Direct Detection of Gravitational Waves
As described immediately above in the Strong field tests: Binary pulsars section, binary pulsar observations have shown conclusively although indirectly that gravitational waves exist. A number of gravitational wave detectors have recently been built with the intent of directly detecting the gravitational waves emanating from such astronomical events as the merger of two neutron stars. Currently, the most sensitive of these is the Laser Interferometer Gravitational-wave Observatory (LIGO), which has been in operation since 2002. So far, there has not been a single detection event by any of the existing detectors. Future detectors are being developed or planned, which will greatly improve the sensitivity of these experiments, such as the Advanced LIGO detector being built for the LIGO facilities, and the proposed Laser Interferometer Space Antenna (LISA). It is anticipated, for example, that Advanced LIGO will detect events possibly as often as daily.
General relativity predicts gravitational waves. These detectors have not yet found any gravitational waves. Continued failure to find waves as the detectors become more sensitive would tend to falsify general relativity. If, in the future, gravitational waves (of the predicted kind) were discovered, this would tend to confirm general relativity.
Read more about this topic: Tests Of General Relativity
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