Sunday, October 27, 2019 - 11:20am to 12:30pm
Theorists who work on big questions in relativity and quantum physics are awash in new data these days. Observations arrive continually from instruments measuring gravitational waves, neutrinos and cosmic microwave background fluctuations, testing ideas about black holes, the Big Bang, spacetime and the building blocks of physics. One of the leading theorists is Abhay Ashtekar, a pioneer of a theory called loop quantum gravity, in which space and time are quantized and the building blocks of the universe are expressed through geometry. Recently Ashtekar and collaborators made the startling assertion that the black hole singularity — a point within a black hole where spacetime simply ends, according to general relativity — does not exist. He will share this and other predictions and assess how they're holding up against the new data.
The black hole, Cygnus X-1, pulls matter from the blue star beside it. Image: NASA/CXC/M.Weiss