David Spergel

Astrophysicist

Born David Nathaniel Spergel, March 25, 1961, in Rochester, NY; married Laura H. Kahn (a doctor), August 26, 1990; children: Julian, Sarah, Joshua. Education: Princeton University, bachelor's degree (astronomy), 1982; Harvard University, master's degree (astronomy), 1984; Harvard University, Ph.D. (astronomy), 1985; post–doctoral work, Harvard, 1986.

Addresses:

Office—Princeton University, Department of Astrophysical Sciences, Peyton Hall—Ivy Lane, Princeton, NJ 08544–1001.

Career

Assistant professor, Princeton University, 1987–92; associate professor, Princeton University, 1992–97; visiting associate professor, University of Maryland, 1995–96; professor, Princeton University, 1997—; helped design NASA's Wilkinson Microwave Anisotropy Probe (WMAP), 1990s; began work on new NASA deep space probe, Terrestrial Planet Finder (TPF), 1999; publicly presented groundbreaking findings of WMAP, 2003.

Member:

Institute for Advanced Study, 1986–88.

Awards:

Alfred P. Sloan Research Fellow, 1988–92; National Science Foundation Young Investigator Award, 1988–93; Helen B. Warner Prize, 1994; Bart Bok Prize, 1994; American Astronomical Society Second Century Lecturer, 2000; John D. and Catherine T. MacArthur Foundation Fellowship, 2001.

Sidelights

Named one of the top scientists in the United States by Time in 2001, astrophysicist David Spergel has been at the forefront of answering fundamental questions about the origin and composition of the universe since the 1980s. A professor at Princeton University, Spergel helped to design and to examine the findings of the National Aeronautics and Space Administration's (NASA) Wilkinson Microwave Anisotropy Probe (WMAP). Launched in 2001, this robotic probe created the clearest–ever pictures of the radiation emanating from the edges of the known universe. This is the oldest radiation in the universe, and examining it in detail allowed Spergel and his team to determine, for the first time, the exact age of the universe (13.7 billion years), and the fact that the 96 percent of the universe is composed of invisible "dark matter." Spergel and his team presented their findings in February of 2003.

Spergel began his work in astrophysics as an undergraduate at Princeton University. There he developed a reputation for diving headfirst into one difficult problem after another. He has always been most comfortable when exploring the edges of what is known about the universe—and trying to push beyond them. He graduated from Princeton in 1982.

After graduating from college, Spergel headed to Harvard to continue his education in astronomy. While a Harvard student, he spent a year in England at Oxford University as a Harvard traveling scholar. He received a master's degree in astronomy in 1984. The following year he completed a Ph.D. in astronomy, also at Harvard. Upon receiving his Ph. D., Spergel spent an additional year at Harvard as a post–doctoral fellow before returning to Princeton in 1987, this time as a professor.

Spergel first made his mark while studying the structure of the Milky Way galaxy, of which the sun and 100 billion other stars is a part. Along with Leo Blitz of the University of Maryland, Spergel discovered that the Milky Way has a much more complex structure than was previously supposed. That structure includes warped edges and a band of stars around its middle section.

Next, Spergel turned his attention to the mysterious "dark matter" said to compose most of the material in the universe. It was this subject that had formed the basis of his Ph.D. thesis. He developed the idea that dark matter, theorized but never directly observed by scientists, should create a kind of cosmic wind that should blow against the Earth as it moves through space. Scientists who have continued Spergel's work on dark matter are now testing this theory.

Moving on from his investigations into dark matter, Spergel turned to the problem of why groups of galaxies form complex structures rather than spreading out evenly through the universe. The theory Spergel came up with to explain this phenomenon involved knots of warped space–time. But the theory, called "brilliant" by Time's Michael D. Lemonick was proven to be false by observational data. Spergel, true to form, instead of fighting to preserve the popularity of his theory as many scientists would do, simply moved on to the next topic.

The next topic Spergel chose moved him into an area usually reserved for engineers, not scientists. In the early 1990s, NASA brought him on the design team for the WMAP. For eight years, Spergel and his team labored to perfect the technology that would provide the best resolution of the oldest radiation in the universe.

Finally, in June of 2001, Spergel was on hand to watch a Delta rocket lift off from Cape Canaveral, Florida, carrying the fruits of many months of hard work for him and the rest of the WMAP team. The satellite, weighing 1,800 pounds, was beginning its mission to explore the extreme edge of the observable universe, a mission that would take it a million miles from home into deep space.

Also in 2001, Spergel received the coveted John D. and Catherine T. MacArthur Fellowship. Informally known as the "genius grant," the fellowship provides financial support, according to a statement issued by the MacArthur Foundation and quoted in the Daily Princetonian, to individuals who show "extraordinary originality and dedication in their creative pursuits." Spergel was one of 23 scientists, artists, scholars, and others who were awarded $500,000 each as part of the grant. The money was to be released to each recipient in installments over a period of five years, and could be used for any purpose.

