What is the latest on gravitational radiation?

[newtonian]

Does gravitational radiation shift in wavelength similar to light shifting either to red or blue as a result of speed of the object radiating gravity?<br /><br />What are the latest discoveries concerning gravitational radiation?

 

[vogon13]

Yoiks!<br /><br />How did you come up with that question?<br /><br />Assuming the propagation occurs at light speed (do we know this?) a red or blue shift would 'adjust' the 'chirp' expected for the coallesence in a way that would mimic objects of a different total mass. So in this probably definitively wrong answer (hey, I tried) yes it would affect the signal, and no, there is no way to tell (just from the gravitational wave signal) that it had been red or blue shifted or by how much.<br /><br /><br /><br />Go not to the elves for counsel, for they will say both yes and no.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[newtonian]

vogon13 - One question leads to another.<br /><br />What did you mean by coalescense? A type of propagation, i.e. formation, of gravity?<br /><br />I remember reading that an observation was interpreted to confirm the existence of gravitational radiation a few years ago.<br /><br />However, the current reference from Wikipedia indicates otherwise, which I do not understand - but here is an excerpt anyway:<br /><br />http://en.wikipedia.org/wiki/Gravitational_radiation <br /><br />"Along with this curvature and gravitational attraction, Einstein's theory also permits space-time to fluctuate in a wave-like manner. This is similar, but not completely analogous, to the situation in electromagnetism where electromagnetic waves were first derived from Maxwell's equations.<br />The gravitational waves are oscillations of space-time itself and yet they also travel through space-time. Compare this to sound waves which are an oscillation of the air and yet travel through the air.<br />Gravitational waves travel at the speed of light and they are of a different character than sound or light waves. Sound waves are longitudinal, spin-0 pressure waves. Spin-0 means that sound is rather ordinary. Light waves are transverse, spin-1 electromagnetic waves. Spin-1 means that light has polarization. But gravitational waves are transverse spin-2 waves, something entirely different from any other known wave.<br />It is important to note that gravitational waves are unique to Einsein's theory of gravity and were not predicted by Newton's theory of gravity. Thus they are a new prediction of General Relativity but they have not been confirmed by observation, perhaps because of inherent difficulties.<br />In electromagnetism, certain motions of charged particles, like electrons, will radiate electromagnetic waves. Analogously in gravity, certain motions of mass or energy will radiate gravitational waves. In electromagnetism,

 

[newtonian]

vogon13 - For some reason Wikipedia did not refer to the observations which have confirmed the existence of gravitational radiation made 12 years ago:<br /><br />"Nevertheless, in the same way that electromagnetic radiation arises from oscillating charged particles, gravitational radiation has been predicted to arise from rapidly oscillating masses. In 1993 U.S. astrophysicists Joseph Taylor and Russell Hulse were awarded the Nobdel Prize for Physics for having observed the progressive miniscule increase in the speed with which two stars in the binary star system PSR 1913+16 are rotating around each other and correctly interpreted this change as resulting from energy loss due to the emission of gravitational radiation. Direct observation of gravitational radiation, however, remained to be achieved." - "Science and the Future," 1998, [Britannica Science Annual Yearbook], copyright 1997, page 363.<br /><br />This source noted that in 1996 physicists at Caltech (= California Institute of Technology) were building LIGO (= Laser Interferometer Gravitational-Wave Observatory which was expected to be fully operational in 1999.<br /><br />That would be 6 years ago - hence my question about the latest observational data.

