Gravity never zero

[Trippy]

. . . "Whether or not they (sic, gravitons) actually exist??" . . . if they don't exist . . . a discussion of their imaginary properties is a moot and ludicrous point!

It's a hypothetical discussion.

If they exist, based on the evidence we have available to us, what properties must they have.

If you can't handle having a discussion about a hypothetical particle that has been neither proven to exist, nor excluded from existing, I suggest you stop interjecting in an aspect of the conversation you clearly have no interest in participating in. Otherwise you simply come accross as a troll and an ass.

For someone who was recently berating someone else for speaking authoritatively on an ambiguous matter, you're certainly doing a good job of that here and now.

 

[wlminex]

It's a hypothetical discussion.

If they exist, based on the evidence we have available to us, what properties must they have.

. . . so . . . you're saying they "DO" exist, based on the 'evidence' available to us . . .? If there is evidence for this (gravitons), doesn't hypothesis evolve to theory? . . . and thus is testable by the scientific method?

 

[Robittybob1]

Again, discussion of whether or not they actually exist is irrelevant to a discussion of what properties they must have if they do.

It was the properties of the hypothetical Graviton that was what I wanted to know. (not their spin characteristics ) but how they link particles and spread out forming an inverse square force field.
You might have covered it. Do they act linear (like light) or circumferentially (like magetism) or some other way?

 

[Trippy]

It's a hypothetical discussion.

If they exist, based on the evidence we have available to us, what properties must they have.

. . . so . . . you're saying they "DO" exist, based on the 'evidence' available to us . . .? If there is evidence for this (gravitons), doesn't hypothesis evolve to theory? . . . and thus is testable by the scientific method?

No, that's a strawman hypothesis. It's not what I am saying at all.

I am saying that if we are considering a theorey which predicts them, then they must have certain properties otherwise theories predicting their existence would be contradicted by available evidence. For example, if you accept Kopeikins methodology, then if gravitons exist, then they must be massless, which in turn implies that gravity has an infinite range. If, they are predicted to be massive, then other observations would provide an upper limit to their mass.

Understand yet?

 

[Trippy]

You might have covered it. Do they act linear (like light) or circumferentially (like magetism) or some other way?

They act in both ways, like photons do.

 

[Robittybob1]

They act in both ways, like photons do.

So you are implying they are particles and waves (is that the "both"?) So their effect is spread by their wave nature?

 

[Trippy]

So you are implying they are particles and waves (is that the "both"?) So their effect is spread by their wave nature?

Is it possible for you to rephrase this so that it can actually be made sense of?

 

[Robittybob1]

Just tell me how gravitons create gravity? How their effects are felt throughout the Universe, and how they can do it and achieve a force with an inverse square relationship?

 

[Trippy]

Yeah, Trippy . . . . . how does this happen? . . . a "MECHANISM", please!

I'm not interested in justifying their existence to someone who can not retain context, doesn't know what he's talking about, and engages in dishonest behaviour. Nor am I interested in getting into a discussion that is off topic, and a side track from a point that was raised by someone else.

The point you have repeatedly failed to comprehend is that RJ Beery posed the hypothesis that "If gravitons exist, then A is implied" to which my response was "Any theory that predicts that gravitons exist, must also imply B, which in turn implies C, which negates your concern".

Do you understand yet? Is your comprehension up to speed? Should I post it in swahili instead?

Understand this, and get it through your skull.

I AM NOT CLAIMING GRAVITONS EXIST.

I'm also not claiming they don't exist, and I'm not interested in debating with you whether or not they actually exist.

I am simply making the point that if you ask a question predicated on the assumption of their existence, then that assumption has other implications, hence the irrelevance of the debate as to whether or not they actually do.

Just tell me how gravitons create gravity? How their effects are felt throughout the Universe, and how they can do it and achieve a force with an inverse square relationship?

Same goes for you (see above).

If you're genuinely interested in these things, then perhaps you should consider starting your own thread and trolling someone elses, or, alternatively, you can do some research in to quantum field theory, String Theory, and maybe if you can find a particle physicist to harass, and maybe if you ask them very nicely, they might explain it to you. Although I suspect Alphanumeric would be able to explain why gravitons couple to the stress-energy tensor, but so far, I am not convinced that either of you would understand that explanation.

Now, the pair of you.

ARE WE CLEAR?

