Gravitational waves:

• are oscillations in the curvature of space-time (i.e. oscillations in the gravitational field).
• are caused by systems with strong gravitational fields which are changing rapidly (sources) .
• are not emitted by spherically or axially symmetric systems.
• have two polarization components (h₊ and h_x).
• travel at the speed of light.
• are not attenuated (weakened) significantly by interactions with matter.
• carry energy and can produce displacements of objects far away from the source.