How fast do gravitational effects travel?

Question

Say I move a chair from one place to the other. How long does it take until this change of the center of gravity of the earth to have on effect on the motion of particles at the opposite end of the galaxy? It's not instantaneous, is it?

Answer 1

gravitation effects travel at the speed of light according to relativity. various experiments have supported this - although people are still working on conclusively proving it.

EDIT:
thanks for highlighting that the speed of gravity has not been conclusively measured and that the Kopeikin experiment has been challenged.
http://www.sciencedaily.com/releases/2003/06/030619075759.htm
however some of those challenges do not claim that the answer is not the speed of light as per general relativity - just that the measurement was flawed
http://math.ucr.edu/home/baez/physics/Relativity/GR/grav_speed.html
for example Samuel argues that the result is unproven as the effect is smaller than we can measure today - not that Einstein was wrong
http://www.lbl.gov/Science-Articles/Archive/Phys-speed-of-gravity.html
http://www.jupiterscientific.org/sciinfo/sog.html

other aspects of relativity have been proven such as frame dragging - whereas quantum gravity is pretty new - so it will be interesting to see what happens over the next few years

Answer 2

Nothing can move faster than the speed of light. If the sun vanished at noon of a particular day it would still be seen for about nine minutes, earthlings would not be aware of any change until 12:09 PM. The opposite end of the galaxy would be totally unaware of the effects of your moved chair.

Answer 3

Your question is really about the propagation speed of gravity. It's still debated among scientists. The 1993 Nobel Prize in physics was awarded to a team who reached this conclusion based on astronomical observations. Watch for results from the LIGO (Laser Interferometer Gravitational-Wave Observatory) and LISA (Laser Interferometer Space Antenna) projects, and the work of Joseph Taylor and Russel Hulse at Princeton.

Gravitation is an extremely weak force, very hard to measure. It's hard to set up an experiment with changing gravitational fields. I wouldn't call it conclusive yet, but I think most physicists would place their bets that gravitation propagates at the speed of light.

So, to answer your question, I would place my bet with most physicists.

Answer 4

I beg to differ but the changes are instantaneous. Gravity is a quantum force (one of the four fundamental forces in the universe) There is plenty of evidence that there are particle interactions that 'defy' the relativistic view of the universe. . . they actually don't.
Try this:
http://www.metaresearch.org/media%20and%20links/press/SOG-Kopeikin.asp

or for those who love wiki:

http://en.wikipedia.org/wiki/Quantum_gravity

Answer 5

At the speed of light.