 

[vogon13]

The strongest possible gravitational signal (apparently since the big bang) is believed to occur when 2 neutron stars (or other massive denizens of the universe) spiral in together and coalesce, (combine) sorry about the spelling in the post. As they enter the final stage of this, the gravity signal, if audible too human ears, would have a characteristic chirp. If the objects were rapidly approaching or receding from earth, the duration of the chirp would be longer or shorter. Most likely, such a distortion of the signal would be interpreted as making the signal appear to have originated in a system containing a different mass. A high radial velocity for such objects would probably not be considered.<br /><br />Caveats:<br /><br />I'm not sure my view is correct, there may be phase distortions in the signal that would tip off what actually happened, but I am clueless as to how that works out. Propagation speed of the signal is also a scary thing for me to think about.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[newtonian]

vogon13 - Yes, I have not read any details on the model for propagation of gravity by rapidly oscillating masses, as in the above quote.<br /><br />Have you heard of any model describing the mechanism - at least in theory?

 

[unlearningthemistakes]

hello newtonian...<br /><br />light radiation = photons ( this one is true )<br /><br />gravitational radiation = gravitons<br /><br />is this correct??<br /> <div class="Discussion_UserSignature"> <p>pain is inevitable</p><p>suffering is optional </p> </div>

 

[CalliArcale]

Now, I'm not a physicist, but my understanding is that that <i>might</i> be correct. However, the concept of gravitons is theoretical, but not yet testable, and does not have majority support yet. Gravity research is definitely a hot topic, partly because it's very hard to come up with a good experiment to test it from within a frame of reference which is itself affected by gravity. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[unlearningthemistakes]

"Gravity research is definitely a hot topic, partly because it's very hard to come up with a good experiment to test it from within a frame of reference which is itself affected by gravity. "<br /><br />Yes...<br />that will be the greatest obstacle...<br />even in space, we'll still swim around the power of gravity...<br /> <br /><br /> <div class="Discussion_UserSignature"> <p>pain is inevitable</p><p>suffering is optional </p> </div>

 

[newtonian]

borman - Oh my, how would one describe a quadrupole wave - sounds rather mind boggling!<br /><br />BTW, have you ever heard of the Cosmic Symphony (Scientific American, 2/04 with said title)? That, btw. is considered as a partial cause of structure in our universe.<br /><br />Also, had you heard of a dipole effect in the CMBR (cosmic microwave background radiation) hotter towards one pole, cooler towards the other?<br />[I posted an excerpt of the article today on the Andromeda collision thread].<br /><br />It was in another Sciam article on Galaxies behind the Milky Way, including the Great Attractor.<br /><br />Gravity waves could also account for structure.<br /><br />Magnetism is also often ignored.<br /><br />Thank you for your input - yes I was wondering about a sort of doppler shift (blue, red - gravity's equivalent of color).<br /><br />No one seems to want to post on my dark energy telescope idea. I was wondering if we could observe dark energy, and if dark energy is FTL, then could we see well beyond our visibility horizon? <br /><br />Is gravity effected by time, i.e. does it also vary according to e=mc^2? <br /><br />If time stops, does gravity stop?<br /><br />Thank you for your response.

 

[siarad]

I take it this is from my remark on another thread.<br />I was trying to do this without red/blue shift as gravity waves have never been found.<br />Think of gravity as concentric rings around the sun. As everything in the universe is moving & gravity restricted to C then it must pile up in the direction of motion & stretch behind i.e. elliptical rings.<br />It seems that this must be manifest by eccentric orbits or precessionary ones. Kind of like swinging a conker on a string by throwing & pulling.<br />

 

[newtonian]

siarad - Which other post on which other thread?<br /><br />Can you elaborate or add detail?<br /><br />Are you saying that gravity waves may be piled up in a ring at a distance equivalent because of c (the speed of light since the big bang?<br /><br />How would one measure that distance from the big bang?<br /><br />Back on gravitational radiation, is the wave 2-d, 3-d or 4-d as Borman seems to postulate? [If I understood his post correctlyi?]

 

[bobvanx]

>>Light moves within space time,<br /><br />Now, that's the part that makes a LIGO type detector mysterious to me. Since light is affected by gravity, and the instrument is trying to measure those gravitational distortions acting on the vacuum tube, won't those distortions also be acting on the laser beam?<br /><br />It feels like using a balance-type scale on the Vomit Comet to try to measure how the weight of a thing is changing; since your reference mass would change as fast as the thing you are attempting to measure, you get a nonsensical result.

