Laser interferometer gravitational-wave detectors: Advancing toward a global network

A new generation of gravitational wave detectors based on precision laser interferometry over long baselines should yield the first detections of these predicted waves in the next five years. The required sensitivity equivalent to displacements of ~10^-19 m over multikilometer baselines puts these detectors among the most precise optical instruments ever. To move the field from simply detecting gravitational waves to using them to probe questions in both astronomy and physics will require an expansion of the current network based in the US and Europe. A recently started project in Japan and a proposed project in Australia offer the best hopes for completing the global network.