Nobel Laureate in Physics to speak at UA this week

4.4.09

Nobel Laureate Joseph Taylor will deliver the 13th annual Robert D. Maurer Distinguished Lecture at UA this week. The lecture series was named after Robert D. Maurer, Ph. D. who invented the first telecommunications-grade optical fiber. It is sponsored by the department of physics in the J. William Fulbright College of Arts and Sciences. Each year, the lecture hosts a variety of scientists to speak on topics such as stars, lasers, molecular beams, Einstein and the Universe in general. Among the former 12 lecturers were supernova experts, three other Nobel Laureates in Physics, various professors and authors, several of which graduated from Harvard and Stanford.

The lecture “Binary Pulsars and Relativistic Gravity” will take place at 7 p.m. Thursday, April 2, in the Donald W. Reynolds Center. The lecture is free and open to the public. The department of physics chose Taylor’s lecture as part of celebrating the International Year of Astronomy, Assistant Professor in Physics, Julia Kennefick said.

Taylor discovered the first binary pulsar, along with Russell Hulse, which earned them the 1993 Nobel Prize in Physics.

Prior to earning his doctorate in astronomy from Harvard University, Taylor was educated mainly in Quaker institutions, a part of his heritage. In his autobiography, Taylor said, “Somewhat backward high-school introductions to chemistry and physics, [though] I failed to recognize them as such at the time, did not dampen any enthusiasm for science…” The last of his experience with Quaker institutions was Haverford College, where Taylor earned his bachelor’s degree in physics. His teaching career began at the University of Massachusetts, Amherst, but has spent the past 29 years as a professor in the department of physics at Princeton University.

In Taylor’s autobiography, he said his thesis was in radio astronomy and built a working radio telescope as part of his senior honors project. Radio astronomy eventually led to the interest in the study of pulsars.

Pulsars are neutron stars, but that has not always been common knowledge. According to Taylor’s Nobel lecture, when he began observing the first four pulsars in 1968 and attempting to find more, it was merely inclination that pulsars were neutron stars: orbiting magnetized remnants of supernova explosions that produce radio waves. As he started to recognize the unique characteristics of pulsars, he made a computer algorithm to identify them, which soon led to finding a fifth pulsar.

The Nobel Prize press release explains that a binary pulsar has two pulsars, each with a mass akin to the sun, that are in orbit at relatively short distances from each other. In addition to emitting radio waves, the binary pulsar emits gravitational waves. Taylor and Hulse’s discovery nullifies Newton’s gravitational physics, but aided in proving Einstein’s general theory of relativity.

Before the discovery of pulsars and binary pulsars, Einstein’s general theory of relativity was not seen as a practical theory. The finding of gravitational waves from binary pulsars brought gravitational physics into the spotlight.

Part of Taylor’s gravitational discovery enabled exploration of a new subfield in astrophysics by testing the relativistic nature of gravity via comparisons of the Universe’s pulsar time with the Earth’s atomic time. The Nobel Prize in Physics press release explains, “The pulsar’s pulse period has proved to be extremely stable… [it] increases by less than 5 percent during 1 million years.”