Joseph H. Taylor Jr.
Wolf Prize Laureate in Physics 1992
Joseph H. Taylor Jr.
Affiliation at the time of the award:
Princeton University, USA
“for his discovery of an orbiting radio pulsar and its exploitation to verify the general theory of relativity to high precision”.
Professor Joseph H. Taylor Jr. is awarded the prize for his fundamental contributions to radio astronomy and experimental relativity. In 1974, Taylor together with his graduate student, Russell Hulse, discovered the first example of a radio pulsar in orbit about an unseen stellar companion. Radio pulsars are spinning, magnetized, neutron stars that function as extremely accurate clocks. It was immediately apparent that this system could be used to perform novel tests of the general theory of relativity. He therefore developed the necessary experimental techniques to measure the arrival times of the faint pulses with extreme accuracy. Three of the four solar system tests of relativity, namely precession of the pulsar orbit, gravitational redshift and relativistic time delay were soon detected in this system and used to solve for the unknown stellar masses. This then allowed a quantitative prediction of the rate of loss of orbital energy through the emission of gravitational radiation, a high order test of general relativity, and constitutes so far the only experimental evidence for gravitational waves. This prediction has been verified to an accuracy of better than one per cent, with the residual error being entirely attributable to uncertainties in the location and acceleration of the system within the Galaxy.
This test also confirms the constancy of Newton’s gravitational constant. In addition, relativistic, periodic perturbations of the orbit have been measured and a limited test of strong field relativistic gravity has been performed.
Taylor is also credited with numerous other advances in the study of radio pulsars and, in particular, their use as astronomical tools. His research combines deep understanding of the theory of relativity, insightful astronomy and, above all, experimental physics of the highest quality.