Edwin “Ed” Turner, professor of astrophysical sciences, will transition to emeritus status after forty-four years on the Princeton faculty. Ed is a scientist of uncommonly broad interests, having made important contributions to our understanding of dark matter, largescale cosmic structure, gravitational lenses, the Cosmological Constant (which is causing the expansion of the universe to accelerate), quasar populations and evolution, and the properties of planets orbiting other stars. He has an abiding interest in the application of advanced statistical techniques for making scientific inferences and enjoys exploring the philosophical aspects and ramifications of modern science. 

Ed was born in Knoxville, Tennessee, and attended public school in Raleigh, North Carolina. When he was three years old, he suffered from polio. The multiple surgeries he underwent kept him largely bed-ridden as a young boy; books were his outlet and opportunity to explore the world. The first person in his family to attend college, Ed went to the Massachusetts Institute of Technology (MIT), followed by Caltech for graduate school. At Caltech, he wrote a pair of seminal papers on the dynamics of pairs of galaxies, demonstrating unequivocally that they are embedded in dark matter halos with significantly more mass than is visible in starlight. 

After a brief postdoctoral appointment at the Institute for Advanced Study and an assistant professorship at Harvard University, Ed came to Princeton in 1978 to join the Department of Astrophysical Sciences. He was the resident observational astronomer among a faculty of theorists at the time and was expected to be knowledgeable about any observational development in the field, no matter how far from his immediate expertise. He held his own, and was granted tenure in 1981. Ed and his wife Joyce raised their two sons, Alex and Danny, in Princeton. They were all active in departmental social events, including the annual soccer game between faculty and students. 

Ed’s work has always straddled the observational-theoretical boundary, with a particular interest in the use of modern statistical techniques to constrain fundamental questions in astrophysics. With Sverre Aarseth and Richard Gott, he developed some of the first computer models of the clustering of galaxies, gaining insights into how gravity gives rise to the large-scale structure of the Universe. With Jeremiah Ostriker and Gott, he wrote a seminal and still widely quoted 1984 paper on the use of gravitationally lensed quasars to probe fundamental questions in cosmology. Gravitational lenses became a key theme of his research for the first twenty-plus years of his time at Princeton: discovering and characterizing them, and using them to measure the expansion rate of the universe and the nature of its acceleration. With his student Stuart Wyithe (now a professor at the University of Melbourne), he wrote important papers on gravitational microlensing by stars in external galaxies, and with Jacqueline Hewitt (now a professor at MIT), Ed discovered the first “Einstein Ring” gravitational lens, in which a radio galaxy is distorted into a full circle. Ed’s work on gravitational lenses contributed to our modern understanding that the energy density of the universe is dominated by “dark energy,” whose physical nature is still hotly debated. With William Press and Sean Carroll, Ed wrote an early and tremendously influential review paper summarizing the case for the existence of dark energy and exploring its implications. 

Ed first visited Japan in 1986 on the way to a conference in Beijing, strengthening an interest in the country that had started in college. He then started a long series of collaborations with Japanese astronomers, both those who came to Princeton as visitors or postdocs and those he met in Japan. Since that first visit, Ed has visited Japan as often as he could, spending all of his sabbaticals there and typically (prepandemic) making two to five visits per year. Ed’s ties to the Japanese science community run deep, and he was instrumental in setting up a number of collaborations between Princeton and Japanese scientists and institutions to carry out major astronomical surveys: the Sloan Digital Sky Survey (SDSS), which has measured the redshifts and thus three dimensional distribution of several million galaxies; Hyper Suprime-Cam, which has taken the deepest wide-field images of the sky to date; Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS), which obtained some of the first images of planets orbiting other stars, the Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS), which studies those planets in detail, and the Prime Focus Spectrograph, which promises to make a map of the galaxy distribution when the universe was only two billion years old to replicate the SDSS’ mapping of the relatively nearby and recent universe. Ed has played a key role in the interactions between Princeton and our Japanese collaborators in each of these ambitious, multimillion-dollar projects; his tremendous knowledge of Japanese culture and the friendships he has built with numerous Japanese colleagues have made all the difference in developing these keystones of Princeton’s activities in observational astronomy over the past thirty years. 

In the early 2000s, feeling that many of the fundamental discoveries in cosmology had been made, Ed turned to a new field in astrophysics: the discovery and characterization of planetary systems around other stars. He played a major role in the above-mentioned SEEDS project; with his student Tim Brandt (now a professor at the University of California-Santa Barbara), Ed used the SEEDS data to constrain the population and distribution of these Jupiter-size bodies. He has explored questions of exobiology and the prospects of discovering evidence for life, intelligent or otherwise, on other worlds. He has become increasingly interested in attempts to send probes to nearby stars, serving on the Advisory Committee to the Breakthrough Starshot Initiative. With Visiting Lecturer Michael Lemonick, Ed long taught a very popular first-year seminar, “Life on Mars - or Maybe Not,” which explores the way in which modern journalism depicts (and sometimes sensationalizes) science to the public. He also developed and taught, with colleagues in geosciences, ecology and evolutionary biology, and chemistry, the interdisciplinary course, “Life in the Universe,” the gateway course for the planets and life undergraduate certificate. 

Ed has served the department, the University, and the broader astronomical community in countless other ways. He developed many of the core courses taught in the department, including the course in galaxies and cosmology for majors. He was director of the Council for International Teaching and Research at Princeton, building ties between Princeton and a number of major universities around the globe. For nine years, Ed was director of the Apache Point Observatory 3.5-meter telescope, in which Princeton held a share of observing time. He also served on the Space Telescope Institute Council, a body that acts as the governing board for the institution charged with carrying out the scientific operation of the Hubble Space Telescope, for nine years, including three as its chair. Most recently he acted as a consultant to Catalina Ouyang’s ongoing contemporary art project inspired by the famous Three Body Problem in gravitational dynamics. 

In retirement, Ed plans to split his time between Princeton and Tokyo while continuing his studies of exoplanets and exobiology, and to build upon his interests in philosophy and artificial intelligence. 

Written by members of the Department of Astrophysical Sciences faculty.