Speed of Gravity Experiment Challenged

An anonymous reader writes "The previous hoopla over the discovery of the speed of gravity has an opponent from the Lawrence Berkeley National Laboratory. Read about the latest calculations."

Comments

Repurcussions

[geek42]

What do you suppose the repurcussions would be if it could be shown that gravity was instantaneous, rather than propagating at the speed of light? Could we use that to transmit information instantaneously? Would that violate causality?

Re:Repurcussions

[shadowbearer]

It's been shown (reference, help! :-) that no matter how fast the propogation medium, information propogation is still limited to c. I believe the latest was in the quantum experiments with electrons which were simultaneously created yet still "knew" what the others' state was.

God, it's late, and I'm tired, someone help me out on this one? I know I've read it over and over :-( just don't remember the specifics.

SB

Re:I, too

[confused one]

I hate feeding trolls, but sometimes I have to...

the question could be more fundamental. Does gravity have a speed? Consider this: light is a particle (wave) traveling along a many dimensional space-time membrane. Now, we've defined (more or less) what a photon is; and, how it behaves. We expect it to travel no faster than c. The problem is, we don't really undertand the space-time thing.

We have some theories as to how space is constructed. One of the things physics is trying to do is to create a theory that ties together space, time, gravity, energy, mass, quantum mechanics (basically everything). It's proving to be very difficult and gravity is the problem. Would a gravity wave have to obey all of the "laws of physics" as we know them? maybe not. Not if our theories are wrong. A lack of understanding wrt gravity might be why we need to make claims about "dark matter" and "dark energy" in order to explain the accelerating universe.

You have to remember that our "laws" are based on observation. The rules (like no speed exceeds c) are based on mathematical models created to explain the observations. What if the models are close, but wrong?

Just something to think about.

Re:I, too

[Ceriel Nosforit]

Switching off my sense of humor for a bit, what he's saying is that 'speed' as we know it won't be a factor in the final equation, but a result of it. Some theories (heard this at CERN in 2001) say that the graviton is a 4D particle/wave. Therefore it would also 'travel' in the time dimension and to call the graviton a tachyon might not even be a silly idea.

Getting off the beaten path of time, velocity and momentum is /essential/ in coming up with the ToE (Theory of Everything). It'll require a new kind of thinking in the proportions the ToR was to Classic physics. The ToE will take the form of mutual dependency between variables where interaction is not a process, but a function.