Listen to exciting, non-technical talks on some of the most interesting developments in astronomy and space science. Founded in 1999, the Silicon Valley Astronomy Lectures are presented on six Wednesday evenings during each school year at Foothill College, in the heart of California's Silicon Valley. Speakers include a wide range of noted scientists, explaining astronomical developments in everyday language. The series is organized and moderated by Foothill's astronomy instructor emeritus Andrew Fraknoi and jointly sponsored by the Foothill College Physical Science, Math, and Engineering Division, the SETI Institute, the Astronomical Society of the Pacific, and the University of California Observatories (including the Lick Observatory.)
http://youtube.com/svastronomylectures
episode 4: Black Holes and the Technology to Find Them
A Non-technical Talk by Dr. Jessica Lu (University of California, Berkeley) on March 13, 2024
The population of black holes, objects left over from dead stars, is almost entirely unexplored. Only about two dozen black holes are confidently known in our Galaxy. As a result, some of the most basic properties of black holes remain unknown, including the true number of black holes in the Galaxy, their masses and sizes, and how the black holes were formed. Dr. Lu discusses how she and other astronomers are using "gravitational lensing" -- something predicted by Einstein’s work -- to open a new window onto black holes, and how the first free-floating black holes are now being discovered. She explains, in everyday language, why astronomers expect that the number of known black holes will increase by a factor of 100 over the next decade.