The speed of gravitational effects has been successfully demonstrated for the first time as being the same as the speed at which light travels.

 

Should lay down the path for some very interesting research

 

http://news.bbc.co.uk/1/hi/sci/tech/2639043.stm

 

Sayonara beat you to it, Edward :]

 

What is it that determines that light and gravity go at a particular speed? If we can find evidence that the speed of gravity has changed over time, as we have found evidence that the speed of light has done so, this seems to suggest a gateway into the superstructure of space-time; since if there is the same relation of time it suggests the number is'nt arbitrary.

Also note there is a 20-25% margin of error.

 

http://arstechnica.com/archive/news/1042065116.html

they cant possibly know the speed of gravity because they havent calculated the mass of gravity.

 

they have only found how fast if works on an object.

I hope you're not planning a career in physics

 

a) don't need mass to find velocity. (photons have no mass, so you're saying the speed of light, the cornerstone of physics, is impossible to measure?)

 

b) interaction with objects can be used to indicate speed.

i thought light had mass because it is effected by gravity and the equation for gravity has mass of the object in it.

 

or else light wouldnt be bent by gravity if it didnt have any mass for the gravity to act on

Gravity curves space-time, this is what alters the trajectory of the photon. You have not learned the complete equations.