Astrophysics

Interview with Mark Trodden, Fay R. and Eugene L. Langberg Professor of Physics, and Co-Director of the Center for Particle Cosmology at the University of Pennsylvania. Trodden describes the overlap between astronomy, astrophysics, and cosmology, and he recounts his working-class upbringing in England. He discusses his undergraduate education at Cambridge, where he focused on mathematics, and he explains his decision to switch to physics for graduate school at Brown, where he worked under the direction of Robert Brandenberger. Trodden describes the impact of the COBE program during this time, and he discusses his work on the microphysics of cosmic strings and topological defects and their effect on baryon asymmetry. He explains his decision to return to Cambridge for his postdoctoral research with Anne Davis and his subsequent postdoctoral appointment at MIT to work with Alan Guth. Trodden discusses his next postdoctoral position at Case Western, which he describes as a tremendously productive period, and he discusses the opportunities that led to his first faculty position at Syracuse. He notes the excellent graduate students he worked with at Syracuse, and he explains what is known and not known with regard to the discovery of the accelerating universe. Trodden describes why the theory of cosmic inflation remains outside the bounds of experimental verification, and he explains the decisions that led to his decision to join the faculty at Penn and his subsequent appointment as chair of the department. He discusses the work that Penn Physics, and STEM in general, needs to do to make diversity and inclusivity more of a top-line agenda, and he describes much of the exciting work his current and former graduate students are involved in. At the end of the interview, Trodden looks to the future and offers ideas on how physicists may ultimately come to understand dark energy and dark matter.

Interview with Feryal Ozel, professor of astronomy and physics at the University of Arizona. Ozel recounts her childhood and family background in Istanbul and how her interest in science was fostered both at home and at the all-girls international school she attended through 12th grade. She describes the opportunities that led to her enrollment at Columbia University for her undergraduate education, where she majored in physics and applied math and where Jacob Shaham influenced her interest in neutron stars. She describes a formative summer internship at CERN where she worked on supersymmetric decays of the Higgs boson, and a postgraduate year at the Niels Bohr Institute, before she began her graduate work at Harvard. Ozel discusses her thesis research on magnetars under the direction of Ramesh Narayan and she describes her postdoctoral position at the Institute for Advanced Study as a Hubble fellow. She describes the academic and family considerations that made Arizona an attractive option and she explains the mechanics behind funding from NASA and the NSF. Ozel describes her favorite physics classes to teach, how she sees her role as a mentor to women students and students of under-represented groups, and she surveys recent developments in neutron star astrophysics and the interaction of gas and black holes. She discusses her contributions to the Event Horizon collaboration, and she relates her ideas on the significance of seeing a photograph of a black hole without needing observational evidence to know that black holes exist. Ozel describes her motivations in serving in scientific advisory roles and the importance of science communication and how advances in computational power have revolutionized astrophysics. At the end of the interview, Ozel discusses the outstanding question mark about making gravity compatible with how we understand the subatomic world and how this serves as a starting point for future research oriented toward fundamental discovery, and why she is particularly interested in continuing to work on black hole imaging.

Interview with Saul Teukolsky, Hans A. Bethe Professor of Physics and Astrophysics at Cornell and Robinson Professor of Theoretical Astrophysics at Caltech. Teukolsky recounts his childhood born in a Jewish family in South Africa, and he explains the tensions between his parents’ politics, who were accepting of apartheid, and his own views which rejected this as a national injustice. He describes his undergraduate education at the University of Witwatersrand and the impact of the Feynman Lectures on his intellectual development. Teukolsky explains his interest in pursuing general relativity for graduate school, and he discusses the circumstances leading to his enrollment at Caltech, where he studied Newman-Penrose equations and perturbations of the Kerr metric under the direction of Kip Thorne. He discusses his year-long postdoctoral research position at Caltech and his subsequent decision to join the faculty at Cornell, where he developed the gravitational theory program. Teukolsky explains the significance of the Hulse-Taylor discovery at Arecibo on general relativity, and he describes the early impact of computers on advancing GR research and specifically on numerical relativity which he worked on with Bill Press. He discusses the rise of computational astrophysics, and he surveys his interests in pedagogical issues in physics and his early involvement in LIGO and the LISA collaboration. At the end of the interview, Teukolsky explains how he has tried to communicate astrophysical concepts to broad audiences, and he expresses optimism that massive advances in computational abilities will continue to drive forward fundamental advances in the field.

