Sleuthing out gravitational waves

The sensing or reception of gravitational waves may deepen the understanding of the dynamics of violent events such as supernovae, exploding black holes, and the interactions between black holes and neutron stars. Because gravitation is 40 orders of magnitude weaker than the Coulomb force, the detection of gravitational waves is a huge challenge to instrument builders. The author describes the pioneering resonant bar detector and its problems, and then describes the laser interferometry approach, and in particular the Laser Interferometry Gravitational-wave Observatory (LIGO). The proposed method of simultaneously monitoring the Doppler shift of the carrier frequency of two or more interplanetary spacecraft in order to detect gravitational waves is also discussed. The problem of sensitivity of gravitational wave detectors and its solution is discussed