Kip Thorne, Ph.D.
2004 California Scientist of the Year

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Kip Thorne , Ph.D.

For more than forty years, Prof. Kip Thorne of Cal Tech has been one of the leading experts regarding the astrophysical implications of Einstein's General Theory of Relativity, our best description of gravity's operation. Though the weakest of Nature's four forces, gravity operates on the grandest scales. Gravity determines the orbits of the planets about the Sun; it is responsible for the formation of stars from interstellar gas clouds, and, on the largest scale imaginable, governs the evolution and fate of the Universe. Prof. Thorne's scientific contributions have spanned the full range of topics in general relativity including means to test general relativity against rival theories of gravity, applications of relativity to stellar structure and evolution, black holes, and gravity waves.

Gravity waves are one of the more counterintuitive concepts to emerge from general relativity. Briefly, when a system bound by gravity changes, for example when two massive stars spiral in towards one another and then coalesce, “ripples” in spacetime propagate away from the system. If a measuring rod were placed in the path of such a ripple, it would lengthen and then shorten, not because any stellar detritus shocked the rod, but because the geometry of space itself would have changed in response to the varying gravitational condition.; Among a handful of physicists, Prof. Thorne is considered one of the world's authorities on gravitational waves. In part, his work has dealt with the prediction of gravity-wave strengths and their temporal signatures as observed on the Earth. These signatures are of great relevance to LIGO (the Laser Interferometer Gravitational Wave Observatory), a multi-institution gravity wave experiment for which Kip Thorn has been a leading proponent.

LIGO is essentially a set of three very large laser interferometers, two in Hanford, WA and one in Livingston, LA. In very general terms, these interferometers comprise mirrors spaced by about 3 km. The goal of the observatories is to detect a change in the mirrors' separations less than the diameter of an atomic nucleus as a gravity wave passes through the interferometer. LIGO is now operating very near its design goals, and is actively searching for gravity waves.

No discussion of Prof. Thorne's contributions to gravity wave research can be complete without mention of his seminal work in the area of quantum nondemolition (QND) measurements. Very early on, Prof. Thorne recognized that the extreme sensitivity required by gravity wave detectors would require them to confront and surmount the barriers to measurement imposed by quantum mechanics. Though difficult to discuss in this limited space, suffice it to say that Prof. Thorne's contributions in QND measurements have expanded well beyond the concerns of gravity wave detectors. For example, QND measurements are discussed today in the context of atomic clocks.

Professor Kip Thorne has been a California scientist of world renown for a number of years. He has trained a generation of scientists; he has highlighted the stimulating intellectual environment of the State, and he has brought considerable recognition and prestige to the State. We are pleased to select Prof. Kip Thorne as the 2004 California Scientist of the Year.

For more information, go to Kip Thorne's homepage.