Astrophysics

n this interview, Stephon Alexander discusses current research into quantum gravity and possible extensions to string theory; work to merge quantum mechanics and general relativity; research into the connection between music and cognitive science; experience as a jazz musician; intersections of philosophy and physics; experience as president of the National Society of Black Physicists (NSBP); challenges and stigmas associated with being a Black academic; growing up in both rural Trinidad and the Bronx; undergraduate experience at Haverford; graduate work at Brown; guidance from Robert Brandenberger into the field of quantum gravity, applying particle physics to astrophysics and cosmology; thesis research on solitons and topological defects and its role in string cosmology and theory; decision to take postdoc at Imperial College London focusing on M-theory and integrating string theory with cosmic inflation; influence of Alan Guth; work on D-brane driven inflation; experience in the underground London music scene; decision to go to SLAC in Stanford and work under Michael Peskin; loop quantum gravity; time as faculty at Penn State; the role and responsibility of the Black academic; recruitment by Brown University; intellectual influence of David Finkelstein; the process of becoming president of NSBP. Toward the end of the interview, Alexander reflects on his books, The Jazz of Physics and Fear of a Black Universe; being an outsider in the field of physics; and revisits his current work on quantum gravity. He emphasizes the importance of in-person collaboration and improvisation. 

Interview with Marc Kamionkowski, William R. Kenan, Jr. Professor of Physics and Astronomy at Johns Hopkins University. He discusses his family heritage of Ashkenazi Jews who left Eastern Europe for Argentina, and his father’s medical research which took the family to Cleveland. Kamionkowski recounts his childhood in Shaker Heights, and he describes his undergraduate work at Washington University, where he switched from pre-med to physics to work with Marty Israel and Joe Klarmann. Despite his lack of preparation, Kamionkowski explains his admission to the University of Chicago, and he describes “the bug” that made him focus on physics and drive to succeed in quantum mechanics and understand quantum field theory. He discusses his thesis research under the direction of Michael Turner on energetic neutrinos from WIMP annihilation in the sun. Kamionkowski discusses his post-doctoral research at the Institute for Advanced Study where he was in Frank Wilczek’s particle theory group. He describes his first faculty appointment at Columbia and how experimental advances had opened up opportunities in cosmology. He explains his decision to move to Caltech because of its strength in theoretical astrophysics and where he became director of the Moore Center. Kamionkowski discusses his subsequent move to Johns Hopkins, and he surveys his recent projects on the Hubble Tension and early dark energy. At the end of the interview, Kamionkowski explains why he has always valued research that bridges the divide between theory and experimentation and why he expects this will continue to inform his broad research agenda.

Interview with Joel Primack, Distinguished Professor of Physics Emeritus at the University of California, Santa Cruz. Primack discusses what he has been able to do in his free time since his retirement, including writing papers, giving lectures, hosting meetings at UC Santa Cruz, leading international collaborations, and supervising research. He sees the new data coming from the Vera Rubin Observatory and the Gaia Survey as exciting developments in the realm of astrophysics, and he is looking forward to adding to this data when we begin receiving images from the James Webb Space Telescope. Primack discusses his work with various simulations that he has utilized to understand what may be occurring within galaxies, and the growing importance of astrobiology in these simulations. He takes us back into his early years in Montana, where his passion for science began to develop, and how his high school education and internships led him to Princeton University for his undergraduate career. While at Princeton, Primack took classes from John Wheeler, worked at the Jet Propulsion Lab under Bill Pickering, and participated in the Students for a Democratic Society, where his interest in the combination of politics and science began to grow. Primack discusses how important the communication between politicians and scientists is, and he saw this need for improved communication early on. He started the Congressional Science and Technology Fellowship program as a preliminary way to work on the relationship between government and science. He then recounts his experiences at Harvard University and his eventual move to Santa Cruz, where he continued working on dark matter and dark energy, among other things. He remarks on his relationship and work with Nancy Abrams, including the courses they taught and the books they wrote together. He ends the interview talking about his family, his recovery from cancer, and the people he’s looking forward to working with in the future.

