Physics

Dr. Frederick J. Raab
LIGO Laboratory, USA

The first direct detections of gravitational waves, announced this past year by the LIGO Scientific Collaboration and the Virgo Collaboration, open the vast new frontier of gravitational-wave astronomy. These first detections of merging black holes confirm that Einstein’s General Theory of Relativity gives a good description of the most extreme spacetimes ever encountered. This provides a comfortable base for future detections of matter in these extreme spacetime conditions. Different methods have been optimized to search for different classes of future events. Extracting the best science from these future observations will require building out the international network of gravitational-wave detectors to optimize localization of the sources and to recover full polarization information from events. From the first observations of merging black holes, we extrapolate that such mergers occur hourly somewhere in the observable universe. This motivates continuation of the evolution of detectors with greater sensitivity, eventually probing mergers of black holes formed by the first generations of stars, deeply probing the nature of extreme spacetime and the nature of matter at extreme density.