Jump to content
Science Forums

Is Space Zero Gravity (0 G)


Darky
 Share

Recommended Posts

 

Since LIGO started operating, two discrete events have been observed. They have been theorized for a long time, and we finally have data that shows they exist.

 

From LIGO:

 

On February 11, 2016, the LIGO Scientific Collaboration and Virgo Collaboration announced the first confirmed observation of gravitational waves from colliding black holes. The gravitational wave signals were observed by the LIGO's twin observatories on September 9, 2015.

 

On June 15, 2016, the LIGO Scientific Collaboration and Virgo Collaboration announced the second confirmed observation of gravitational waves from colliding black holes. The gravitational wave signals were observed by the LIGO's twin observatories on December 26, 2015.

Yeah, no
Link to comment
Share on other sites

Read the article before you post the link, for heaven's sake.

 

Date of that article - "12 Jan 2016 at 10:35 ET "

 

First announcement of discovery by LIGO - 11 Feb 2016

Second announcement of discovery by LIGO - 15 Jun 2016

 

It's like you are posting an article from 1965 that "proves" Man will never land on the Moon.

that link doesn't confirm your story.
Link to comment
Share on other sites

Yeah, that's totally what the article said.

 

Tsk tsk. Another Wikipedia.

 

Static fields was one of over 5 different models for gravity in that article, all of which predate the test in the .edu I hyperlinked, read the "Lorentz-Poincare" model in that article. Fits better with modern results.

No you are misreading the article.

 

The section on static fields is not an alternative earlier model that has now been superseded, but is part of the current model. This section has been written to make clear the distinction that has to be drawn between static effects of gravitational fields and disturbances in a gravitational field, which indeed GR predicts should travel outward from the source of the disturbance at c.

 

This is obvious if you read it properly, i.e. understand what you are reading.  

Link to comment
Share on other sites

No you are misreading the article.

 

The section on static fields is not an alternative earlier model that has now been superseded, but is part of the current model. This section has been written to make clear the distinction that has to be drawn between static effects of gravitational fields and disturbances in a gravitational field, which indeed GR predicts should travel outward from the source of the disturbance at c.

 

This is obvious if you read it properly, i.e. understand what you are reading.

Yet we've never observed gravity waves.

 

If you read the peer reviews over Kopeikin's attempt to measure the speed of gravity, and I posted two papers and the more credible one who is in the department of physics as opposed to "theory" like the other author mathematically affirms that gravitational fields propagate.

 

And that goes against what you & OceanBreeze said earlier.

Edited by Super Polymath
Link to comment
Share on other sites

Yet we've never observed gravity waves.

 

If you read the peer reviews over Kopeikin's attempt to measure the speed of gravity, and I posted two papers and the more credible one who is in the department of physics as opposed to "theory" like the other author mathematically affirms that gravitational fields propagate.

 

And that goes against what you & OceanBreeze said earlier.

The Wiki article makes quite clear that what people sometimes call the "speed of gravity" is the speed with which a disturbance in the gravitational field propagates.

 

We are all happy to agree that GR predicts such disturbances should propagate at c.  

 

As to whether they have yet been unambiguously detected or not, I read that they have, but it may well be that this is challenged. I take no position on that, not having read up how the detection has been done, though I do find the change in period of that binary star system very suggestive.   

 

None of this is contradicted by any source or paper you have posted. We are all in agreement with the theory behind them all. 

 

However, to reiterate the key point we have been making to you, the gravitational field itself, in which such disturbances may arise under certain circumstances, does not consist of waves: it is just there.  

 

Gravitation is not itself a wave phenomenon.  

Edited by exchemist
Link to comment
Share on other sites

The Wiki article makes quite clear that what people sometimes call the "speed of gravity" is the speed with which a disturbance in the gravitational field propagates.

 

We are all happy to agree that GR predicts such disturbances should propagate at c.

 

As to whether they have yet been unambiguously detected or not, I read that they have, but it may well be that this is challenged. I take no position on that, not having read up how the detection has been done, though I do find the change in period of that binary star system very suggestive.

 

None of this is contradicted by any source or paper you have posted. We are all in agreement with them all.

 

However, to reiterate the key point we have been making to you, the gravitational field itself, in which such disturbances may arise under certain circumstances, does not consist of waves: it is just there. Gravitation is not itself a wave phenomenon.

It would still go against what you & OceanBreeze are saying because Kopeikin didn't measure gravity waves! We haven't been able to produce gravity waves nor have we observed them!

 

Anyone can write **** on Wikipedia, don't be too trusty of that information, I gave you a legit experiment & a physicist's peer review!

Edited by Super Polymath
Link to comment
Share on other sites

It would still go against what you & OceanBreeze are saying because Kopeikin didn't measure gravity waves!

What we are saying is that a gravitational field does not consist of waves.

 

Can you please explain how this reference of yours contradicts that statement? 

Link to comment
Share on other sites

What we are saying is that a gravitational field does not consist of waves.

