speed of gravity

Hi All

Maybe someone has an answer to this.
How fast is gravity?
In other words if the sun vanished, how long before we on earth would feel this. Would we feel it instantly or can gravity only travel as fast as the speed of light so would we have 8.5 minutes or there abouts before we would feel the suns absence

The speed of gravity is the same as the speed of light, apparently - see here for an article on this.

I wondered about this... is there such a thing as a 'speed of gravity'? It is, after all, an invisible attravtive force between ANY object and another.

I often thought that the speed of gravity was dependant upon the bodies interacting. My reason being, on Earth, (acceleration due to) gravity is 9.8m/s-m/s. On the Moon, it is different, as on any other larger-than-me body, anywhere else. Would this figure remain proportional to my distance if I was e.g. 1,000 miles above Earth? If I head in a straight line towards e.g. the Sun, I will meet the La Grange point whereby my attraction to the Earth is equal to the Sun. Then, go a little farther again, and the attractive force towards Earth is outnumbered by the Sun, therefore I will be attracted from then on by the Sun.

Confusing really!

How fast is gravity?
In other words if the sun vanished, how long before we on earth would feel this. Would we feel it instantly or can gravity only travel as fast as the speed of light so would we have 8.5 minutes or there abouts before we would feel the suns absence

Yep, its the speed of light and we'd have to wait for 8.5 minutes before it got dark and we went flying in a tangent.

I wondered about this... is there such a thing as a 'speed of gravity'? It is, after all, an invisible attravtive force between ANY object and another.

I often thought that the speed of gravity was dependant upon the bodies interacting. My reason being, on Earth, (acceleration due to) gravity is 9.8m/s-m/s. On the Moon, it is different, as on any other larger-than-me body, anywhere else. Would this figure remain proportional to my distance if I was e.g. 1,000 miles above Earth? If I head in a straight line towards e.g. the Sun, I will meet the La Grange point whereby my attraction to the Earth is equal to the Sun. Then, go a little farther again, and the attractive force towards Earth is outnumbered by the Sun, therefore I will be attracted from then on by the Sun.

Confusing really!

You seem to be confusing the acceleration due to gravity with the speed of gravity, totaly differnt things. The way to look at it is this. If the mass of an object chagnes, at what speed with the effect of that change propagate. A dramatic example would be if the sun where to dissapear, how long would it take for the graviational field as felt at the earth to see the effect of this change and for earth to shoot off into space?

If you believe Einstein (and lets face it there are good reasons to do so) then the answer is C.

BB

Thanks lads. Just one more question..

Is gravity
a wave
a particle
a wave and particle
a warp in spacetime
or all of the above?