Does gravity travel?

Question

Okay, so we all know that nothing travels faster than the speed of light. And we know that the force of gravity that the sun exerts on the earth keeps us rotating around in a nice circular fashion.
Now, let's say, one day, the sun BLOWS UP!!! Oh my god, it's a disaster! Everybody's about to die! But wait...
Did we have a warning? Or didn't we?
It's been said that it takes approximately 7 minutes for light to travel from the sun to the earth. So nothing can get to our location, from where the sun is, any faster than 7 minutes. Light is the limit!
But... if the sun is no longer there, nothing is keeping us in orbit! Let's assume, just for simplicity, that the sun blew up and left the earth intact, and there is not enough collective matter to give the earth an even orbit. The earth starts wobbling out of orbit...
but WHEN? Do we start wobbling out of orbit immediately when the sun blows up, or does it take 7 minutes for the earth to recieve information that the sun has been destroyed

If we are ejected into space immediately, how did gravity travel faster than light? And if it takes 7 minutes, how can the earth orbit around something that doesn't exist anymore?,
http://img219.imageshack.us/my.php?image=a1ht2.jpg

Answer 1

Yes - definitely.

Answer 2

This is a great question. Most people tend to agree with Einstein, his theories basically tend to lead one to believe that gravity travels at roughly the speed of light. By reading some of the responses I see that some people have a hard time grasping this concept, I don't blame them, it's pretty strange. Take for account the stars you see at night. Some of those stars do not exist anymore but you still see they're light and many stars will keep on shinning for thousands of years even though they've been extinguished for thousands of years...

Deep Thoughts by bcgood

Going back to your original question, scientist have done some recent experiments using the alignment of Jupiter with a quasar known affectionately as quasar J0842+1835. They used Jupiter's gravitational influence to measure the distortion of energy from the interaction between our observation of the quasar behind Jupiter. As a result of this study it has been determined that the speed of gravitational influence is finite and that it is most likely very close to the speed of light which is 186,282 miles per second, (Although the speed of light is slower when traveling through things like water and especially slower when moving through diamonds). Think about that speed for a second... A second, or two or three, wow you just traveled 558,846 miles in three seconds flat! So once again, if the sun suddenly disappeared, earths orbit wouldn't be effected immediately it would take about 8 minutes. To give another example of the sheer speed of light think about this. The sun is 193 million miles away from earth, 8 minutes is pretty fast to travel that many miles, don't you think?

Answer 3

I believe we have to wait for the event to strike us, seven-eight minutes after the Sun disappears.

To take a slightly more realistic... Several billion years from now, the Sun will expand to a red giant, and then will form a planetary nebula, shedding a fair amount of its mass. What will happen to the outer planets?

If the mass of the sun were reduced, then the planets would have too much momentum for their orbits, and either would perturb out to a more distant orbit, or just break away from the Sun's gravity altogether. However, the event has to reach them; I am not sure if gravitational propagation is instantaneous or is carried by a particle.

Answer 4

If the sun blew up we would not know for at least 8 minutes. As far as gravity goes, it follows relativity, it does not travel faster than light. If the sun blew up and it's mass started scattering out in all directions, untill that mass exceeded a sphere of the earths radius, we would still feel the normal gravitational pull of the sun.

Answer 5

This isn't a simple question, as you probably know.

Fundamentally, we don't know what gravity is -- not exactly. If it is a force, it is a very, very weak one, and we don't know what particle "carries" gravitational force (in the sense that an electronic "carries" electromagnetic force).

Your fundamental question is, "does gravity move at the speed of light?" --and the answer is, well, yes -- and no. In Einstein's theory of General Relativity it does, but some other effects from the theory cancel out the "retardation" effect (the delay that propagation at the speed of light would seem to entail.)

Here are a lot more details for you:

http://math.ucr.edu/home/baez/physics/Relativity/GR/grav_speed.html

Answer 6

Whether or not gravity has any velocity is not known. Einstein theorized and it's been proven over and over again that what we call gravity is actually a distortion of space caused by the presence of mass (..like our sun). You can get an idea of this concept by imagining a thin sheet of rubber (..space) with a bowling ball (..matter) sitting on it. The bowling ball causes there to be a dimple in the sheet. That dimple is sort of like gravity.

Several research programs are currently underway to try and detect waves of gravity from deep space. It's thought that when neutron stars or black holes collide space is so violently disturbed that ripples of gravity rush outward. If/when such gravity waves are detected science will hopefully be able to solve some of the mysteries surrounding gravity, including its velocity.

Answer 7

Ok now, rationalize!!
All physics is based on: MATH
So about your question: Does gravity travell?

Define gravity: ACCELERATION
it has m/s^2 (meters per segonds square)
If you have meters per segonds you have a
MOVEMENT if you have a movement you have a distance and a displacement trough that distance wich implies it needs time and space in order to move right?

So you see gravity is defined by the variable "a"
(acceleration)
and > a=d/t^2 (acceleration is proportionnal to the distance in meters divided by time in segonds square)
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About the sun blowing up: we will all be dead by then!! So dont worry!
And when it does blow up, the earth wont go out of orbit, it will fry up...(14 minutes not 7)
then it will cool down (after the sun has released all its energy from blowing up)

Answer 8

Gravity goes the speed of light. If the sun were to disappear, we would continue in our orbit for 8 minutes and THEN go straight. Exactly when we saw it disappear.

Answer 9

The "stress" of gravity does not commute at any velocity, it extremely is a container that exists everywhere in area. variations to this container (i.e. gravity waves) commute on the cost of light although. BTW the occasion you gave of shifting an merchandise returned and forth and detecting the variations in gravity is exactly what a gravity wave detector does. however the gadgets that they desire to discover this way are issues like merging black holes, which generate a great variety of gravity waves, theoretically.

Answer 10

Gravity travels at the speed of light.

Einstein built this assumption into his general theory of relativity (along with the principle of equivalence). Because the predictions of general relativity have been so successfully tested it is fair to conclude that the assumption was correct.

However, for the doubters, the speed of gravity was measured directly for the first time in 2003. See link. The result was - you guessed - it travels at the speed of light.

Answer 11

Standard experimental techniques exist to determine the propagation speed of forces. When we apply these techniques to gravity, they all yield propagation speeds too great to measure, substantially faster than lightspeed. This is because gravity, in contrast to light, has no detectable aberration or propagation delay for its action, even for cases (such as binary pulsars) where sources of gravity accelerate significantly during the light time from source to target. By contrast, the finite propagation speed of light causes radiation pressure forces to have a non-radial component causing orbits to decay (the “Poynting-Robertson effect”); but gravity has no counterpart force proportional to to first order. General relativity (GR) explains these features by suggesting that gravitation (unlike electromagnetic forces) is a pure geometric effect of curved space-time, not a force of nature that propagates