The speed of gravity

[aaron38]

In another thread there was a post suggesting that gravity could possibly propagate faster than c.<br /><br />Even IF gravity has the ability to travel FTL, I don't see how it ever possibly could in our universe.<br /><br />Gravity is coupled tightly to mass (that's what we observe anyway). The gravity field changes as mass moves around. But since mass moves slower than light, wouldn't the gravity changes also always move at the same speed?<br /><br />When a star explodes in a supernova, why would a distant planet suddenly feel anything? The mass is still all there at the center of the system. The gravity field would change slowly as the mass spreads out.

 

[maxtheknife]

www.metaresearch.org

 

[dragon04]

That brings me to a question or 10 that maybe someone can answer for me.<br /><br />Take two beakers of water. Connect them at the bottom with a tube that has a valve in it.<br /><br />With the valve closed, you fill one beaker but only half fill the other. When you open the valve, the water will instantly seek level between the two beakers.<br /><br />Please understand that I know that "instantly" is not an accurate term, but indulge me. <img src="/images/icons/smile.gif" /><br /><br />It's the effect I'm thinking about here. Not the amount of time it takes for the effect to complete its action.<br /><br />What if space-time is like that? If we could instantly double the mass of the sun (with the valve open, of course), would space-time begin to alter its shape in our neighborhood immediately?<br /><br />If it DOES alter immediately, is it due to the effect that we similarly see in a wire that conducts electrical current (the light turns on "immediately due to the wire being "full" of electrons and applying electrical presure yields the instant result) ?<br /><br />Or could gravity actually be a quantum force or effect that has pairs of "gravity particles" that immediately interact and begin to alter the shape of space relative to the difference in mass of the larger and smaller objects regardless of distance?<br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[diogenes]

<font color="yellow">What if space-time is like that? If we could instantly double the mass of the sun (with the valve open, of course), would space-time begin to alter its shape in our neighborhood immediately? </font><br /><br />It would take about 8 minutes for changes to reach earth. That is, if the doubled mass maintained the same volume. <br /><br />Gravity propagates at the speed of light. <br /><br />You might want to follow Gravity Probe B http://einstein.stanford.edu/ <br /><br />If it works as planned, it demonstrated the speed of gravity as it <br /><br /><b>Gravity Probe B is an experiment being developed by NASA and Stanford University to test two unverified predictions of Albert Einstein's general theory of relativity. The experiment will check, very precisely, tiny changes in the direction of spin of four gyroscopes contained in a satellite in a 650 km polar orbit.. The gyroscopes will measure how space and time are warped by the presence of the Earth, and, more profoundly, how the Earth's rotation drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe <br /></b>

 

[diogenes]

For proof of gravity affecting time see Gravity Probe A http://en.wikipedia.org/wiki/Gravity_A_mission

 

[i_think]

<font color="yellow"> Gravity propagates at the speed of light. <br /> </font><br /><br />Sorry but I could not find any data at the links you provided which gave any indication of the speed of gravity.<br /><br />Until we know everything, we can't be 100% sure of anything.