What is gravity?, What is gravity "made of"?

We often hear that gravity is curvature of space-time.

But how does gravity look like/act at the very smallest lengthes of the universe?
Can we quantisize the gravity? If yes, then what does it consist of?

dktekno -

You have asked what Americans historically refer to as a "$64,000.00 question". The sage Elvish one, yQ, or mattweston are all likely better equipped for this one than I. Gravity is an acceleration (a force), classically speaking, of 2 bodies toward one another, governed by:

Fg = Gm1m2/r^2

Where G is a constant. Note that the effects of gravity depend on the inverse square of the distance b/t the 2 masses, and that all bodies accelerate at the same rate (recall Galileo's experiments).

Below a certain particle size (or de Broglie wavelength for protons, neutrons, electrons), gravity does not appear to have any appreciable effect, which is why the Law of Gravity is a misnomer. QM has absolutely no term for gravity, and there is only a postulated particle (the graviton) as far as physicists are concerned - note that it has never been found, either. LIGO (Laser Interferometer Gravitational-Wave Observatory) facilities have been set up around the world to look for gravity waves, but to date have not found any.

-ss

Fg = G * M1 * M2 / d^2

M1 = M2 = 2.176 × 10-8 kg
d = 1.616*10-35 m


YOU do the math - my shift just ended.... NOW

I asked my physics proff once what was gravity made of? he said he didn't know. Its not like anything else. you can't isolate yourself from it like a electronic field.

Hi dktekno, solidspin, a_ht and Asimov,

The "ultimate" answer to this question may not be "on the table" yet. I have said this before but though it "appears" that gravity is proportional to acceleration due to mass it is clearly not the case. The curvature of spacetime is the primary "motive" since even massless particles (photons) are affected by curvature and probability other "massless" particles as well. What this is saying is spacetime is curved due to acceleration. This is due to possibly mass or possibly "simple" acceleration as in a rocket when the engines are firing. We know the "identity" of these two types of "force" are identical in every way that can be tested. So far no quantization of gravity has been detected and indeed it has been shown that attempts to quantize it are incompatible with current mathematical techniques and "fundamentally" at odds with Einstein's Theory of Gravitation. This is the reason behind the alternative approach through String Theory.

for your understanding. You can remove the force of gravitation in every possible scenario by an appropriate transformation of the frame of acceleration into a "rest frame". Some of these frames are "inconvenient" to say the least but the possibility always exists showing that there are There is something I contribute to the argument of preferred frames where the "force" of acceleration disappears. For instance if you jump off a building the force of gravity literally disappears. In your vicinity spacetime is now flat... literally. The relative motion around you is not due to "force " on you but the impending "geodesic" path you are taking will probably smack you into the ground where force will surely catch up to you.

Remember to measure a "force" you will need to completely understand the Principle of Equivalence where inertial and gravitational forces are said to be equivalent. What it effectively says is the force of gravity you feel inside an elevator is identical in all respects to the force of acceleration due to gravity. Cut the elevator cable and there will be no force on you at all. Try it out by standing on a bathroom scales. This is the same situation as being in free fall around the Earth as in the International Space Station. The strange thing is and you must accept it as an experimentally proven fact is that light is affected in the same way.

Though you cannot "weigh" light and it would weigh nothing if you could find some way to do it. Light will follow the same path in spacetime as a material object traveling at the speed of light provided it was massless. That is gobbledygook but it is verifiable as an experiment. So while gravity cannot be "shielded" (apparently) it can be "removed" by a suitable transformation of the frame of reference. This would only occur if gravity is a pseudo-force and not a true force at all.

The next point I would like to state is that there is only one rest frame in orbit around the Earth where it is truly at rest this is in "geostationary" orbit. When there is differential movement between the surface of the earth and an object in orbit there is a higher order effect that can result in "inertial frame dragging" on the object. What this tends to do is change the orientation of an axis of rotation and in the case of a gyroscope causes the axis to precess around this extra "apparent" component of gravity (acceleration). Think of gravity on the surface of the Earth "undulating" in a sine wave as you travel above the equator due to changes in density or mass below the object in orbit. There is a tendency for this gear-toothed wave of gravity peaks and wells to slightly drag the object in orbit above the earth around in the direction of the disturbance as if the "teeth had some invisible grip on the object. If gravity responds "perfectly" this undulation would not have any tangential effect at all but this effect has been predicted and has been seen in some preliminary examples. Gravity Probe B is currently testing this effect to a high level of precision.

