Is Gravity a Result of Mass Attracting Quanta of Mass?

[Goolds]

I was thinking a bit about gravity. As is known, Physicists have yet been unable to unify the Theory of Relativity (describing gravity) and Quantum Theory (decribing the other three fundamental forces).
As mass is a measure of a system's energy, the force of gravity (presumably carried by gravitons), increases for that system as it's mass increases.
Knowing that mass and gravitational strength are directly proportional, could it be safe to assume that gravity is quanta of mass that is attracted in a larger degree by more massive objects (though still attracted by less massive objects).
Let us examine a system containing a larger mass and a smaller mass.
The quanta of mass (gravitons) would therefore be removed from the smaller mass by the larger mass, while simultaneously the smaller mass removes an equal magnitude of gravitons from the larger mass, creating a sort of ''gravitational equilibrium'', whenre no net mass is lost by either object.
The greater mass is not accelerated as largely because it has a higher mass, and therefore requires a larger force to accelerate it to the same degree as the smaller mass.
The interaction between the objects would create a force of attraction between them, as the proximity of the gravitons to their parent object would be stronger the closer they are to said object. Therefore the more gravitons removed from the smaller mass, the greater the proximal force of attraction.
And since the force of gravity increases with the mass of an object, this explains why there is a larger acceleration of the smaller object when the larger object's mass increases (more gravitons are removed from the smaller mass, which have a greater net proximal force of attraction on the smaller mass).
Now, this begs the question: Why do the two bodies become more suitable when in closer proximity to each other?
The answer would be that there would be a smaller distance for the gravitons to travel between the constituent particles of the two objects, therefore more energy is conserved.

 

[SinghRP]

I am interested in gravity as well.
At the macroscopic level, gravity iis due to the curvature in spacetie that a mass (matter) creates. The space-time ggemetry is the gravitational field.
Then on the other hand, to every acceleration, there is an equal and opposite gravitational field!
At the microscopic level, gravitational interactions are medietd by gravitons. So, won't gravitons be the quanta of space-time geometry field?
Then another problem is that all the other fundaental fields (the strong, the weak, and electromagnetic) are of similar type. But gravity's space-time geometry field is a very different type of field!
They say, I think, that supersymmetry and hidden dimensions yield gravity!
What's going on?

 

[cosmik debris]

Two things, there is no quantum theory of gravity so anything said about it is speculative. Secondly according to GR gravity is spacetime curvature produced by the energy/momentum tensor, so energy as well as mass are important.

 

[SinghRP]

Thanks for the answers. I know those anyway.
But can you tell me, as a physicist, as a physicist, how matter creates and warps space-time?

 

[cosmik debris]

Thanks for the answers. I know those anyway.
But can you tell me, as a physicist, as a physicist, how matter creates and warps space-time?

Well from what you said in your other post you don't understand it at all. You stated it is matter/mass that creates the spacetime curvature, this is incomplete, energy also curves spacetime.

Then you said:

Then on the other hand, to every acceleration, there is an equal and opposite gravitational field!

This is not true in any way that I can see.

Then you said:

At the microscopic level, gravitational interactions are medietd by gravitons. So, won't gravitons be the quanta of space-time geometry field?

I pointed out that there is no quantum theory of gravity and gravitons are certainly not part of GR.

The question of how is difficult. Physics makes models of reality, the models don't explain why or how really.

 

[SinghRP]

Well, I never said I did not understand at all. What I don't understand is so many theories are floating arond that I can't figure out where physics is going to!
I think physics has become too mathematical to be physics. I recall Feynman: "The glory of mathematics is that you don't have to say what you are talking about." For me, physics comes first, math next. I must have a physical picture, model, etc.

I really don't distinguish between matter and energy. Both can warp space-time. This point is not even worth discussing.

If there is an acceleration, there would be a gravitational force opposite to it. That's how they, not I, explain zero gravity. You may find it in Einstein's "Meaning of Relativity," which was my first textbook on relativity.

Quantum gravity. I agree with you here. Now I use reading glasses, I don't care about Planck length?

Please don't find faults with wordings. It's not worth it.

Please answer the last question I asked: How matter creates and warps space-time?
Thanks.

 

[WannabeNewton]

I think physics has become too mathematical to be physics. I recall Feynman: "The glory of mathematics is that you don't have to say what you are talking about." For me, physics comes first, math next. I must have a physical picture, model, etc.

Well the language of physics is math so why use English to explain very abstract concepts? For example your question about how mass warps space - time: this would be very hard to explain in words but I can just tell you "hey this is how mass - energy warps space - time R_{\mu \nu } - \frac{1}{2}g_{\mu \nu }R = 8\Pi GT_{\mu \nu }" and your question would be answered very succinctly and without the confusing English.

