What Gravity Is

[martu]

Yep it’s grand claim time. I have read a lot of pop science physics recently and the other day realised I was picturing 3D space in a particular way. Thinking about it more it seemed to explain how things are influence by gravity.

My explanation is below though it may contain errors, I have a picture in my head what I mean but explaining it is difficult. It’s not rigorous physics (obviously) merely a way of explaining behaviour, similar to thinking about rubber sheets and billiard balls.

So is this plausible? Does it make any sense? Have I read it (or similar) somewhere and forgotten doing so? What doesn’t it explain? I’d appreciate your comments.


The Gravity Field - here is how to think of ‘empty’ space:

Imagine a 3D Grid and at each line intersection consider a particle

Each particle repels the other equally - think of an imaginary spring between each adjacent particle which can contract and expand caused by the particles repelling each other.

Anything that has mass is too big to fit between the gaps (where the imaginary springs are) so has to push the particles out of the way. Anything small enough can move between the particles and hence has no mass.

The denser the particles the higher the gravitational force – it’s harder for the atoms, for example, to push past.

Massless Particles:

Photons, for example, travel around the gravity particles as they are small enough to do so hence no mass.

As the gravity particles get denser it makes travelling through them harder

If the particles get dense enough the photon has nowhere to go and gets ‘trapped’ – a black hole.

Scenarios/Descriptions of behaviour:

Add a mass – consider an iron sphere. The sphere influences the position of the particles or, more accurately, the atoms take up space causing the particles to shift. This creates gravity – the particles push against each other creating gravity by also pushing on the atoms.

Consider a photon getting close to the iron sphere – the denser particles are closer to the sphere (as the atoms in the sphere are taking up some space) this directs the photon towards the sphere ‘bending’ light.

Not only do atoms ‘push’ the particles but the particles also ‘push’ the atoms, this is what creates the attractive force. Consider two iron spheres near each other – there are fewer particles, and hence less force, in the area between the masses hence they get pushed together.

Consider a human jumping on Earth – as you go up you contract the particles above you but eventually you run out of energy and can’t push the particles anymore so they push\spring back and you travel back to earth.

Consider the two split experiment – a particle as it got close to the barrier would be moving towards denser particles (caused by the atoms of the barrier) increasing the potential movement off a straight line. The particle field isn’t uniform hence the particle’s position can’t be predicted as each photon could pick a different path through the particles. This explains the wave\particle duality of light, some photons, a small amount, don’t take the ‘straight’ line (for example in a 2D plane it could go over first particle, under next, over, under etc) but can get moved off it (go over first particle, over the next, over the next, under next etc).

Dark Matter is merely areas where the particles are denser than usual, they are not spread uniformly. No matter at all.

[Lothian]

Originally Posted by martu

Yep it’s grand claim t.....My explanation is below though it may contain errors.....,

S4it loads of em. Why not explain what gravity is not how it could give the same effect if different.

[martu]

Originally Posted by Lothian

S4it loads of em. Why not explain what gravity is not how it could give the same effect if different.

Erm what? Could you elaborate please?

[Lothian]

Originally Posted by martu

Erm what? Could you elaborate please?

As gravity is the attraction I don’t think an example suggesting it is caused by other particles repelling helps..........

but it might just be me.

[martu]

Originally Posted by Lothian

As gravity is the attraction I don’t think an example suggesting it is caused by other particles repelling helps..........

but it might just be me.

Pah no imagination some people... I feared this, I haven't explained it well enough, if only I could download the pictures in my head!

The particles that are repelling are only repelling each other - they do not repel atoms or photons they just get in the way of atoms and photons. But when an atom, say, pushes a particle to move it out of the way this pushes the particle closer to another particle which pushes back. This causes the attractive force - two objects near each other have fewer particles between them compared to everywhere else hence there is a greater force pushing them together or to put it another way less of a force (particles repelling each other) to keep them apart.

Does this help? Probably not....

[ben m]

Nope. Among a bunch of particles, all pushing on one another, a test particle doesn't accelerate by bumping into them. Bumping into things slows you down.

[Loss Leader]

Why is it that people think they can forego the ten years of math and science courses and just skip right to theorizing about the universe?

If you don't understand exactly what it is that is know about the behavior of the universe today, you can't make any guesses about the causes of that behavior.