Alternatively the curvature of spacetime can be used to "tow" particles around in spacetime like a man with a dog on a leash or tidbit of food, always staying ahead, causing the dog to follow.

Both these effects indicate how the velocity of propagation of light and gravity leads to slight "imbalances" in the general effect. Obviously if gravity acted with infinite speed this effect would not appear.

Now to think further about the nature of gravity at the level of the quantum. It could be there are levels of quantization at that scale. What if gravity is purely a pseudo-force and is the result of some acceleration in the "bulk" or even in higher spaces. We also know that gravity is dependent on the primary existence of mass. That is the curvature of spacetime depends on the property of mass. Consider that fact that photons that have no mass are not able in themselves to "bend" spacetime at all. That mass is necessary to curve spacetime. This cannot be true since we have the principle of Equivalence. We see mass curving spacetime and this is equivalent to acceleration. Well the converse must also be true that acceleration must be the source of mass which in turn curves spacetime. This is not explicitly stated in the literature but if "equivalence" really means what I and the rest of the world thinks it is it must be true.

I will state this again... that the Corollary of Einstein's Principle of Equivalence of accelerated frames of reference or the equivalence of inertial and gravitational force implies that the curvature of spacetime usually reserved for the provenance of "mass" also means that acceleration is the "source" of mass. Think about that.

This must also mean that mass in all things is the result of some continuous acceleration that is invisible to us. It is the inevitable consequence of Einstein's General Theory of Relativity and it's Principle of Equivalence. We have already established that Einstein stated that Gravity is the same as acceleration so once again acceleration is linked to gravity too. Now we have also linked acceleration to mass.... at least logically.

The conclusion now is that mass is also a pseudo-property like gravity due to a property of "intrinsic" acceleration. We know mass is not a vector like acceleration so as I have mentioned before in previous posts, mass is more likely to be a tensor of rank 3. However since we have demonstrated that mass is dependent on acceleration it must also depend on the second derivative of time (acceleration) so it will have a hidden dimension of "time". Hence actually a tensor of rank 4.

This is evidence for a higher dimensional explanation for mass since this acceleration is not seen in our three dimensional space but must manifest in "higher dimensions". If anyone would like to comment intelligently please do. I would appreciate that.

Cheers

The "ultimate" answer to this question may not be "on the table" yet. I have said this before but though it "appears" that gravity is proportional to acceleration due to mass it is clearly not the case. The curvature of spacetime is the primary "motive" since even massless particles (photons) are affected by curvature and probability other "massless" particles as well. What this is saying is spacetime is curved due to acceleration. This is due to possibly mass or possibly "simple" acceleration as in a rocket when the engines are firing. We know the "identity" of these two types of "force" are identical in every way that can be tested. So far no quantization of gravity has been detected and indeed it has been shown that attempts to quantize it are incompatible with current mathematical techniques and "fundamentally" at odds with Einstein's Theory of Gravitation. This is the reason behind the alternative approach through String Theory.

for your understanding. You can remove the force of gravitation in every possible scenario by an appropriate transformation of the frame of acceleration into a "rest frame". Some of these frames are "inconvenient" to say the least but the possibility always exists showing that there are There is something I contribute to the argument of preferred frames where the "force" of acceleration disappears. For instance if you jump off a building the force of gravity literally disappears. In your vicinity spacetime is now flat... literally. The relative motion around you is not due to "force " on you but the impending "geodesic" path you are taking will probably smack you into the ground where force will surely catch up to you.

Remember to measure a "force" you will need to completely understand the Principle of Equivalence where inertial and gravitational forces are said to be equivalent. What it effectively says is the force of gravity you feel inside an elevator is identical in all respects to the force of acceleration due to gravity. Cut the elevator cable and there will be no force on you at all. Try it out by standing on a bathroom scales. This is the same situation as being in free fall around the Earth as in the International Space Station. The strange thing is and you must accept it as an experimentally proven fact is that light is affected in the same way.