 

[SinghRP]

That's not the answer.
By the way you forgot to add the cosmological constant.
I suggest we terminate this discussion.
Thanks anyway.

 

[bcrowell]

That's not the answer.
By the way you forgot to add the cosmological constant.
I suggest we terminate this discussion.
Thanks anyway.

In my opinion it would help in these discussions if you would make more of an effort to engage in dialog rather than making brief, nonmathematical pronouncements. It's not helpful when you jump into the end of discussions without looking at what has been said before, and it's not helpful when you claim that what you've said is the last word and should naturally lead to the termination of discussion. Cosmik debris pointed out some mistakes you made (such as "Then on the other hand, to every acceleration, there is an equal and opposite gravitational field!"), and it would be gracious of you to admit that that you've made a mistake.

 

[Naty1]

Please answer the last question I asked: How matter creates and warps space-time?

No one has so far claimed via any theory that matter CREATES space time. Matter does warp space-time via the Einstein stress-energy-momentum tensor...but no one knows what THAT mathematical description and not some other formulation is the way nature works.

But Einstein's forumlation fits what we observe, except at extremely high energy gravitational field levels like at the big bang and near the singularity of a black hole...nothing works there inlcuding quantum mechanics.

Other theories postulate that energy vibrations of unseen dimensions or string like vibrations are the foundation of everything around us.

 

[SinghRP]

I don't know where to start.

Matter creating space. This is the latest thinking.

Matter/energy warping space-time. We all know what GR says.

The great astrphhysicist E. A. Milne asked "How matter warps space? We have not answered it yet.

Gravitational field opp. to an acleration. This has been thought-experimented with an elevator acclerating up/down. A body falling toward the Earth - it is acclerating downward, a gravitational force acting upward. (Personally I think entrifugal force is fictitious.)

Look, if I have offended someone's sensibility/belief, I apologize. But I DID NOT make any physics mistake. I would think that, in a discussion, I may have some free thoughts to convey to my colleague physicists.

I think, in this round, my involvement in this discussion should be end. It was very nice talking physics with you all.

 

[bcrowell]

Matter creating space. This is the latest thinking.

No, that's incorrect. If you want to keep claiming that, please provide a reference to a peer-reviewed scientific paper to back it up.

Gravitational field opp. to an acleration. This has been thought-experimented with an elevator acclerating up/down. A body falling toward the Earth - it is acclerating downward, a gravitational force acting upward. (Personally I think entrifugal force is fictitious.)

Here you seem to have a muddled and/or oversimplified understanding of how GR handles acceleration.

Look, if I have offended someone's sensibility/belief, I apologize. But I DID NOT make any physics mistake. I would think that, in a discussion, I may have some free thoughts to convey to my colleague physicists.

You have not offended anyone's beliefs. but in my opinion you've simply made some mistakes in physics.

 

[cosmik debris]

I think expecting any answer as to why or how something happens in nature is fraught with difficulty. I've said this many times but physics uses mathematics to create models of the world we inhabit. These models, if they are good ones, make predictions which can be verified by experiment. These experiments either add weight to the correctness of the model or refute it. Why or how doesn't enter into it and seems more in the realm of philosophy than physics.

 

[Dale]

I think expecting any answer as to why or how something happens in nature is fraught with difficulty. I've said this many times but physics uses mathematics to create models of the world we inhabit. These models, if they are good ones, make predictions which can be verified by experiment. These experiments either add weight to the correctness of the model or refute it. Why or how doesn't enter into it and seems more in the realm of philosophy than physics.

I agree generally with this train of thought except that I think the models do answer "how", just not "why". I.e. To me a "how" question is asking for the details of the model while a "why" question is asking for the story behind the model. That could just be my usage of language.

 

[Naty1]

I posted above:

No one has so far claimed via any theory that matter CREATES space time

and Crowell posted:

Matter creating space. This is the latest thinking.

No, that's incorrect. If you want to keep claiming that, please provide a reference to a peer-reviewed scientific paper to back it up.

I was just rereading Michio Kaku's HYPERSPACE (1994) and he has some comments that might appear to support "matter creates space" (but actually do not).

Kaku explains (pg 157)

As a string moves in space time it executes a complicated set of motions...which require a string to obey a large set of self consistency conditions...they place extraordinary restrictions on space-time.

So a string (representing matter,energy, forces) requires certain space-time characteristics, like the number of dimensions, and some curled up dimensions, and these create required symmetries.

