Galaxies -- Formation

In this interview, astronomer Massimo Stiavelli discusses his involvement with the Hubble and James Webb Space Telescopes. He recounts his early childhood growing up in Italy, higher education at the Scuola Normale Superiore in Pisa, and his interest in elliptical galaxies. He reflects on his time as a postdoctoral researcher at Rutgers University, his time at the European Southern Observatory, and his role deriving signs from the Hubble Space Telescope’s aberrated data. Stiavelli discusses his position with the European Space Agency in Baltimore, along with the initial developments of the Next Generation Space Telescope. He also offers his perception on the Space Telescope Science Institute and the scientists working there. He recalls his early involvement with the NGST’s Science Working Group, his role as Project Scientist, and his perspective on the growing schedule and budget delays that led to Congressional hearings. Stiavelli also recalls the impact of the Covid-19 pandemic on the final stages of Webb’s development, the launch, and its current operation. The interview concludes with an overview of Stiavelli’s views on the future of cosmology and the impact of JWST.

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.

Interview with Steven Weinberg, Jack S. Josey-Welch Foundation Chair in Science and Regental Professor at the University of Texas at Austin. The focus of the interview is on how and when Weinberg became interested in cosmology, and how he defines it as a distinct discipline from astronomy and astrophysics. Weinberg explains that between the intensity of interest in particle physics in the 1950s and the speculative nature of cosmology, he had neither the interest nor the outlet to pursue cosmology in a rigorous way. He discusses some of the theoretical and experimental limitations at the time that kept cosmology in a largely “mystical” realm, and why the discovery of the microwave background by Penzias and Wilson “changed everything.” Weinberg explains what new questions can be considered as a result of evidence for a hot early universe, and he discusses when he first became interested in the formation of galaxies. He describes why the cosmological constant has bothered him for a long time, and he traces this problem back to Einstein and what Weinberg considers Einstein’s incorrect approach to his own theory. Contrasting his own experience as a graduate student, he cites John Preskill as his first student to pursue cosmology, and he explains that while his interests in particle physics and cosmology are generally separate, he always looks for intersecting research opportunities, which is well represented in the relevance of beta decay physics in the first three minutes of the universe. At the end of the interview, Weinberg surveys the value and problems associated with the term “Big Bang,” and he reflects on his career-long effort not to be dogmatic in his views on cosmology.

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.