Testing Einstein in Space: The Gravity Probe B Mission

Mention the word relativity and everyone thinks 'Einstein'. Less well known is the fact that Einstein invented two theories of relativity, his 'special' theory (1905) which tells what happens to bodies moving at very high speeds, and his 'general' theory (1916) which is about gravity. General relativity states that massive bodies act to distort and twist space and time. The special theory has been accurately confirmed; the general theory is more problematical.

The NASA-Stanford Gravity Probe B Mission (GP-B), launched from Vandenberg Air Force Base in April, 2004, tests with extreme accuracy two extraordinary predictions of general relativity. William Fairbank, one of its three originators, once said that it would be hard to imagine a simpler experiment than GP-B. All it is is a star, a telescope, and a spinning sphere (the gyroscope). Making it happen has been rather more challenging. It has required a new kind of gyroscope, a new kind of telescope, and other inventions including the world's roundest spheres.




All this has been the result of a unique 40-year-long collaboration between Stanford physicists and engineers, plus NASA and Lockheed Martin. GP-B has been described as the most elegant spacecraft ever built. The research leading up to it has resulted in 79 PhD's at Stanford, 13 at other universities, and pioneering research experience for 350 undergraduates from 11 university departments and more than 50 high school students.




Join Professor Francis Everitt for a lively explanation of GP-B's development. No scientific knowledge is necessary—just a keen imagination and the love of a good story.


Location & date
18 May 2006
Thursday, 7:30 - 9:00 PM
William R. Hewlett Teaching Center
Free. No registration required.
Limited seating, please arrive early.


C.W. Everitt
Professor of Physics

A research professor at Stanford's W.W. Hansen Experimental Physics Laboratory (HEPL), C.W. Francis Everitt is the principal investigator for Gravity Probe B. With a wide interest in scientific advancements—both past and future—he has written nearly 100 research papers and five books, including a biography of James Clerk Maxwell, a 19th-century Scottish physicist who predicted the existence of radio waves 26 years before they were proven to exist. In his free time, Professor Everitt has run three marathons, remains active in his church, and visits his home country, Great Britain, as often as he can.

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