Why Does Gravity Exist? Exploring the Phenomenon of Gravitational Attraction

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In summary: Thanks Steve, for the reminder.So, in summary, Newton believed that the gravitational force is due to the force of attraction between objects, and that it is not an explanation for the underlying cause.
  • #71
Thanks
 
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  • #72
OnlyMe said:
Newtonian gravity required gravity to function instantaneously between bodies. For a kinetic model as they have been presented to do this the force carriers have to have velocities many orders of magnitude greater than c. This was also noted below.

I don't think Kinetic gravity is presented that way and it wouldn't need force carriers. The physics behind kinetic gravity are just as simple as two billard balls hitting each other or fields passing through each other causing drag. GR and Newtonian models on the other hand may need some kind of instantaneous and mystical force that can reach infinantly across the universe and grab hold of something and then pull it back.

OnlyMe said:
I have seen no kinetic model that explains either precession (a limitation of Newton's model also) or gravitational lensing.

Why should it? Could you explain?


OnlyMe said:
Kinetic energy does in fact require a force carrier, either in the form of a super luminal particle as most LeSage style kinetic models involve or in the form of an ether like substance in space that transfers the kinetic energy as would a "liquid". The particle problem is covered below. The ether model has its own problems. There have been some ether models of GR proposed. I am unaware of any that have been successful in duplicating the success of GR. If an ether model were found that was consistent with GR, it might provide some basis for a kinetic model of gravity, of some sort.

It would not be from ether it would be particles, most likely the smallest form of anything as in quanta. GR has never been successful at explaining how gravity works it only helps predict what it will do. GR never even attempts to explain it. As far as I know Kinetics have been the only idea offered to mechanically explain gravity.



OnlyMe said:
When using a kinetic model for gravity that involves a particle as a force carrier, some portion of the kinetic energy exchange winds up as heat. There is a heat build up that exceeds any reasonable rate of dissipation, which results in the vaporization of atomic structures.

If this is the best argument against kinetic gravity then its still doing better than any other theory offered. I don't think the heat dissipation would be a problem besides it could never be as big a problem as the singularity that standard gravity causes and no one has a problem with that. As for heat there seems to be plenty at the center of dense planets.
One idea I never hear anyone speak of is the possibility of quanta being packed so dense at the center that they couldn't move anymore. Without movement there could be no heat and wouldn't that be completely cold? Wouldn't that be the perfect heat sink?




OnlyMe said:
I think that the kinetic models that have been proposed have been dismissed, because they have not duplicated the predictive success that GR has and in each case there have been some fatal flaw(s), as mentioned above.

Kinetic models conform to the standard laws of motion and are completely predictable.

OnlyMe said:
Personally, I like the idea of a kinetic model, though I have not seen or come up with one that stands up to the issues raised above. Still, it seems that a kinetic model would provide a better opportunity to reconcile some of the problems that stand between GR and QM. That does not change the fact that there is a great deal of current experience and experimental evidence that does not seem explainable from within a kinetic model. In some sense quantum gravity and loop quantum gravity do begin to approach some of those issues from what could be described as involving a kinetic model. They also have not yet been entirely successful.

Other than the issue of heat dissipation (which I don't see as a problem) what else is wrong with kinetic gravity?
Standard gravity has at least two problems much greater as in singularities and having to come up with a mystical force that can reach out billions of light years in every direction, grab hold of everything and then pull everything back and still no physical or mechanical description of how it does this.
 
  • #73
Kinetic gravity "Although it is not regarded as a viable theory within the mainstream scientific community, there are occasional attempts to re-habilitate the theory outside the mainstream"
:)

So the best explanation so far seems to be that gravity arises from the need for the laws of physics to be invariant under acceleration.
And the need for invariance can often be explained as simply massively bumping up the likelihood of us being in that system. Just as it is massively more likely that you will find yourself in an invariant orbit around a star than heading towards or away from one. Or massively more likely that your will be in a universe that conserves energy.

