Is Gravity Faster Than Light?

I just got laughed off the leisure forums in computing.net but Ill let you guys have a go.

So lets say something happened to the Sun, aliens came by and zapped it into another dimension. So in an instant our Sun had just disappeared. We know that the speed of light is the universal speed limit. My question is (Simply for demonstrating this question), would the loss of the suns gravity tethering us to current orbit lead to an instantaneous "un-tethering", where would would fly off into space at the moment the sun disappeared and continue to see the light from the sun for 8 minutes while we slowly froze into a big ice ball. Or....... is gravity restricted to the speed of light, where the "un-tethering" and the loss of light would correspond (we would lose light and gravity at the same time). Because without the sun I think we know what that means.......Grues..........

Not an astrophysicist and not expecting any of you to be just looking for some input.....

gravity travels at the speed of light afaik

The earth would no longer travel in an orbit ... it would seek an escape vector at the time the suns gravitational mass ceased.

You would receive solar radiation for another 5 - 9 minutes then the light would go out.

Earth would rapidly decrease in temp.

If the mass was removed by tesseract then you have a further problem not identified ... the shock wave caused by vacuum. That implosion and resultant shock wave would effect the planets vector around 16 minutes later ... and the remaining pieces of the planet would then travel outwards ...

I would be forced to get my spaceship out of the garage, top up the lithium fuel cell and pickup badge to return home.

Sadly we have enjoyed our time here.

I'll have to madly collect as much music as possible now ... most annoying.

crash ... do you want a lift back to Alpha Centauri ??

I'm wanted by the global government of the only habitable planet there...which probably explains my opinion of global governance.

Thsis pretty much explains it.

http://www.youtube.com/watch?v=Ej4gQKhsfo8

An object in motion tends to stay in motion unless another force acts on it. If the sun disappeared instantaneously, the earth would still try to continue in its orbit. It would no longer have the sun's gravitational force acting on it, however the other forces acting on it (The moon, other planets) would be miniscule in comparison to the gravitational force of the sun. It's orbit would deteriorate slowly because of the massive amount of inertia involved in its current motion.

This is not like a yoyo that suddenly gets released from your hand and flies off in one direction. If the earth suddenly disappeared would the moon go flying off on a tangent? Does that make sense to you?

No, we know it would continue to spin and continue in its arc, I think it would take some time before completely leaving its orbit. How much? I am sure this could be calculated, but I am not certain how long. Much like a satellite that cannot maintain its orbit any more, it doesn't come crashing into earth immediately. Its orbit decays over several days until the inertia of its movement is not enough to fight the earth's gravity. Then it will begin an ever increasing acceleration toward the surface.

I know (Theoretically) what would happen with the loss of gravity, our nice little planet would fly off in the most convenient trajectory and slowly become an ice ball of death, if it doesn't run into anything else..... But since Gravity is one of the four forces that keep our universe doing it thing is it also restricted by the speed of light. The story was an illustration asking if the loss of mass, in this case our sun, would be an instantaneous loss of gravity/orbit?

Neptune would be a better example, or Pluto if your one of "those" guys. But really how trippy would it be to lose the gravitational tether while still receiving light from your host star?

As a side note life would exist on our planet for several thousand years after the sun goes our from our own internal heat sources. The ice would be a mile thick and everything on the surface would be dead, but ocean life would thrive at the deepest parts of the ocean.

Yes but the question is then, if light is the fastest thing in the universe, are you saying gravity is faster that light?

This is what the OP wants to know. If you think gravity is faster than light and can prove it, you will receive a Nobel prize.

Conclusion: The Speed of Gravity is ≥ 2x10¹º c
http://metaresearch.org/cosmology/speed_of_gravity.asp

The speed limit of light is merely the speed limit of time. Beyond that speed there is no time, but direction. A pseudo dimension gravity operates in.

Thank you lancecraft. At first I was like "Oh shite this thread again" But you understand the question and provided a more than satisfactory answer. Your prize is being shipped to you and will hopefully arrive before it dies.

Best answer selected by reynod.

Physics major here...

The gravitational force travels at the speed of light, not slower, not faster (lancecraft's figure is complete BS). Scientists are pretty sure about this. The gravitational force can be used as a means of communication and is thus prohibited (by special relativity) from traveling faster than the speed of light. Astronomical observations support this.

I dunno - has anybody ever actually detected gravity waves? Seems to me there was an experiment going on, using a couple of lasers bouncing off mirrors a kilometer or so away, each arm's laser oriented 90 degrees from each other. Supposedly a gravity wave impinging on the system would compress one arm more than another and thus be detectable. Last I heard (Scientific American article from ~ 10 years ago), no signal had been detected in several years of operation.

Anyway, according to Wiki:

So the explanation seems to be that in a static (pre-existing & unchanging) gravitational field between 2 masses, the field vectors are completely radial (point to the instantaneous centers of the 2 masses), vs. partly tangential as espoused in the article Lancecraft linked to. Of course the latter would also be correct if the speed of gravity was infinite. And it would also explain why the collapse of a star into a black hole doesn't remove the gravitational field emanating from it, despite the presence of an infinite gravitational well at the event horizon.

However if the Sun's mass were suddenly removed from existence, I'd think that "change" would propagate as a gravitational wave which would mean it's limited to c and thus the earth wouldn't find out about it (and continue to orbit the Sun's former position) until some 8.3 minutes later, in which case it would head off along the tangent. I'd also expect some small tsuanmi would occur, as the Sun's tidal force would disappear instantaneously as well, albeit much smaller than if the Moon would disappear (the Moon being 240 times closer and hence the gravitational gradient between the near & far sides of the Earth much larger than that of the Sun).

Gravity travels greater than or equal to 2x10¹º times the speed of light = faster. If the sun spontaneously disappeared, the Earth would 'instantly' careen off into space while it would take more than 8.3 minutes for us on Earth to notice because we would still see the light arriving after it died.

Whats the make up of light?
If its trajectory is said to be known instantanaeously, why then does gravity have an impact on it, while not simply stopping it, as a solid object of course would?

I say Einsteins discovery of seeing light bend proves that gravity is more a constent in time than light

This topic has been moved from the section Toms Network to section Tom's Guide by Reynod

This topic has been closed by Mousemonkey