Cosmology

Interview with Henry Tye, professor emeritus of physics at Cornell, and subsequently professor emeritus of physics at Hong Kong University of Science and Technology (HKUST), and currently, Researcher at the Jockey Club Institute for Advanced Study at HKUST. Tye provides a brief history of HKUST, and he offers his views on China’s long-term goals in high energy physics. He recounts his childhood in Hong Kong where his family fled from mainland China during the Communist revolution, and he explains the opportunities that led to his undergraduate admission to Caltech. Tye describes how discussions of the Vietnam War permeated his college experience, and he describes the influence of Gerry Neugebauer on his interest in physics but that cosmology was far from his considerations at that point. He discusses his decision to study at MIT, where Francis Low became his advisor, and how he worked closely with Gabriele Veneziano on the relationship between the Thirring model and bosonic string theory. Tye explains the excitement surrounding the “November Revolution” which was unfolding just as he arrived at the SLAC Theory Group in 1974. He describes the origins of his interests in cosmology, and the source of his collaboration with Alan Guth during his postdoctoral work at Cornell, where he pursued matter-antimatter asymmetry. Tye explains how this collaboration ultimately created the field of inflation and why this addresses fundamental cosmological problems associated with flatness and the horizon. He explains how and why the original theory of inflation was revised by Andrei Linde and Paul Steinhardt, among others, and why he developed a subsequent interest in cosmic superstrings and branes which he recognized would give a perfect model for inflation. Tye describes why he is optimistic that technological advances will make cosmic superstrings a testable proposition, and that collaborations including the Sloan Digital Sky Survey and LIGO/Virgo are positive steps in that direction. He bemoans the dearth of string theorists focused on phenomenological work and why he thinks string theory will solve the quantum gravity problem. Tye describes his decision to join the Cornell faculty, why his notions of a “string landscape” suggest philosophical implications, why the cosmic landscape is central for understanding the wavefunction of the universe, and why both the universe and all multiverses can begin from truly nothing. At the end of the interview, Tye discusses his recent interests on the cosmological constant problem, the KLT relation, and the observations and experiments that are most likely to push cosmology into new and exciting areas of discovery. 

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 Michael Dine, Professor of Physics at the University of California at Santa Cruz. Dine conveys his provisional excitement over the g-2 muon anomaly experiment at Fermilab and he recounts his childhood in Cincinnati. Dine discusses his undergraduate education at Johns Hopkins, his developing interests in physics, and the opportunity that led to his graduate research at Yale. He describes working under the supervision of Tom Appelquist and trying to understand the force between heavy quarks within quantum chromodynamics. Dine describes his earliest exposure to string theory and his decision to take a postdoctoral appointment at SLAC, where he worked with Jonathan Saperstein on the next order calculation of the total electron-positron cross section. He discusses Lenny Susskind’s work on Technicolor and his subsequent appointment at the Institute for Advanced Study, his close collaboration with Willy Fischler, and the excitement surrounding supersymmetry at the time. Dine describes the impact made by Ed Witten when he arrived in Princeton and he discusses the origins of axion-dark matter research. He discusses his first faculty position at City College in New York and his reaction to the “string revolution” of 1984 and AdS/CFT a few years later. Dine explains his decision to move to UC Santa Cruz and his burgeoning interest in cosmology, he reflects on when his research focused to physics beyond the Standard Model, and he explains why it is possible to decouple the expectation that supersymmetry must be detected at the LHC. He explains why string theory is making strides toward experimental verifiability, and he reflects on the utility of being a theorist. At the end of the interview, Dine emphasizes his optimism about the axion as a dark matter candidate and why the field is moving steadily toward a greater understanding of physics at both the largest and smallest scales.

