Gravitational waves: a new window on the Universe (**note this is an additional, special seminar added to the schedule**)

In 1916, Einstein realised that his theory of General Relativity predicted the existence of gravitational waves, small ripples in gravity that travel at the speed of light.  In February this year, one hundred years later, this outstanding prediction of Relativity was verified in spectacular style, with the announcement of the detection of gravitational waves from two colliding black holes.  In this talk, I will describe how this amazing discovery was made, and how the new field of gravitational wave astronomy promises to open up a new window on the Universe.  I will also talk about other possible sorts of detections that might be made, some involving theory that was originally developed to describe waves in the Earth’s oceans.