Kip Stephen Thorne (born June 1, 1940) is an American astrophysicist and author. He shared the 2017 Nobel Prize in Physics with Rainer Weiss and Barry C. Barish "for decisive contributions to the LIGO detector and the observation of gravitational waves".
With John A. Wheeler and Charles Misner, he coauthored the general relativity textbook Gravitation in 1973. He has also written popular science, notably Black Holes and Time Warps in 1994 which was awarded the Phi Beta Kappa Award in Science for that year.
Thorne was the Richard P. Feynman Professor of Theoretical Physics at Caltech from 1991 until 2009. A longtime friend and colleague of Stephen Hawking and Carl Sagan, he advised Sagan on the physics of wormholes for his novel Contact. He was a scientific consultant for Christopher Nolan's films Interstellar and Tenet. He received the 2018 Lewis Thomas Prize for science writing.
Thorne was born on June 1, 1940, in Logan, Utah. His father, D. Wynne Thorne (1908–1979), was a professor of soil chemistry at Utah State University, and his mother, Alison (née Comish; 1914–2004), was an economist and the first woman to receive a PhD in economics from Iowa State College. Raised in an academic environment, two of his four siblings also became professors. Thorne's parents were members of the Church of Jesus Christ of Latter-day Saints (LDS Church) and raised Thorne in the LDS faith, though he now identifies as an atheist. Shortly before his mother's death, she urged Kip and his siblings to leave the LDS Church because of its discrimination against women, which they all did. Regarding his views on science and religion, Thorne has stated: "There are large numbers of my finest colleagues who are quite devout and believe in God .... There is no fundamental incompatibility between science and religion. I happen to not believe in God."
Thorne excelled at academics early in life, winning recognition in the Westinghouse Science Talent Search as a senior at Logan High School. He received his BS in physics degree from Caltech in 1962, and his master and PhD in physics from Princeton University in 1964 and 1965 under the supervision of John Archibald Wheeler with a doctoral dissertation on Geometrodynamics of Cylindrical Systems.
He returned to Caltech as an associate professor in 1967 and became a professor of theoretical physics in 1970, becoming one of the youngest full professors in the history of Caltech at age 30. He became the William R. Kenan Jr. Professor in 1981, and the Feynman Professor of Theoretical Physics in 1991. He was an adjunct professor at the University of Utah from 1971 to 1998 and Andrew D. White Professor at Large at Cornell University from 1986 to 1992. Since 2009, Thorne has been the Feynman Professor of Theoretical Physics, emeritus.
Thorne and Linda Jean Peterson married in 1960. Their children are Kares Anne and Bret Carter, an architect. Thorne and Peterson divorced in 1977. Thorne was set up on a blind date with Lynda Obst, later a film producer, by physicist Carl Sagan. They dated in 1979–1980, and parted and remained friends, to the extent that they later collaborated on the movie Interstellar. Thorne and his second wife, Carolee Joyce Winstein, a professor of biokinesiology and physical therapy at USC, married in 1984. In 2015, he collaborated with Obst and Stephen Hawking on a movie script, for which they wrote several drafts.
Throughout the years, Thorne has served as a mentor and thesis advisor to many students who became leaders in observational, experimental, or astrophysical aspects of general relativity. Approximately 50 physicists have received PhDs at Caltech under Thorne's personal mentorship.
Thorne is known for his ability to convey the excitement and significance of discoveries in gravitation and astrophysics to both professional and lay audiences. His presentations on subjects such as black holes, gravitational radiation, relativity, time travel, and wormholes have been included in PBS shows in the U.S. and on the BBC in the United Kingdom.
In 2017, Thorne gave the George Gamow Memorial Lecture at the University of Colorado Boulder, on “Probing the Warped Side of the Universe with Gravitational Waves: From the Big Bang to Black Holes.”
Thorne's research has principally focused on relativistic astrophysics and gravitation physics, with emphasis on relativistic stars, black holes and especially gravitational waves. He is perhaps best known to the public for his controversial theory that wormholes can conceivably be used for time travel. However, Thorne's scientific contributions, which center on the general nature of space, time, and gravity, span the full range of topics in general relativity.
Thorne's work has dealt with the prediction of gravitational wave strengths and their temporal signatures as observed on Earth. These "signatures" are of great relevance to LIGO (Laser Interferometer Gravitational Wave Observatory), a multi-institution gravitational wave experiment for which Thorne has been a leading proponent – in 1984, he cofounded the LIGO Project (the largest project ever funded by the NSF) to discern and measure any fluctuations between two or more 'static' points; such fluctuations would be evidence of gravitational waves, as calculations describe. A significant aspect of his research is developing the mathematics necessary to analyze these objects. Thorne also carries out engineering design analyses for features of the LIGO that cannot be developed on the basis of experiment and he gives advice on data analysis algorithms by which the waves will be sought. He has provided theoretical support for LIGO, including identifying gravitational wave sources that LIGO should target, designing the baffles to control scattered light in the LIGO beam tubes, and – in collaboration with Vladimir Braginsky's (Moscow, Russia) research group – inventing quantum nondemolition designs for advanced gravity-wave detectors and ways to reduce the most serious kind of noise in advanced detectors: thermoelastic noise. With Carlton M. Caves, Thorne invented the back-action-evasion approach to quantum nondemolition measurements of the harmonic oscillators – a technique applicable both in gravitational wave detection and quantum optics.
On February 11, 2016, a team of four physicists representing the LIGO Scientific Collaboration, announced that in September 2015, LIGO recorded the signature of two black holes colliding 1.3 billion light-years away. This recorded detection was the first direct observation of the fleeting chirp of a gravitational wave and confirmed a prediction of the general theory of relativity.
In 1963–1964, Thorne's PhD mentor at Princeton, John Wheeler, assigned him a problem to think about: find out whether or not a cylindrical bundle of repulsive magnetic field lines will implode under its own attractive gravitational force. After several months wrestling with the problem, he proved that it was impossible for cylindrical magnetic field lines to implode.
Thorne determined that the gravitational force can overcome all interior pressure only when an object has been compressed in all directions, as in the case of a spherical star imploding under gravitational force. To express this realization, he proposed his hoop conjecture, which describes an imploding star turning into a black hole when the critical circumference of the designed hoop can be placed around it and set into rotation. That is, any object of mass M around which a hoop of circumference
{\displaystyle {\begin{matrix}{\frac {4\pi GM}{c^{2}}}\end{matrix}}}
can be spun must be a black hole.
Thorne and his students have developed an approach to the theory of black holes called the "membrane paradigm", and used it to clarify the Blandford–Znajek mechanism by which black holes may power some quasars and active galactic nuclei.