Gravity does not exist outside a solar system

[R1]

Yevaud, <br />funny, I think I remember learning that the experiment of gravity at c did take place too.<br /><br />Perhaps what's happening is merely that Lisa is just running way behind, as a lot of space projects <br />do, from time to time.<br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[MeteorWayne]

Yes the experiment did take place, but there are different interpretations of the results, so the question remains open. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[themage]

<font color="yellow">What is it about microwave and gamma rays that allow them to escape a 'black hole' where light (if its being emitted) cannot? </font><br /><br />I think you may be confused a little bit. Gamma and X-rays can not escape a black hole. Anything that passes the event horizon can not come out again. What your thinking of is more likely the X-ray emissions that come from accretion disk right before the event horizon.

 

[bobunf]

If gravity waves propagate faster than C, and if it were possible to detect the gravity waves produced by, say, two 10 kilogram masses revolving about each other, it would be easy to encode information in those gravity waves by stopping and starting or varying the revolution.<br /><br />Thus, super-luminal communication would be a possibility. <br /><br />General Relativity does not permit super-luminal transfer of information, so that finding out whether gravitational waves propagate faster than C will confirm or disprove part of General Relativity. <br /><br />Potential super-luminal communication would certainly change a lot of thinking about a lot of things. Maybe ET is sending us all kinds of messages from millions of light years away; if only we could detect gravity waves. But, I think I’d bet on General Relativity.<br /><br />Bob<br />

 

[themage]

Here is that article everyone is talking about btw<br /><br />http://www.space.com/scienceastronomy/gravity_speed_030107.html<br /><br />Also another article cutting down the first one<br /><br />http://www.space.com/scienceastronomy/gravity_speed_030116.html

 

[fffranklin]

Interesting stuff. I didn't know they were still trying to experimently prove this because I thought something would go back in time if it was faster than c. Sounds like there is a lot of debate about the experiment, but I'm still under the impression that the vast majority of physicists think gravity propagates at c, and I think it has been that way at least since Einstein came up with GR.<br /><br />Also, while gravity is a force classically, I think in GR it's thought of as the geometry of spacetime.

 

[R1]

yes, Lisa will directly measure the speed at which those spacetime distortion waves propagate<br /><br /><br /><br />thanks for the article links, Mage, I think this excerpt from the second one describes best why<br />they need to be extremely accurate and know exactly what it is they're measuring :<br />(quote from your second article link<br /><font color="yellow"><br />'Even a slight difference in the speeds of light and gravity would give theorists nifty wiggle room to craft bizarre ideas about the mechanics of the unseen universe.'</font><br /> <br /> <div class="Discussion_UserSignature"> </div>

 

[vandivx]

"If gravity waves propagate faster than C"<br /><br />if there is such a thing as gravity waves in the first place, that is the question<br /><br />and if there are they are damn weak I should say or we don't know what are we doing in trying to measure them<br /><br />and if we do find them what use will they be if their mere detection is being so difficult, the fact that we have hard times detecting them (given we go right way about detecting them) means they are damn tenuous phenomenon in which case the question of their usefullness is the question to ask<br /><br />if gravity speed is c, I think we should have detected the waves by now (that is given there are any waves to begin with) and because we have not detected them it means they might travel way faster<br /><br />but instantaneous propagation implies infinte speed and that poses a huge problem, same as it poses in QM and its non-local phenomenon as in entaglement experiments...<br /><br />vanDivX <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

But Reber gave sort of proof.

 

[themage]

Well, van is right. We don't know if gravity waves exist yet (although they were theorized in GR). But one good place too look for them would be 2 massive objects in a orbital dance together falling into each other (such as 2 neutron stars). If we can find something like this, we will know one way or the other if GW's exist.

 

[richalex]

<blockquote><font class="small">In reply to:</font><hr /><p>Why should a mystical unseen force take precedence over a known vissible force?<p><hr /></p></p></blockquote>Because the path of non-magnetic objects with mass are affected in the absence of magnetic fields.

 

[richalex]

<blockquote><font class="small">In reply to:</font><hr /><p>This would show's that gravity is energy, based on the fact that since gravity can pull and bend a light photon.If gravity wasn't energy then gravity would not have any eefect on a light photon.<p><hr /></p></p></blockquote>Actually, gravity does not bend light. Gravity does not directly interact with matter or energy. Instead, gravity bends space-time. It is the warping of space-time that causes the effects that we associate with gravity.

 

[space_coops]

The best thing to understand is that gravity is not a force. Mass bends spacetime and as a result, near by mass "rolls" across the fabric of spacetime towards it. This causes the illusion that there is a force that attracts to bodies together.

 

[vandivx]

it depends entirely what you take a force to be, I imagine that all forces including you pushing a cart on street could be interpreted as not being a 'force' after all if youtake the view you do<br /><br />that's because if you dig deep enough into detail you find that every so called force has some 'mechanism' explaining it other than primitive idea of force that people have, like when you push that cart you are not really even touching its handles and so you are not really pushing it, its molecular dipole electric fields that don't allow your molecules to touch the molecules of the cart's handles<br /><br />now its electric field that we still happen to call force but what is electric field, I don't believe its photons in their multitude, at least I don't understand how they can push and pull around charged particles, electric field is some condition in space that nobody has made a theory (a la Einstein's curved space of gravitation) of as yet and it is that condition that is causing charges to attract and repulse and no 'force' is involved in that<br /><br />I find it silly to try to shunt forces away for the sake of some modern stuff like curved or bent space, if that's what is responsible for gravitation then gravitation is a force which is mediated by space curvature, bingo<br /><br />for that matter space curvature is mysterious just as electric field/force are, on that rubber sheet analogy what makes bodies attracted and move as 2D rubber sheet 'space' dictates is the gravitation acting on bodies as they slide downslope or follow slopes of the rubber sheet but that's just analogy and in space we have no idea what pushed the bodies to follow the space curvature or what makes two large bodies (or one big and one small like Earth and my body say) wanting to come together from inital static conditions, something is making it to want moving together and there is no 'gravitation' working underneath space curvature as it works in that rubber sheet analogy to make bodies mo <div class="Discussion_UserSignature"> </div>

 

[siarad]

<blockquote><font class="small">In reply to:</font><hr /><p>Picture the extreme case: When eclipsed, one of them is an inch away from us and the other a million miles away. We would feel a huge force. When they are at maximum separation, and each is 700,000 miles away, we would feel a smaller force. <p><hr /></p></p></blockquote><br /><br />If gravity moved faster than c we would feel it before we see it in your instance