[Jon Francis (OP)]

Do we really understand what gravity is? Could it be that gravity is not a distinct force but just a residual force created from all the attractive forces within the mass that it is related to?

[JP]

There is speculation that all the forces come from the same mechanism at high enough energies, but that's just speculation at the moment.

Regardless of what happens at high energies, in terms of what we see in the universe around us, the other three forces we know of (electromagnetic, strong and weak nuclear) can't account for gravity.  Specifically, the strong and weak nuclear forces are short-range, while the electromagnetic force can be repulsive.  Gravity is long range and only attractive. 

[Kerry]

We're just about to cover this in our latest issue. We've been talking to an author who's been writing on Expansion Theory - which I believe hopes to unify all fundamental forces - include gravity. He said:
"In the end, all known forms of matter and energy become manifestations of the singular unifying phenomenon of expanding matter."

[peadmore]

I fail to understand why people still talk about gravity as a force or, for that matter, why they talk about any forces at all. Einstein demonstrated that gravity was distortion in space/time and not a force at all. Forces do not exist as nothing moves in any manner at all unless acted upon by something else.

If we could find out what a distortion in space/time, or any other field, is we would know how things act upon other things at what seems to be a distance. In the meantime why confuse the issue by calling the phenomena something it is not.

[Murchie85]

In my humble opinion I think the jury is still out on whether they are all forces or just distortions of space. The way I was taught at uni about EM for example is they can be analogous to gravitational distortions but not exactly the same.

At the end of the day all the four fundamental forces are not completely understood and we are just another layer of the onion deeper. Until we gain a deeper understanding of quantum gravity on the smaller scale and a theory that brings the forces closer together but with more credibility than something solely theoretical then we will still be guessing.

[chrisdsn]

There is a good understanding of gravity as it applies to human sized objects and
the solar system. It can not be explained as a residual effects of the other forces that
we currently know of (they are either too weak, short range, or cancel over large
distances).

We may get some understanding that gravity "unifies"  with the other forces at a large
enough energy (as JP mentions), but such unifications are only interesting if you have
a guiding principle to predict (correctly) where such a unification will happen. In the
case of gravity such a unification has the problem that we can only formulate theoretical
models for the low energy limit of gravity, while a full theory is needed to make such
a unification (string theory could be considered a full theory of quantum gravity, but they
have yet to show that the rest of the forces can be found within it).

[yor_on]

Peadmore, I'm with you
Gravity is a matter of the gravest matter, totally twisting my space.
And that one was interesting Murchie. Are you saying that forces also could be seen as relations becoming a focus from 'distortions'? Or is that me twisting your words? Do you have any link to how they thought there?
Seems reasonable to me

But it will make for a very different 'world image', I think? It's easier to treat what we observe transforming and shaping energy into 'work done' as results of singular 'forces' working together than to see it as a 'field' with 'distortions' bringing us matter and light, motion, time and distance.
 
Hmm, should get some sleep here I guess

[Soul Surfer]

This question is very badly worded. Gravity clearly DOES exist but in some ways the suggestion of its root origin may be in some way valid.  The quantum vacuum is believed to contain a vast virtual potential of all the states possible within that space We are aware of the Casimir effect an attractive force between conducting plates due to the exclusion of certain virtual quantum vacuum states.  The real existence of specific particles or energy effectively excludes some of the virtual states.  The attractive gravity may therefore possibly be the slight excess pressure of the full quantum vacuum on the volume where a few of the virtual states are missing because there are real particles there.

[yor_on]

Very interesting SoulSurfer

I like it a lot, especially as I might want to stretch it to include all things there are into such a definition. If I do so, then there becomes a harmony, it seems to me with matter, space, light and distance, the question left being time possibly? But that could be a ultimate relation to those other, getting its arrow through the specific combination of circumstances and 'distortions' or 'potential states' creating our universe. And then it becomes useless to discuss what came 'first'. Time, or matter or light or gravity etc etc.

In such a universe it will be 'emergences' that defines the SpaceTime, and times arrow will just be what exists in certain combinations. What one can notice, if that was true, is that even if it may include universes where 'time' might act differently, I believe that what allows intelligence and our questioning to  exist is just a universe ordered like ours, with an arrow giving us a a constant growth from the simple to the complex. Maybe there are other time-states that could create consciousness, but I doubt we would make sense of them.

To me it's like looking down a well of half transparent mirrors They all reflect reality back to you, but looking down you will find for ever more mirrors waiting under those you see, and there will be different interpretations, depending on what level of observation you choose to observe from, from Planck size and up. I use Planck size as a guess for what make sense to us, but maybe there is no limit to it?

I still expect there to be a fractal order to it though, it seems so reasonable that there should be. And this way of looking at it also takes care of if light is 'traveling' or not, well, as I see it that is It becomes a matter of from where you look upon it, rather than any 'absolute truth' a three (four if you like) dimensional field 'bubbling', or a particle traveling. I never liked 'absolute truths', it doesn't seems like the universe is built on any single interpretation. To me it seems more like different combinations allows for different answers. And if so it, in a wider sense, becomes a matter of from where you decide to make your observations, that give you your answers, if that makes sense?

