1. ## Grasping Gravity?

I've been trying to get a handel on most of the mainstream, and less mainstream theroies out there reguarding gravity, but not sure i've found them all.

1. Quantum Gravity: - Gravity is a function of a force carrier particle called a graviton, which interacts at the speed of light.

2. Einstien/Newtonian Gravity: - Gravity is a curvature of space when mass or energy is present, the curving of space is near instantanious.

3. Gravity as Property: - Gravity is an intrestic property of space/time itself and neither a particle nor a force. Remove all the matter and energy just leaving space itself, and there will still be some intristic gravity. (Ref: Hubbles Constant). Mass and Energy concentrate the effects of gravity locally through spacial compression. Although gavity in this construct is always present (intsantanious) Variations in mass/energy can cause gravitational ripples(waves), which propagate at near light speeds, due to the limited mass/energy which formed them.

4. Gravity Duality: - Gravity is a curvature of space time, and also has a quantum particle/wave components. Therory seems to fit some emperical evidence of the other throeies but has a major flaw in that it can violate conservation of energy through a 'run away' gravity effect. (the run away effect does describe the catastopic univere collapse therory well though)

5. String Theroy Gravity: - I don't understand this one, someone would need to fill in the blanks here.

6. Particle Symetry Gravity: - (Disclaimer: This is my own pet theroy of which I invented to explain the light speed reaction of gravitons, but the seemingly faster then light proagation of the attractive force. I freely admit to not knowing enough high level match to figure out how to put this down and make mathmatical predictions with it.) - Gravity is a composite virtual particle made from joining of therorectical negative 1/3 mass Tacheon (nutrino like) paritcles and therorectical negative 1/3 mass Kronotron (time) particles, and a 2/3 positive mass quark. When these particles team up, a zero mass product is formed (called Gravitons) that always travels at the speed of light (if unbound) but decays quickly. The Oddity here is that the 2/3 mass quark is normaly already bound in a normal particle. Rhe attactive force of gravity a result of the decayed Tacheon/Kronoton pair (traveling at faster then light sppeds) recombining with another 2/3 mass quark in another normal particle. The exchangeing of Tacheon/Kronoton pairs between normal mass matter causes the attration between the two due to temporal effects of faster then light exchange causing a momentary link. The Tacheon/Kronoton pair arrives at desitnation just slightly before they left causing the two normal mass particles to be temporaly linked and be attracted to each other during the duration of the temporal discrepancy.

7. Pushing Gravity - Gravity is a repulsive force pushing object together. (After thinking on this one is appears to have exactly the same problems regular gravity theroies has. It's Akin to the thought experiment is our universe Matter or Anti-Matter? Is Gravity Attractive? or Repulsive? A fun experiment but the end result seems to be being unable to tell the difference. Probably should be called Anti-Gravity Therory)

8. Looping Quantum Gravity - Ok this one threw me for a loop literaly and don't even understand the basics of it yet. Another one to be filled in.

9. Graviton/Dilaton Gravity - Found this mentioned on the AIP (american Institute of Physics) site. Where Gravity is a combination of a 2 spin particle (Gravitons) and a 0 spin particle (Dilaton).

2. ## Re: Grasping Gravity?

I won't comment on all the ideas you presented here (I'm not familiar with the details of several of them), but I'd like to present a small correction.

Originally Posted by dgavin
2. Einstien/Newtonian Gravity: - Gravity is a curvature of space when mass or energy is present, the curving of space is near instantanious.
This isn't correct. Well, not quite. It's strange that you'd group these together, since Newton's ideas and Einstein's are so different. Newton thought gravitational influences propagated instantaneously, but under general relativity, gravity propagates at the speed of light. You may be thinking of Van Flandern's ideas (he seems to be one of the chief proponents of gravity propagating much faster than light), but to be frank, he's simply mistaken. His arguments are based on simple misunderstandings, and the results from general relativity match our observations without the need for superluminal propagation of gravity.

Originally Posted by dgavin
6. Particle Symetry Gravity: - (Disclaimer: This is my own pet theroy of which I invented to explain the light speed reaction of gravitons, but the seemingly faster then light proagation of the attractive force. I freely admit to not knowing enough high level match to figure out how to put this down and make mathmatical predictions with it.)
Since gravity doesn't seem to propagate instantaneously, I'm not certain that it's necessary to come up with a new model.

