The effects of gravity have been observed to be faster than the speed of light.
If the sun suddenly vanished then our orbit would almost instantaneously be affected long before we could see that the sun had in fact, gone.
http://metaresearch.org/cosmology/speed_of_gravity.asp
If the sun suddenly vanished then our orbit would almost instantaneously be affected long before we could see that the sun had in fact, gone.
http://metaresearch.org/cosmology/speed_of_gravity.asp