How did observations of a binary pulsar provide evidence for gravitational radiation?

Observations of the binary pulsar PSR 1913 + 16 provided the first experimental evidence for gravitational waves by confirming a key prediction of Albert Einstein’s general theory of relativity.

In 1974, astronomers Joseph H. Taylor, Jr. and Russell A. Hulse used the Arecibo radio telescope to monitor the pulsar’s radio pulses. They discovered that the pulsar was in a tight orbit with a companion neutron star. According to general relativity, such massive, accelerating objects should emit gravitational radiation, causing the system to lose energy and the stars to spiral closer together.

By precisely timing the pulsar’s emissions over several years, Taylor and Hulse measured a gradual, annual decrease in the orbital period. This observed orbital decay matched the predictions of general relativity to within 0.5 percent accuracy, providing powerful experimental support for the existence of gravitational waves.12