Interview with Robert H. Brandenberger, Canada Research Chair and professor of physics at McGill University. Brandenberger recounts his childhood in Switzerland as the son of organic chemists, and he describes his undergraduate education at the ETH Zurich in physics. He discusses his graduate research at Harvard to work under the direction of Arthur Jaffe, and he describes his first exposure to cosmic inflation. Brandenberger describes his postdoctoral appointment at the ITP in Santa Barbara where he worked with Neil Turok and Andreas Albrecht, and his subsequent postdoctoral work with Stephen Hawking at Cambridge. He explains his initial ideas on cosmic strings as an alternative to inflation and his encounters with Cumrun Vafa and Slava Mukhanov. Brandenberger describes the origins of string gas cosmology, its implications for a multiverse and how it was received among string theorists. He discusses his faculty appointment at Brown and he explains his decision to move to McGill where the opportunity to work with graduate students was stronger. Brandenberger surmises what string theory as a testable proposition would look like, and he reflects on some of the obvious philosophical implications of unknowability in the universe. He explains the difference between a toy model and a proper theory, and he conveys optimism that string gas cosmology will advance research on dark energy. At the end of the interview, Brandenberger reflects on the idea that string theory is "smarter than we are."

Interview with Phillip James Edwin Peebles, Albert Einstein Professor of Science, Emeritus, at Princeton University. Peebles describes his enjoyment in pursuing the issues in cosmology that are most interesting to him in retirement and he explains his appreciation for the importance of taking a sociological perspective to science. He describes his first exposure to cosmology as a field to specialize in during graduate school and he surveys some of the experiments and observational advances that have propelled theoretical cosmology. Peebles recounts his childhood in Manitoba, and he discusses his undergraduate education at the University of Manitoba. He describes arriving at Princeton in 1958 and how he became a student of Bob Dicke's. Peebles discusses his thesis research on the possibility that the fine-structure constant might be evolving. He describes staying at (and never leaving) Princeton for his postdoctoral work, and some of the exciting promises of infrared astronomy and radio astronomy. Peebles conveys the simple process of joining the faculty, and he describes the developments leading to the prediction of the cosmic microwave background. He discusses the trend of particle theorists pursuing questions in cosmology, and he reflects on the impact of the Vietnam era on Princeton. Peebles conveys the significance of the introduction of cold dark matter and his perspective on the inflationary theory of the universe. He explains why LambdaCDM has become standard in the field and why COBE was so important. Peebles surveys the many observational projects that are currently being planned, and he reflects on the "buzz" that he felt in advance of winning the Nobel Prize. He describes how his life has been affected by this honor, and he reflects on how the Department of Physics has changed over the course of his long career. At the end of the interview, Peebles emphasizes his interest in remaining close both to theory and experimentation, and he shares his sense of curiosity at what clues might be found from the epoch of light element production in the very early universe.

Interview with Hiranya Peiris, Professor of Astrophysics at University College London and Director of the Oscar Klein Centre and Professor of Cosmo-Particle Physics at Stockholm University. Peiris describes her dual affiliation, she discusses diversity in STEM over the past year, and she surveys the current interplay between theory and observation in her field. She recounts her childhood and family heritage in Sri Lanka and the circumstances that led her family to relocate to the United Kingdom. Peiris describes her interests in math and science the opportunities that led to her enrollment at Cambridge as an undergraduate and a formative experience at JPL in California. She explains her decision to pursue a PhD at Princeton, where she worked with David Spergel on WMAP. Peiris discusses her postdoctoral appointment as a Hubble fellow at the University of Chicago to continue to work on WMAP, and her subsequent work as a Halliday fellow at Cambridge. Peiris discusses her work on the Lyman-alpha forest and her faculty appointment at UCL where cosmology was just coming into maturity. She conveys the excitement as WMAP results were becoming available and her contributions to the search for dark matter. Peiris explains why the LSST project is so significant, what it was like to win the Breakthrough Prize, and the gratitude she feels by having eminent physicists as mentors. At the end of the interview, Peiris emphasizes the importance of following inquiry into the most fundamental questions surrounding gravity and space time, and why Stephen Hawking remains an intellectual inspiration to her.