In this interview, Sandra Faber, Professor Emerita in the Department of Astronomy and Astrophysics, UC Santa Cruz and Astronomer Emerita at the University of California Observatories discusses her career and her involvement in various projects. Faber describes the relationship between these appointments, and she describes some of the benefits that remote work has allowed during the Covid-19 pandemic. She describes the DEIMOS spectrograph project as an outgrowth from her interest in galaxy formation and the centrality of steady state theory to this research. Faber discusses the importance of NSF support for her work, and she explains some of the cultural sensitivities in setting up a major telescope project in Hawaii. She explains the difference between ancient and more recent galaxy formation, and she explains how the next generation of spectrographs has surpassed what DEIMOS has been able to achieve. Faber discusses the famous optical flaw that threatened the viability of the Hubble Telescope and how this issue was resolved and the import of the CANDELS project. She explains the value of advanced computing for black hole quenching models, and she discusses her long-term collaboration with Chinese scientists and some of the political and international considerations inherent in these partnerships. Faber describes the origins of the Osterbrock Leadership Program and its value for fostering the careers of the next generation of scientists. At the end of the interview, Faber describes the meaning of “Cosmic Knowledge,” and she explains how this concept of humanity’s greater appreciation of our place in the universe can have ethically positive and long-lasting impacts beyond astronomy.

Physics Graduate student Eline V. A. van den Heuvel (University of Amsterdam) interviews Professor Emeritus of Physics and Senior Research Scientist at the University of Maryland Charles W. Misner. After obtaining his BA at the University of Notre Dame in 1952, Prof. Misner continued his education at Princeton University, where he completed his PhD in Physics under supervision of Prof. John. A. Wheeler (1911-2008) in 1957. In the spring semester of 1956, Prof. Wheeler fulfilled the Lorentz professorship at Leiden University, the Netherlands, accompanied by his student Misner. Prof. Misner discusses this trip, focusing on his personal experience and his work on the Already Unified Field. He also discusses Wheeler’s relativity work and possible motivations for Wheeler to go to Leiden. The remainder of the interview deals with the many-worlds interpretation of Dr. Hugh Everett, a friend of Misner and former a PhD student of Wheeler, and Misner expresses his disappointment in how the physics community has treated Everett.

Elliott Bloom, Professor Emeritus of Particle Physics and Astrophysics at SLAC, recounts his childhood in Brooklyn and then in Los Angeles, and he describes his early interests in physics. He discusses his undergraduate experience at Pomona College where he became interested in particle physics and cyclotrons. Bloom describes his graduate work at Caltech, where he worked under the direction of R.L. Walker and did his thesis experiment on studying gamma ray production of charged pions from hydrogen or deuterium. He discusses his postdoctoral research at SLAC to work with Richard Taylor, who was building spectrometers in End Station A at the end of the linear electron accelerator. Bloom discusses his early interests in online computing and he describes the origins of the Parton model and his collaboration with Joe Ballam on BC-42. He explains his original involvement with axion research and the significance of the DORIS-II storage ring at DESY. Bloom discusses his subsequent work at the SLAC B-factory on PEP-II, he describes his interests in the COBE satellite, and he explains SLAC's entrée into astrophysics. He discusses the collaborative effort with NASA on the GLAST experiment and his focus with DOE support to understand dark matter. At the end of the interview, Bloom reflects on his career trajectory as part of a larger narrative of particle physicists who became engaged in astrophysics later in their careers, and why it is important for physicists to remain open to new avenues of inquiry.

