or new equations needed for it. I don't have that kind of expertise. 

 

 

 

At this point it's clear to me that you're too closed minded to understand any of the corrections to your misconceptions that I post so I don't see how it would be worth my time.

 

You think that I'm close minded because you assume that I'm not informed of developments in science. I've been attentive and fascinated by it for 60 years (I'm 72); so I know what was their progression in their way of thinking. I think it wouldn't be a bad idea to look at what I've written as a "whole" instead of trying to fight each words I'm using. Words are as dangerous as math, in a different way. And since telepathy doesn't exist we have to accept the situation. Thank you for your friend's link site I'll go to it.

 

Amicably

Edited July 5, 2015 by Andrex

[Andrex]

I just whent rapidly trough the link that explains the "inertia of stress". I also checked the previous paper that this link mentioned which analysed Radiation reaction of a classical quasi-rigid extended particle.

I didn't get trying to contest the equations (which I wouldn't dare try) even thouh they are rather easy to understand (but you have to put your mind to it quite a bit; that's for me naturally). The paper states that the momentum of the electromagntic field of a particle is 1/3 more than what is predicted by relativity.

 

The only thing that bothered me a bit was the implication of "forces". Specially in the second paper.  But nobody's perfect, I guess.

 

I noted this phrase: "In many cases such an effect is negligible, but for the case of the stress produced by electrostatic interactions, it is comparable to the inertial effects of the electromagnetic fields. If the inertia of stress is neglected, the calculations are inconsistent."

 

I'm glad to see that physicist are stopping saying that some things are "negligible". I agree that noting really is. As an example: another quantity of energy is said “negligeable” to calculate mass;, it’s called the “binding energy”. At the atomic level the atomic binding energy of the atom derives from electromagnetic interaction and is the energy required to disassemble an atom into free electrons and a nucleus.

 

Another thing that is always "neglected" is the space deformation around a massive object like a baseball or a rock or again a metal surface. Nobody takes in consideration the surrounding deformed space and then when they bring two surfaces very near to one another they discover a "new force" that "attract" each one to the other.

 

.In FIG. 2 of the paper, it says: The forces between elements of the faces. The forces are repulsive for elements in the same face and attractive for elements in opposite faces.

 

The figure shows the result as if the disks where rotating and so expanding under a centrifugal force. This is rather intriguing. I’ll have to get back to it.

 

Finally, there's a lot of problems in physics and astrophysics that are caused simply by that "force notion" some scientists can't get rid of in their unconscious (to put it nicely). When you get rid of it, everything falls in order mostly. Scientists established equations at a time when most of the informations we have today where not available and, now, they evaluate the correctness of actual findings and interpretations with those (could be) pass dated equations. It would be a wonder if they didn't have any problems. At least that's what I would expect.

 

But thank you for the link; it will give me work for the next few days.  I can assure you that I'll try to compensate those wonderfull "forces" by a simple deformation of space-time around the "objects". I can't say I'll succeed but until today, I have with at least the 4 fundamental forces.

Edited July 9, 2015 by Andrex

[Andrex]

I must have said something very bad! :-(

[Pmb]

No. You didn't say something bad. At least not that I see. Why do you say that?