Interview with Scott Tremaine, emeritus professor at the Institute for Advanced Study in Princeton. Tremaine discusses his current affiliation with the University of Toronto, and he provides a historical overview of the boundaries between astronomy and astrophysics. He recounts his childhood in a town north of Toronto, and he explains his early interests in science. Tremaine describes his undergraduate experience at McMaster, the opportunities that led to his graduate admission to Princeton, and the exciting developments that compelled him to focus his thesis research on astrophysics. He describes his dissertation on the dynamics of galaxies done under the direction of Jerry Ostriker, who at the time was focused on the earliest research on dark matter. Tremaine discusses his postdoctoral term at Caltech where he worked with Jim Gunn and Peter Goldreich, and he explains his decision to take a second postdoctoral position at the Institute of Astronomy at Cambridge. He describes his appointment at the Institute for Advanced Study, his decision to join the faculty at MIT, and he explains his ongoing research collaboration with Goldreich on studying Saturn's rings. Tremaine describes the intellectual origins of his book, co-authored with James Binney, Galactic Dynamics, and he explains his decision to join the University of Toronto to become the director of CITA. He describes his interests in the origins of comets, his contributions to black hole research, and his appointment at the Institute for Advanced Study. Tremaine discusses his work on exoplanets, and at the end of the interview, he surveys the importance of increasing computational power over the course of his career, the exciting advances that have been made in understanding galaxy development, and why the "three-legged" stool upon which cosmology rests - namely, on inflation, dark matter, and dark energy, is problematic.

Interview with Wick Haxton, professor of physics at UC Berkeley. Haxton recounts his childhood in Santa Cruz and his early interests in math and science. He describes his undergraduate education at the newly created UC Santa Cruz where his initial interest was in mathematics before he was given the advice that he did “mathematics like a physicist.” Haxton discusses his graduate work at Stanford where his original intent was to study general relativity before he connected with Dirk Walecka and Bill Donnelly to focus on nuclear theory and dense nuclear matter. He discusses his postdoctoral research at the University of Mainz where he concentrated on photo-pion physics during the early days of chiral perturbation theory, and he explains the opportunities that led to his next appointment at the LAMPF facility at Los Alamos. Haxton emphasizes the excellence of both his colleagues and the computational capacity at the Lab, and he describes his faculty appointment at Purdue and the solar neutrino experiment he contributed to in Colorado. He explains the opportunities that led to him joining the faculty at the University of Washington where the DOE was about to fund the Institute for Nuclear Theory. Haxton explains the “breakup” between nuclear theory and particle theory and how the INT addressed that. Haxton discusses the opportunities afforded at the INT to engage in nuclear astrophysics and he explains the rise and fall of the Homestake DUSEL project. He explains his decision to go emeritus at UW and to join the faculty at UC Berkeley and to be dual hatted at the Berkeley Lab, and he describes his tenure as department chair. At the end of the interview, Haxton describes his current work organizing the new Physics Frontier Center and the challenges presented by the pandemic, and he credits his formative time as Los Alamos for the diverse research agenda he has pursued throughout his career.

Interview with Marcelle Soares-Santos, assistant professor of physics at the University of Michigan. Soares-Santos recounts her childhood in Brazil, her early interests in science, and her graduate work in physics at the University of São Paulo. She describes her graduate visit to Fermilab to study galaxy clusters as a way to map the history of the expanding universe, which formed the basis of her thesis research. Soares-Santos discusses her return to Fermilab as a postdoctoral researcher, where she joined the Dark Energy Survey, and she explains how DES is getting us closer to understanding what dark energy is. She describes Fermilab’s broad-scale transition into astrophysics, and she explains the opportunities that led to her faculty appointment first at Brandeis before moving to Michigan. Soares-Santos discusses her current work in gravitational waves, and she prognosticates on what the discovery of dark energy (or energies) will look like. She shares her perspective on recent efforts to improve diversity and inclusivity in STEM. At the end of the interview, Soares-Santos explains why observation is leading theory in the current work of astrophysics and cosmology and why she is optimistic for fundamental advances in the field.

Interview with Joshua Frieman, head of the Particle Physics Division at Fermilab, and professor of astronomy and astrophysics at the Kavli Institute for Cosmological Physics at the University of Chicago. He recounts his childhood in Princeton as the son of a physicist and his decision to attend Stanford as an undergraduate, where his interests in cosmology developed. Frieman explains that his options for graduate research in cosmology were narrow and his reasons for going to the University of Washington to work with Jim Bardeen before moving to Chicago to be Michael Turner’s first graduate student. He discusses his interest in approaching cosmology from the perspective of particle theory and his thesis focus on curved space time within a cosmological context. Frieman describes his postdoctoral work at SLAC and his first position at Fermilab in the theory group that Dave Schramm had started. He discusses his work on the Sloan Digital Sky Survey and then the Dark Energy Survey. Frieman explains what might be needed to understand dark energy, he describes his appointment at Chicago, and he explains the origins of the Magellan Telescopes project. He discusses the value of the Aspen summer sessions and his involvement with P5, and explains the value of the 2010 Decadal Survey. At the end of the interview, Frieman surveys the current slate of project at Fermilab and emphasizes the value of incorporating cosmological perspectives to high-energy and particle physics. 

