Gravity question

[rjain]

Originally posted by: silverpig
Whoa, I can't belive I'm this late coming into this thread.

Gravity travels at c. The reason why black holes don't trap themselves with their gravity is because gravitons are the messenger particles (theorized) that transmit the gravitational force. They are not limited to the curvature of spacetime. In order for them to be so, gravitons must be able to interact with themselves (like, one graviton has mass and sends a graviton to another one with mass thereby affecting it).

That would just make them attract even more strongly and be totally unable to escape any group of particles with gravitational charge, as happens with the strong force. I can't figure out what exactly the consequences would be without quite a bit of work, but it's definitely nothing like what we have now. Although gravity is weak enough that electromagnetic interactions can push particles apart... Still, I think that kind of interaction would cause gravity to be much stronger than EM, as it would grow exponentially. In any case, do you have any way that your system would keep orbiting bodies from flying apart spontaneously, generating angular momentum from nothing?

Unless, of course, you mean that they travel at c in a dimension which allows them to get anywhere in 0 time... Actually, the article referenced earlier does support the idea that there is some finite propagation speed to gravity, which would cause this effect to be very small. Maybe it somehow explains the expansion of the universe...

 

[grant2]

Originally posted by: rjain
It's the rotational equivalent of momentum, using rotational rates and moments of inertia instead of velocities and masses.

Ok that wasn't very elucidating. How is this momentum supposed to be lost by C-Speed gravity?

 

[grant2]

Originally posted by: silverpig
Gravity travels at c. The reason why black holes don't trap themselves with their gravity is because gravitons are the messenger particles (theorized) that transmit the gravitational force. They are not limited to the curvature of spacetime. In order for them to be so, gravitons must be able to interact with themselves (like, one graviton has mass and sends a graviton to another one with mass thereby affecting it).

If gravity is transmitted by gravitons, why would there be a curvature of spacetime? (or vice versa)

These ideas appear to support contrary theories.

 

[grant2]

Originally posted by: silverpig
Gravity travels at c.

BTW do you say that as a fact because that's conventional wisdom, or because you have such incredible faith in the single highly contested experiment that supports the theory?

 

[grant2]

Originally posted by: Mookow
I have been sitting here trying to figure out an experiment that would test this, but since gravitational force is so weak at a particle level, and rapidly accelerating a planet is difficult, I dont know what form a good experiment would take. Maybe if you could accurately measure the force of the moon while on earth, and then compare that to the observed angle to the moon, correct that for the time that light takes to reach the earth, and then see... but I dont know if the pull of the moon as felt from earth's surface is enough to be accurately measurable (ie, I know that the moon is why we have tides, but does the moon exert enough force on a object that we can accurately measure the direction [which, for this question, would seem to be more important than the magnitude of the pull] it is being pulled in to a very small degree of uncertainty).

Ok here's a theoretical experiment:

Place a spacecraft on the gravitational neutral point between the earth & the moon, i.e., where the moon & earth both exert equal gravitational pull.

You verify your position by using plumb bobs, one on the earth side of the spacecraft, one on the moon side. When they are aligned, you know you've got your spot.

If the plumb bobs are pointing at where the earth & moon appear to be, then you know gravity travels at C. If they are pointing somewhere else, you use the difference to calculate how fast gravity is transmitted.

 

[silverpig]

Originally posted by: grant2

Originally posted by: silverpig
Gravity travels at c. The reason why black holes don't trap themselves with their gravity is because gravitons are the messenger particles (theorized) that transmit the gravitational force. They are not limited to the curvature of spacetime. In order for them to be so, gravitons must be able to interact with themselves (like, one graviton has mass and sends a graviton to another one with mass thereby affecting it).

If gravity is transmitted by gravitons, why would there be a curvature of spacetime? (or vice versa)

These ideas appear to support contrary theories.

That's because they do

The curvature of spacetime is a human-interpreted effect of a massive object. It is an explanation that fits into a model which is of course incomplete.

Joe says the world is flat, which is fine because he's just a farmer and wants to level his fields.
Dave says the world is infinite, which is fine because he's an explorer and doesn't want to fall off the edge of the world.

