In May I got to learn about research into black holes from some folks who know a lot about them. This is the first of a series of posts sharing some of that black hole info with readers of Sacred Space Astronomy.
May 10-14 I was at the 25th Seven Pines Symposium in Stillwater, Minnesota. The symposium is a small gathering (under twenty this year) of scientists, philosophers, and historians at The Outing Lodge in rural Minnesota, east of St. Paul. Across more than two decades these symposia have featured a number of Nobel Laureates in physics as well as eminent historians and philosophers.
The whole thing is something of an idyllic scholarly setting. A 2004 article about Seven Pines in the journal Science (below) described scholars “packed into a wonderfully rustic lodge”, eating good meals, visiting the bar, and talking physics: “Perhaps not since the famous Solvay Conferences of the early 20th century, at which Niels Bohr and Albert Einstein debated the meaning of quantum theory in their free time, has physics seemed so genteel.”
The organizers of Seven Pines state that it is —
dedicated to bringing together leading historians, philosophers, and scientists for several days in a collaborative effort to probe and clarify significant foundational issues in science as they have arisen in the past and continue to challenge our understanding today…. [Participants] come not to deliver carefully prepared research papers, but rather prepared to talk. Those invited to speak will make a presentation that will focus on, as they choose, some combination of the current state of knowledge, salient issues, principal themes, and problems. The aim of these presentations will be to identify pressing issues and stimulate a deeper analysis of them.
The theme of this year’s symposium was “Windows on the Universe: from Galileo to LIGO and beyond” — “devoted to the role of instruments as ‘windows’ to observe the universe.” The issues to be discussed were “what is the history that led to these instruments being developed? What kind of new information did they offer? And how does that affect conceptual changes in our understanding of the universe?” The sessions and speakers were as follows:
1. The naked eye window: ancient traditions in astronomy
- “Ptolemy’s Epistemology of Astronomy” – Jacqueline Feke (U of Waterloo, Canada)
- “Disputes about Ptolemy’s system of the world in Islamic and Indian astronomy” – Jos Uffink (U of Minnesota)
2. The optical telescope window (Galileo, Kepler and the Herschels)
- “Making Visible: The Galilean Telescope” – Anna Marie Roos (U of Lincoln, UK)
- “A cloudy window: On early telescopes showing stars as discs and why that matters” – Me (and this is a topic that longer-time readers of Sacred Space Astronomy have certainly seen before).
3. The history of infrared spectroscopy and radio astronomy
- “History of Infrared Spectroscopy: From Herschel to the James Webb Space Telescope” – Inigo González de Arrieta (U Basque Country, U Orléans)
- “Technoscience: Opening the Radio Astronomy Window” – Woody Sullivan III (U of Washington, and a former Vatican Observatory Summer School faculty member!)
4. The radio range window: history of radio astronomy and the Event Horizon Telescope (EHT)
- “The next-generation Event Horizon Telescope: From still images to black hole cinema” – Sheperd Doeleman (Harvard, Breakthrough Prize in Physics, with the rest of the EHT team, 2022)
- “An Illumination of Spacetime” – Peter Galison (Harvard)
5. The microwave window: the Cosmic Microwave Background (CMB)
- “How the Hot Big Bang Theory was Found and Recognized” – Jim Peebles (Princeton, Nobel Prize in Physics, 2019)
- “The Cosmic Microwave Background and Tests of the Standard Cosmological Model” – Lloyd Knox (UC Davis)
6. The gravitational waves window: the history of gravitational wave astronomy and the results of LIGO
- “First gravitational wave detection: how could we be sure?” – Daniel Holtz (U Chicago)/Gabriela González (Louisiana State U)
- “The ‘Direct Detection’ of Gravitational Waves” – Jamee Elder (Harvard)
Black holes were a big part of the symposium. Sheperd Doeleman is the guy behind the Event Horizon Telescope (EHT) that produced the first images of black holes in the galaxy M87 and in the Milky Way. Peter Galison’s talk was about creating the next generation of EHT, and the possibility of observing traces of light orbiting a black hole. The two gravitational waves/LIGO talks were about gravitational waves produced by circling black holes. Thus, black holes took up the equivalent of a full day’s worth of talks — a third of the symposium (May 10 and 14 were each half days, for getting acquainted and wrapping up; no formal talks those days).
And so, for the next two months or so my posts every other week are going to be about black holes and the black holes discussions at Seven Pines, or at least the parts of those discussions that stuck with me. The next post in this series will be a discussion of the basic physics behind the idea of black holes. After that we will get into cool stuff like whether a black hole can remember the universe or show us the past, and whether we can really see a black hole or detect gravitational waves produced by one — straight from some of the people who know black holes the best. More black holes in two weeks!