In Memory of Professor Rainer Weiss — A Pioneer of Gravitational Wave Research

We are deeply saddened to announce the passing of Professor Rainer Weiss, Professor Emeritus at the Massachusetts Institute of Technology and a co-founder of the LIGO project in the United States. He passed away on August 25, 2025. On behalf of all researchers involved in the KAGRA project, we extend our heartfelt condolences.

Professor Weiss was awarded the 2017 Nobel Prize in Physics, together with Barry C. Barish and Kip S. Thorne, for their “decisive contributions to the LIGO detector and the observation of gravitational waves,” following the first detection of gravitational waves in 2015.

Before his involvement in gravitational wave research, Professor Weiss made significant contributions to the measurement of the cosmic microwave background spectrum using balloon-borne instruments and was a co-founder of NASA’s COBE (Cosmic Background Explorer) mission.
His pioneering work in precision observational techniques has greatly advanced our understanding of the universe.

We share below a message from Takaaki Kajita, Distinguished University Professor of the Institute for Cosmic Ray Research, University of Tokyo, and Principal Investigator of the KAGRA project:
“Professor Weiss’s proposal to use laser interferometry for gravitational wave detection laid the foundation for the golden age of gravitational wave astronomy we are now experiencing.
At KAGRA, we are committed to carrying forward his brilliant ideas and hope to contribute to the advancement of gravitational wave astronomy by detecting gravitational waves as soon as possible.”

References
MIT News: https://news.mit.edu/2025/professor-emeritus-rainer-weiss-dies-0826
Virgo News: https://www.virgo-gw.eu/news/goodbye-rai-weiss/