[martu]

Originally Posted by Loss Leader

Why is it that people think they can forego the ten years of math and science courses and just skip right to theorizing about the universe?

If you don't understand exactly what it is that is know about the behavior of the universe today, you can't make any guesses about the causes of that behavior.

Nice attitude - did you miss the bit where I asked if I was right? If it made sense?

It's merely how I picture it in my mind and I was asking those who know more about it their opinion. No mathematics, no equations but the equivalent to the rubber sheet explanation for classical physics.

Thanks anyway.

[martu]

Originally Posted by ben m

Nope. Among a bunch of particles, all pushing on one another, a test particle doesn't accelerate by bumping into them. Bumping into things slows you down.

Hmm yes indeed let me think on this one, this could be the fundamental error in how I picture it.

I was thinking that acceleration being the equivalent to gravity could be explained by the fact that you have to push past more particles as you move hence they push back on you causing the same effect as the gravity of a mass.

[Dogdoctor]

Sounds interesting. Now all you have to do is to prove the existance of "a 3D Grid and at each line intersection consider a particle "
Then we can discuss this more meaningfully.

[Paul]

Originally Posted by martu

I was thinking that acceleration being the equivalent to gravity could be explained by

Are you saying that as acceleration is the same as gravity, acceleration can be explained by..., or that you can explain why acceleration is the same as gravity?

Quote:

the fact that you have to push past more particles as you move hence they push back on you causing the same effect as the gravity of a mass.

Wouldn't that, for example, make bigger things fall more slowly than smaller things?

[aggle-rithm]

Originally Posted by ben m

Nope. Among a bunch of particles, all pushing on one another, a test particle doesn't accelerate by bumping into them. Bumping into things slows you down.

In physics terms, acceleration is any change in velocity. Therefore, changing direction or slowing down counts as acceleration.

That's why you experience just as much force slowing down or changing direction as you do speeding up -- force is mass times acceleration.

[aggle-rithm]

Originally Posted by Dogdoctor

Sounds interesting. Now all you have to do is to prove the existance of "a 3D Grid and at each line intersection consider a particle "
Then we can discuss this more meaningfully.

Isn't that the quantum vacuum?

...sort of?

[aggle-rithm]

Originally Posted by martu

Add a mass – consider an iron sphere. The sphere influences the position of the particles or, more accurately, the atoms take up space causing the particles to shift. This creates gravity – the particles push against each other creating gravity by also pushing on the atoms.

Gravity moves at the speed of light. Can your model account for this?

[martu]

Originally Posted by Paul

Wouldn't that, for example, make bigger things fall more slowly than smaller things?

Yes that's why it's wrong, it's the opposite. My error. A dumb one.

The density is less, there are fewer particles therefore less 'resistance'. A photon travels better through the bigger 'gaps'.

[martu]

Originally Posted by aggle-rithm

Gravity moves at the speed of light. Can your model account for this?

Yes this is waves in the grid, 3D waves of course.

I think I may be in SF territory. Maybe I should write fiction. Badly.

[martu]

Originally Posted by aggle-rithm

Isn't that the quantum vacuum?

...sort of?

Yes.

[martu]

Black Holes are caused by particles being so far apart that there is a hole in the grid.

[martu]

Originally Posted by martu

I was thinking that acceleration being the equivalent to gravity could be explained by the fact that you have to push past more particles as you move hence they push back on you causing the same effect as the gravity of a mass.

Hell's teeth that's almost timecube territory my apologies.

If you move through the grid you have to push past more partciles creating gravity.

[Reality Check]

Newton's third law means that these hypothetical particles need a force to stop them moving.

Your gravitational force depends only on the density of the particles and not the mass of the object. Actual gravitational force depends on the mass of both objects.

Thus this is not even bad fiction.

[martu]

Originally Posted by Reality Check

Newton's third law means that these hypothetical particles need a force to stop them moving.

Your gravitational force depends only on the density of the particles and not the mass of the object. Actual gravitational force depends on the mass of both objects.

Thus this is not even bad fiction.

You're probably right but imagine for a second, what else would a uniform spread of particles in a volume look like if it did exist? Stationary particles right, why would they move?

[martu]

Originally Posted by Reality Check

Your gravitational force depends only on the density of the particles and not the mass of the object. Actual gravitational force depends on the mass of both objects.