Though you cannot "weigh" light and it would weigh nothing if you could find some way to do it. Light will follow the same path in spacetime as a material object traveling at the speed of light provided it was massless. That is gobbledygook but it is verifiable as an experiment. So while gravity cannot be "shielded" (apparently) it can be "removed" by a suitable transformation of the frame of reference. This would only occur if gravity is a pseudo-force and not a true force at all.

The next point I would like to state is that there is only one rest frame in orbit around the Earth where it is truly at rest this is in "geostationary" orbit. When there is differential movement between the surface of the earth and an object in orbit there is a higher order effect that can result in "inertial frame dragging" on the object. What this tends to do is change the orientation of an axis of rotation and in the case of a gyroscope causes the axis to precess around this extra "apparent" component of gravity (acceleration). Think of gravity on the surface of the Earth "undulating" in a sine wave as you travel above the equator due to changes in density or mass below the object in orbit. There is a tendency for this gear-toothed wave of gravity peaks and wells to slightly drag the object in orbit above the earth around in the direction of the disturbance as if the "teeth had some invisible grip on the object. If gravity responds "perfectly" this undulation would not have any tangential effect at all but this effect has been predicted and has been seen in some preliminary examples. Gravity Probe B is currently testing this effect to a high level of precision.

Alternatively the curvature of spacetime can be used to "tow" particles around in spacetime like a man with a dog on a leash or tidbit of food, always staying ahead, causing the dog to follow.

Both these effects indicate how the velocity of propagation of light and gravity leads to slight "imbalances" in the general effect. Obviously if gravity acted with infinite speed this effect would not appear.

Now to think further about the nature of gravity at the level of the quantum. It could be there are levels of quantization at that scale. What if gravity is purely a pseudo-force and is the result of some acceleration in the "bulk" or even in higher spaces. We also know that gravity is dependent on the primary existence of mass. That is the curvature of spacetime depends on the property of mass. Consider that fact that photons that have no mass are not able in themselves to "bend" spacetime at all. That mass is necessary to curve spacetime. This cannot be true since we have the principle of Equivalence. We see mass curving spacetime and this is equivalent to acceleration. Well the converse must also be true that acceleration must be the source of mass which in turn curves spacetime. This is not explicitly stated in the literature but if "equivalence" really means what I and the rest of the world thinks it is it must be true.

I will state this again... that the Corollary of Einstein's Principle of Equivalence of accelerated frames of reference or the equivalence of inertial and gravitational force implies that the curvature of spacetime usually reserved for the provenance of "mass" also means that acceleration is the "source" of mass. Think about that.

This must also mean that mass in all things is the result of some continuous acceleration that is invisible to us. It is the inevitable consequence of Einstein's General Theory of Relativity and it's Principle of Equivalence. We have already established that Einstein stated that Gravity is the same as acceleration so once again acceleration is linked to gravity too. Now we have also linked acceleration to mass.... at least logically. The conclusion now is that mass is also a pseudo-property like gravity.

If anyone would like to comment please do. I would appreciate that.

Cheers

Did someone actually understand the above post? Come on, raise your hand!
Nobody? really?

Well, off course not! (it's nonsense). (I'm not sure Good Elf knows what is talking about).

Dktekno, the answer to your question is: NOBODY KNOWS. (but keep looking for an answer in an experimental way).

See, the problem is, some scientists believe that it's best to give a weird answer with confusing terms/vocabulary than to give no answer at all.

There is a saying that goes: "What is well understood can be easily explained". Obviously, the post above is nonsense, since it makes NO SENSE to pretty much everybody.

Next time you hear someone raising the "string theory" to give you an answer, my advice is: run as fast as you can! String theory is the new religion for some scientists. String theory is not even a science since there is NO WAY to make experiments to prove it. (One would need a collider the size of the solar system to prove the String Theory, so as you can see it's a very convenient way to "explain it all" in one theory without actually having to prove anything...like religion).


My friend, science can not explain EVERYTHING, only religious people pretend to be able to do that.

