What is the Speed of Gravity?
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What is the Speed of Gravity?
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Re: What is the Speed of Gravity?
#2My first thought was 'Find a way to create some matter and we'll measure it', but apparently they have a way. ;)
Re: What is the Speed of Gravity?
#3The point of the article is in
Clifford M. Will
"The Confrontation between General Relativity and Experiment" (2001)
http://relativity.livingreviews.org/Articles/lrr-2001-4/
"Gravitational wave damping has been detected in an amount that agrees with general relativity to half a percent using the Hulse-Taylor binary pulsar,"
I also have something to say to the first question in comments there, to which the article author answered that he can't answer. The question was "Is the speed of gravity reduced by the medium through which it travels in a analogous manner to the slowing of the speed of light through various media?"
I was lucky enough to read Feynman Lectures recently, so as far as I understood him, the photons themselves don't really slow down in various media. That is, what we see as the result is the slowdown, but only because it's a new light (new photons) on the other side of the media. The photons on the other side are photons which were pushed out of the atoms of the media, that's why it appears that they come out slower. Inside, between the atoms of the media, photons still move at the speed of light.
Re: What is the Speed of Gravity?
#4The speed of gravity is either infinity or millions of times faster than the speed of light. If the speed of gravity was the speed of light, then heavy objects passing near the earth would have more gravity than objects passing away. Less of the gravity beans would be arriving to be measured. Like the red shift in light or the doppler effect with sound.
I see gravity as more of a property of the universe, every atom in the universe is attached to each other atom in some way.
Re: What is the Speed of Gravity?
#5The speed of gravity is either infinity or millions of times faster than the speed of light. If the speed of gravity was the speed of light, then heavy objects passing near the earth would have more gravity than objects passing away. Less of the gravity beans would be arriving to be measured. Like the red shift in light or the doppler effect with sound. I see gravity as more of a property of the universe, every atom…
[deleted]
Re: What is the Speed of Gravity?
#6The speed of gravity is either infinity or millions of times faster than the speed of light. If the speed of gravity was the speed of light, then heavy objects passing near the earth would have more gravity than objects passing away. Less of the gravity beans would be arriving to be measured. Like the red shift in light or the doppler effect with sound. I see gravity as more of a property of the universe, every atom…
Wait, what? Did you read the article? The propagation of the curvature of spacetime happens at the speed of light. If it didn't you could use large amounts of energy to propagate information faster than the speed of light, which screws the hell out of causality (using the light cones). If you have a good math background you can solve for it using the equation.
I see gravity as more of a property of the universe, every atom in the universe is attached to each other atom in some way.
Please don't do science like this. You should use experimentation to differentiate between theories.
Re: What is the Speed of Gravity?
#7I've always thought what we call 'speed of light' is the indirect observation of a structural property of (this) the universe. A property that has something to do with movement in general and not only the movement of light (the movement of space itself?).
Another interisting property is the 0º Kelvin (absolute zero) http://en.wikipedia.org/wiki/Absolute_zero
Re: What is the Speed of Gravity?
#8The speed of gravity is either infinity or millions of times faster than the speed of light. If the speed of gravity was the speed of light, then heavy objects passing near the earth would have more gravity than objects passing away. Less of the gravity beans would be arriving to be measured. Like the red shift in light or the doppler effect with sound. I see gravity as more of a property of the universe, every atom…
I feel a Timecube coming on...
Re: What is the Speed of Gravity?
#9My first thought was 'Find a way to create some matter and we'll measure it', but apparently they have a way. ;)
Your trouble is on focusing on the analogy too much. Instead of, "how can we measure what the effects of gravity would be if matter or energy were created or destroyed?" ask "how can we measure the movement of the curvature of spacetime?"
Re: What is the Speed of Gravity?
#10The speed of gravity is either infinity or millions of times faster than the speed of light. If the speed of gravity was the speed of light, then heavy objects passing near the earth would have more gravity than objects passing away. Less of the gravity beans would be arriving to be measured. Like the red shift in light or the doppler effect with sound. I see gravity as more of a property of the universe, every atom…
Wait, what? Did you read the article? The propagation of the curvature of spacetime happens at the speed of light. If it didn't you could use large amounts of energy to propagate information faster than the speed of light, which screws the hell out of causality (using the light cones). If you have a good math background you can solve for it using the equation. I see gravity as more of a property of the universe, ever…
Maybe data could travel faster than light if we find a property of the universe which goes faster than light.
I imagine a bowling ball rolling down a blanket stretched tight at half light speed. The bowl shape of the blanket in front of the bowling ball would be very different from the rear. I'm just pointing out that if gravity goes light speed, then something coming toward the earth at half light speed will have a longer delay for us to feel the gravity, and as the object leaves the earth, its gravity will linger longer. Maybe it's true, it boggles my mind.
If gravity is light speed, then an object travelling toward you at light speed will have no gravity until it has touched you. We should be able to detect shock waves like a jet breaking the sound barrier breaking all the windows in a community because the sound builds up. Gravity would build up too.