Speed of gravity vs speed of light?

[Edtharan]

I thought photons were entities in their own right, like a drop of water being compared to a ripple on a pond...?

Yes and No. They are both a wave and a particle. They are a wave as in a ripple in the electromagnetic field and at the same time a descrete entity (particle). It is strange but that is QM . Actually all matter is also subject to this priciple (and AFAIK has been messured).

 

How does changing B's position give virtual energy back to A?

As long as the total energy "borrowed" due to the hisenberg's uncertenty principle is paied back the transfer is allowed. I'm not sure of the mathematics involved but the virtual photon is treated like an energy carrier between the two particles. This energy can puch them in different directions. One of which is closer together. This depends on the charge of the two particles.

[Daecon]

As long as the total energy "borrowed" due to the hisenberg's uncertenty principle is paied back the transfer is allowed. I'm not sure of the mathematics involved but the virtual photon is treated like an energy carrier between the two particles. This energy can puch them in different directions. One of which is closer together. This depends on the charge of the two particles.

Ah of course.

 

Like the energy expended in the kinetic force of movement.

[swansont]

Ah of course.

 

Like the energy expended in the kinetic force of movement.

 

What is "kinetic force of movement" supposed to mean?

[Daecon]

What is "kinetic force of movement" supposed to mean?

D'OH!

 

I knew what I meant, just had a mental block so my vocabulary went AWOL.

 

I was refering to the energy expended in "pushing" the mass, relative to the rest of the Universe.

 

Does that make sense?

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(From another thread on a similar subject)

'']Hasn't there been more than one experiment to determine that gravity does indeed seem to propegate at c? One was observing the collapse of a binary neutron star system, I dont remember what the other one was.

Wouldn't you not be able to really tell though as you'd only be able to recieve and record data on that experiment at c, as the information about the experiment would only be able to travel to you at c?

[swansont]

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(From another thread on a similar subject)

 

Wouldn't you not be able to really tell though as you'd only be able to recieve and record data on that experiment at c' date=' as the information about the experiment would only be able to travel to you at c?[/quote']

 

The speed of the information isn't the issue. It's the orbital decay of the binary system - the energy is radiated away, and the rate of decay is what is expected if the speed of gravity is c. For a radial force like gravity to exert a torque and allow the radiation, it can't act instantly - it has to come from where the other body was at some previous time (called a retarded force). The rate of decay depends on the retardation.