Gravity is a relative vacuum of wave density in the "electromagnetic sea" that we think of as empty space. Just as two boats alongside one another in a choppy sea will accelerate toward one another (as a result of harmonics), objects having mass do the same. One sees this same phenomenon in the "Casimir effect" (although this, to my knowledge, has never been measured outside earth's gravitational field and is thus beleived to be "weaker.") There are no "gravitons." The "vacuum" can be "engineered" through field effects (eg rotating/precessing em field) to achieve buoyancy or to accelerate in any direction, including "up." If one's mass is effectively "zero" (due to such effects), he can accelerate to any velocity, up to and beyond the "speed of light." Looking for "gravitons" is like searching for unicorns. There aren't any.

Hi I love strings,

Einstein once said to the effect that...

The argument is based entirely on Einstein's General Theory of Relativity and the "very well known" Principle of Equivalence of Inertial and Gravitational Acceleration. There is no maths so it should be ‘relatively” easy to understand. From your criticism you must have missed everything following the word "Hi" since you have no questions and you state that "String Theory" was used in this exposition proves you understood nothing of the argument. No matter you quoted as much. It shows that not only are you woefully uninformed in matters related to Physics, you wish to remain so.

I invited “If anyone would like to comment intelligently please do. I would appreciate that." Please note that you even changed my direct statement to hide that fact. You changed it to...

Obviously you agree that you do not want to comment intelligently on the matter... so why did you bother? I have made no alteration to my statement but you have presumed to do so to mine without my consent. People who quote others then change quotes to their own fancy are "liars"…. since this is no accident. I leave others to form their own opinions.

The offer still stands about comments, negative if they like, but it is conditional on people forwarding an ‘argument’ rather than this ad hominem whingeing. I stand bye the fact this is one of the most "deeply profound" thoughts that "Good Elf" has expressed on this Forum.

Cheers

PS: I advise you to change your "quote" pronto or I will notify the moderators.

Good Elf,

notify the moderators or your mum if you want...

I didn't change your sentence at all, I just clicked on "quote" and the text came like that.
Believe it or not, frankly I don't care AT ALL.
It is either a bug in the quoting protocol (which I doubt) or you changed the text WHILE I WAS WRITING AN ANSWER or you are lying.

Dude, I know A LOT about physics. Actually, I seems that I am the only one in this forum who is able to notice that your post about gravity is nonsensical (in the sense that it doesn't make any sense to anyone with... common sense)...but since your post is made of very complicated words, people think that It might mean something (priests used to talk in Latin during the mass during the dark ages so that people could not understant them, that's basically what your are doing is the same).

It seems that you have acquired some kind of Priest-like status on this forum...so I just wanted to let you know that you can't fool everybody all the time. (you know how the saying goes...)

Back to my point now since you have troubles understanding my argument: science has a lot of answers BUT nobody knows what gravity is YET. (of course it's easier to talk about "curvature of space-time" and "vibration of the strings").

If you keep talking like that about science, two things will occur: 1) people will think that science is not understandable or worse that they are not smart enough to grasp it. (and that's very bad) 2) you will become very popular (like priests basically)...

To those reading this thread and who would like to understand physics, I recommend you should read something like: 'Asimov's New Guide to Science' (5$ on amazon) and remember one rule: when you don't understand an explanation there are 2 only reasons for that:

1) there is missing information in the explanation.
2) the one giving you the answer doens't know what is he talking about.

Cheers
I like strings.

something to which I completely agree on:

At the turn of the twentieth century, the special and general theories of relativity were developed to reconcile the extraordinary mathematical derivations of Maxwell's electromagnetic theory with the experimentally observed properties of light and gravity. The Michelson and Morley interferometer experiments demonstrated that light has an apparent constant velocity independent of any particular frame of reference. Lorentz and Einstein took this one observable characteristic of light, and, treating it as an absolute characteristic, developed a theory by which motion slows time and contracts length, and velocities no longer add in a common sense way. Combining this new model with Newton's laws of conservation of energy and momentum then required also that mass increase with velocity. This set an upper limit on attainable velocities at c, the speed of light, since reaching this speed would require infinite energy. Generalization of the special theory to the case of free-fall in a gravitational field produced the theory that gravity curves space and time. The end result is a universe that is not only counterintuitive, but is practically beyond the bounds of reason to the lay-person.

Taken from http://renshaw.teleinc.com/intro.stm

Hi I love strings and dktekno.

"I love strings" I still see no argument. You do not place a single scientific point forward in defense of your "abuse".

