Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Bob Gorton on 23/10/2010 09:30:08

Title: At what speed does gravity move?
Post by: Bob Gorton on 23/10/2010 09:30:08

Bob Gorton  asked the Naked Scientists:
   
A Question Relating to Gravity and Time

If gravity is a distortion of space-time, illustrated by the rubber sheet analogy, what happens when a star goes nova and its gravitational field changes?

Does the effect propagate instantaneously or at the speed of time?

Does the effect propagate for an infinite (universe wide) distance or is it limited?

If the effect is instantaneous and infinite (implied by circumstance that we cannot yet read "gravitational history" only the electromagnetic background), might we find a way to modulate a gravitational field to communicate instantly over infinite distances? Or is that like me throwing a rock into the sea off the coast of England and you seeing the ripple in Australia?

Best Regards

Bob Gorton

What do you think?

Title: At what speed does gravity move?
Post by: donchiragjain10036 on 23/10/2010 10:25:13

Gravity moves at the speed of light !

That's the reason why Physicist around the world are in search of an evidence for Graviton !

Title: At what speed does gravity move?
Post by: syhprum on 23/10/2010 10:35:11

According to General relativity the influence of gravity propergates at the speed of light, experiments have been done to test this but the results are not completely accepted.
It is assumed that the strength of gravity extends to an infinite distance and falls of according to the inverse square law.
The problem in trying to use gravity waves for communication is that they are very weak, the most sensitive receivers built can only hope to detect radiation from closely orbiting or merging blackholes and we have no possibility of building any transmitters.

Title: At what speed does gravity move?
Post by: Murchie85 on 23/10/2010 11:42:56

A question I have been pondering for a while now.
With any luck in the near future when the satellite trio "lisa" is launched this may help to understand more about gravity waves.

Title: At what speed does gravity move?
Post by: Bill S on 24/10/2010 18:04:28

Quote from: donchiragjain10036

That's the reason why Physicist around the world are in search of an evidence for Graviton

 

Einstein tells us that gravity is not a force.  If that is the case, what would the proposed graviton mediate?

Title: At what speed does gravity move?
Post by: Vereava on 24/10/2010 23:07:50

Quote from: donchiragjain10036 on 23/10/2010 10:25:13

Gravity moves at the speed of light !

That's the reason why Physicist around the world are in search of an evidence for Graviton !

If gravity "moves" at the speed of light, why doesn't it radiate/illuminate? If it really "moved" at the speed of light, couldn't light reflect off of it? Wouldn't this mean that gravity is "moving" faster than the speed of light? I placed the word move in quotes because as far as I am aware, there are no particles that make up gravity and therefore, nothing about gravity is 'moving' the way that light moves, or physical spacial objects move