 

Can you please explain how this reference of yours contradicts that statement?

You both said "a gravity field does not propagate" only the "wave" generated by a disturbance in its field, there's a physicist's peer review explaining where y'all went wrong! Edited by Super Polymath
Link to comment
Share on other sites

I believe our best view of gravity is to look at it as waves of space time emanating outward from matter & energy in a spherical fashion given Einstein's "gravity waves" remain speculation and gravitons have not been observed either.

 

As matter & energy are infitely dispersed by expansion these waves no longer interact with matter & energy beyond points we call causal limits (our particle horizon), within each particle horizon a nigh-infinitude of waves (micro-gravity) from all of the causally connected matter & energy in the observable universe must momentarily clash together from every angle with equal strength, effectively neutralizing the effects of any gravity. This is a total Lagrange point.

Edited by Super Polymath
Link to comment
Share on other sites

You both said "a gravity field does not propagate" only the "wave" generated by a disturbance in its field, there's a physicist's peer review explaining where y'all went wrong!

This paper is calculating what the effects would be if the speed of a gravitational disturbance propagated at a speed c(g) which was different from c. 

 

Its object is to challenge the findings of this guy Kopeikin in his measurements of Jupiter. 

 

It does not assert that a gravity field is made of waves, nor that a static field "propagates". 

 

Also it is published on arxiv, which means it has not been peer-reviewed.  

Edited by exchemist
Link to comment
Share on other sites

I believe our best view of gravity is to look at it as waves of space time emanating outward from matter & energy in a spherical fashion given Einstein's "gravity waves" remain speculation and gravitons have not been observed either.

 

As matter & energy are infitely dispersed by expansion these waves no longer interact with matter & energy beyond points we call causal limits (our particle horizon), within each particle horizon a nigh-infinitude of waves (micro-gravity) from all of the causally connected matter & energy in the observable universe must momentarily clash together from every angle with equal strength, effectively neutralizing the effects of any gravity. This is a total Lagrange point.

Aha, at last we get to it: you have a crank theory of gravity. That is what lies behind all this.

 

(I presume the title "Super Polymath" that you give yourself is intended humorously.)  

Link to comment
Share on other sites

nor that a static field "propagates".

It states that, that's what the entirety of the physics there is based on. Not once do I see static field, I see gravity field, but never do I see " static field". You need to drop it with the Wikipedia arguments.

 

Also it is published on arxiv, which means it has not been peer-reviewed.

Moderator reviewed, equitable in practice. Edited by Super Polymath
Link to comment
Share on other sites

It would still go against what you & OceanBreeze are saying because Kopeikin didn't measure gravity waves! We haven't been able to produce gravity waves nor have we observed them!

 

Anyone can write **** on Wikipedia, don't be too trusty of that information, I gave you a legit experiment & a physicist's peer review!

 

 

 

This is getting to be bizarre. Your link takes us to a review authored by physicist Clifford M. Will, of the claim made by Kopeikin and colleagues, to have calculated the “velocity of gravity” by measuring the delay in the propagation of a light signal past a massive body (Jupiter) that moves with speed v.

 

Do you agree that is what you have linked to?

 

If so, I suggest you actually read the paper you linked to, and try to understand what it is saying.

 

I will save you some time and quote directly from your linked paper:

 

Since we are working to first order in v/c, only Jupiter’s rectilinear motion is

relevant; its acceleration generates effects higher order in Gm/c2. The vector K is simply

the spatial unit vector of the photon’s direction as seen in the rest frame of Jupiter; the

correction terms in Eq. (4) are nothing but the effect of aberration. They depend only on c,

which is the velocity relevant for Lorentz transformations and the propagation of light, not

on cg. Indeed, from the viewpoint of Jupiter’s rest frame, cg is completely irrelevant, since the

gravitational field is static (again, ignoring Jupiter’s acceleration). The velocity-dependent

prefactor is a combination of a gravitomagnetic effect (the fact that the gravitational field is

not a scalar quantity, but contains both a vector and tensorial part) and a simple Doppler

effect in transforming from Jupiter’s rest frame to the barycentric frame.

 

We thus conclude that the v/c corrections to the Shapiro time delay are normal 1.5PN

corrections that occur when there are moving bodies, but that they have nothing to do

with the speed of propagation of gravity, insofar as it affects the retardation of gravitational

interactions. Furthermore, as a potential test of alternative gravitational theories, measuring

these v/c terms is not promising, because a variety of solar system measurements already

constrain α1 and γ to such a degree that |ζ| < 4 × 10−3 under relatively weak assumptions

or |ζ| < 5 × 10−5 under assumptions that invoke so-called “preferred-frame” tests of the

parameter α1 (see Will (2001) for the latest bounds on the PPN parameters). In fact, the

VLBI measurements are sensitive mainly to the velocity dependence in the logarithmic term,

not to the prefactor. Therefore, measurements of the propagation of radio waves past Jupiter

do not directly constrain the propagation speed of the gravitational interaction.

