In this series of posts, we sit down with some of the plenary speakers for the 240th AAS meeting to learn more about them and their research. You can see a complete schedule of their calls hereand read our other interviews here!
There is no doubt that the mother astronomical surveys has totally revolutionized cosmology. For example Sloan Digital Sky Survey (SDSS) was the first to detect acoustic baryon oscillations using measurements of over one million galaxies. Professor David Weinbergone of the early designers of SDSS, has almost so many research interests. Weinberg was not only the key in the design of the main spectroscopic galaxy sample of SDSS; his research has changed our understanding of the chemical evolution of the Milky Way, galaxy formation and the content and properties of dark energy and dark matter.
Weinberg is a Distinguished University Professor and Chair of the Department of Astronomy at Ohio State University. He is the 2021 winner of Dannie Heineman Prize for Astrophysics, for his significant contribution to facilitating, guiding and participating in transformative science that is the result of modern large-scale astronomical studies at optical wavelengths, in particular SDSS. The title of his lecture at # AAS240 is “Asteroids to Reionization: The Broad Reach of Survey Astronomy.”
A beginning anchored in popular science books
Weinberg first became interested in physics around the age of 12 by reading popular science books. A book that had a particularly significant influence on him was “One Two Three … Infinity,” by George Gamow. This book inspired him to continue reading other popular physics books and to take physics courses in high school. Weinberg notes that reading popular science books early on helped create a strong foundation for his physics career. “I think the fact that I had read many popular science books and science books was important to me because the first physics courses were quite interesting … but they were a lot of work and a lot of solving equations about inclined planes. So it was really important to the popular science reading left me with a vision of where [physics] may result.” After high school, Weinberg would continue to take his bachelor’s degree in physics from Yale University and his doctorate. in astrophysics from Princeton University.
I asked Weinberg how he became interested in such a wide range of different research topics. He replied that he had always followed only the path set by observers and instrumentalists. “Especially for theorists, in [choosing problems] and deciding what to do over the next five years, seeing where the observations improve is a good guide. Because it usually means that the current models that usually exist are not yet sufficient. And in 20 years, [you should think about where] new instrumentation will allow major changes in observational data five to ten years ahead – it is a good opportunity to get into a new project before other theorists realize that the project will be important. So it is very valuable to have instrumentalists that you can talk to and learn from. ”
Recently, Weinberg has focused on understanding the chemical development of the Milky Way with the help of measurements from Sloan APOGEE surveya high-resolution spectroscopic survey of 100,000 Milky Way red giant stars. His goal is to better understand the formation history of the Milky Way and then link it to the formation history of other galaxies. Last month was his article on the star formation history of the Milky Way’s galactic disk covered by astrobites! In summary, Weinberg and his colleagues used the ages and metallicity of the Milky Way stars to try to draw conclusions about its star formation history. When stars die, the heavier metal by-products from their explosions and pulsations are released interstellar medium where new stars are then born under more metallic conditions than older ones. This leads to a well-understood trend where younger stars are metal-rich and older stars are metal-poor. The authors used this relationship to establish that most of the Milky Way’s disk stars we observe today were created during and after a massive star formation event 13 years ago.
Focus on the bigger picture
Weinberg is also busy on the cosmology side, where he investigates S8 voltage, a discrepancy between the level of clustering of dark matter measured from galaxy studies versus from the cosmic microwave background. This excitement is not worrying but exciting for Weinberg, who emphasized that one of the biggest (pleasant!) Surprises of his career has been the incredible speed with which progress has been made in cosmology. Weinberg recalls, “When I was a doctoral student, Lambda seemed like an opportunity, but really a pretty extreme one. When I gave lectures as a doctoral student and postdoc in the late 80’s and early 90’s, I started with my list of what I considered to be the five main issues in cosmic structure formation. (1) Was cosmic structure formed by gravitational instabilities? (2) If so, what were the original terms? (3) What is dark matter? (4) What is w? (5) What is the relationship between galaxies and dark matter? And what’s especially encouraging to me, having been in the field for 30 years now, is that to a large extent, most of these questions have been answered. ”
Advice for Astronomers in Early Careers: Focus on Your Writing!
Weinberg’s advice to future researchers is to improve your writing skills at an early stage. “My best advice to physicists in undergraduate education is to work on becoming the best writer you can, because your product – what lasts is paper, and the quality of the magazines has an effect on how effective they are. And to be good it makes great difference.” Weinberg recalls that “the single most effective class in college he took in terms of its impact on him” was not a physics course, but a writing course, where they had to write one thing every day. And getting good at writing early really helped him succeed even today. “Between newspapers, letters of recommendation and mostly e-mails, I probably write 1000 pages a year if I add it all up. So the ability to write something that is decently fast has been super important.”
To hear more about survey astronomy, listen to David Weinberg’s plenary lecture at 16:40 PT on Monday 13 June on # AAS240!
Edited by: Katya Gozman
Selected image credit: AAS
About Abby Lee
I’m a doctoral student at UChicago, where I study cosmic distance scales and the Hubble Voltage. Outside of astronomy, I enjoy playing soccer, running and learning about fashion design!
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