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http://tinyurl.com/7962a

4. I might be missing something with GR then, I thought that Einstien was refering to gravitational waves (akin to Quantum Gravity) only, and the curves of space were a function of mass. (IE the Curves just are, and waves are the Curves interacting with matter) But other then that both the therioes tneded to yeild the same results, with expection of einstiens formulas able to handle the prescession of orbits.

As to throry 6.

It dawned on my when reading on time dilation due to gravity, that maybe some of the differences in Gravity, Gravitons and Gravity waves, might be explainable because Gravity had a Temporal component to it. Hence the Kronotron/Tacheon exchanging of my pet theroy. The nice thing about theroy 6 is it can possibly explain some of the gravitational shielding effects that some experiments have shown.

Although 6 is my own pet theory, I usually lean towards theroy 4, even with it's 'run away' problems, as it incoorporates both theroy's 1 and 2, and fits in with some other unrelated theories as well. Not trying to say my pet theroy is correct at all, just that it makes some sense as a posibilty.

Still intrested in learnign about others I may not know of, or some of the details on String Theroies version of Gravity which i couldn't grasp.

5. Originally Posted by dgavin
I might be missing something with GR then, I thought that Einstien was refering to gravitational waves (akin to Quantum Gravity) only, and the curves of space were a function of mass. (IE the Curves just are, and waves are the Curves interacting with matter) But other then that both the therioes tneded to yeild the same results, with expection of einstiens formulas able to handle the prescession of orbits.
Only when?

The three classical tests of (general) relativity are the precession, the bending of light, and gravitational redshift. Let's see, googling gives up this webpage which mentions a fourth.

6. ## Re: Grasping Gravity?

Originally Posted by dgavin
5. String Theroy Gravity: - I don't understand this one, someone would need to fill in the blanks here.
I found this explanation rather helpful but alas, I don't completely understand it either.

...But it wasn't enough that there be a graviton predicted by string theory. One can add a graviton to quantum field theory by hand, but the calculations that are supposed to describe Nature become useless. This is because, as illustrated in the diagram above, particle interactions occur at a single point of spacetime, at zero distance between the interacting particles. For gravitons, the mathematics behaves so badly at zero distance that the answers just don't make sense. In string theory, the strings collide over a small but finite distance, and the answers do make sense.
This doesn't mean that string theory is not without its deficiencies. But the zero distance behavior is such that we can combine quantum mechanics and gravity, and we can talk sensibly about a string excitation that carries the gravitational force.
Is this theory presently the most accepted?

7. M-theory unites the various SuperString theories. As I understand it, gravity is a particle, the graviton. It is represented as a closed string. All other strings are open, and their tail ends are attached to the 3D brane which is our universe.

The graviton is, therefore, the only particle not tied to our brane. It can disappear into higher dimensions.

Strings having the Planck length, this becomes the smallest distance we can talk about. This allows both quantum mechanics and gravity to be united, since the problems with the equations for size smaller than the Planck length is no longer relevant.

A lab test for M-theory, is first to detect the graviton, then see if it can suddenly disappear or appear.

8. Originally Posted by dgavin
I might be missing something with GR then, I thought that Einstien was refering to gravitational waves (akin to Quantum Gravity) only, and the curves of space were a function of mass. (IE the Curves just are, and waves are the Curves interacting with matter) But other then that both the therioes tneded to yeild the same results, with expection of einstiens formulas able to handle the prescession of orbits.
It's true that in the limit of weak fields, relativity gives the same predictions as Newton's theory, but that's going to be true of any successful theory of gravity (since observation shows that Newton's theory actually describes what we see quite well in these cases).

Under general relativity, a static distribution of matter will result in a static curvature of spacetime, with results that behave like a force between objects. But a changing distribution of matter will result in a changing curvature of spacetime, and for certain types of changing distributions, those changes in curvature will continue propagating outward as waves - that's gravitational radiation.

