  Gravity is one of the fundamental forces of Nature, and it is the dominant
force in most astronomical systems. In common with all other phenomena, gravity
must obey the principles of special relativity. In particular, gravitational
forces must not be transmitted or communicated faster than light. This means
that when the gravitational field of an object changes, the changes ripple
outwards through space and take a finite time to reach other objects. These
ripples are called gravitational radiation or gravitational waves. This article
gives a brief introduction to the physics of gravitational radiation, including
technical material suitable for non-specialist scientists.