Mass is stuff - things that take up space pushing apart the particles.

[Reality Check]

Originally Posted by martu

Mass is stuff - things that take up space pushing apart the particles.

Your force does not depend on the mass of the object doing the pushing. It depends on the size of the object. So 2 objects of the same mass but different density will experience different 'gravitational' forces. There are quite sensitive experiments that show that gravity does not depend on the density (or composition) of the object.

[Reality Check]

Originally Posted by martu

You're probably right but imagine for a second, what else would a uniform spread of particles in a volume look like if it did exist? Stationary particles right, why would they move?

What is the force that stops them moving as soon as another object coomes into your 'empty' space? As you state in your posts - this object pushes the particles. What pushes back?

[zosima]

Originally Posted by martu

You're probably right but imagine for a second, what else would a uniform spread of particles in a volume look like if it did exist? Stationary particles right, why would they move?

Also, your model ignores relativity. Mass-Energy equivalence means that even though a photon is massless it has energy and thus should be expected to exert a tiny force on the objects around it. If light falls into a black hole, it increases the energy of the hole and therefore increases the gravitational pull of the black hole.

This same objection applies to energy from the motion of objects in your model.

If you ask me, the bending of 4-dimensional spacetime is probably as easy as it is going to get. That model doesn't postulate the existence of some crazy grid. Just smooth curves of geometric structures.

Also, your two-slit example doesn't explain how a particle could appear to travel through both slits. It posits only one or the other.

So I think I have to agree with reality(check), it doesn't even have utility as an educational model, and it doesn't have one or two little flaws. The best educational tool would be a physics textbook.

ETA: actually this fixed particle grid seems a lot like the aether model which has been widely discredited.

[The Man]

You leave out one critical dimension in your analysis, time. As zosima mentioned the bending of 4-dimensional spacetime is the most accurate way we currently have of describing gravity. Since we live in a perceptually 4-dimentional universe (3 spatial dimensions and one temporal dimension) any concept that does not involve all of those dimensions can not accurately describe gravity. Please see Spacetime and General Relativity.

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

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

[chran]

Originally Posted by Loss Leader

Why is it that people think they can forego the ten years of math and science courses and just skip right to theorizing about the universe?

If you don't understand exactly what it is that is know about the behavior of the universe today, you can't make any guesses about the causes of that behavior.

This needs to be quoted again.

[martu]

Originally Posted by chran

This needs to be quoted again.

How much physics and maths do I have to do before I can ask other people, people who probably know a lot more than me about the physics hence I am asking a question and not just stating "I am right", their opinion on how I am picturing something in my head exactly?

I only have 3 years of maths I'm afraid, my apologies.

To put it another way if you were thinking about something out of your area of expertise how would you go about finding out if your thoughts were absolute nonsense or not?

Why the attitude? I am asking questions, nothing more.

[martu]

Originally Posted by Reality Check

Your force does not depend on the mass of the object doing the pushing. It depends on the size of the object. So 2 objects of the same mass but different density will experience different 'gravitational' forces. There are quite sensitive experiments that show that gravity does not depend on the density (or composition) of the object.

Can you send me a link to write ups of these experiments?

Thank you btw for answering how I had hoped people would, I am merely trying to learn here.

[martu]

Originally Posted by Reality Check

What is the force that stops them moving as soon as another object coomes into your 'empty' space? As you state in your posts - this object pushes the particles. What pushes back?

The other gravity particles - consider just a simple 2D plane like a page of maths paper where the lines can bend. As you push a gravity particle (at the intersection of two lines) in one direction it gets closer to other gravity particles which push back.

[martu]

Originally Posted by zosima

Also, your model ignores relativity. Mass-Energy equivalence means that even though a photon is massless it has energy and thus should be expected to exert a tiny force on the objects around it. If light falls into a black hole, it increases the energy of the hole and therefore increases the gravitational pull of the black hole.

This same objection applies to energy from the motion of objects in your model.

Another good point, thank you. How I picture it, and again I am just trying to relate what I see in my head, is sometimes a photon could influence the position of the gravity particles by lightly grazing it as it goes past. This could explain the tiny force exerted, gravity particles being pushed just a little bit.