Interview with Jonathan Dorfan, emeritus director of SLAC, and emeritus president of the Okinawa Institute of Science and Technology, Graduate University. Dorfan recounts his childhood in South Africa and his experiences with apartheid, and he explains how he developed his early interests in science. He discusses his time at the University of Cape Town and a formative visit he made to SLAC where his older brother was working. Dorfan describes his subsequent studies at UC-Irvine and he explains his interest in pursuing a graduate degree in particle physics and high-energy physics during the excitement surrounding the Standard Model. He discusses his move to SLAC to conduct research with rapid cycling bubble chambers which turned into his thesis. Dorfan describes his postdoctoral research at SLAC with Martin Perl and his involvement with the Mark I and Mark II experiments, and he describes the opportunities leading to his faculty position at SLAC. He discusses the centrality of the B-factory project, and he describes his considerations when he was offered the directorship at Fermilab. Dorfan describes the impact of the rise and fall of the SSC on SLAC, and he explains the leadership positions which at a certain point put him on track to assume the directorship of SLAC. He describes SLAC’s entrée to astrophysics and the strategic partnership it developed with NASA, and he reflects on whether this transition would have been conceivable to Panofsky’s founding vision for the lab. Dorfan describes the changing culture of SLAC and its increasingly bureaucratized nature toward the end of his directorship, his work in support of advancing cancer research at Stanford, and he discusses the circumstances leading to his directorship of the Okinawa Institute. At the end of the interview, Dorfan emphasizes continuity over change as the dominant theme of his career in science with an arc that has increasingly bent toward concerns of broad societal relevance.

Interview with Rainer Weiss, professor emeritus of physics at MIT. Weiss recounts his family history in pre-war Europe and the circumstances of his parents' marriage. He describes his childhood in New York City, and he explains his interests in experimenting and tinkering from an early age. Weiss explains the circumstances leading to his undergraduate study at MIT and his original plan to study electrical engineering before focusing on physics. He recounts his long and deep relationship with Jerrold Zacharias, who singularly championed Weiss's interests over the years. He discusses his graduate work on the hyperfine structure of hydrogen fluoride. Weiss describes his formative work with Bob Dicke at Princeton, and he explains how technological advances was beginning to offer new advances in general relativity. He explains how Dicke's influence served as an intellectual underpinning for the creation and success of LIGO. Weiss emphasizes the importance of Richard Isaacson as one of the founding heroes of LIGO, and he describes the fundamental importance of joining his research institutionally with Caltech. He describes his early research with John Mather, and the numerous administrative challenges in working with the NSF throughout the LIGO endeavor. Weiss describes the geographical decisions that went into building LIGO, the various episodes when LIGO's ongoing viability was in doubt, and how both Barry Barish and Kip Thorne contributed to ensuring its success. At the end of the interview, Weiss describes some of the sensitivities regarding who has been recognized in LIGO and who has not, in light of all the attention conferred by the Nobel prize, and he reflects on how LIGO will continue to push discoveries forward on the nature and origins of the universe.