Prove your point.... If not... this is just abuse. I care little about people who say they know science but do not use any at all. Put up now... If General Relativity is not your area of knowledge then go to other threads with smaller words in them... try thinking one up for yourself. Gravity is not an easy subject but it does need some explanation. I make no apology if I can't do it in shorter form.

If you had any point at all you would have stressed it by now other than that claptrap about Relativity just being wrong. I have made my point and it is open to scientific discussion... that is the point. It is not about "stealing" my whole post and repeating it. It is not your work and copyright allows you to quote only 10%. At best what you did was not legitimate quoting... at worst you changed it to something that was unintended by me. You did what you did without my permission. You have set yourself as that "high priest" you mentioned above around here and asked people to believe what you are saying without any legitimate justification.

If I have a reputation as you suggest, it is because I have "earned" it. You have not even earned my respect yet. I call that a twisted jealousy... The kind that takes a spray can to someones else's artwork. Do your own work... figure your own ideas genius.... stop "copying mine" and then mouthing off.

I suggest that regarding the ideas that you espoused in this latest post of yours ...

I apologise for the bad english but a quote is a quote. Once again you have no supporting argument.

Alternatively you can show us your great wisdom with some ideas of your own for once. Back them up with some lucid argument instead of "decrees".

Cheers

PS: If you are going to "block quote" Mr. Renshaw you should fully acknowledge it and not keep pillaging other peoples ideas. Write something yourself.

Good Elf

Are you saying that the theory of Gravity you exposed was yours?

If you are saying that, then it's a lie. And if you are not, then your are using someone else material, exactly what you are accusing me of doing...What's that crap about copyright now? Are you saying it's illegal to quote more than 10% of a post on forums? Where u got that from? Quoting a full post is made on usenet since the 80's, do you thinks someone complained about that before?

Besides I never said I could come up with a theory about Gravity...did you?
I thought you were explaining Einstein's point of view...(which nobody understands, you included).

Anyway, let's go back to my point again: That theory you exposed is nonsense. You want a real theory about gravity/light that explains it all in a way that everybody can understand? here we go: http://renshaw.teleinc.com/

Don't need to thank me for the enlightment that this theory will bring to you...off course you can still think that the Einstein/string theory mix explain something.

I have wasted enough time with you.
bye

String Theories I've read appear to support the power of mathematics, spread by two dimensional "press", that threads of strings have to ways at the least of connecting to other "dots" [say here flat areas of uncertainty, part because our apparent finite extents).

The dots I found are related to the conjected "Higgs" particles, once read decades ago some 10 to the 58th power connections.

Dot pairs, triplets, yes, visually the threads are so small, dense (are there 26 dimension maximum?) and each dimension apparently contains much energy.

Four elementary forces to travel along these threads, e-m transversely maybe in helical "static" form, gravitation force maybe the tension of a number of dimensions. The Higgs particles I guess can be sort of a "static" structure.

Traveling from dot to dot, I guess both directions along, say gravity, longitudinal, 20 to 40 times the speed that the threads can move transversely.

Add to this the "sociograms", for N dots, some N(N-1)/2 Links.

That's it, works at both phases, the macro and the macro.

May model same as brain's chromosome spindals for conjectured Roger Penrose spindal connections for brains cells.

Take it from there brothers and sisters.

Best, rmuldavin

Hi I like strings,

You are beneath contempt. I did not come up with Einstein's Theory of General Relativity but I did come up with that Corollary. That is "all my own work" and I did it myself. Go look for it elsewhere. I do not lie. I do not have to.

I quote nobody on that point because that idea is mine and only mine. The argument is also mine. It is an "original" thought. I do not and will not apologize for my own work. I have had many original thoughts and the way I arrange them is up to me but I do quote where I have used others ideas. The ideas may not ultimately be right but they are no fraud.

So when you attack me in this way I am upset because you not only insult me but you insult those who read this post leading them to think what I say is a fraud. You are totally without any character and say things without exhibiting any personal morality.

Hi rmuldavin,

I see that you are accepting the idea of a "pure" string theory derivation for gravity with Higgss particles. What if the Higgs is not able to be found? To this point in time it has not. There has been a couple of false alarms though. It does beg the question... what are these strings made of that can "conduct" all four forces in nature? They are certainly not material as we know it and it's properties cannot be determined by laboratory experiment.