Kaku then quotes quotes David Gross, one of the founders of Heterotic string theory, who looks at geometry (spacetime) creating matter:

To build matter itself from geometry-that is in a sense what string theory does. It can be thought of that way, especially in a theory like heterotic string which is inherently a theory of gravity in which the particles of matter as well as the other forces of nature emerge in the same way that gravity emerges from geometry.

and Kaku goes on to say

Gross takes satisfaction in believing that Einstein, if he were alive, would love superstring theory. He would love the fact that...superstring theory ultimately comes from a geometric principle, whose precise nature is still unknown.

 

[cosmik debris]

I agree generally with this train of thought except that I think the models do answer "how", just not "why". I.e. To me a "how" question is asking for the details of the model while a "why" question is asking for the story behind the model. That could just be my usage of language.

Yeah I agree with you too, it depends on how the how question is asked. Often people are wanting to know the exact mechanism. The OP asked it in this way IMHO. He said "how does matter/energy curve spacetime". All you can say really is:

G = T;

Is there an explanation of how this works?

 

[Goolds]

With regards to the Matter Creates Spacetime arguement.

I am no professional physicist (im only studying Advanced Higher Physics at high school), but to me, it seems silly to assume that spacetime would be created independently from matter and energy.
My logic being that an object must have mass and/or energy to interact with the universe, as it could not exist if it can not interact with anything.
So, everything in the universe must have mass and/or energy. This leads me to think that the universe's boundaries (i.e. spacetime) must expand in order to contain an ever-expanding area of mass and energy.
Otherwise you would be saying that it is possible for matter to simply fly out of spacetime. Which, as we know, is impossible, as matter can only exist in the environment created by spacetime.
Hope I made sense to everyone.

 

[ZapperZ]

You need to back up your argument with physics that either has been established, or been published. If you can't, this is a speculative post and in violation of the https://www.physicsforums.com/showthread.php?t=414380" that you had agreed to.

Either this thread sticks with physics, or it will end immediately.

Zz.

 

[Goolds]

Are all objects gravitationally aware of every other object in the universe?

 

[Dale]

Are all objects gravitationally aware of every other object in the universe?

Very few objects are aware at all AFAIK, gravitationally or otherwise. Can you ask your question again, without anthropomorphizing? Are you simply asking about the range of gravity?

 

[Goolds]

I thought anthropomorphising was a more accurate way if asking, but yes, I was asking if gravity is limited in range.

 

[bcrowell]

Very few objects are aware at all AFAIK, gravitationally or otherwise.

I think I'm aware, and other people are, but I could be wrong about other people. Actually I could be wrong about myself.

I was asking if gravity is limited in range.

In Newtonian gravity, gravitational forces fall off as 1/r². GR has basically the same behavior, although there are some twists, e.g., changes in gravity propagate at c rather than instantaneously. If you want to learn some relativity, a fun book to start with is Gardner's Relativity Simply Explained. If you want to get into it more seriously and mathematically, there are other books we could recommend.

 

[Goolds]

Yeh I knew a bit about gravity propagating at 'c', but I am asking if, mathematically or otherwise, every object exerts a gravitational force on every other object in the universe. This is also taking into account truly negligible magnitudes over vast distances.

 

[WannabeNewton]

Yeh I knew a bit about gravity propagating at 'c', but I am asking if, mathematically or otherwise, every object exerts a gravitational force on every other object in the universe. This is also taking into account truly negligible magnitudes over vast distances.

Well bcrowell already answered that. The gravitational attraction between two masses falls off as 1/r^2 so even at large distances there would be an, if negligible, attraction.

 

[Dale]

I thought anthropomorphising was a more accurate way if asking, but yes, I was asking if gravity is limited in range.

Gravity is not limited in range according to modern theory, nor is electromagnetism. Note bcrowells post, which contains a lot of information.

 

[Goolds]

So the inverse square law is accepted by general relativity as well as Newtonian gravity?
Does this mean then that spacetime is never truly uniform, and that it's limits could be a result of the mass of the universe curving it?

 

[WannabeNewton]

So the inverse square law is accepted by general relativity as well as Newtonian gravity?

If you are dealing with an asymptotically flat space - time then in the far limit gravity should behave as per the normal inverse square law so its kind of like a limiting case.

 

[Goolds]

So you are saying that you can describe space as an asymptote with massive objects intersecting it, and curving spacetime around them?
could you explain the second part of your point differently?

 

[bcrowell]

So you are saying that you can describe space as an asymptote with massive objects intersecting it, and curving spacetime around them?
could you explain the second part of your point differently?

No.

http://en.wikipedia.org/wiki/Asymptotically_flat_spacetime

 

[bcrowell]

Does this mean then that spacetime is never truly uniform,

No.

and that it's limits could be a result of the mass of the universe curving it?

This depends on what you mean by "limits."

You're not going to get a coherent understanding of GR by posting vague questions without defining your terms and trying to get people to give you one-sentence explanations without mathematics. PF is not a university, and it's not a substitute for books.