Masses in the Stellar Graveyard – Hobart and William Smith Colleges \
The HWS Update

Masses in the Stellar Graveyard

More than 30 new black hole events are detailed in a new report from the LIGO-Virgo-KAGRA international scientific collaboration, which includes Associate Professor of Physics Steve Penn.

This month, the LIGO-Virgo-KAGRA Collaboration released the largest catalog ever of collisions involving black holes and neutron stars. Gravitational waves, or ripples in spacetime, from these collisions were picked up by a worldwide team of scientists using the international gravitational-wave observatory network.

For more than 20 years, Associate Professor of Physics Steve Penn has been part of the international group of researchers studying stellar phenomena and pursuing direct detection of gravitational waves to explore the fundamental physics of gravity and to advance astronomical discovery. Hobart and William Smith were among the first small colleges to join the LIGO Scientific Collaboration when Penn joined the faculty. He currently serves as Chair of the LSC Council.

As detailed in several papers which appeared this month, the LIGO-Virgo-KAGRA team has detected a further 35 gravitational wave events since the last catalog release in October 2020, bringing to 90 the total number of observed events since gravitational-wave observations began.

Click here to read about what LIGO-Virgo-KAGRA found and the rapidly developing progress in gravitational wave detection.

An MIT-trained physicist, Penn joined the HWS Physics Department in 2002 following postdoctoral fellowships at University of Washington and Syracuse University. It was at Syracuse, in 1998, that he became a member of the LSC, an international group of approximately 1,400 researchers focused on the direct detection of gravitational waves.

Penn was a co-author of the Physical Review Letters article announcing the 2015 detection of gravitational waves by LIGO (Laser Interferometer Gravitational-Wave Observatory), which confirmed for the first time the existence of ripples in the fabric of spacetime, a major prediction of Albert Einstein’s 1915 general theory of relativity. In 2017, for his work pioneering the discovery of gravitational waves, Penn was among the international team of scientists recognized with the prestigious and highly selective Special Breakthrough Prize in Fundamental Physics, through which Penn was awarded a “Breakthrough Prize: Scientists Changing the World” medal. Later in 2017, the Nobel Prize in Physics was awarded to Rainer Weiss of MIT, and Barry Barish and Kip Thorne of California Institute of Technology for the discovery of gravitational waves, a scientific breakthrough made possible thanks to the global LSC research team, including Penn.

Penn’s original LSC research was on the mirror design for Advanced LIGO. He discovered how to significantly reduce the thermal noise in the material fused silica, which led to the selection of fused silica for the Advanced LIGO mirror substrates and suspensions. With that upgrade, scientists will be able to increase the amount of the universe that can be probed by a thousandfold.