gravity does not propagate but is instantaneous

[bonzelite]

the speed of gravity is greater or = 2x10^10 c<br /><br />from: http://www.metaresearch.org/cosmology/speed_of_gravity.asp<br /><br /><font color="yellow">... gravity, in contrast to light, has no detectable aberration or propagation delay for its action, even for cases (such as binary pulsars) where sources of gravity accelerate significantly during the light time from source to target. By contrast, the finite propagation speed of light causes radiation pressure forces to have a non-radial component causing orbits to decay (the "Poynting-Robertson effect"); but gravity has no counterpart force proportional to v/c to first order. General relativity (GR) explains these features by suggesting that gravitation (unlike electromagnetic forces) is a pure geometric effect of curved space-time, not a force of nature that propagates. </font><br /><br /><font color="yellow">...all gravitational interactions between bodies in all dynamical systems [have] to be taken as instantaneous.</font>/safety_wrapper>

 

[contracommando]

<b>gravity does not propagate but is instantaneous</b><br /><br />Do you mean over all bodies in the universe, or over those objects that are very close?

 

[bonzelite]

<font color="yellow"> the speed of gravity in Newton's Universal Law is unconditionally infinite.</font><br /><br />paraphrased: in computer models, if you implement a delay in gravitational interactions between bodies, the results do not jibe with conservation of angular momentum; the bodies' orbits or mutual influences destabilize. gravitational attraction must remain instantaneous to garner what is actually observed. <br /><br />if gravity is truly, then --literally-- a geometric property of spacetime and not an independent force, then the ramifications of this are far reaching, to make an unintentional pun. <br /><br />spacetime, then, in a cool and mind-boggling way, would in essence be space-gravity-time. apparently, "gravitational radiation" does propagate at light speed, but is not one and the same as this thing called "gravity." <br /><br />a few of you conoisseurs of GR can certainly have a field day with this premise.......

 

[kmarinas86]

<font color="yellow">if you implement a delay in gravitational interactions between bodies, the results do not jibe with conservation of angular momentum</font><br /><br />Not really.<br /><br />Think of all waves as having momentum.<br /><br />Water waves, sound waves, and light waves, all transfer momentum.<br /><br />Photon Energy / speed of light = momentum<br /><br />I prefer to think of gravity as a gravitational field that influences the permittivity and magnetic permeability of the vacuum, and thus effect the speed of all electromagnetism (including light) and of observers themselves. That is much more intuitive than speaking of time dilation. That is simple a conversion of angular momentum in the atoms to linear momentum of the rocket and exhaust.<br /><br />The electromagnetic energy in rockets is converted into to the velocity of the rocket ship. I like to think of that as influencing a local change in the velocity and angular velocity of electromagnetic energy instead of as time dilation (decreased velocity and angular velocity of electromagnetic energy within the subatomic particles of the speeding rocket). <br /><br /><font color="yellow">Refraction means the bending of a wave resulting from a change in its velocity as its moves from one medium to another. Since the frequency of a wave cannot change, independently of the source changing its frequency when it emits the wave, this change in wave velocity is must result from a change in wavelength in the second medium.</font><br /><br />The slowing of light is the same as so called time dilation. The refractive index increases with the density of the electric and magnetic fields. That is why ice has a lower refractive index than water.<br /><br />http://www.google.com/search?q=ice+water+refractive+index<br /><br />http://www.goog

 

[bonzelite]

i sort of follow your thinking and sort of do not. in the way i understand it, more simply, when we see the sun, we see it as it was eight minutes ago because it takes light eight minutes to reach us from the sun. when the gravitational force attracts the earth, the force of attraction is occuring where the sun is NOW, not from where it was eight minutes ago, so gravity would seem to act at infinite speeds.

 

[astrophoto]

We can conduct a simple test. All we need to do is make the Sun instantaneously disappear and see how long it takes the Earth to react to the loss of gravitational influence. Let's get crackin!

 

[bonzelite]

indeed, spoken as a true scientist! i'll help you remove the sun.

 

[unlearningthemistakes]

MY opinion:<br />should it be proven in due time, that gravity is graviton, then we can assume that particles, as such a graviton is supposed to be, are limited to C. If otherwise, gravity <i>just and only just</i> a curvature of spacetime, we can perhaps assume that gravity has a near instantaneous effect. <br /><br /><i>near instantaneous:</i> I just supposed spacetime as a fabric. well, strecthing a fabric is not totally instantaneous, since pulling one side towards the other side still requires time to take effect. <br /><br />as in cause and effect needs time. <div class="Discussion_UserSignature"> <p>pain is inevitable</p><p>suffering is optional </p> </div>

 

[robnissen]

Reminds me of an experiment I heard of (maybe here), for proving string theory. First, we need a particle accelerator the size of the Milky Way. As soon as we get that, we can move on to item 2.

