To clear up things for you folks, gravity can be considered to be a force that is not even close to to being understood by physist. One theory for Gravity is that it is a curvure in 4 dimentional space/time, however this theory is a clasical field theory, which lacks the fundimental understanding of gravity at a quantum level, and hence the uncertainity principal. At the present time a quantum theroy for gavity is being proposed. In this theory virtual graviton{energy packets} are exchanged, resulting in the force. A gravity wave can then be thought of as a ripple in the fabric of space/time caused by an accelarating mass, or in quantum terms, a herd of virtual gravitons. A person passing through a gravity wave would have her time slow down and lengt shrink, but what I reall want to ask is how a graviton be responsible for time dilation? Does anyone know.