I will no longer be addressing your inane attempts at trolling. If you're incapable of inferring that I was simply discussing other implications of the existence of gravitons without neccessarily arguing for or against their existence, then I strongly reccomend you both work on your prose literacy skills.

If you can't figure out that considering the implications of a model makes no implications about acceptance, well then maybe the pair of you need to consider careers other than science.

Either way, kindly stop trolling.

Meanwhile, I leave you with these words from Aristotle:
"It is the mark of an educated mind to be able to entertain a thought without accepting it."

 

[OnlyMe]

EDIT: THIS HAS NOTHING TO DO WITH THE GRAVITON DISCUSSION

There's the work of Kopeikin et al which suggests that gravity propagates at a velocity within 20% of c (they made the measurements using Jupiter and it's effects on a quasar (there is, it seems, some controversey over this is to whether they actually measured c instead).

There's also the Hulse-Taylor binary systerm, which suggests that it propagates at c to within 1%.

Trippy, I don't believe that what I know of either of these, confirms a propagation velocity for gravity. The observations, can be interpreted as such, but this is not without, as you mentioned controversy.

Yes we do, the work of Kopeikin, and the measurements of the Hulse-Taylor binary system (which, incidentally, also gives us evidence for gravitational waves, even though we have yet to measure them directly).

Again here, the "evidence" for gravitational waves is not actually present... They have not been confirmed just theorized to result from, such binary systems.

We have, by measuring their rate of orbital decay.

The orbital decay again, requires an application of theory to arrive at the conclusion.

There are so many things we have thought were more or less settled physics, that are now beginning to be challenged by recent astronomical/cosmological observations. GR itself begins to fall short where galactic orbital velocities are involved.., without the introduction of dark matter, which we have not yet confirmed...

 

[Robittybob1]

@ Trippy You seem to have misunderstood the simplicity of my question. I was never questioning their existence but trying to understand their proposed mechanism. I have looked at Wikipedia yesterday and at the time it was too technical, so I was hoping for a layman's version first.
Sorry to upset you, but it was not trolling but a genuine desire to understand it.

 

[Trippy]

Trippy, I don't believe that what I know of either of these, confirms a propagation velocity for gravity. The observations, can be interpreted as such, but this is not without, as you mentioned controversy.

Again here, the "evidence" for gravitational waves is not actually present... They have not been confirmed just theorized to result from, such binary systems.

In so far as the Huse-Taylor binary system goes, it is my understanding that:
The rate of energy loss has been measured to be as predicted by relativity.
Relativity predicts that the energy loss occurs via gravity waves.
Relativity predicts that, among other things, the rate of energy loss from the system is dependent on the 'speed of gravity', because the radiation of gravity waves is itself dependent on the retarded (relative) positions rather than their instantaneous positions.

Do you see?

If Gravity traveled at some speed other than c, then relativity would make a prediction that is different from what is observed, and so the assumption that gravity travels at c is confirmed as being accurate, until someone comes along with a theory that gravity travels at something other than c and makes all of the same predictions as relativity and does so at least as accurately as relativity does, and predicts that in circumstances such as the Huse Taylor binary system, it will look almost like relativity predicting that gravity travels at c even though it really doesn't.

GR itself begins to fall short where galactic orbital velocities are involved.., without the introduction of dark matter, which we have not yet confirmed...

And yet, when combined with Dark Matter, it remains the only theory that can account for things such as the observed distribution of gravitational lensing in the bullet cluster, and accurately predicts the arisal of early SMBHs.

Point of trivia - MOND (and presumably by extension TeVeS) also requires the existence of dark matter, it just requires less of it.

 

[Trippy]

@ Trippy You seem to have misunderstood the simplicity of my question. I was never questioning their existence but trying to understand their proposed mechanism. I have looked at Wikipedia yesterday and at the time it was too technical, so I was hoping for a layman's version first.

You can understand how I might have been (or might be) feeling a little dog piled yes?

Sorry to upset you, but it was not trolling but a genuine desire to understand it.

Accepted.

At this point, though, my advice remains the same. You would be better off talking to Alphanumeric than you would be talking to me. I am, first and foremost an environmental chemist whos full time employment is enforcing environmental legislation, whose job involves applying the scientific method to real world problems to come to pragmatic conclusions that meet certain minimum legal standards of proof, and writing papers in language that politicians and lawyers can understand.

Alphanumeric, on the other hand, is a published, peer reviewed author in a relevant field to the question you're asking me.