Interview with Frank Shu, University Professor emeritus at UC Berkeley and UC San Diego, and Founder and CEO of Astron Solutions Corporation. Shu describes his current work on climate mitigation through his company, Astron Solutions Corporation, and he reflects on how his expertise in physics is useful for this endeavor. He recounts his family origins in Wenzhou, China, and their experiences during the Japanese occupation. Shu describes his family’s journey to the United States through Hong Kong and Taiwan, and the opportunities that led to his undergraduate study in physics at MIT. He describes his early interests in gravitational collapse, and he explains his decision to pursue graduate research at Harvard, where he worked on density wave theory of spiral structure under the direction of Max Krook. Shu explains his broader interest in star formation and his work at Stony Brook before taking a faculty position at Berkeley. He describes the “inside out” collapse model and the formative influence of Peter Goldreich. Shu explains how he came to lead Tsing Hua University and his achievements in raising its stature before joining the faculty at San Diego, and he discusses his original interests in climate change research. He describes the Heat Exchanger (HX) Project and how his research on nuclear energy has therapeutic benefits for cancer patients. Shu discusses his patent on sealed carbon fiber reinforced carbon nanotubes and the hurdles that are preventing the widespread adoption of molten salt technology. At the end of the interview, Shu describes the importance of taking multi-pronged approach to climate mitigation and that humanity’s best response at this point is to recognize climate change as an emergency.

Interview with Alan Rogers, Research Affiliate and retired as Associate Director of the MIT Haystack Observatory. Rogers discusses his current work on the EDGES project and he suggests the possibility that this research will yield insights on the nature of dark energy. He recounts the circumstances of his birth in Rhodesia and the opportunities that led his family to the United States. Rogers discusses his education at MIT, his interest in radio astronomy, and his research under the direction of Alan Barrett. He narrates the origins of Very Long Baseline Interferometry and its application at the Haystack Observatory. Rogers explains geodesy and why the Mansfield Amendment changed the funding structure at Haystack. He describes becoming Associate Director of Haystack and how he became involved in cell phone infrastructure projects in the 1990s. Rogers explains how EDGES started, its value for measuring ozone concentrations, and he discusses his work for the Event Horizon Telescope. He explains his research contributions for the discovery of hydrogen in the early, cold universe and the value he places on the SRT telescope for educational purposes. At the end of the interview, Rogers explains his desire to expand understanding of low-frequency arrays, particularly in the SKA.

Interview with Alan Dressler, Astronomer Emeritus at The Carnegie Institute for Science Observatories. He describes his current focus on the James Webb Telescope and he conveys concern for a "post-reality" political environment that has taken a grip on American politics. He recounts his upbringing in Cincinnati, and how his curiosity about how things worked naturally pulled him toward astronomical interests. Dressler discusses his undergraduate education at UC Berkeley and his decision to pursue a PhD in the newly created Department of Astronomy at UC Santa Cruz. He describes the importance of the Lick Observatory for his research under the direction of Joe Wampler, and how Jim Peebles gave this thesis project a "seal" of approval. Dressler describes the origins of the Dressler Relation in his study of the morphology of galaxies and the density of their environment, and he describes the opportunities leading to his postdoctoral appointment at Carnegie. He explains the history of the Caltech-Carnegie partnership in astronomy, and he describes working with Allan Sandage and Jim Gunn. Dressler emphasizes the revolutionary effect the Hubble Telescope imparted to the field, and he discusses his time as a Las Campanas fellow. He describes how his work on galaxy formation fed into larger questions about the origins of the universe and the broader philosophical implication of our understanding of Earth's place in the universe. Dressler explains the Great Attractor Model and the state of play in black hole research in the 1980s, and he describes why he did not need to "see" an image of black holes to be convinced of their existence. He narrates the origins of the Association of Universities for Research and Astronomy, and the drama surrounding the repair of the Hubble. Dressler describes presenting the HST & Beyond report to NASA administrator Dan Goldin, and he discusses the natural progression for his work on the NASA Origins program. He discusses his subsequent focus on the Magellan Telescope and the EOS Decadal Survey. At the end of the interview, Dressler reflects on the strides made in galaxy formation research over the course of his career, and he conveys pride in playing a role in science, for which he appreciated since youth as a field that offered limitless opportunities to improve the world.