Or should I just go to bed )

[Farsight]

...Gravity clearly DOES exist but in some ways the suggestion of its root origin may be in some way valid.

Agreed. It is something of a "residual force".

The quantum vacuum is believed to contain a vast virtual potential of all the states possible within that space We are aware of the Casimir effect an attractive force between conducting plates due to the exclusion of certain virtual quantum vacuum states. The real existence of specific particles or energy effectively excludes some of the virtual states.

Nothing much wrong with that, though some people tend to forget the significance of "virtual".

The attractive gravity may therefore possibly be the slight excess pressure of the full quantum vacuum on the volume where a few of the virtual states are missing because there are real particles there.

Interesting way of putting it. You know Einstein talked about pressure in The Foundation of the General Theory of Relativity? He didn't talk about quantum vacuum, but he did talk about space and stress-energy, and said the energy of a gravitational field acts gravitatively just like any other kind of energy. Stress is just directional pressure, so read stress-energy as pressure-energy, and then you see what Einstein was talking about: a gravitational field is a pressure gradient in space. Sadly nobody ever seems to read the original material, and they don't read what Newton said either. See Opticks queries 20 and 21 for something similar couched in archaic language:

"Doth not this aethereal medium in passing out of water, glass, crystal, and other compact and dense bodies in empty spaces, grow denser and denser by degrees, and by that means refract the rays of light not in a point, but by bending them gradually in curve lines? ...Is not this medium much rarer within the dense bodies of the Sun, stars, planets and comets, than in the empty celestial space between them? And in passing from them to great distances, doth it not grow denser and denser perpetually, and thereby cause the gravity of those great bodies towards one another, and of their parts towards the bodies; every body endeavouring to go from the denser parts of the medium towards the rarer?"

Newton was talking about an aether and density rather than space and pressure, and he's got the density the wrong way round, but it's close enough for me. If you're put off by mention of aether, don't be, because Einstein talked of space as "the aether of general relativty" in his 1920 Leyden Address. Space sustains fields and waves, it isn't the same as nothing.   

[SuperPrincipia]

Gravity exist in four forms as described in current models of Cosmology and General Relativity.

The four forms are:
1)Inertial Mass Gravitation
2)Aether Gravitation
3)Vacuum Gravitation
4)Heat Radiation Gravitation

These fundamental forces and energies are clearly described in the new book series, Super Principia Mathematica - The Rage to Master Conceptual and Mathematical Physics, "The General Theory of Relativity" by Robert Louis Kemp

The book can be found at Amazon.com and BarnesandNobel.com. As well as Amazon.com.uk

There the Stress-Energy as Pressure-Energy tensor of the vacuum of spacetime are described using classical mechanics. Also described in the book is a Unified Vortex Field Theory which gives a mathematical description for how these gravity forces work together.

Quote from pages: 260 - 261

"The elasticity of a system mass body is described by a linear relationship between the “Stress Pressure” which is pressure acting normal to a surface and the “Strain Pressure” which is pressure acting tangential to a surface.

The classic example is a metal spring, which has a fixed amount of mass and can be compressed or extended. This idea was first stated by Robert Hooke in 1675 which states "As the extension, so the force." This linear relationship is called Hooke's law.

Although the general proportionality constant between stress and strain in three dimensions is a 4th order tensor, when considering simple situations of higher symmetry such as a rod in one dimensional loading, the relationship may often be reduced to simple applications of Hooke's law.

However, in General Relativity elasticity refers to the linearized theory of the continuum of stresses and strains in the vacuum of spacetime. Similarly The Stress Energy Tensor is elastic energy that changes in direct proportion to the distance from the center of the system mass body; and is derived by integrating the constant Vacuum “Dark” Cosmic Force over a distance measured relative to the Mean Center of the system mass body."


Farsight based on your post, if you picked that book up, you would not be able to put it down to even sleep at night. You would sleep with that book under your pillow!

[Geezer]

SP,

You wouldn't happen to be the author by any chance?

[Farsight]

All points noted, SP. No issue re treating space like a ghostly elastic solid, because it does sustain waves and you can curve it. But hmmn, I'm a little concerned about "four forms" of gravity - that's the sort of thing that would stop me sleeping at night. But what the hell, I ordered it off Amazon.com you sweet-talking thing you.   

Geezer, seeing as the book is called SuperPrincipia, that's a given. But don't get the wrong idea about this, from what I know already it's as mainstream as Newton and Einstein and Maxwell. As a demonstration of what I mean, see http://photontheory.com/Kemp/Kemp.html then take a look at a picture of the electromagnetic spectrum:



See that constant amplitude? What you're looking at it the quantum of quantum mechanics. Unfortunately "quantum" tends to mean "weird" in some sections of the scientific media, when actually it's derived from quantus, and means "how much". 

[Geezer]

Geezer, seeing as the book is called SuperPrincipia, that's a given.

It was an invitation for the author to step forward. TNS is not a site for free commercial promotion.

[yor_on]

How do gravitons explain frame-dragging?