 

We have shown that the speed of propagation of gravity has no direct influence on the

time delay of light to 1.5PN order. The only effect comes from any modification of the PPN

parameters that might arise in a theory with a different propagation speed. This contradicts

claims made by Kopeikin (2001, 2002).

 

In case you don’t understand the above, I will translate it into plain English for you:

 

Physicist Clifford M. Will says the claim made by Kopeikin ( the claim that you are using as an arguing point ) is bullshit.

 

And, to be clear, he also says the gravitational field is static. When he mentions the propagation of gravity, he is talking about the gravitational interactions, those are gravity waves.

 

 

 

 

 

 

 

 

 

Link to comment
Share on other sites

It states that, that's what the entirety of the physics there is based on. Not once do I see static field, I see gravity field, but never do I see " static field". You need to drop it with the Wikipedia arguments.

 

Moderator reviewed, equitable in practice.

 

The paper is just fine. Too bad it hoses over your hero Kopeikin and the experiment you place so much faith in.

Link to comment
Share on other sites

This is getting to be bizarre. Your link takes us to a review authored by physicist Clifford M. Will, of the claim made by Kopeikin and colleagues, to have calculated the “velocity of gravity” by measuring the delay in the propagation of a light signal past a massive body (Jupiter) that moves with speed v.

 

Do you agree that is what you have linked to?

 

If so, I suggest you actually read the paper you linked to, and try to understand what it is saying.

 

I will save you some time and quote directly from your linked paper:

Since we are working to first order in v/c, only Jupiter’s rectilinear motion is

relevant; its acceleration generates effects higher order in Gm/c2. The vector K is simply

the spatial unit vector of the photon’s direction as seen in the rest frame of Jupiter; the

correction terms in Eq. (4) are nothing but the effect of aberration. They depend only on c,

which is the velocity relevant for Lorentz transformations and the propagation of light, not

on cg. Indeed, from the viewpoint of Jupiter’s rest frame, cg is completely irrelevant, since the

gravitational field is static (again, ignoring Jupiter’s acceleration). The velocity-dependent

prefactor is a combination of a gravitomagnetic effect (the fact that the gravitational field is

not a scalar quantity, but contains both a vector and tensorial part) and a simple Doppler

effect in transforming from Jupiter’s rest frame to the barycentric frame.

 

We thus conclude that the v/c corrections to the Shapiro time delay are normal 1.5PN

corrections that occur when there are moving bodies, but that they have nothing to do

with the speed of propagation of gravity, insofar as it affects the retardation of gravitational

interactions. Furthermore, as a potential test of alternative gravitational theories, measuring

these v/c terms is not promising, because a variety of solar system measurements already

constrain α1 and γ to such a degree that |ζ| < 4 × 10−3 under relatively weak assumptions

or |ζ| < 5 × 10−5 under assumptions that invoke so-called “preferred-frame” tests of the

parameter α1 (see Will (2001) for the latest bounds on the PPN parameters). In fact, the

VLBI measurements are sensitive mainly to the velocity dependence in the logarithmic term,

not to the prefactor. Therefore, measurements of the propagation of radio waves past Jupiter

do not directly constrain the propagation speed of the gravitational interaction.

 

We have shown that the speed of propagation of gravity has no direct influence on the

time delay of light to 1.5PN order. The only effect comes from any modification of the PPN

parameters that might arise in a theory with a different propagation speed. This contradicts

claims made by Kopeikin (2001, 2002).

In case you don’t understand the above, I will translate it into plain English for you:

Physicist Clifford M. Will says the claim made by Kopeikin ( the claim that you are using as an arguing point ) is bullshit.

And, to be clear, he also says the gravitational field is static. When he mentions the propagation of gravity, he is talking about the gravitational interactions, those are gravity waves.

 

 

You're misinterpreting my argument and he said that the field is static "ignoring Jupiter's acceleration", you do know that Jupiter's orbit gives it a velocity & that Jupiter's spin generates centrifugal force, and that the angle of Jupiter's spin and orbit change all the time, which means acceleration right?

 

So no gravitational field is ever really "static" is what I'm getting from all of this, every bit (from quark to neutrino) of energy in the universe seems to experience acceleration in its day to day interactions. I don't really care what gravity's velocity is. That was never why I brought it up.

 

& saying that it doesn't predict the speed at which gravity propagates=/=gravity in general doesn't propagate.

 

What all these physicists seem to have in common, is that they all believe gravity propagates, & they all want to know the velocity at which it propagates.

Edited by Super Polymath
Link to comment
Share on other sites

The paper is just fine. Too bad it hoses over your hero Kopeikin and the experiment you place so much faith in.

Lol, are you employing dun moch?

 

I don't see him saying that the speed of gravity hadn't been measured, he's simply pointing out where he thinks Kopeikin miscalculated according to his understanding.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...