Gravity, does it have speed?

[TimeWizardCosmo]

Re: Gravity, does it have speed?

I thought it was proven that it does...?

 

[sam mower]

Re: Gravity, does it have speed?

Perhaps, the question was a bit weird, knowing that time as we see it, only exist on this planet.

We can only measure this kind of things here, in reality (reality - huh), time out there, by being near gravity field, surely acts differently than if the field ain't there.
Maybe around sun the event just flips (time a to time B) and we still measure it somehow differently...
quantum theory I guess.
By changing the point of view maybe both statements apply. (weirder things had happen)

have a good one

 

[StarLord]

Re: Gravity, does it have speed?

<div class='quotetop'>QUOTE(\"preethi1986\")</div>

does extreme gravity affect time?[/b]

Most deffinately it does!!

I recently went to a MeatLoaf concert with guest Star Cindy Lauper. Those two were so heavy that it was as if time stood still, untill that guy at the ball park made it to home plate. *wink wink*

 

[Lucidus]

Re: Gravity, does it have speed?

<div class='quotetop'>QUOTE(\"preethi1986\")</div>

Eh, excuse me, but gravitational forces do NOT travel. with the sun existing there will be a gravitational field due to the sun. in the presense of this gravitational field, the earth follows its orbit. if the sun was to disappear, so will its gravitational field instantaneously. so earth's reaction to the loss of the sun's gravitational force on it will also be instantaneous.[/b]

Are you sure about this. I as I understood it, graviton waves do travel at speed c, therefore the Earth would continue to experience gravity from the sun for 8 1/2 minutes after the sun disappeared.

 

[Lucidus]

Re: Gravity, does it have speed?

<div class='quotetop'>QUOTE(\"TheHeggy\")</div>

Gravity does not have a speed because it exists as a field of energy if you will. It's not linear like light. Your question can be applied to electro-magnetic fields as well: If I have an electromagnet running, and a small piece of metal stuck to it, how long does the metal stick after I turn off the electo-magnet? It's immediate, like flipping off a light.[/b]

Also here, electo-magnetic waves travel at speed c also. The reason why the metal will fall immediately is because it is so close to the magnet that at the incredible speed of c it just doesn't take long.

 

[TimeWizardCosmo]

Re: Gravity, does it have speed?

I stand corrected

 

[StarLord]

Re: Gravity, does it have speed?

<div class='quotetop'>QUOTE(\"lucidus\")</div>

Are you sure about this. I as I understood it, graviton waves do travel at speed c, therefore the Earth would continue to experience gravity from the sun for 8 1/2 minutes after the sun disappeared.[/b]

Actually, it is said that the speed of Gravity is insanely faster than the speed of light Something in the order of 2 X 100,000,000,000 c, (2 x 10 to the power of 10 c) I think that that 8.5 min would be reduced considerably.

 

[Lucidus]

Re: Gravity, does it have speed?

<div class='quotetop'>QUOTE(\"StarLord\")</div>

Actually, it is said that the speed of Gravity is insanely faster than the speed of light Something in the order of 2 X 100,000,000,000 c, (2 x 10 to the power of 10 c) I think that that 8.5 min would be reduced considerably.[/b]

Really? I haven't heard that. Could you provide a link? If that is true, then the effect would seem to occur immediately.

 

[Chronodynamic Jim]

Re: Gravity, does it have speed?

<div class='quotetop'>QUOTE(\"StarLord\")</div>

Actually, it is said that the speed of Gravity is insanely faster than the speed of light Something in the order of 2 X 100,000,000,000 c, (2 x 10 to the power of 10 c) I think that that 8.5 min would be reduced considerably.[/b]

I'm Sorry, Most of you are wrong.

First off, light IS a electromagnetic wave, so therefore, speed of electromagnatism = speed of light. The effect of magnatism travels at the speed of light.

Secondly, Gravity doesn't have a speed really. light and electromagnatism are made up of exchange particles called photons that travel at the speed of light. Gravity is theorized to be composed of exchange particles called gravitons, though no one has observed them, and there's not a lot of hope that anyone ever will.

The catch is that Gravity is not a classic force field like Electromagnatism, the Strong and the Weak forces. According to General Relativity, Gravity is best thought of as an effect. The typical illustration is that of a bowling ball resting on a sheet of rubber. The bowling ball would warp the surface of the rubber sheet as a result of its weight. A marble rolling on the warped surface of the rubber sheet would follow a curved path similar to the path of the Earth as it orbits the Sun.

Gravity is simply the warping of the fabric of space caused by the presence of mass. If we Imagine the rubber sheet without a bowling ball it would be flat. As we rest the bowling ball on the rubber sheet a depression is formed, small at first and confined to the immidiate vicinity of the bowling ball. But as the bowling ball sinks deeper, the depression spreads outward from the center of the bowling ball.

The same thing would happen with the Sun. The spreading effect of the warping of space in the presence of mass is the closest you'll ever come to the "speed" of gravity. That being said, your question is what exactly is that speed? Newton thought as some of the posters here thought, that this effect would make its presence felt instantaneously across any distance. General Relativity predicts though, that this effect decreases at the square of the distance and does so at precisely the speed of light.

Ergo the answer to your question, Gravity, does it have speed? is Yes, and that speed is 186,282 miles per second.

A more interesting question is, Why does the effect of gravity propigate at the speed of light?

One last point before I go. In the above illustration regarding the rubber sheet and the bowling ball to explain gravity (an illustration I did not come up with BTW), the bowling ball represents the Sun, the rubber sheet represents the fabric of space-time, and the marble represents the Earth.

What does the pull of gravity on the bowling ball and marble represent?

Why do we invoke gravity as an integral part of an illustration explaining gravity?

 

[Lucidus]

Re: Gravity, does it have speed?

Of course you are correct Jim. I should be more careful when I write, when I said graviton wave I should have said gravitational wave. And, when I said travel, I should have said propagate. Oops.

One last point before I go. In the above illustration regarding the rubber sheet and the bowling ball to explain gravity (an illustration I did not come up with BTW), the bowling ball represents the Sun, the rubber sheet represents the fabric of space-time, and the marble represents the Earth.
?
What does the pull of gravity on the bowling ball and marble represent?
?
Why do we invoke gravity as an integral part of an illustration explaining gravity?

This last question is what always bugged me about this analogy. And it is thoughts along these lines that make me tend to "believe in" the theory of gravity as the interaction of gravitons.