The 2,421st Meeting of the Society

May 15, 2020 at 8:00 PM

Virtual Meeting

The 89th Joseph Henry Lecture

The Event Horizon Telescope

First Ever Images of a Black Hole

Sheperd S. Doeleman

Founding Director, Event Horizon Telescope
Harvard-Smithsonian Center for Astrophysics

With Colleagues:
Michael Johnson, Astrophysicist, Harvard-Smithsonian Center for Astrophysics
Andrew Strominger, Professor of Physics, Harvard University

Sponsored by MWZB

About the Lecture

Black holes are the most exotic objects in the universe, and they constitute laboratories of extremes where we can put our fundamental theories of nature to the most stringent tests. At their center lies a singularity of infinite density whose character requires the union of general relativity and quantum mechanics. This singularity is shielded from view by the event horizon where the gravitational potential prevents anything, even light, from escaping. In a paradox created by their small size and enormous gravitational pull, black holes can convert the energy of infalling matter into intense electromagnetic radiation, making them some of the most luminous objects in the sky. At the cores of most galaxies, black holes that are millions or billions of times the mass of our Sun can outshine all the stars in the host galaxy, and can launch jets of near light-speed material that extend for millions of light years. If we could resolve and image such a black hole down to event horizon scales, we could test general relativity in an entirely new cosmic context and study with precision how black holes power some of the most energetic phenomena in the universe.

The Event Horizon Telescope (EHT) is a global array of radio dishes, linked together by a network of atomic clocks to form an Earth-sized virtual telescope that can resolve the nearest supermassive black holes. Einstein’s general relativity predicts that a distant observer should see a ring of light encircling the black hole, which forms when radiation emitted by infalling hot gas is lensed by the extreme gravity near the event horizon. On April 10th, 2019, the EHT project reported success. It imaged a black hole and saw the strong gravitational lensing at the black hole boundary, confirming the predictions of General Relativity theory.

This talk will cover how this was accomplished, details of the first results, and future directions that will enable real-time black hole movies.

Shep’s talk will be followed by presentations by Michael Johnson and Andrew Strominger. Michael is on the faculty at Harvard University and he co-led the imaging team that produced the image of a black hole. He will discuss photon rings of black holes, the information they can provide about the structure of the universe and how they might be resolved by expansions of the Event Horizon Telescope.

Andy’s talk will cap the evening’s lectures. He will discuss implications of black hole imaging to fundamental theoretical physics and our understanding of the physical universe. Following Andy’s talk, all three speakers will join together for a Q&A session with the audience.

About the Speaker

Sheperd Doeleman is the Founding Director of the Event Horizon Telescope (EHT) Collaboration, an Astrophysicist at the Center for Astrophysics of Harvard University and The Smithsonian Institution, and a Harvard Senior Research Fellow. He is also the co-Founder of the Harvad Black Hole Initiative (BHI). Previously, Shep was Assistant Director and Principal Research Scientist at the MIT Haystack Observatory. Over the past twenty years, he has been Principal Investigator on over $50M in public and private foundation grants to support and develop the Event Horizon Telescope project.

Shep’s research interests focus on problems in astrophysics that require ultra-high resolving power. He has used radio interferometry on continent-scales at high frequencies to study the atmospheres of dying stars, as well as stars that are just being born. His group pioneered the development of instrumentation that enables such interferometers to achieve the greatest resolving power possible from the surface of the Earth. Using these new systems, he carried out the first global experiments that successfully measured the size of the supermassive black hole at the center of the Milky Way Galaxy and a black hole in the galaxy M87. And he led the international EHT team that recently succeeded in making the first image of a supermassive black hole.

Shep has published over 100 technical and scientific papers. He lectures widely to scientific and public audiences.

Among other honors and awards, Shep has been awarded a Guggenheim Fellowship, the NSF Diamond Achievement Award, the Breakthrough Prize in Fundamental Physics (on behalf of the EHT Collaboration), the Smithsonian American Ingenuity Award (together with the EHT Collaboration), the Bruno Rossi Prize of the American Astronomical Society, and the AAS Lancelot M. Berkeley Prize.

Shep earned a BA in Physics at Reed College and a PhD in Astrophysics at MIT. In between the two course of study he spent a year in Antarctica conducting space-science experiments at McMurdo Station on the Ross Ice Shelf.

*************
Michael Johnson is a Smithsonian astrophysicist, a Lecturer in the Harvard Department of Astronomy, and an inaugural member of the Harvard Black Hole Initiative. He co-led the Event Horizon Telescope imaging team that produced the first image of a black hole, and he is the youngest member of the Event Horizon Telescope Science Council.

He studies the most compact objects in the universe – black holes and pulsars – through imaging with extremely fine resolution. His research on pulsars utilized interstellar scattering as a vast stochastic lens, and his studies of active galactic nuclei have used Earth-to-space interferometry to achieve the highest direct resolution in the history of astronomy. His contributions across the Event Horizon Telescope project include developing new imaging methods to produce movies of rapidly evolving black holes, and studies of magnetic fields near black holes using polarimetry. He is an author on more than 80 publications.

Michael’s awards include the Breakthrough Prize in Fundamental Physics, the Smithsonian Magazine’s American Ingenuity Award, the National Science Foundation Diamond Achievement Award, the Nelson P. Jackson Aerospace Award, the Smithsonian Secretary’s Research Award, and the Max Planck Society Sabbatical Award. In 2019, he was named to the Bloomberg 50 list.

Michael graduated summa cum laude with BS degrees in mathematics and physics from the University of Southern California, and he holds MA and PhD degrees in physics from the University of California, Santa Barbara.

*************
Andrew Strominger is the York Professor of Physics and Director of the Center for the Fundamental Laws of Nature at Harvard University. Before coming to Harvard he was on the faculty at UC-Santa Barbara.

He has made many significant contributions to theoretical physics in the areas of quantum gravity and string theory, including his work on Calabi–Yau compactification ds/CFT correspondence, Kerr/CFT correspondence, the SYZ conjecture, S-branes, aspects of topology change in string theory, and the stringy origin of black hole entropy.

Andy is an author on over 200 scientific publications.

Among many honors and award, Andy is the recipient of the Physics Frontiers Breakthrough Prize, the Klein Medal, the Dirac Medal, the Dannie Heineman Prize, and a Guggenheim Fellowship.

He earned his AB at Harvard, his MA at UC-Berkeley and his PhD at MIT.