Both models work for each observers just fine. Joe can have level fields without having to deal with any curvature, and Dave can travel as long as he wants without falling off the earth. Neither is entirely correct though.

It's well known that general relativity and quantum mechanics are two of the most elegant, and most useful theories in physics. They both work perfectly well when tested within their bounds. However, they do not agree when they are tested on an even playing field. Joe says spacetime curves, Dave says gravitons are flying around. Chances are neither of them are correct. This however doesn't mean that the theories are invalid. They are likely just approximations to a more complete theory given certain conditions, much like how Newtonian mechanics are just low velocity approximations to special relativity.

 

[rjain]

Originally posted by: grant2

Originally posted by: rjain
It's the rotational equivalent of momentum, using rotational rates and moments of inertia instead of velocities and masses.

Ok that wasn't very elucidating. How is this momentum supposed to be lost by C-Speed gravity?

http://www.ldolphin.org/vanFlandern/gravityspeed.html

 

[rjain]

Originally posted by: grant2


Ok here's a theoretical experiment:

Place a spacecraft on the gravitational neutral point between the earth & the moon, i.e., where the moon & earth both exert equal gravitational pull.

You verify your position by using plumb bobs, one on the earth side of the spacecraft, one on the moon side. When they are aligned, you know you've got your spot.

If the plumb bobs are pointing at where the earth & moon appear to be, then you know gravity travels at C. If they are pointing somewhere else, you use the difference to calculate how fast gravity is transmitted.

Yeah, and the experiment has been done (in different ways and with many different systems) and there is a difference that requires that gravity travels at over 10^10 c.

E.g., the direction of photons from the sun and the direction of the gravitational pull of the sun are different by exactly the angle the earth moves around the sun in the time it takes the light to get to earth.

 

[grant2]

Originally posted by: rjain

http://www.ldolphin.org/vanFlandern/gravityspeed.html

If you remember, I was the one who originally linked that article to this thread

If you can't explain it, that's ok, I'm not expecting you to play teacher

 

[rjain]

Originally posted by: grant2

Originally posted by: rjain

http://www.ldolphin.org/vanFlandern/gravityspeed.html

If you remember, I was the one who originally linked that article to this thread

If you can't explain it, that's ok, I'm not expecting you to play teacher

Well, why don't you read the article? I read it about a year ago and didn't understand it fully. I reread it when this thread started and understand it quite well now. If you have specific questions, go ahead and I or anyone else who wants to will do our best to answer them.

Edit: for the record, I posted the link about a day before you did, so nyah.

 

[KRandor]

Hi... I thought I'd post a reply to this topic aswell, after posting a lot to the last gravity themed thread... I have a couple of ideas about gravity, that seem to fit aswell as any other ideas, but am still not sure... However, I remember a lot of stuff about the 'speed of gravity' experiments and I mostly remember the reaction of a friend of mine - (who has been a physicist for a while) - who after reading through all the documentation a few times, was pretty sure that in fact all that had been accomplished was another measurement of the speed of light, which of course = c... However, there might have been more research/experiments since then so that may be out of date by now... I just wish he had time to explain everything before he left...:-(

My own 'theory' of gravity is pretty much at odds with the 'established' theory - (if there is one...;-) ) - but it still seems to fit the evidence - (which isn't that hard, because there isn't much of it, really).

Anyway, rather than repeat everything here, read this:

http://forums.anandtech.com/messageview.cfm?catid=50&threadid=1116658&FTVAR_MSGDBTABLE=

According to my theory, although, because gravity is constant, (which produces it's own set of problems - which IS the problem...:-/), and because of it's level of efficiency, I think that the speed of gravity is the rate at which things travel under it's effects - i.e. it varies with distance from an object, though it's rate of acceleration IS constant...

Oh well, just my 2 cents...;-)

 

[glugglug]

Originally posted by: KRandor
Hi... I thought I'd post a reply to this topic aswell, after posting a lot to the last gravity themed thread... I have a couple of ideas about gravity, that seem to fit aswell as any other ideas, but am still not sure... However, I remember a lot of stuff about the 'speed of gravity' experiments and I mostly remember the reaction of a friend of mine - (who has been a physicist for a while) - who after reading through all the documentation a few times, was pretty sure that in fact all that had been accomplished was another measurement of the speed of light, which of course = c... However, there might have been more research/experiments since then so that may be out of date by now... I just wish he had time to explain everything before he left...:-(

My own 'theory' of gravity is pretty much at odds with the 'established' theory - (if there is one...;-) ) - but it still seems to fit the evidence - (which isn't that hard, because there isn't much of it, really).