 

[bonzelite]

the thing is, gravity is non-local. and acts instantaneously upon any object no matter the proximity. it is far faster than c. planetary motion, and all else, would not be predictable or function as it is observed if there was a c speed limit to gravitational attraction. as well, if gravity is geometrically bound to spacetime, as a trait of it, then that eliminates a gravity particle. gravity, then, must be some other strange beast entirely. <br /><br />if information could be sent via gravity --god knows how-- we'd have superluminal communication rather efficiently. would make a good sci-fi short story.

 

[astrophoto]

If spooky interaction at a distance works, I don't see why gravity can't be some unexplainable phenomena of the Universe at this time and works instantaneously just 'because it does'. We'll probably figure it out one day, but we just don't have all the facts yet or are missing some fundamental understanding of what we're measuring to draw a conclusion.

 

[bonzelite]

+10. i agree. i think gravity, as commonly thrown around as a household word, is barely understood. <br /><br />i am surprised, too, that the instantaneousness of gravity is nearly never mentioned or ever talked about in discussions here --you'd think it would be, as there are many "superluminal" freaks on here, and quite a few others who can talk at length about exotic processes such as entanglement and decoherence, dark matter, black holes, all of this. <br /><br />we've already got superluminal phenomena in our universe and it is gravity. and gravity is an endemic trait of spacetime and not a propagating force of nature, even though it looks like it should be. <br /><br />

 

[unlearningthemistakes]

<br /><font color="yellow">that the instantaneousness of gravity is nearly never mentioned or ever talked about in discussions here </font><br /><br />it was...<br /><br />http://uplink.space.com/showflat.php?Cat=&Board=sciastro&Number=364091&page=20&view=collapsed&sb=5&o=0&fpart=all <div class="Discussion_UserSignature"> <p>pain is inevitable</p><p>suffering is optional </p> </div>

 

[abq_farside]

I think there was a thread in ask the astronomer a while back too and couple on going gravity related threads now. <div class="Discussion_UserSignature"> <p> </p><p><em><font size="1" color="#000080">Don't let who you are keep you from becoming who you want to be!</font></em></p> </div>

 

[unlearningthemistakes]

right... <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p>pain is inevitable</p><p>suffering is optional </p> </div>

 

[dragon04]

I don't think gravity propogates at FTL velocities. You can have, say, the sun's gravity well acting on an object perpendicular to the plane of the solar system "instantly", just by seeing gravity as tension on the fabric of space-time itself.<br /><br />But that goes back to whether or not gravity is a field or particle effect, doesn't it?<br /><br />I'm obviously no physicist, but all matter in space is gravitationally interacting with itself on both the macro and microscopic level. Like a big, twisted tangle of sticky rubber bands all under tension from the interactions between them.<br /><br />I think "instant" is a relative term. Take two 100kg bowling balls, for example. They both have a quantifiable gravitational influence.<br /><br />Put them on opposing edges of a trampoline, for example, and then roll them towards each other. Their net effect as a (system?) will alter the shape of the trampoline individually, but as they come closer to one another, their net effect changes the shape of the trampoline as a whole.<br /><br />The end result didn't happen immediately. Am I making sense?<br /><br /><br /><br /><br /><br /><br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[astrophoto]

Prove to me that gravity travels at c.

 

[nojocujo]

Stevehw33<br />I asked you to attack me and you won't don't! Why? Am I always right?? <br />I think that gravity causes a spacetime contraction ftl below the schwartzchild radius.<br />If there were a canceling wavefront from a singularity the spacetime expansion would be ftl beyond the schwartzchild radius. My opinion!

