Figure 1: The gravitational-wave spectrum
Gravitational waves open up a new window on the universe that will allow us to probe events for which no electromagnetic signature exists. In the next few years, the ground-based interferometers GEO-600, LIGO, VIRGO and TAMA should be able to detect the high-frequency gravitational waves produced by extreme astrophysical objects, providing the first direct detection of these disturbances in space–time. With its much longer arm lengths, the space-based interferometer LISA will, if launched, be able to detect lower-frequency gravitational waves, possibly those generated by phase transitions in the early universe. At even lower frequencies, other experiments will look for tiny signatures of gravitational waves in the cosmic microwave background. Source: NASA.