Anyway, rather than repeat everything here, read this:

http://forums.anandtech.com/messageview.cfm?catid=50&threadid=1116658&FTVAR_MSGDBTABLE=

According to my theory, although, because gravity is constant, (which produces it's own set of problems - which IS the problem...:-/), and because of it's level of efficiency, I think that the speed of gravity is the rate at which things travel under it's effects - i.e. it varies with distance from an object, though it's rate of acceleration IS constant...

Oh well, just my 2 cents...;-)

This theory, including the linked thread..... I don't think you quite "get" the concepts of mass and energy.

 

[KRandor]

I don't think you quite "get" the concepts of mass and energy.

Errr... Are you sure? I understand them perfectly well in-line with their definitions - which I spelt out in that thread, and explained my theory in relation to them... As far as I am aware, those definitions are still current and have not been superceded... If anything, I think you'll find that if you have a problem with my working with that, then the actual definitions, by your reckoning, must be wrong... I may be dealing with them at their most basic level, but, because of the way they are defined, that cannot be a problem, unless, yes, their definitions are wrong... If needs be, I'll spell everything out again so that others might comment - but only if I have to/am requested to, though I might just do so anyway, because energy and work are the two MAIN concepts underpinning physics, and therefore our understanding of the universe, (i.e. literally how it WORKS), as a whole... All I have done in the thread above is merely applied those concepts to gravity in a different way.

Like I said in the last tread, gravity in itself, is actually quite basic, (it must be, otherwise it wouldn't be so consistent and efficient - (i.e. it's even more efficient and consistent than light etc.) - it's just that everyone dealing with it is trying to make it more complicated than it actually is to try and fit it in with current research into quantum mechanics, when it obviously DOES NOT WORK AT THE SAME LEVEL - (because it's too efficient). (It's like trying to fit neutrons in when talking about Earth, Air Wind and Fire, lol). Which means it dosen't operate with the same rules, which is why there's so many problems... Don't get me wrong - it's only natural that people should try and fit gravity in when they discover something new like quantum physics, but at the rate they are going, it's going to take a long time, because it looks like they'll need to understand it's cause before accepting just how efficient it really is...

 

[glugglug]

Originally posted by: KRandor

I don't think you quite "get" the concepts of mass and energy.

Errr... Are you sure? I understand them perfectly well in-line with their definitions - which I spelt out in that thread, and explained my theory in relation to them...

ok, explain what you think the relationship between mass and volume is in light of these comments:

P.S. Note that gravity is also affected by DENSITY - not just mass....

Of course the density of an object affects it's gravitational field - if the area decreases, (i.e. density increases), then the rate of transfer must increase to maintain E=E... (Which is why black holes can exist).

 

[KRandor]

O.k. let's see if you can understand this... I wrote that at the time, (in a hurry), and I don't think I fully understood why, which is why I replied to the following comments as I did - now, however, I understand why, and I am in fact correct.

All I said was that gravity is affected by the density of an object, not just the 'amount' (mass) of an object - which is true. Gravity is a force, whose strength can vary with distance, which I theorize is because of the area being affected. Two objects of the same mass but different densities WILL have different strength gravitational fields - if an object of, say, 2^200Kg is compressed to the size of a ball bearing, it will have a stronger gravitational field than if it was the size of planet Earth... The amount of energy being transferred/used in either situation - i.e. E - will be the same, but the area/rate of transfer will be different, and it's the force caused by this 'transfer' we call gravity... The thing is - this density/mass-vs-gravitational field, as far as I am aware, has been PROVEN. - i.e. black holes/neutron stars ETC. If that's true, then how can my theory BE WRONG??????????!!!!!! And if I'm RIGHT?????!!!!!!

