Public Lectures
The Fourth Seven Pines Public Lecture
10 May 2022
Philosophy of the Shadow: Imaging a Supermassive Black Hole
Peter Galison, Harvard University
Register: https://z.umn.edu/SevenPines
In thousands of atlases depicting the working objects of inquiry—from bodies, clouds, plants, to crystals and insects—, physicians and natural philosophers worked out what counted as scientific objectivity. This long-term history, with its various takes on what a reliable scientific image should be, converged in the years-long struggle of the Event Horizon Telescope (EHT) to produce a picture of a black hole robust enough to make public. On April 10, 2019, the team released the first image of a black hole, an image viewed within a very few days by more than a billion people. This is a talk about how the EHT team of some 200 scientists came to judge the glowing, crescent-like ring as objective.
The Third Seven Pines Public Lecture
14 May 2019
Is Time Travel Possible?
John Norton, University of Pittsburgh
Well, is it? To decide, there are two questions we need to address. Do our best physical theories allow time travel? Can we escape the logical paradoxes of time travel? This talk will address both questions in popular terms and show that the answers are “yes” and “yes.”
The Second Seven Pines Public Lecture
15 May 2018
Black Holes
Robert Wald, University of Chicago
A black hole is a region where gravity is so strong that nothing—not even light—can escape. Black holes are produced by the complete gravitational collapse of massive bodies. Remarkably, although black holes are not composed of matter, they obey laws that correspond precisely to the ordinary laws of thermodynamics satisfied by ordinary matter. As Stephen Hawking discovered in his groundbreaking work, they also “emit” thermal radiation due to quantum particle creation effects. In this talk, I will describe the theory of black holes in general relativity and discuss the remarkable connection between black holes and thermodynamics.
The First Seven Pines Public Lecture
16 May 2017
Gravitational Waves are Here
William Unruh, University of British Columbia
A hundred years after Einstein argued that his new theory of gravity predicted them, and over 50 years since the experimental search for them began in earnest, gravitational waves were detected passing through the earth by the LIGO detectors in Sept 2015, in probably the most dramatic way possible. They were created about a billion years ago, at the end of a dance between two black holes each with a mass about 30 times that of the sun, proving not only that gravitational waves exist, but that black holes do as well. This talk will review this incredible saga.
