Dr. Peter Saulson
Professor of Physics, Syracuse University
Listening to the Universe with Gravitational Waves
Abstract: On September 14, 2015, a gravitational wave signal was received by the Laser Interferometer Gravitational-wave Observatory (LIGO). It was generated by the collision of two black holes, each around 30 times as massive as the sun, about 1.3 billion light years away. The signal, the first ever reception of gravitational waves, tells the story of the last two tenths of a second of the lives of those two black holes, and the first few milliseconds of the life of the 60 solar mass black hole that they formed. Since then, LIGO and its sister project Virgo have heard signals from a number of other collisions; the most spectacular was the reception on August 17, 2017 of the signal of a collision between two neutron stars, similar in “sound” to a black hole collision, but in this case also accompanied by flashes of gamma rays, visible light, radio waves and X-rays. This talk will explain the basics of gravitational waves, how we detect them, and the highlights of what we are beginning to learn about the universe by observing it in this new way.