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Nobel Laureate in Physics, Joseph Taylor spoke at UA this week about the process of observing, data recording, and devices he used that led him to discovering the first binary pulsar. His speech was the 13th annual Robert D. Maurer Distinguished Lecture, a lecture that hosts a variety of scientists to speak on topics such as stars, lasers, molecular beams, Einstein and the Universe in general.


Taylor discovered the first binary pulsar along with Russell Hulse, which earned them the 1993 Nobel Prize in Physics. When they began their observations, their goal was not to discover other astronomical bodies. Taylor said they wanted to establish how the pulsars were related to other stars and how they were distributed through the galaxies, an interest that had stemmed from the Cambridge group’s discovery of the first four pulsars. “Einstein would have made this discovery if he had our information,” he said.


Despite the late-arriving students, the audience also included many eagerly awaiting physicists. Utsab Khadka, physics teaching assistant, said he was looking forward to the insights from Taylor’s speech. In preparation, he read a couple of speeches given by Taylor, so he would be able to process the new information the lecture provided. “His Nobel banquet speech was really cool. I think he will be very inspiring,” Khadka said.


Taylor and Hulse spent their hours of pulsar research in 1974 at the National Astronomy and Ionosphere Center in Arecibo, Puerto Rico. A normal day at the observatory for them included only two and a half hours of observing due to a limited window of visibility. To determine when these hours would be in the earth's orbit, Hulse and Taylor consulted “Time Keeping Bulletins”, which would arrive in the mail about every two weeks and are now available by email. “So if you ever need to know exactly where the earth is in its orbit, this is the way to go,” Taylor said. The remainder of their pulsar research days were spent recording the data and interpreting it.


The two physicists used a device that was known as a mini-computer in the 1970s. “It was about the size of a refrigerator, which we kept in the shipping crate that it arrived in and Russ would make a mark on the side [of the crate] each time we found another pulsar,” Taylor said.
The many hours of data collection and observation were a difficult endeavor since the binary pulsar was 25,000 light years away, Taylor explained. “It’s a little like studying a factory machine by standing in the parking lot listening to the squeaks,” he said.


Pulsars are 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. Since pulsars are known as nature’s most accurate clocks, 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.”


Although the binary pulsar is nature’s most accurate clock, they speed up in minute amounts, about one millimeter per orbit/approximately eight hours. Eventually, the two pulsars (that make the binary pulsar) orbits will shrink progressively until they collide. Taylor explained that at this rate, it will take about 300 million years before it creates a “hell of a big gravitational bang.”


The radio telescope at the Arecibo Observatory is a web of aluminum panels held up by cables over a sinkhole. In the center of the device are two objects that swing back and forth to maintain its balance. The radio telescope serves two functions, to receive radio signals from outer space as well as emit radio signals to bounce off of objects. Both functions provide data that enable a better understanding of astronomical objects. Receiving signals provides information about bodies that emit them, such as pulsars. Emitting signals provides information about the bodies that the signals hit. This is one way that we learn about the moon and Venus, Taylor explained.


Taylor has spent the past 29 years as a professor in the department of physics at Princeton University and seemed to deliver the lecture primarily as a teacher, than as a scientist.


He set the foundation for his speech by giving a basic history of physics and by briefly summarizing the most fundamental physicists and their accomplishments from the 15th-17th centuries, such as Nicolaus Copernicus, Tycho Brahe, Galileo Galilei, Johannes Kepler, and Isaac Newton. The entire lecture was reinforced by a detailed, structured PowerPoint presentation, which was followed by a question-and-answer session for further clarification.


UA student Meagan Howard originally attended primarily for extra credit, but afterwards she left pleasantly surprised. Howard agreed that Taylor’s speech was accessible, even for non-science students, “I really liked that he used a PowerPoint presentation, it helped me to understand more.”