Originally Posted by gzhpcu
As I understand it, gravity is a particle, the graviton. It is represented as a closed string. All other strings are open, and their tail ends are attached to the 3D brane which is our universe.
From NC More's link, it's not quite that simple.

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You can grasp gravity by studying the matematics of manifolds. This is a natural domain in which to express the formulas of G.R., which is both beautifully elegant and very accurate. I'd suggest Greg Egan's tutorial, which goes beyond the typical "popular" literature. Then, if you really want to know more, try "The Road to Reality" by Penrose.

Warped spacetime is a direct physical interpretation of the manifold. This model includes "gravity waves" and why it seems in several respects to be instantainious when it really propigates at a finite speed.

Meanwhile...
When you get down to sub-nuclear sizes, everything has a particle and wave nature both. Anything that isn't still shows up as quasi-particles! It's only natural that those in the quantum field of study will say that gravitons enter the picture. That is nothing mysterious really. After all, crystal lattice vibrations show up to them as particles call "phonons", and that's not even as "real" as gravity! Don't worry about them. That stuff doesn't have direct common-sense analogies, so you just have to trust the folks who can do the math.

The problem is that G.R. and quantum mechanics are fundimentally incompatible. GR is smooth and continuous, while QM is discrete. If you need to apply GR and QM at the same time to a problem, you have problems. So what's smaller than an atom but heavy enough that gravity is a concern at that scale? Black holes, and not much else. Loop quantum gravity is an effort to overcome that. String theory/M-theory is an attempt to explain everything including gravity.

Good luck.

10. Grey,
N C Moore's link gives an overview of how all the different string theories depict gravity. Aren't these overhauled?

M-theory replaces all of these conflicting views. I would think that only the M-theory view is relevant.

11. Added three Throries to the list

12. Originally Posted by gzhpcu
M-theory replaces all of these conflicting views. I would think that only the M-theory view is relevant.
M theory combines the various string theories by showing that they're really just different ways of looking at the same thing. For example, exchanging a large scale for a small one, while at the same time exchanging momentum and winding modes. In that sense, the view of either string theory is valid. So it may not even be meaningful to talk about whether a string is open or closed, any more than it's meaningful to try to decide whether a photon is a particle or a wave.

13. ## HUMMM

8) Gravity, i would say.. is nuetral spatial tension.

it ends up doing some warping of space, and looks and acts like strings.
is quantifiable like gravitons, and is... i propose, likenned to the pure energy orginating in the 4Th dimensional rise...

-MT

14. Originally Posted by Grey
Originally Posted by gzhpcu
M-theory replaces all of these conflicting views. I would think that only the M-theory view is relevant.
M theory combines the various string theories by showing that they're really just different ways of looking at the same thing. For example, exchanging a large scale for a small one, while at the same time exchanging momentum and winding modes. In that sense, the view of either string theory is valid. So it may not even be meaningful to talk about whether a string is open or closed, any more than it's meaningful to try to decide whether a photon is a particle or a wave.
Not quite sure that I follow: Since the various string theories are incomplete, and M-theory (which will still take 20 years or more to detail out...) encompasses all of them, the various string theories present pictures for certain cases (like GR, but GR speaks of spatial distortion... not gravitons...), which are relevant only there. They seem just like different mathematical constructs to me.

Also, as far as I understand it, in M-theory it is meaningful to speak of closed strings, because these relate to gravitons only. With M-theory, in addition to strings, branes are introduced as objects, and our universe is considered to be a brane. All fundamental particles (except gravity) are open strings with the end points attached to the 3D brane (which is why we can not detect the higher dimensions it is alleged...).

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## Re: HUMMM

Originally Posted by Mosheh Thezion

-MT
Until there is some actual quantitative analysis on that page (even some definitions would be an improvement), it's nothing but a bunch of useless drawings and meaningless words, ie, handwaving.

16. ## Re: HUMMM

Originally Posted by Mosheh Thezion
8) Gravity, i would say.. is nuetral spatial tension.

it ends up doing some warping of space, and looks and acts like strings.
is quantifiable like gravitons, and is... i propose, likenned to the pure energy orginating in the 4Th dimensional rise...

-MT
This is a joke, right? Just esoteric, unfounded assertions.