My advice to you based on that is to start a thread in the Physics and Math forum, entitled something useful like "Mechanics of Graviton Coupling", and ask him, politely:
What the stress-energy tensor represents, what it means, and how gravitons couple to it.
Keep in mind that he currently has a great deal going on in his personal life, and that Prometheus has also published papers in a similar (or the same) field.

Take the time to try and understand what they tell you, and if you have genuine questions, do not be afraid to ask.

 

[RealityCheck]

.

Hi wiminex. Pleased to meet ya. Can't stay long.

It's a hypothetical discussion.

If they exist, based on the evidence we have available to us, what properties must they have.

. . . so . . . you're saying they "DO" exist, based on the 'evidence' available to us . . .? If there is evidence for this (gravitons), doesn't hypothesis evolve to theory? . . . and thus is testable by the scientific method?

I think Trippy meant for you to read the relevant bit somewhat differently (as I paraphrase below):

"If they exist, what properties must they have (based on the evidence we have available to us....about the whole universal phenomena)?

See? He wasn't talking of evidence for the hypothetical graviton, but rather talking of evidence overall in the physical/cosmological sciences, which must necessarily put limits/parameters regarding any such hypothetical graviton if it is to be 'consistent' with all the OTHER available evidence around so far.

Cheers.

.

 

[AlexG]

Just tell me how gravitons create gravity? How their effects are felt throughout the Universe, and how they can do it and achieve a force with an inverse square relationship?

Gravitons create gravity the same way as photons create an electromagnetic field. The gravitational field exists and causes space to 'bend'. It's the field which we see the effects of. The graviton is the exchange particle of the field, in the same way that photons are the exchange particle of the electromagnetic field, or the W and Z bosons are the exchange particle of the strong and weak force.

You can't think of the graviton and the gravitational field as two different things.

 

[wlminex]

. . . in the famous words of Clara Peller (a properly cited, non-plagiarous reference here) . . . "WHERE'S THE BEEF??" . . . . or rather, "Where's the graviton" . . .

 

[AlexG]

. . . in the famous words of Clara Peller (a properly cited, non-plagiarous reference here) . . . "WHERE'S THE BEEF??" . . . . or rather, "Where's the graviton" . . .

We're looking.

Since the energy levels we're trying to detect are so low, it takes an incredibly accurate, stable detection instrument.

If LISA is ever constructed, it might do it.

 

[Trippy]

We're looking.

Since the energy levels we're trying to detect are so low, it takes an incredibly accurate, stable detection instrument.

If LISA is ever constructed, it might do it.

Or VIRGO.

 

[Robittybob1]

Gravitons create gravity the same way as photons create an electromagnetic field. The gravitational field exists and causes space to 'bend'. It's the field which we see the effects of. The graviton is the exchange particle of the field, in the same way that photons are the exchange particle of the electromagnetic field, or the W and Z bosons are the exchange particle of the strong and weak force.

You can't think of the graviton and the gravitational field as two different things.

Thanks AlexG

Right consider this please: If the graviton's field causes the space to bend. We run an experiment.
1. So say we take 2 neutrons close to each other (1 meter apart) floating in deep space, they would bend space between them so they would fall toward each other.

2. But if they then were separated such that the bend in the Space Time was so minimal (less than a Planck length/X meters) so that the acceleration was less than a Planck length per Planck time^2, would there be no movement for there is "no slope", and the attractive force would be less than a "quantum force". It would not overcome the particle's momentum and hence not move.

Conclusion: Gravitational attraction would be essentially zero?

 

[Robittybob1]

Let a = 1 Planck length/Planck time^2
Mass = mass of Neutron
Force = Mass * acceleration
if G force is less than Force will it be able to move the Neutron???

Planck Time (hG/c5)1/2 1.3513 x 10^-43 s
Planck Length (hG/c3)1/2 4.0510 x 10^-35 m

A = Pl/Pt^2 = 8.85127E+50
Since Planck Time is such a small quantity of time this actually comes out to a horrendous acceleration.
Let a = 1 Planck length/second^2
then a = 1.616252E-35 m/sec^2 which will get absorbed by the Uncertainty of position.


Mass of a Neutron 1.6749 x 10^(-27) kg
F = Ma = 1.6749 x 10^(-27) kg * 1.616252E-35 m/sec^2
F = 2.70706E-62 Newtons
So how far apart do 2 neutrons have to be to have this amount of force between them?