| 1959 | Harvard University | A.B. in Physics and Chemistry |
| 1964 | University of Chicago | Ph.D. in Astrophysics |
| 1964-65 | University of Cambridge(England) | Postdoctoral Fellow |
| 1965-66 | Princeton University | Research Associate and Lecturer |
| 1966-68 | Princeton University | Assistant Professor |
| 1968-71 | Princeton University | Associate Professor |
| 1971- | Princeton University | Professor |
| 1979-1995 | Princeton University | Chairman, Department of Astrophysical Sciences |
| 1979-1995 | Princeton University | Director, Princeton University Observatory |
| 1982-2002 | Princeton University | Charles A. Young Professor of Astronomy |
| 1982-84, 1986 | Princeton University Press | Member of the Editorial Board and Trustee |
| 1987 | Harvard University | Visiting Professor |
| 1984-85, 1987 | Smithsonian Institute | Regents Fellow |
| 1990 | University of California-Berkeley | Visiting Miller Professor |
| 1992 | University of Chicago | H.D., Doctor of Science |
| 1995-2001 | Princeton University | Provost |
| 1997-2007 | American Museum of Natural History | Trustee |
| 2001-2004 | Univ. of Cambridge(England) | Plumian Professor of Astronomy & Experimental Philosophy, IoA |
| 2002 | University of Cambridge (England) | Master of Arts |
| 2004-2005 | Distinguished Visitor | Institute for Advanced Study |
| 2005-2009 | Director | Princeton Institute for Computational Science and Engineering (PICSciE) |
| 2008-2012, 2012-2016 |
Treasurer | US National Academy of Sciences |
| 2012 - | Princeton University | Charles A. Young Professor Emeritus |
| 2012 - | Princeton University | Senior Research Scholar |
| 2012-2017 | Columbia University | Professor of Astronomy |
Professional Societies
| 1963- | American Astronomical Society | |
| 1978-80 | Councilor | |
| 1988-89 | Chairman, Committee on Astronomy and Public Policy | |
| 1966- | International Astronomical Union | |
| 1978-81 | U. S. Representative | |
| 1988-91 | Commission 48, High Energy, Vice President | |
| 1991-94 | Commission 48, High Energy, President | |
| 1974- | National Academy of Sciences | |
| 1977-78, 1987-88, 1993 | Astronomy Representative, Class Membership Committee | |
| 1977-80 | Assembly of Mathematical and Physical Sciences | |
| 1987-91 | Commission on Physical Sciences, Mathematics and Resources | |
| 1992-95 | Committee on Astronomy and Astrophysics | |
| 1992-95 | Council Member | |
| 1993-95 | Board of Governors | |
| 1994-95 | Audit Committee | |
|
1969-73, 1978-83, 1988-91 |
Executive Committee of Decennial Surveys | |
| 2002-03 | Chair, Committee to Examine the Methodology for the Assessment of Research-Doctorate Programs; and Member, Panel on Quantitative Measures |
|
| 2005-10 |
Chair committee to perform a Data Based Assesment of Research - Doctorate Program in the United States |
|
| 2008-12, 2012-2016 |
Board of Governors |
|
| 1975- | American Academy of Arts and Sciences | |
| 1994- | Royal Astronomical Society, Fellow | |
| 1994- | American Philosophical Society | |
| 1999- | Royal Netherlands Academy of Arts and Sciences, Foreign Member | |
| 2007 | Royal Society (London), Foreign Member |
|