As to how the light falling into a black hole increases the gravitational pull - the more stuff you have the bigger the gap between particles (as stuff is taking up volume the particles can’t occupy) and therefore the larger the acceleration\gravity.

Originally Posted by zosima

If you ask me, the bending of 4-dimensional spacetime is probably as easy as it is going to get. That model doesn't postulate the existence of some crazy grid. Just smooth curves of geometric structures.

I picture it as smooth geometric structures in a way, consider an atom moving towards a mass then it travels down a sort of funnel where the gaps between the gravity particles are further apart closer you get to the mass hence the atom can travel further without being influenced by the gravity particles.

Originally Posted by zosima

Also, your two-slit example doesn't explain how a particle could appear to travel through both slits. It posits only one or the other.

Ah this is probably the bit of the two split experiment I don’t completely understand then, again thank you. Can you explain briefly, or point me to a source that does, why it is considered an individual photon goes through both slits?

Originally Posted by zosima

So I think I have to agree with reality(check), it doesn't even have utility as an educational model, and it doesn't have one or two little flaws. The best educational tool would be a physics textbook.

Thanks again.

Originally Posted by zosima

ETA: actually this fixed particle grid seems a lot like the aether model which has been widely discredited.

No it’s not like the aether model, the aether model relied on a medium through which things travel the grid is a medium which things travel around.

[Zeno]

Originally Posted by Loss Leader

Why is it that people think they can forego the ten years of math and science courses and just skip right to theorizing about the universe?

If you don't understand exactly what it is that is know about the behavior of the universe today, you can't make any guesses about the causes of that behavior.

He is brainstorming here and never once passed off his ideas as facts. You have no business oppressing fellow members of the forum and if you didn't notice, this would be a perfect opportunity to do some instruction.

[Reality Check]

Basically you are replacing gravity with 2 forces - the force between your particles that keeps them on the grid and the force between the particles and an object. Now you are stating that photons can "graze" the particles.
This seems too ornate when General Relativity is much simpler, works and is much easier to understand.

One prediction of your model that can be tested:
Make 2 balls, one made of lead and another of iron. Let them have the same mass. The lead ball will be smaller then the iron ball (lead is denser than iron). The lead ball will push past fewer particles than the iron ball. Thus the gravitatinal force on the lead ball will be less than that of the iron ball.
This is not observed. Therefore the grid of particles does not exist.

[martu]

Originally Posted by The Man

You leave out one critical dimension in your analysis, time. As zosima mentioned the bending of 4-dimensional spacetime is the most accurate way we currently have of describing gravity. Since we live in a perceptually 4-dimentional universe (3 spatial dimensions and one temporal dimension) any concept that does not involve all of those dimensions can not accurately describe gravity. Please see Spacetime and General Relativity.

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

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

I know what these are but thank you - why do you think this doesn't explain it? Or what specifically isn't explained by it?

[martu]

Originally Posted by Zeno

He is brainstorming here and never once passed off his ideas as facts. You have no business oppressing fellow members of the forum and if you didn't notice, this would be a perfect opportunity to do some instruction.

Thank you for getting to the crux of the OP, I want a discussion with people more knowledgeable than me on this subject.

I have been a member here for a long time, I can understand the initial feelings of 'Sweet FSM here comes another kook who thinks he has all the answers' but think it's unwarranted here.

[martu]

Originally Posted by Reality Check

Basically you are replacing gravity with 2 forces - the force between your particles that keeps them on the grid and the force between the particles and an object. Now you are stating that photons can "graze" the particles.
This seems too ornate when General Relativity is much simpler, works and is much easier to understand.

No it’s just one force, the repelling of the gravity particles. The gravity particles do not exert a force on the object they get in the way. But is that what you mean – when I say getting in the way this assumes a force that acts between them?

Thanks very good point.

Originally Posted by Reality Check

One prediction of your model that can be tested:
Make 2 balls, one made of lead and another of iron. Let them have the same mass. The lead ball will be smaller then the iron ball (lead is denser than iron). The lead ball will push past fewer particles than the iron ball. Thus the gravitatinal force on the lead ball will be less than that of the iron ball.
This is not observed. Therefore the grid of particles does not exist.

I think I can answer this one believe it or not, both balls will hit the same number of particles. Though the lead ball is smaller it contains more stuff therefore more particles are being hit. So the way to think of mass is that it’s the number of particles displaced by something – though the lead ball is smaller as it’s denser more particles are displaced in a smaller volume.

