Rainer Weiss ( , ; September 29, 1932 – August 25, 2025) was a German-American physicist, known for his contributions in gravitational physics and astrophysics. He was a professor of physics at the Massachusetts Institute of Technology and an adjunct professor at Louisiana State University. He is best known for inventing the laser interferometric technique which is the basic operation of LIGO. He was Chair of the COBE Science Working Group.

In 2017, Weiss was awarded the Nobel Prize in Physics, along with Kip Thorne and Barry Barish, "for decisive contributions to the LIGO detector and the observation of gravitational waves".

Weiss helped realize a number of challenging experimental tests of fundamental physics. He was a member of the Fermilab Holometer experiment, which uses a 40m laser interferometer to measure properties of space and time at quantum scale and provide Planck-precision tests of quantum holographic fluctuation.

Early life and education

Rainer Weiss was born in Berlin, Brandenburg, Prussia, Germany, on September 29, 1932, the son of Gertrude Loesner and Frederick A. Weiss. His father, a physician, neurologist, and psychoanalyst, was forced out of Germany by Nazis because he was Jewish and an active member of the Communist Party. His mother, an actress, was Christian. His aunt was the sociologist Hilda Weiss. His younger sister is playwright Sybille Pearson. Weiss spent his youth in New York City, where he attended Columbia Grammar School. with the excuse that he had abandoned his coursework to pursue a romantic relationship with a music student from Chicago. While this affair was a contributing factor, Weiss's concurrent vacillation between MIT's engineering and physics tracks may also have played a significant role. Jerrold Zacharias, then an influential physicist and MIT professor, intervened, and Weiss, after working as a technician in Zacharias's lab, eventually returned to receive his S.B. degree in 1955. He would complete his PhD in 1962, still with Zacharias as advisor/mentor. When Weiss's students asked him about Weber's work, he was unable to explain it to them, as it seemed to contradict his understanding of general relativity. In 1967, to illustrate the principle of gravitational wave detection in a simpler way, Weiss devised a thought experiment involving time of flight measurements of light between free masses in space, which in principle required "impossibly precise clocks". About a year later, as Weber's claims remained unconfirmed, Weiss started to realize that maybe Weber was wrong. He eventually revisited his idea and replaced the clocks with laser interferometry and concluded that such an approach could realistically detect gravitational waves, at sensitivities beyond what Weber's resonant bars could achieve.

Vietnam Era cuts to science grants

In 1973, Weiss was forced to pivot with his work as the US military cut funding for any science that was not determined to be "directly relevant to its core mission." Weiss wrote a proposal to the NSF that described "a new way to measure gravitational waves." This was the work that would eventually lead to his 2017 Nobel Prize, though it was many years before the interferometers Weiss and his students built were sensitive enough to actually detect gravitational waves, making for numerous unpleasant doctoral thesis defenses where Weiss's graduate students were unable to present positive (in layman's terms: any) results. After the study of prototypes at MIT, Caltech, Garching, and Glasgow, and Weiss's estimates what it would take to build a full scale interferometer, Caltech and MIT signed an agreement about the design and construction of LIGO in 1984, with joint leadership by Ronald Drever, Weiss, and Thorne.

In a 2022 interview given to Federal University of Pará in Brazil, Weiss talks about his life and career, the memories of his childhood and youth, his undergraduate and graduate studies at MIT, and the future of gravitational waves astronomy.

Achievements

Weiss brought two fields of fundamental physics research from birth to maturity: characterization of the cosmic background radiation, He co-founded the NSF LIGO (gravitational-wave detection) project, which was based on his report "A study of a long Baseline Gravitational Wave Antenna System".

Both of these efforts couple challenges in instrument science with physics important to the understanding of the Universe.

In February 2016, he was one of the four scientists of the LIGO/Virgo collaboration presenting at the press conference for the announcement that the first direct gravitational wave observation had been made in September 2015.

Kip Thorne described Weiss as "by a large margin, the most influential person this field [the study of gravitational waves] has seen."

According the Nobel Prize website, Weiss received one half of the 2017 Nobel Prize for Physics prize money share, while his LIGO colleagues and co-winners Barry Barish and Kip Thorne only received one quarter of it.

Personal life and death

Classical music was reportedly an influence and shaping force in Weiss's life, from his early youth in an immigrant family, through his shared love of Beethoven's Spring Sonata, which cemented his deep personal relationship with mentor Jerrold Zacharias.

  • In 2016 and 2017, for the achievement of gravitational waves detection, he received:

::*The Special Breakthrough Prize in Fundamental Physics,

::*Gruber Prize in Cosmology,

::*Shaw Prize,

::*Kavli Prize in Astrophysics

::*The Harvey Prize together with Kip Thorne and Ronald Drever.

::*The Smithsonian magazine's American Ingenuity Award in the Physical Science category, with Kip Thorne and Barry Barish.

::*The Willis E. Lamb Award for Laser Science and Quantum Optics, 2017.

::*The Cocconi Prize (2017) of the European Physical Society (jointly with Kip Thorne and Barry Barish).

::* Princess of Asturias Award (2017) (jointly with Kip Thorne and Barry Barish).

::* The Nobel Prize in Physics (2017) (jointly with Kip Thorne and Barry Barish)

  • In 2018, he was awarded the American Astronomical Society's Joseph Weber Award for Astronomical Instrumentation "for his invention of the interferometric gravitational-wave detector, which led to the first detection of long-predicted gravitational waves."
  • In 2020 he was elected a Legacy Fellow of the American Astronomical Society.

Selected publications

Notes

See also

  • List of Jewish Nobel laureates

References

Further reading

  • Rainer Weiss's website at MIT
  • LIGO Group at the MIT Kavli Institute for Astrophysics and Space Research
  • Q&A: Rainer Weiss on LIGO's origins at news.mit.edu
  • Archived at Ghostarchive and the Wayback Machine:
  • including the Nobel Lecture December 8, 2017 LIGO and Gravitational Waves I