My thoughts on this point are that it relies too much on properties that are unable to be determined. My suspicion is that the Higgs will not be found. There will be some "explanation" ultimately proposed to save the "particle" model of the Standard Model. This does not mean that particle theories are "wrong". What it means is the paradigm cannot be extended to include the Higgs. This is a failure that might have been predicted because the Standard Model does not incorporate higher dimensions. If higher dimensions do indeed exist then even the Standard Model must change.

I have taken the opposite point of view here and postulate that the origin of gravity and now mass are due to "acceleration". The former (gravity) is a measurable "extrinsic" acceleration as can be seen with a rocket and to a less obvious extent in spacetime curvature resulting from the "distant" influence of mass. Mass curves space and the "distant" curvature of spacetime tells "distant" particles how to move from the local effect in place where the particle physically presently is situated.

The latter (mass) is acceleration that is "intrinsic" and hidden. If a particle exhibits mass it is "intrinsically" accelerating and it is not necessarily "extrinsically" accelerating. Could be both but not necessarily. Hold an ball in your hand and note it has "mass". I am exerting a force on it. Even though it is "apparently" stationary relative to the earth it is accelerating at the rate of 1 gee. The less obvious statement is that the ability of that ball to curve spacetime is an intrinsic property called mass rather than the response of the ball to the external influence of curved spacetime. That This is due to an "internal" acceleration we are not able to presently see. If I had placed this ball in space, freely falling, it would still exhibit mass but no "force of gravity" because it is in an inertial frame. There would be a tiny "self gravity" due to it's own mass though.

What I have said is that it is known that light follows a geodesic path in spacetime just like a high speed particle. It has a "special" trajectory ... that of light. What is important is that the photons which have no rest mass "fall" along geodesics just like you or me and even tennis balls. The difference is they are "thrown" at the speed of light ©. The difference is the light suffers "extrinsic" acceleration due to the curvature of spacetime (gravity) but cannot suffer the "intrinsic" acceleration (mass) because photons are massless. This also means light has no "self gravity" either.

Now quantization of gravity has been proposed but what if gravity is not quantized and is the result of acceleration in higher dimensions. The idea that gravity must be quantized comes from the analogy of light quanta being quantized and other phenomena being quantized as well. The question is do we need a special particle to exchange a "force" to create mass or to attract objects together? It is possible to have a consistent cosmology without quantized gravity. Gravity could be due solely to this concept of "acceleration" and dropping the idea of mass being "primary" altogether.

In fact if the Universe was spinning in higher dimensions but not "obviously" in the "Bulk" of 3D + T dimensions of Spacetime then what would we see? Now th "Bulk" could be spinning but lets say the "bulk" of the Universe spun at one revolution per million years. If the radius of the Universe was 15 Billion Light Years across then the linear speed would be then equal to...
v = r*

A "quick" calculation shows if the Universe was 15 billion light years in diameter and was rotating once every 50 Billion years, the edge would be "spinning" at almost the speed of light tangentially. This is the maximum possible velocity. This would be enough to "close" our Universe through length contraction. It would not be enough to be noticed in the bulk. However this would lead to a slight extra force between points in the Universe that is larger the greater the distance between those points becomes and might explain the "dark force". This is sort of similar to a Merry-go-Round which spins "apparently" slower near the middle but the further our toward the edge you go the greater the tendency to be thrown out further and faster. Naturally to keep all this together you need to have gravitational frame dragging or "stuff" would get stuck up on the "wall" of our Universe.

A single plane of rotation is insufficient to close the universe. It would need to spin in at least three orthogonal directions. This would need extra dimensions to be able to do this trick. Lets say this happened. Our entire universe would have an "intrinsic" spin that every atomic particle would have "picked" up by being carried along by the Universe. Spin is just the sort of thing needed to apparently "quantize" many parameters in our Universe and lead to quantum numbers we see and may lead to the assumption that it was of a sub-quantum origin and not of a "global" impressed spin phenomenon. This effect would be carried by T-Duality in String Theory. n the large scale it might account for the excess spinning of Galaxies.

As to your String Theory and particles resulting in Gravity... could you explain more please.

Cheers