Selection for the grant is through a confidential process, and requires no application. Spergel had heard rumors that he was being considered for the grant, but he did not know for sure until he received a telephone call informing him that he had won. Spergel especially appreciated the fact that the grant money came with no strings attached. He joked that he could now afford to hire someone to do his home maintenance projects instead of doing them himself. But he also said that the money would not change his life in a major way—it would just allow him more time to pursue his research.

In early 2003, Spergel and his colleagues made public their findings from their analysis of the data sent by the WMAP for the first time. The results had far–reaching implications for the field of astrophysics. Data from the probe proved, according to Spergel, that the universe did indeed start with a period of accelerated growth—a big bang, which had been theorized, but not proven. The data also allowed Spergel and his colleagues to pinpoint the age of the universe—13.7 billion years—to, as he told Tim Folger in Discover, "an accuracy of one percent. We know that ordinary matter accounts for only four percent of the mass of the universe. The rest consists of dark matter." Spergel was very excited by these results, which were beyond his wildest imaginings of what he thought would be possible to obtain when he first became an astrophysicist.

Spergel called his work on WMAP among the most satisfying experiences of his life. He also worked harder than he ever had before, rising at seven in the morning and working until two in the morning for months at a time. Many questions remained unanswered, however, including the question of what exactly is dark matter. All that was known at the time the WMAP results were made public was that dark matter seemed to be an invisible substance that, as Spergel told in Discover's Folger, "seems to be driving the universe to speed up." Much remained for Spergel to investigate.

After seeing WMAP on its way, Spergel found himself addressing his next challenge. This was to work on NASA's next far–seeing robotic probe, called the Terrestrial Planet Finder (TPF). This is a probe whose mission will be to directly see, for the first time, Earth–like planets outside of the solar system. So distant and so dim are these objects, that no ordinary telescope could ever hope to see them. This is why special optics must be designed, and why only an instrument operating beyond the distorting effects of Earth's atmosphere can be used. Added to the challenge is the fact that the stars around which extrasolar planets orbit outshine the planets by millions of times, effectively drowning out the weak, reflected light from the planet.

With characteristic fervor, Spergel threw himself into this new challenge in 1999. The fact that he had never studied telescope design did not bother him. All that was required, thought Spergel, was to read up on the subject. His task was complicated by the fact that building the new space probe involved solving technical challenges that had never been faced by telescope builders before. But, Spergel told Discover's Lemonick, "I had a few months with nothing special to do, so I figured it would be fun to think about something new. I took home a standard textbook, and every night after the kids went to sleep, I'd spend an hour or two reading it."

The result of Spergel's after–hours studying was the invention of a new kind of telescope that will block the light emitted by a star so that the telescope can resolve the far fainter reflected light coming from the star's orbiting planets. "This is a completely new idea," Michael Littman, an optical engineer at Princeton University told Discover's Lemonick, "and once you see it, you realize how simple and elegant it is. I'm kicking myself that I didn't think of it first." Spergel, Littman, and other members of their team at Princeton unveiled a working demonstration of the revolutionary design as 2000 drew to a close, and NASA has expressed great interest in incorporating aspects of Spergel's design into the Terrestrial Planet Finder, which it planned to launch by 2015.

One of Spergel's main objectives is to immerse himself in the study of questions whose answers will appeal to non–scientists, as well as to his colleagues. With his work on the two NASA space probes, he seemed well on his way to doing just that.

Sources

Periodicals

Daily Princetonian, October 25, 2001.

Discover, March 2002.

Time, August 20, 2001, p. 47.

Online

"America's Best: Science and Medicine: Astrophysics: David Spergel," CNN.com, http://www.cnn.com/SPECIALS/2001/americasbest/science.medicine/frameset.dspergel.exclude.html (July 10, 2003).

"Astrophysicist David Spergel Receives MacArthur Fellowship," Princeton University, http://www.princeton.edu/pr/news/01/q4/1024–spergel.htm (July 10, 2003).

"David Spergel's Home Page," Department of Astrophysical Sciences, Princeton University, http://www.astro.princeton.edu/~dns/ (August 20, 2003).

"Echo of the Big Bang," Princeton University Press, http://pup.princeton.edu/titles/7481.html (August 22, 2003).

"R&D: Discover Dialogue: David Spergel," Discover,http://www.discover.com/may_03/breakdialogue.html (July 10, 2003).

"TPF at Princeton University," Princeton University, http://www.princeton.edu/~tpf/ (August 22, 2003).

—MichaelBelfiore