Gravity is a state of space-time, however gravitational waves, predicted by Enstein general relativity yet not directly proven, travels with the speed of light, the highest possible speed, because simply gravitational waves take the form of energy radiation. when a body , with huge mass, moves with acceleration it emits gravitational waves. the only available proof of its existence is the binary star system when one of the star is a pulsar ,white dwarf or a netron star, since these stars has a very high mass , they rotate with the other star with an orbital motion, accelerated motion, and the =effect of the gravitational waves is conceivable since there is another near star to it. the garvitational waves/ radiation can be detected; since it results in a loss of energy the distance between the two stars decreases.