Gravitational waves are caused by any particle or object with mass. Gravitational waves were predicted by Albert Einstein in 1916 on the basis of his theory of general relativity. 
Sources of detectable gravitational waves could possibly include
binary star systems composed of white dwarfs, neutron stars, or black holes.
On February 11, 2016, the Advanced
LIGO team announced that they had directly detected gravitational waves from a pair of black holes merging.   
physics, gravitational waves are ripples in the curvature of spacetime that move as a wave, travelling outward from the source. Albert Einstein predicted them in 1916 on the basis of his theory of general relativity.  In theory, gravitational waves transport energy as  gravitational radiation. Sources of detectable gravitational waves might include binary star systems composed of white dwarfs, neutron stars, or black holes.
general relativity, gravitational waves cannot travel faster than the speed of light. They do not exist in the Newtonian theory of gravitation, in which physical interactions propagate at infinite speed. However, the detection of gravitational waves proves the last prediction of Einstein’s general theory of relativity.
In 1993, the
Nobel Prize in Physics was awarded for measurements of the Hulse-Taylor binary star system that suggests gravitational waves are more than mathematical anomalies.