%0 Journal Article %T Observational evidences for the speed of the gravity based on the Earth tide %A KeYun Tang %A ChangCai Hua %A Wu Wen %A ShunLiang Chi %A QingYu You %A Dan Yu %J Chinese Science Bulletin %@ 1861-9541 %D 2013 %I %R 10.1007/s11434-012-5603-3 %X We have found that the current practical Newtonian formula for the gravity tide of the Earth implies a hypothesis that gravity travels at the speed of light; furthermore, we have derived and solved the propagation equation of gravity using the observation data of Earth tides from Shiquanhe and Wushi, after correction of phase lag due to the anelasticity of the Earth, and found that the speeds of gravity are from 0.93 to 1.05 times the speed of light with a relative error of about 5%. This provides first set of strong evidences to show that the speed of gravity is the same as the speed of light. %K Earth tide %K apparent position %K phase lag %K speed of light %K speed of gravity %K propagation equation of gravity %U http://link.springer.com/article/10.1007/s11434-012-5603-3