In 1916, Albert Einstein revolutionized the physics world with his theory of general relativity. This theory was the first to predict the existence of gravitational waves - a fascinating concept. Gravitational waves are effectively ripples in the curvature of spacetime which travel outward from the source - sources could possibly include binary star systems composed of white dwarfs, neutron stars or black holes. Gravitational waves cannot exist in the Newtonian theory of gravitation, since in it physical interactions propagate at infinite speed.
Einstein’s theory of general relativity effectively states that gravity is a phenomenon due to the curvature of spacetime. Massive objects cause this curvature - with mass being roughly proportional to the strength of the curvature that object produces. As massive objects move around in spacetime, this curvature inevitably changes. In general, gravitational waves are produced by objects whose motion include acceleration and are not symmetric (examples of symmetrical motion would be an expanding balloon or spinning cylinder). When accelerated, these objects would cause disturbances in spacetime which would spread like ripples on the surface of a pond. This disturbance is known as gravitational radiation - which is thought to travel at the speed of light and never stop or slow down, yet weaken with distance.
Although gravitational radiation has not been directly detected, there is indirect evidence for its existence. The 1993 Nobel Prize in Physics was awarded for measurements of the Hulse-Taylor binary system, which suggests that gravitational waves are much more than mere mathematical anomalies. gravitational wave detectors exist, yet they remain unsuccessful in detecting such phenomena.