In this interview, David Zierler, Oral Historian for AIP, interviews Joseph Silk, Homewood Research Professor of Physics at Johns Hopkins, Researcher Emeritus at the Institute of Astrophysics in Paris, and Senior Fellow at the Beecroft Institute for Cosmology and Astro-Particle Physics. Silk recounts his childhood in London as the child of working-class parents, and he describes his early interests in math and his acceptance to Cambridge. He discusses the influence of the fluid dynamicist George Batchelor and the gravitational theorist Denis Sciama, and his decision to pursue graduate work at Manchester before enrolling at Harvard for his PhD research under the direction of David Layzer. Silk describes the revolutionary discovery of the cosmic microwave background and some of the observational advances that were driving the young field of cosmology and galaxy formation. He discusses his postdoctoral appointment with Fred Hoyle back at Cambridge and his next research position working with Lyman Spitzer at Princeton, and with Jerry Ostriker on black holes and pulsars. Silk describes the circumstances leading to his first faculty appointment at Berkeley and the excitement surrounding the high red shift universe, the birth of X-ray astronomy, and he describes Berkeley Laboratory’s gradual emphasis on astrophysics over his 30-year career at UC Berkeley. He discusses his long-term research endeavor to verify the prediction of the Big Bang theory and the incredible results of the COBE project. Silk describes his budding interests in particle astrophysics, which he considers a discipline distinct from astronomy, cosmology and astrophysics, and which grew from cosmic inflation. He describes the import and future prospects of supersymmetry, how his namesake contribution “Silk damping” came about, and he conveys his excitement about moon-based telescopes. Silk draws a distinction between understanding the very beginning of the universe (t = 0) and the tiniest fraction of time after that (t = epsilon) and why an understanding quantum gravity will be necessary to make advances in this field. He discusses the current controversy around the Hubble constant, he describes his decision to transfer from Berkeley to Oxford and how this led to his current slate of affiliations, including his appointment at Johns Hopkins. At the end of the interview, Silk discusses his current interests in the moon telescope project and what the legal ramifications of a permanent moon presence might look like and why, in his popular talks, he finds it important to project a sense of awe about the universe.

Interview with Anne Kinney, Deputy Center Director of the NASA Goddard Space Flight Center. Kinney recounts her childhood in Wisconsin and her early interests in science. She describes her undergraduate experience at the University of Wisconsin where she pursued degrees in physics and astronomy. Kinney discusses her time in Denmark at the Niels Bohr Institute before completing her graduate work at NYU relating to the International Ultraviolet Explorer. She explains the opportunities leading to her postdoctoral appointment at the Space Telescope Science Institute in Baltimore where she focused on obtaining optical data and near-infrared data to understand spectral energy distribution for quasars and blazars. Kinney discusses her work on the aberrated Hubble Telescope and her new job at NASA Headquarters where she became head of Origins before she was transferred to Goddard where she became division direct of the Planetary Division. She describes Goddard’s efforts to promote diversity and she describes her subsequent position as chief scientist at Keck Observatory before returning to Washington to join the National Science Foundation to be head of the Directorate for Mathematical and Physical Sciences. Kinney provides a broad view of the NSF budgetary environment, and she explains the circumstances that led her back to NASA to her current work. She describes where Goddard fits into NASA’s overall mission and she explains her interest in promoting NASA in an educational framework to children. At the end of the interview, Kinney conveys her excitement about the James Webb Telescope and why she is committed to ensuring that NASA is a driver behind the broader effort to make astronomy and physics more diverse.

Interview with Tsuneyoshi (Tune) Kamae, Professor Emeritus, both of the University of Tokyo, Department of Physics and of SLAC. Kamae discusses his current work configuring digital devices on science education for the visually impaired, and he recounts his childhood in Himeji and then Osaka, Japan and his early memories of World War II. He describes his undergraduate education at Kyoto University and his developing interest in physics and the opportunity that led to his acceptance at Princeton to work with Val Fitch on the root cause of CP violation. Kamae describes his postdoctoral work at KEK in Japan, where he studied the internal motion of the proton inside the nucleus, and he explains the circumstances that led him to LBL and then SLAC to work on the Time Projection Chamber. He discusses his involvement with the SSC planning and how he became involved in X-ray astronomy. Kamae discusses SLAC’s embrace of astrophysics under the leadership of Burt Richter, and he reflects on some of the cultural differences in physics environments in the United States and Japan. At the end of the interview Kamae shares his hopes for the future of the education program he is developing, and he discusses some of the strategic challenges Japan is facing in light of its demographic trends.