[Spud1k]

I think I can sort of see what you're getting at, but a lot of what you're describing doesn't jive with general relativity. For starters, the whole mesh thing implies some kind of granularity to space-time, which just isn't the case (within our measurement capabilities). Also, it implies some kind of universal frame of reference, which doesn't match up with special relativity.

The double slit experiment is a bad example - scattering of light is caused by the electromagnetic force, not gravity.

[martu]

Originally Posted by Spud1k

I think I can sort of see what you're getting at, but a lot of what you're describing doesn't jive with general relativity. For starters, the whole mesh thing implies some kind of granularity to space-time, which just isn't the case (within our measurement capabilities). Also, it implies some kind of universal frame of reference, which doesn't match up with special relativity.

Why does it imply a universal frame of reference do you think, could you elaborate for me?

OK slightly moving into fantasy territory here but stick with me - The LHC could find the Higgs boson and in turn we could find out that the Higgs field is created by the Higgs bosons all repelling each other to form the grid. Completely nuts do you think?

Originally Posted by Spud1k

The double slit experiment is a bad example - scattering of light is caused by the electromagnetic force, not gravity.

Again can you elaborate for me please, how do we know this? Apologies if I'm asking you to do a thesis on a forum, if so can you suggest a source I should read?

[Spud1k]

Originally Posted by martu

Why does it imply a universal frame of reference do you think, could you elaborate for me?

Your description is about things moving within a 'grid', so something moving with a constant velocity through space would be moving relative to these hypothetical particles (if I understand you right). This was the line of thinking when people were theorising about the aether, which turned out to be a load of rubbish. I'm not sure what would be a good reference for this. I did it when I did my degree and I doubt that material is what you're after. However, the key phrase is 'Lorentz invariance', which is a key part of special relativity.

Originally Posted by martu

OK slightly moving into fantasy territory here but stick with me - The LHC could find the Higgs boson and in turn we could find out that the Higgs field is created by the Higgs bosons all repelling each other to form the grid. Completely nuts do you think?

Yes, that is completely nuts. That isn't how the Higgs boson is theorised to behave at all.

Originally Posted by martu

Again can you elaborate for me please, how do we know this? Apologies if I'm asking you to do a thesis on a forum, if so can you suggest a source I should read?

The photon is the force carrier for electromagnetism and all their behaviour regarding scattering etc. can be explained with classical wave theory and on a finer scale, QED. Given that electromagnetism is a much stronger force than gravity, it'd be daft to even suspect that gravity would somehow be responsible. Still, we've got not grand unified theory yet, so you never know...

[martu]

Originally Posted by Spud1k

Your description is about things moving within a 'grid', so something moving with a constant velocity through space would be moving relative to these hypothetical particles (if I understand you right). This was the line of thinking when people were theorising about the aether, which turned out to be a load of rubbish. I'm not sure what would be a good reference for this. I did it when I did my degree and I doubt that material is what you're after. However, the key phrase is 'Lorentz invariance', which is a key part of special relativity.

But wasn’t aether a medium for light to travel through like sound needs a medium to travel through? I am thinking the grid is things to avoid, without the grid a photon could travel no problem, in fact this is what happens when the gaps between the gravity particles gets stretched by a mass, the photon travels with less of a hindrance from the gravity particles.

I’ll read up on aether and get back to you, I probably misunderstand that as well.

Originally Posted by Spud1k

Yes, that is completely nuts. That isn't how the Higgs boson is theorised to behave at all.

Thought so.

Originally Posted by Spud1k

The photon is the force carrier for electromagnetism and all their behaviour regarding scattering etc. can be explained with classical wave theory and on a finer scale, QED. Given that electromagnetism is a much stronger force than gravity, it'd be daft to even suspect that gravity would somehow be responsible. Still, we've got not grand unified theory yet, so you never know...

I don’t see it as gravity as being responsible per se – it’s more that the photons have to travel around the particles which is causing the photon to travel in a wave which can be explained by classical wave theory. So we have a force carrying photon avoiding the gravity particles as it travels causing an unpredictable path.

Thank you for your input I think this is the level of detail that I lack and that I need to somehow understand so I can picture it differently and, hopefully, more accurately.