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## Re: HUMMM

Originally Posted by gzhpcu
Originally Posted by Mosheh Thezion
8) Gravity, i would say.. is nuetral spatial tension.

it ends up doing some warping of space, and looks and acts like strings.
is quantifiable like gravitons, and is... i propose, likenned to the pure energy orginating in the 4Th dimensional rise...

-MT
This is a joke, right? Just esoteric, unfounded assertions.
Unfortunately no. "Mosheh Thezion" appears quite adamant that the answers to the universe can be found in pages of circles, whirlpools and curvy lines.

There has yet to be any clear quantitative or even qualitative posits of this interpretation of the universe, as the response to questions appears to be to generate another page such as the one above.

18. ## hummm

My feeling are hurt.
-MT

19. ## Re: hummm

Originally Posted by Mosheh Thezion
My feeling are hurt.
-MT

Believe me, many of us would be happy to see something significant, or at least some answers to the many questions that have been asked. Pictures and "quality of applied energy" (which has never been explained) won't cut it.

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## Re: hummm

Originally Posted by Mosheh Thezion
My feeling are hurt.
-MT
Why? If your really serious about this, do some more work, find some evidence, and make some predicitons or at least show how your idea matches some observations. If you do some more work and you may realize you idea doesn't do what you think it does.

21. Originally Posted by gzhpcu
Not quite sure that I follow: Since the various string theories are incomplete, and M-theory (which will still take 20 years or more to detail out...) encompasses all of them, the various string theories present pictures for certain cases (like GR, but GR speaks of spatial distortion... not gravitons...), which are relevant only there. They seem just like different mathematical constructs to me.
In that sense, M theory is just a mathematical cosntruct, too. What I'm saying is that, the manner in which M theory unifies the string theories is similar to the manner in which particle and wave views are simply different ways of looking at the same thing. Neither is right or wrong, they're just different perspectives, and which seems more apparent may depend on the nature of your experiment.

Originally Posted by gzhpcu
Also, as far as I understand it, in M-theory it is meaningful to speak of closed strings, because these relate to gravitons only. With M-theory, in addition to strings, branes are introduced as objects, and our universe is considered to be a brane. All fundamental particles (except gravity) are open strings with the end points attached to the 3D brane (which is why we can not detect the higher dimensions it is alleged...).
I assume this is someone's view of M theory, but I'm fairly certain that it's not necessarily a standard, nor a universally accepted, one.

22. ## hummm

8) I dont have the energy... and im much to busy trying to end world hunger and poverty, and homelessness...
-MT

23. ## Re: Grasping Gravity?

Originally Posted by Mosheh Thezion
8) I dont have the energy... and im much to busy trying to end world hunger and poverty, and homelessness...
-MT
Well, that's one way to go on a diet: spread yourself thin.

Afraid the only kind of doodles hungry, impoverished, and homeless people would be interested in would be these:

trying to end world hunger and poverty, and homelessness
My, but you're a busy guy. What sort of results have you had?

BTW, I see you still have that "hummm" problem. You should really see a doctor before it leads to complications. :-k

24. Originally Posted by Grey
Originally Posted by gzhpcu
Not quite sure that I follow: Since the various string theories are incomplete, and M-theory (which will still take 20 years or more to detail out...) encompasses all of them, the various string theories present pictures for certain cases (like GR, but GR speaks of spatial distortion... not gravitons...), which are relevant only there. They seem just like different mathematical constructs to me.
In that sense, M theory is just a mathematical cosntruct, too. What I'm saying is that, the manner in which M theory unifies the string theories is similar to the manner in which particle and wave views are simply different ways of looking at the same thing. Neither is right or wrong, they're just different perspectives, and which seems more apparent may depend on the nature of your experiment.

Originally Posted by gzhpcu
Also, as far as I understand it, in M-theory it is meaningful to speak of closed strings, because these relate to gravitons only. With M-theory, in addition to strings, branes are introduced as objects, and our universe is considered to be a brane. All fundamental particles (except gravity) are open strings with the end points attached to the 3D brane (which is why we can not detect the higher dimensions it is alleged...).
I assume this is someone's view of M theory, but I'm fairly certain that it's not necessarily a standard, nor a universally accepted, one.
The view of M-Theory I mentioned is mentioned by Brian Greene. It is, or course, a very new and yet really to be defined theory.