A lot of people have tried to pick holes in this theory for a long time, but it always emerges stronger, rather than being completely disproved. The problem is that in 'real' physics, what we are dealing with here is pure theory, with few facts to back anything up - and until that changes, this theory will stay... The fact is - what we are chasing here, is a constant I call r (R?)... - The rate at which mass uses energy, which should - (hopefully) - be a constant - and one of the fundamental constants in the Universe - unless there's something else about the constituents of 'mass' that puts a spanner in the works? Time will tell...

Keill Randor...

 

[rjain]

If you're outside the object, only the total mass and the distance to the center of gravity matters. The shape and size of the object is irrelevant. It's rather simple calculus to prove this, at least if the gravitational force does follow an inverse-square law. It's just that it's easier to get closer to the center of gravity of a smaller object. Energy is merely force times distance. This "theory" (looks more like conjecture to me, and it contradicts observations) that you're proposing is nothing I've ever seen before. Who came up with it, and how do they explain the contradictions with any theory or observations of gravity we've ever had?

I don't see how any of this is pure theory, as it's well-studied in experimental situations.

 

[rjain]

Getting back to an earlier post, KRandor discussed how gravity seems to be fundamentally distinct from QM. This could be true, but I like Penrose's theory presented in The Emperor's New Mind, where gravity and quantum coherence operate on space-time itself, circumventing the usual quantum interactions. Whether they are fundamentally distinct is a different matter, as the forces could unify in some way, but at a much higher level than the weak, strong, and EM forces do.

Since gravity and coherence seem to be transmitted faster than the speed of light and they operate at a sort of "meta-quantum-mechanical" level. We could consider them to be interactions of space-time itself (just as GR presents gravity), and the three other forces (along with the Higgs force?) would be mediated through space-time, constrained to the speed of light limitation that occurs in traveling along space-time. Just some random conjecture of mine; poke holes or elaborate at will, especially w.r.t. the Higgs force.

 

[KRandor]

Originally posted by: rjain


The shape and size of the object is irrelevant.

Not if you're concerned on how fast you are going to get there, LOL Area affects RATE of transfer, not direction - thats why a black-hole has a gravitational pull a lot greater than Earth does, lol.

 

[KRandor]

Originally posted by: rjain
where gravity and quantum coherence operate on space-time itself.

You have read my definitions of space and time haven't you? (Linked thread a few posts up).

 

[lucky9]

i'm almost sure that i've read/seen that it's the speed of light as far as propagation goes.

 

[Chaotic42]

I just want to say that I :heart: all of you for having this discussion.

:beer:

 

[dmcowen674]

Originally posted by: Chaotic42
I just want to say that I :heart: all of you for having this discussion.

:beer:

Ditto, Yes indeed, it is most excellent.

 

[rjain]

Originally posted by: lucky9
i'm almost sure that i've read/seen that it's the speed of light as far as propagation goes.

One experiment has said that. Dozens have said that it MUST be significantly larger than the speed of light. In fact, I don't know of any experiment that can put an upper limit on the speed of gravity, only ones that can put a lower limit on it.

 

[rjain]

Originally posted by: KRandor

Originally posted by: rjain
The shape and size of the object is irrelevant.

Not if you're concerned on how fast you are going to get there, LOL Area affects RATE of transfer, not direction - thats why a black-hole has a gravitational pull a lot greater than Earth does, lol.

LoLl, A black hole has a stronger gravitational pull because it has a larger mass. Nothing to do with the shape or size. This is elementary physics, really, loll...

 

[rjain]

Originally posted by: KRandor

Originally posted by: rjain
where gravity and quantum coherence operate on space-time itself.

You have read my definitions of space and time haven't you? (Linked thread a few posts up).

Ok, I just tried reading your posts in that thread quickly and I'm totally lost as to what you're trying to say. You're proposing some concept of "efficiency" which is totally undefined and used in no way that helps me understand what it is. You obsess about density as though it had some other effect on the gravitational charge that no one has observed yet. Gravity is just an attractive force. That's all that applies as far as you're taking it.

Of course, there have been observations of a gravity-like repulsive force, but that's only in the presence of special kinds of superconductors and rapid changes in current or voltage. Basically, it seems that those kinds of superconductors can "translate" between gravity and EM. I wonder if it has to do with the cooper pairs managing to be coherent over long space-time distances, causing some sort of funkiness in space-time due to the proposed connection between coherence and gravity...