Interview with William H. Press, Leslie Suringer Professor in Computer Science and Integrative Biology at the University of Texas at Austin. Press recounts his childhood in Pasadena and the influence of his father Frank Press, who was a prominent geophysicist, Caltech professor, and who would become science advisor to President Jimmy Carter. He describes the impact of Sputnik on his budding interests in science, and he discusses his undergraduate experience at Harvard, where Dan Kleppner, Norman Ramsey, Ed Purcell and Dick McCray were influential in his development, and where he realized he had an aptitude for applying abstract equations to understanding physical reality. Press describes trying his hand with experimentation in Gerald Holton’s high-pressure physics lab, he recounts his involvement in student activism in the late 1960s, and he discusses his involvement in computer hacking in its earliest form. He explains his decision to attend Caltech for graduate school and his interest in studying with Dick Feynman and Kip Thorne. Press describes the opportunity leading to his work at Lawrence Livermore, how he got involved with Thorne’s group of mathematical general relativists, the origins of Thorne’s work on gravitational waves, and his collaborations with Saul Teukolsky and Paul Schechter. He describes the formative influence of Chandrasekhar. Press discusses his first faculty position at Princeton where he joined John Wheeler’s relativity group, and he describes his research interests flowing more toward astrophysics. He explains the opportunities leading to his tenure at Harvard, where he was given separate appointments in physics and astronomy and where he founded theoretical astrophysics within the Center for Astrophysics. Press describes his entrée into science policy work in Washington with the NSF Physics Advisory Committee and then later on the National Academy of Science and the National Research Council, and he explains the origins of his long-term association with the JASON Study Group. He describes his interest in gravitational collapse, Ia supernovae and galaxy formation, and why the study of black holes reinvigorated the field of general relativity. Press describes the singular genius of Freeman Dyson, and he recounts his contributions to nuclear risk reduction in science policy and his service with the Defense Science Board and the Institute for Defense Analyses. He discusses his tenure as chair in Harvard’s Department of Astronomy, his experience with the Numerical Recipes books, and his collaboration with Adam Riess and Robert Kirshner. Press recounts his decision take a position at Los Alamos as Deputy Director to John Browne, he describes his education there in the concept of leadership which he never received in his academic career, and he provides his perspective on the Wen Ho Lee spy case and the existential crisis this caused at the Lab. He describes the Lab’s role in the early days of computational biology and how this field sparked his interest. Press contextualizes this interest within his conscious decision not to stay connected to astrophysics during his time at Los Alamos, and he explains the opportunity leading to him joining UT-Austin where he remains invested in computational biology. He describes his work for the President’s Council of Advisors in Science and Technology during the Obama administration, he describes Obama’s unique interest in science and science policy, and he narrates the difficulties in the transition to the Trump administration. Press reflects on what it means to be a member of the rarified group of scientists who did not win a Nobel Prize but who were advised by and taught scientists who did. At the end of the interview, Press explains that he has always been a dilettante, which has and will continue to inform how he devotes his time to science, service, and policy matter, and he advises young scientists to aspire to mastery in a specific discipline early in their career before branching out to new pursuits.

Interview with Robert M. Wald, Charles H. Swift Distinguished Service Professor of Physics at the University of Chicago, where he also has appointments with the Kadanoff Center and the Kavli Institute for Cosmological Physics. Wald recounts his childhood in New York, he describes the tragedy of losing his parents in an airplane crash when he very young, and he explains the ongoing legacy of his father Abraham Wald who was a prominent professor of statistics at Columbia. He describes his high school education at Stuyvesant and his decision to pursue a physics degree at Columbia, where he became close with Alan Sachs, who supervised him at Nevis Laboratory. Wald explains his decision to focus on general relativity for graduate school and his interest in working with John Wheeler at Princeton. He describes the excitement surrounding recent advances in approaching astrophysics through relativity, the significance of the discovery of pulsars and the field of black hole uniqueness, and he discusses his postdoctoral research with Charles Misner at the University of Maryland. Wald describes the impact of Saul Teukolsky’s discovery of a variable Weyl tensor component that satisfied a decoupled equation, and he explains the circumstances leading to his faculty position at Chicago, where he was motivated to work with Bob Geroch. He reflects on the experience writing Space, Time, and Gravity, the advances in black hole collapse research, and he explains why he felt the field needed another textbook which motivated him to write General Relativity. Wald discusses his work on the Hawking Effect and his long-term interest in quantum field theory, and he explains the influence of Chandrasekhar on his research. He describes his contributions to the LIGO collaboration, and he explains what is significant about the Event Horizon Telescope’s ability to capture an image of a black hole. Wald explains the state of gravitational radiation research and the accelerating universe, he prognosticates on what advances might allow for a unification of gravity and the Standard Model, and he explains why dark energy is apparently a cosmological constant. At the end of the interview, Wald discusses his recent work on the gravitational memory effect and, looking to the future, he explains his interest to continue working to understand the S-matrix in quantum electrodynamics.