 

[lightfront]

Is it widely accepted, then, that gravity travels at lightspeed? <div class="Discussion_UserSignature"> </div>

 

[newtonian]

lightfront - see my thread on:<br /><br />What is the speed of gravity?<br /><br />borman - No rush, but response is welcome.

 

[lightfront]

Ok thank you! <div class="Discussion_UserSignature"> </div>

 

[gurutc]

Gravitational waves don't move through a pre-existing static space-time but are ripples of space-time itself. - Hmmm<br /><br />Ripples occur at an interface or in a medium. What is the 'super space' that space and time (gravity) are ripples in?<br /><br />Not calling you out on this, but can we even conceive of a reference to use that will allow us to measure gravity waves? For all we know, we're on a roiling tempest of a storm made up of huge and violent gravity waves, but we can't measure the waves because the rules are defined by them.

 

[newtonian]

Calli - What is the latest data from LIGO? Or other relevant data that you may be aware of?

 

[newtonian]

gurutc - Not from my originality - note the quotes from Wikipedia and Brittanica Science Annual on page 1 of this thread which I posted.<br /><br />My favorite model is the stretching fine gauze of Isaiah 40:22:<br /><br />(Isaiah 40:22) 22 There is One who is dwelling above the circle of the earth, the dwellers in which are as grasshoppers, the One who is stretching out the heavens just as a fine gauze, who spreads them out like a tent in which to dwell. . .<br /><br />We have now observed the universe sufficiently to detect its threads and filaments, and computer simulations show (as on the Science channel today) the gauze like appearance and expansion.<br /><br />This observed fabric of space is 3-d plus time - it does not show a space-time fabric to my knowledge - correct me if I'm wrong.<br /><br />Part of the problem is determining the speed of gravity [see my thread on this], or, in effect, the effect of time on gravity.<br /><br />Time can be considered a 4th dimension.<br /><br />I hope this helps, because I really don't understand myself how gravity would be a wave in the space-time fabric rather than a wave in 3-d space.<br /><br />That is likely because I don't understand what a spin-2 wave is, as in the Wikipedia quote.<br /><br />So, before I can answer your question, I need help.<br /><br />Can anyone explain what a spin-2 wave is and how it differs from light waves, for example? <br /><br />BTW - One version of String theory posits that gravity is weak in 3-d because it leaks into other dimensions and is only partially felt in 3-d.

 

[nojocujo]

I would think that an inspiral would enhance the ability to be detected due to frequency shift but the most powerful would be a head on. I suspect that the schwartzchild radius might enjoy a brief canceling wavefront allowing energy to escape. Several spikes of energy as the graviatational potential relaxed for a direct hit and merger. Inspiral would be intereference or frequency shifts with a minor chirp or several chirps if it breaks up.

 

[eric2006]

"The strongest possible gravitational signal (apparently since the big bang) is believed to occur when 2 neutron stars (or other massive denizens of the universe) spiral in together and coalesce, (combine) sorry about the spelling in the post. As they enter the final stage of this, the gravity signal, if audible too human ears, would have a characteristic chirp. If the objects were rapidly approaching or receding from earth, the duration of the chirp would be longer or shorter. Most likely, such a distortion of the signal would be interpreted as making the signal appear to have originated in a system containing a different mass. A high radial velocity for such objects would probably not be considered."<br /><br />This may be off topic but I have to ask. But if two neutron stars came into contact with each other (or any other matter) wouldn't there be a huge release of Gamma Rays? I bet that would chirp on a radio telescope. <img src="/images/icons/wink.gif" /> <br /><br />Also I would think the strongest possible gravitational signals would come from AGN quasars or Seyfert's. I have been wrong many times though. <img src="/images/icons/frown.gif" />