An alumnus and faculty member advances Iowa’s reputation for space research.
University of Iowa physics and astronomy professor Don Gurnett perhaps sealed his destiny in his first year as an undergraduate at Iowa—when he marched into James Van Allen’s office and asked for work.
The year was 1958, and the young electrical engineering student was unfazed—excited, rather—by the recent celebrity of Van Allen, the renowned Iowa physicist who had just been part of the successful launch of Explorer 1. The first American satellite had carried onboard an experiment designed by Van Allen.
“I was interested in airplanes, electronics, and rockets,” says Gurnett, who had been a national champion model-airplane flyer as a high school student in Fairfax, Iowa, and planned to be an aeronautical engineer. “The Russians had just launched Sputnik, and it had a tremendous impact on me—on the entire country. I watched it fly over. With Explorer, we had almost caught up with the Russians. I couldn’t resist going over to Physics Hall to see if they needed help.”
When Van Allen offered him a job, a career was begun. Although Gurnett maintained a major in engineering, he worked in Van Allen’s lab throughout his undergraduate education and eventually earned master’s and doctoral degrees in physics.
“I went from constructing model rockets in high school to working on real rockets,” he says.
Fifty years later, Gurnett is a J.A. Van Allen/Roy J. Carver Professor of Physics and Astronomy in the College of Liberal Arts and Sciences and has conducted experiments on more than 30 space missions. The most notable have been Voyagers 1 and 2, twin spacecraft on their way out of the solar system; the Galileo mission to Jupiter; the Cassini mission to Saturn; and Mars Express, presently orbiting Mars. His UI research team currently is building instrumentation for Juno, a planned 2011 mission to Jupiter.
Gurnett, a member of the National Academy of Sciences and a fellow of the American Academy of Arts and Sciences, investigates wave phenomena. Hearing sounds from space when he was an undergraduate—detected by a very-low-frequency radio receiver he designed for Injun III—pushed him permanently to the study of physics.
“When the spacecraft was launched, we heard an astonishing variety of whistling radio sounds, and I was intrigued,” he says, “so I decided to go into physics to try to understand them.”
Whistlers, Gurnett explains, are rapidly descending tones—akin to the whistling sound some firecrackers make before they pop—caused by lightning discharges in Earth’s magnetosphere and at other planets. Understanding whistlers and other sounds from space helps scientists understand the most common state of known matter in the universe: plasma, or ionized gas.
“Space is not a vacuum—there is gas out there,” he notes. “We have found that particles in plasma will spontaneously start producing musical sounds. That doesn’t happen in a quiet room like my office, but it happens in plasma.”
These sounds are so compelling, in fact, that the National Aeronautics and Space Administration commissioned Terry Riley to compose a musical piece based on Gurnett’s collected sounds. The Kronos Quartet premiered the result, Sun Rings, at Hancher Auditorium in 2002 and has performed it around the globe.
Although the Sun Rings collaboration was an interesting sidelight in his career, Gurnett says his motivation is rooted in a hunger for knowledge.
“When I first heard those sounds, what leapt to my mind is the question that drives all scientists: How does it work?” he says. “I find my mind asking that question all the time—it’s not restricted to my field—and I try to come up with answers. I challenge my students to every day look at something in nature and propose ideas for how it works.”
Story by Sara Epstein Moninger; Photo by Tom Jorgensen
July 28, 2008