James (Jim) Cordes- Feldstein Professor of Astronomy, Cornell University

Arrive 30 minutes prior for refreshments and great company!

Description:

Gravitational waves are incredibly weak ripples in spacetime. Predicted by Einstein, their existence was demonstrated indirectly only in the 1980s and were directly detected in 2015 with terrestrial laser detectors (the LIGO facility). I will quickly summarize LIGO results on mergers of black holes and neutron stars. Then I will focus on a more recent discovery based on the monitoring of neutron stars (pulsars) in the Milky Way using radio telescopes. This represents a very different kind of detector that is on the scale of our own galaxy. In 2023, a North American collaboration involving Cornell reported gravitational waves originating from the most massive black holes in the universe with a billion times the mass of the Sun and having wavelengths measured in light years. The 15 years of data used to make this discovery are being extended into the indefinite future. This requires new radio telescopes, one of which is of primary interest to Cornell and will come on line by the end of this decade.

Bio:

Jim Cordes is the George Feldstein Professor of Astronomy at Cornell. His work concentrates on turbulence in the interstellar medium, neutron stars and black holes, and gravitational waves. He has worked extensively on fast radio bursts, an engimatic phenomenon of cosmological origin. In recent years data analysis in these areas has made increasing use of machine learning and neural networks. He came to Cornell in 1979 as an assistant professor and made use of the Arecibo Observatory for more than 40 years in studies of neutron stars and other objects. His Ph.D. in applied physics is from the UC San Diego and his B.Sc. is in electrical engineering from UC Santa Barbara. Before Cornell he was a post-doc at U. Mass Amherst with Joseph Taylor in the years immediately after the discovery of the binary pulsar that led to the 1993 Nobel Prize in Physics for Hulse and Taylor. He was PI of the U.S. technology development project for the Square Kilometer Array in the early 2000s and he is a Co-PI on the NSF-funded Physics Frontiers Center for NANOGrav (the North American Nanohertz Observatory for Gravitational Waves). To distract himself from the funding frustrations and rabbit holes of astronomy, he greatly enjoys street, landscape, and bird photography (and even occasional astro-photography).