Speed of Gravity?

In September 2002, Sergei Kopeikin and Edward Fomalont announced in a conference in Seattle, WA that they had made an indirect measurement of the speed of gravity, using their data from VLBI measurement of the retarded position of Jupiter on its orbit during Jupiter's transit across the line-of-sight of a bright radio source - quasar QSO J0842+1835. Kopeikin and Fomalont concluded that the speed of gravity is between 0.8 and 1.2 times the speed of light, which would be fully consistent with the theoretical prediction of general relativity that the speed of gravity is exactly the same as the speed of light.

Several physicists, including Clifford M. Will and Steve Carlip, have criticised these claims on the grounds that they have allegedly misinterpreted the results of their measurements. However, Kopeikin and Fomalont continue to vigorously argue their case. (See the citations below for the details of the arguments pro and con.)

It is important to understand that none of the participants in this controversy are claiming that general relativity is "wrong". Rather, the debate concerns whether or not Kopeikin and Fomalont have really provided yet another verification of one of its fundamental predictions








www.ldolphin.org...

www.newscientist.com... ( a conflicting view)

en.wikipedia.org...

As far as we know gravity is a force, not matter. If its not matter and its not energy (like light) how can it have speed/velocity?

Gravity can cause acceleration but cannot have acceleration or therefore velocity. Right?

Unless gravitons are REAL

I've always had a problem with the theory gravity is particular. Dunno why. Old-fashioned I guess. I won't believe it till they detect them.

so is electromagnetic force yet it has certain speed limits

I think the statement is best posed like this:

Subtract everything from the solar system except the Sun and Earth. The Earth rotates around the Sun, creationists be damned, because of the gravitational pull of the Sun. The earth also has it's insignificant-when-compared-to-the-sun gravitational pull. Now, there is some high-end fireworks and the sun dissapears from sight. Poof. Gone. No longer a factor. Now, people on earth will not know this for several minutes, because it takes light that long to reach Earth.

Now, what happens to the Earth's Orbit in that time? The orbit, that is, which is caused by the sun's gravitational well. Will, when the sun is taken out of the equation, the Earth jump out of it's orbit at a tangent heading the instant the sun dissapears? Or will it continue in the same orbit forever? General relativity states that Velocity of Gravity = Velocity of Light. As soon as the last photon reaches earth, the planet will jump orbit.

Another way to put it is a model of spacetime, which is actually a circle of rubber held at the edges. Put a pea at one end, representing earth, and pinch down the very center, representing the sun's graviational well. Release said Sun, and the rubber will, expectedly, shoot straight back up, causing the pea to jump out of it's place.

This is the first (?) measurement of the speed of gravity, and they present the SoG as being .8 to 1.2 times the speed of light. Going back to our model of the Earth and sun, their presentation says that the Earth will jump orbit a little sooner or later (Or at the exact same time) than light reaches earth. There's room for interpretation.