 

[bonzelite]

in essence, there is no real velocity to gravity. that term does not apply, per se, to this phenomenon. gravity is not a propagating force. it is a non-local geometric property of spacetime. this is real physics. so i must have some knowledge of real physics. this is beyond physics 101. they do not tell you this in physics 101. <br /><br />there is no gravitational delay between bodies. if there was, the observed universe would not remain as it is seen. orbits would not be calculable. objects are instantly affected by gravity. and scientists for years have been in a conundrum over this fact. they don't know why this is so. i don't know. you don't know. the world does not know why. <br /><br />this area is avoided generally in classroom curricula because it would complicate the basics of physics that are taught in a lower level framework. yet the fact is elementary and very simple. but the ramifications are incredible: if atoms, then, are affected instantly by gravity, then this communication between atoms is instantaneous via the dimension of "gravity." fundamentally, gravity has zero time and is therefore a spatial coordinate framework, ie, a dimension, and NOT a force as we know it. <br /><br />this makes gravity even more bizarre than ever. <br /><br />

 

[robnissen]

"there is no gravitational delay between bodies."<br /><br />Stating something as a fact, does not make it a fact. Other than your say so, what proof do you have that there is "no gravitational delay?"<br /><br />"if there was, the observed universe would not remain as it is seen. orbits would not be calculable." <br /><br />Why? Once again stating something with conviction does not make it so. Unless you can state "why," your statement is no more useful than if I were to say: "Earth must be standing on the backs of turtles because otherwise it would fall down."<br /><br />"Objects are instantly affected by gravity."<br /><br />Re-stating a bald assertion a second time with conviction, still does not make it so.<br /><br />"scientists for years have been in a conundrum over this fact. they don't know why this is so."<br /><br />Wrong once again. Indeed, although not without some controversy, there is pretty strong evidence from an experiment done a couple of years ago that the speed of gravity has been measured. The space.com article is here: http://www.space.com/scienceastronomy/gravity_speed_030116.html<br /><br />

 

[raghara2]

"Stating something as a fact, does not make it a fact. Other than your say so, what proof do you have that there is "no gravitational delay?" "<br /><br />I never seen one, you did?<br />No aberration is clear hint. Much better than any counterarguments.<br /><br />" Indeed, although not without some controversy"<br /><br />I hope you didn't mean Kopeikin work. It should be viewed as he measured speed of light. If he measured anything, then speed of light measured with precision of 1/10 is kinda inprecisse. We had better experiments. <br />From what I seen he might be overrelying on math. It could happen. Math can't substitute thinking, or extrapolations, however. Also current field isn't exactly filled by completely exact and proven equation, it's more filled by artifical restrictions, and aproximations. For this reason reliance to math would be wrong.<br />I think that Kopeikin, van Flander letters are better than that article. Van Flanders nearly drove Kopeikin nuts, and from theirs argumentations we could discover a lot. <br />If Asada's arguments against his measurment weren't retracted, then we could say Kopeikin measured just a speed of light with 1/10 precision.<br /><br />What was your definition of a term strong evidence? <br />I don't think the term strong evidence is even close in meaning to the term no evidence.

 

[tomadams]

it will be interesting if the boys at stanford come up with a measurement for mu via gravity probe b.<br /><br />this should really shed some light on the topic.<br /><br />seems to be enough heat already...

 

[bonzelite]

<font color="yellow"><br />Stating something as a fact, does not make it a fact. Other than your say so, what proof do you have that there is "no gravitational delay?" </font><br /><br />of course. i can boldly claim anything with supreme confidence and it may not necessarily be true. <br /><br />in the case of gravity, it is so, however, that it acts instantaneously or nearly so. i'm not the one who arrived at this observation. others have and it is so. if you allow for any delay in gravitational attraction in computer models, for example, of the planetary orbits, their orbits will not resemble what is actually observed. <br /><br />there is nothing wrong about any of it.

 

[bonzelite]

any computation program for orbital motion. you can probably buy one off the shelf. put in a c value for the gravity and the outcomes are not consistent with actual planetary motion. <br /><br />GR essentially uses instant propagation times as well, but mathematically says that it is not "really" so. but it is. <br /><br />http://www.gravitywarpdrive.com/Speed_of_Gravity.htm

 

[bonzelite]

http://www.space.com/scienceastronomy/gravity_speed_030116.html<br /><br />thre are all kinds of claims that the speed of gravity has "definitely been confirmed to be the speed of light," but in reality this is b.s. <br /><br />the thing is, physicists right now do not agree on this point. there is reluctance to outright accept that light is not the speed limit for gravity. the popular consensus is that there is no consensus because GR proponents cannot reconcile it. <br /><br />and this:<br />http://www.lbl.gov/Science-Articles/Archive/Phys-speed-of-gravity.html<br /><br />the sun acts upon the earth in real time, not in an 8 minute delay. gravity is considered to be a force rather than a dimension. the mere act of doubting the geometric dimensionality of gravity helps perpetuate the idea that it is a propagating force. <br /><br />