The Search for Gravitational Waves

Norna A Robertson
University of Glasgow and Stanford University

The existence of gravitational waves, ripples in the curvature of 
spacetime, is a prediction of Einstein's general theory of relativity. 
As yet these elusive waves remain undetected. However there is a 
currently a large international effort to build long baseline 
interferometric detectors whose expected sensitivity is such that we may 
see the first detection of these waves from astrophysical sources. The 
experimental challenge is formidable: detection relies on sensing 
displacements of order 10^(-18) m over a wide bandwidth. However the 
potential pay-off is exciting - the detection of these waves could lead 
to a new branch of astronomy. In this talk I will give an introduction 
to this topic, including possible astrophysical sources and general 
principles of detection. I will review the status of the long baseline 
detectors including the German /UK GEO 600 project and the US LIGO 
project. I will also look to the future to consider possible 
improvements in sensitivity for ground-based detectors, and briefly 
cover the proposed space-based detector LISA.