As far as the mathematical constructs are concerned, that is an opinion I have stated here a number of times, that it is very difficult to know if all of the mathematics-based theories we come up with, actually correspond to reality.

25. ## Re: hummm

Originally Posted by Mosheh Thezion
8) I dont have the energy... and im much to busy trying to end world hunger and poverty, and homelessness...
-MT
Excuse me, but do you happen to be a comedian by any chance?

26. Originally Posted by gzhpcu
As far as the mathematical constructs are concerned, that is an opinion I have stated here a number of times, that it is very difficult to know if all of the mathematics-based theories we come up with, actually correspond to reality.
You don't say...I was of the opinion that only the mathematical constructs were valid and that corresponding to reality wasn't really an issue. After all, couldn't one just say that reality itself would change depending upon what mathematical construct one was utilizing?

27. Originally Posted by gzhpcu
The view of M-Theory I mentioned is mentioned by Brian Greene. It is, or course, a very new and yet really to be defined theory.
Is that from Fabric of the Cosmos, which you'd mentioned before? I haven't read all of his work, but perhaps I'll check out a copy next time I pass the university library.

Originally Posted by gzhpcu
As far as the mathematical constructs are concerned, that is an opinion I have stated here a number of times, that it is very difficult to know if all of the mathematics-based theories we come up with, actually correspond to reality.
Right. That's why I just mentioned that M theory itself was such a construct, so if you weren't taking the various string theories' representations of reality too seriously, you probably shouldn't take M theory's all that serioously either, if you want to be consistent. (Rather than going into a more detailed discussion, since I was already aware of your views on the matter).

I think I've already mentioned my own thoughts on the matter in some of those previous threads, but I'll repeat it here anyway. I'd agree that we can't ever really prove that our models represent what's "really" happening at the smallest levels. However, I do think that when a model works well and matches our observations to a high degree of precision, that's at least good corroborating evidence that the model has some correspondence with reality. I'm content to disagree on that with you, though.

28. ## Re: Grasping Gravity?

Originally Posted by gzhpcu
Originally Posted by Mosheh Thezion
8) I dont have the energy... and im much to busy trying to end world hunger and poverty, and homelessness...
-MT
Excuse me, but do you happen to be a comedian by any chance?
He left little doubt concerning his propensity for that particular vocation on this thread.

29. Originally Posted by Grey
Originally Posted by gzhpcu
The view of M-Theory I mentioned is mentioned by Brian Greene. It is, or course, a very new and yet really to be defined theory.
Is that from Fabric of the Cosmos, which you'd mentioned before? I haven't read all of his work, but perhaps I'll check out a copy next time I pass the university library.

Originally Posted by gzhpcu
As far as the mathematical constructs are concerned, that is an opinion I have stated here a number of times, that it is very difficult to know if all of the mathematics-based theories we come up with, actually correspond to reality.
Right. That's why I just mentioned that M theory itself was such a construct, so if you weren't taking the various string theories' representations of reality too seriously, you probably shouldn't take M theory's all that serioously either, if you want to be consistent. (Rather than going into a more detailed discussion, since I was already aware of your views on the matter).

I think I've already mentioned my own thoughts on the matter in some of those previous threads, but I'll repeat it here anyway. I'd agree that we can't ever really prove that our models represent what's "really" happening at the smallest levels. However, I do think that when a model works well and matches our observations to a high degree of precision, that's at least good corroborating evidence that the model has some correspondence with reality. I'm content to disagree on that with you, though.
Yes, that is the book which brings this up.

As far as whether or not a mathematical model corresponds to reality, since we can really prove it, maybe we should leave it at that, because taking either or pro or con standpoint, would amount to a personal belief.

30. ## Re: Grasping Gravity?

Originally Posted by Maksutov
Originally Posted by gzhpcu
Originally Posted by Mosheh Thezion
8) I dont have the energy... and im much to busy trying to end world hunger and poverty, and homelessness...
-MT
Excuse me, but do you happen to be a comedian by any chance?
He left little doubt concerning his propensity for that particular vocation on this thread.