But that doesn't explain to me why we don't see invariance in higher derivatives of time, why aren't the laws invariant under a frame of reference that is jerking?
 
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  • #74
TGlad said:
Kinetic gravity "Although it is not regarded as a viable theory within the mainstream scientific community, there are occasional attempts to re-habilitate the theory outside the mainstream"
:)

So the best explanation so far seems to be that gravity arises from the need for the laws of physics to be invariant under acceleration.
And the need for invariance can often be explained as simply massively bumping up the likelihood of us being in that system. Just as it is massively more likely that you will find yourself in an invariant orbit around a star than heading towards or away from one. Or massively more likely that your will be in a universe that conserves energy.

But that doesn't explain to me why we don't see invariance in higher derivatives of time, why aren't the laws invariant under a frame of reference that is jerking?


I'm not sure if your for or against kinetic gravity?

If you were explaining how gravity actually work in some way I didn't get it.
 
  • #75
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  • #76
Yikes! This thread is a mess, particularly the last page or so. Rather than wasting my energy to clean it up, this thread is locked.

Final note: Le Sage's theory of gravitation is and always has been a crackpot theory. Discussions of fringy and crackpot notions are not condoned at this site. PhysicsForums is a site for discussions and questions regarding mainstream science.
 
<h2>1. What is gravity?</h2><p>Gravity is a fundamental force of nature that causes objects with mass to be attracted to each other. It is responsible for keeping planets in orbit around the sun, and for keeping objects on Earth from floating off into space.</p><h2>2. Why does gravity exist?</h2><p>The existence of gravity is a fundamental aspect of our universe. It is a result of the curvature of space-time caused by the presence of mass and energy. This curvature causes objects to follow the path of least resistance, which is towards each other due to their mutual gravitational attraction.</p><h2>3. How does gravity work?</h2><p>Gravity works by creating a force of attraction between objects with mass. The strength of this force depends on the masses of the objects and the distance between them. The larger the masses and the closer the distance, the stronger the gravitational force.</p><h2>4. Why do objects fall towards the ground?</h2><p>Objects fall towards the ground because of the Earth's gravitational pull. The Earth has a large mass, which creates a strong gravitational force that pulls objects towards its center. This is why objects always fall towards the ground, regardless of their size or weight.</p><h2>5. Can gravity be explained by a single theory?</h2><p>Currently, there is no single theory that fully explains the phenomenon of gravity. Scientists have developed several theories, such as Newton's Law of Universal Gravitation and Einstein's Theory of General Relativity, to explain different aspects of gravity. However, a unified theory of gravity that can fully explain its existence and behavior is still being sought after by scientists.</p>

1. What is gravity?

Gravity is a fundamental force of nature that causes objects with mass to be attracted to each other. It is responsible for keeping planets in orbit around the sun, and for keeping objects on Earth from floating off into space.

2. Why does gravity exist?

The existence of gravity is a fundamental aspect of our universe. It is a result of the curvature of space-time caused by the presence of mass and energy. This curvature causes objects to follow the path of least resistance, which is towards each other due to their mutual gravitational attraction.

3. How does gravity work?

Gravity works by creating a force of attraction between objects with mass. The strength of this force depends on the masses of the objects and the distance between them. The larger the masses and the closer the distance, the stronger the gravitational force.

4. Why do objects fall towards the ground?

Objects fall towards the ground because of the Earth's gravitational pull. The Earth has a large mass, which creates a strong gravitational force that pulls objects towards its center. This is why objects always fall towards the ground, regardless of their size or weight.

5. Can gravity be explained by a single theory?

Currently, there is no single theory that fully explains the phenomenon of gravity. Scientists have developed several theories, such as Newton's Law of Universal Gravitation and Einstein's Theory of General Relativity, to explain different aspects of gravity. However, a unified theory of gravity that can fully explain its existence and behavior is still being sought after by scientists.

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