Kip Stephen Thorne (born June 1, 1940) is an American theoretical physicist , known for his
contributions in gravitational physics and astrophysics . A longtime friend and colleague of
Stephen Hawking and Carl Sagan, he was the Feynman Professor of Theoretical Physics at the
California Institute of Technology (Caltech) until 2009 [2] and one of the world's leading experts
on the astrophysical implications of Einstein's general theory of relativity . He continues to do
scientific research, and is reported to work on the 2014 science-fiction film Interstellar . [3]
Biography
Thorne was born in Logan, Utah, the son of Utah State University professors D. Wynne Thorne
and Alison C. Thorne, a soil chemist and an economist , respectively. Raised in an academic
environment, two of his four siblings are also professors. He became interested in science at the
age of eight, after attending a lecture about the solar system. Thorne and his mother then
worked out calculations for their own model of the solar system.
Thorne rapidly excelled at academics early in life, becoming one of the youngest full professors
in the history of the California Institute of Technology . He received his B.S. degree from Caltech
in 1962, and Ph.D. degree from Princeton University in 1965. He wrote his doctoral thesis,
Geometrodynamics of Cylindrical Systems , under the supervision of relativist John Wheeler .
Thorne returned to Caltech as an associate professor in 1967 and became a professor of
theoretical physics in 1970, the William R. Kenan, Jr. Professor in 1981, and the Feynman
Professor of Theoretical Physics in 1991. In June 2009 he resigned his Feynman Professorship
(he is now the Feynman Professor of Theoretical Physics, Emeritus) to pursue a career of writing
and movie making. His first film project will team him with Christopher Nolan .
Throughout the years, Thorne has served as a mentor and thesis advisor for many leading
theorists who now work on observational, experimental, or astrophysical aspects of general
relativity. Approximately 50 physicists have received Ph.D.s 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. In 1999, Thorne made some
speculations on what the 21st century will find as the answers to the following questions:
Is there a "dark side of the universe" populated by objects such as black holes?
Can we observe the birth of the universe and its dark side using radiation made from space-
time warpage, or so-called "gravitational waves"?
Will 21st century technology reveal quantum behavior in the realm of human-size objects?
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 in the United Kingdom on the
BBC .
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 and his second wife, Carolee Joyce
Winstein, a professor of biokinesiology and physical therapy at USC , married in 1984.
Research
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 .
Gravitational waves and LIGO
Thorne considers gravitational waves. In part, his work has dealt with the prediction of gravity-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 gravity-
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. [4] 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 quadrature
amplitudes of harmonic oscillators – a technique applicable both in gravitational wave detection and
quantum optics.
Black hole cosmology
Main article: Hoop Conjecture
Thorne has made contributions to black hole cosmology . Thorne proposed his Hoop Conjecture that cast
aside the thought of a naked singularity. The Hoop Conjecture 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. [5] That is, any object of mass M around which a hoop of circumference can be spun
must be a black hole. As a tool to be used in both enterprises, astrophysics and theoretical physics, Thorne has developed an unusual approach,
called the " Membrane Paradigm ", to the theory of black holes and used it to clarify the "Blandford-Znajek" mechanism by which black holes may
power some quasars and active galactic nuclei . Thorne has investigated the quantum statistical mechanical origin of the entropy of a black hole and
the entropy of a cosmological horizon in an inflationary model of the universe. With Wojciech Zurek he showed that the entropy of a black hole of
known mass, angular momentum , and electric charge is the logarithm of the number of ways that the hole could have been made. With Igor Novikov
and Don Page he developed the general relativistic theory of thin accretion disks around black holes, and using this theory he deduced that with a
doubling of its mass by such accretion a black hole will be spun up to 0.998 of the maximum spin allowed by general relativity, but not any farther.
This is probably the maximum black-hole spin allowed in nature. He, along with his mentor John Wheeler , additionally proved that it was impossible
for cylindrical magnetic field lines to implode . Both Hawking and Thorne have theorized that a singularity exists in the interior of a black hole.
Wormholes and time travel
Thorne was one of the first people to conduct scientific research on whether the laws of physics permit space and time to be multiply connected (can
there exist classical, traversable wormholes and " time machines "?). With Sung-Won Kim, Thorne identified a universal physical mechanism (the
explosive growth of vacuum polarization of quantum fields ), that may always prevent spacetime from developing closed timelike curves (i.e., prevent
"backward time travel" ). With Mike Morris and Ulvi Yurtsever he showed that traversable Lorentzian wormholes can exist in the structure of spacetime
only if they are threaded by quantum fields in quantum states that violate the averaged null energy condition (i.e. have negative renormalized energy
spread over a sufficiently large region). This has triggered research to explore the ability of quantum fields to possess such extended negative energy .
Recent calculations by Thorne indicate that simple masses passing through traversable wormholes could never engender paradoxes – there are no
initial conditions that lead to paradox once time travel is introduced. If his results can be generalised, they would suggest that none of the supposed
paradoxes formulated in time travel stories can actually be formulated at a precise physical level: that is, that any situation in a time travel story turns
out to permit many consistent solutions.
Relativistic stars, multipole moments and other endeavors
With Anna Żytkow, Thorne predicted the existence of red supergiant stars with neutron-star cores ( Thorne–Żytkow objects ). He laid the foundations
for the theory of pulsations of relativistic stars and the gravitational radiation they emit. With James Hartle, Thorne derived from general relativity the
laws of motion and precession of black holes and other relativistic bodies, including the influence of the coupling of their multipole moments to the
spacetime curvature of nearby objects. Thorne has also theoretically predicted the existence of universally antigravitating " exotic matter " – the
element needed to accelerate the expansion rate of the universe, keep traversable wormhole "Star Gates" open and keep timelike geodesic free float
" warp drives " working. With Clifford Will and others of his students, he laid the foundations for the theoretical interpretation of experimental tests of
relativistic theories of gravity – foundations on which Will and others then built. Thorne is currently interested in the origin of classical space and time
from the quantum foam of quantum gravity theory.
Publications
Thorne has written and edited books on topics in gravitational theory and high-energy astrophysics. In 1973, he co-authored the classic textbook
Gravitation with Charles Misner and John Wheeler ;[6] from which most of the present generation of scientists have learned general relativity theory. In
1994, he published Black Holes and Time Warps: Einstein's Outrageous Legacy , a book for non-scientists for which he received numerous awards. This
book has been published in six languages, and editions in Chinese, Italian, Czech, and Polish are in press.
Thorne's work has appeared in publications such as:
Scientific American ,
McGraw-Hill Yearbook of Science and Technology , and
Collier's Encyclopedia among others.
Thorne has published more than 150 articles in scholarly journals.