Babak Malek

Last week I was in Portland, OR for Applied Super Conductivity Conference. The opening Plenary Session was  on Testing General Relativity in Space. Below is an article on Stanford University website about this experiment.

Early theoretical discussions of gyroscope tests of general relativity were given in the 1920’s by J. A. Schouten and A. S. Eddington. In the 1930’s, P. M. S. Blackett investigated the possibility of a ground-based experiment, concluding correctly that it was beyond the reach of technologies known at that time. It was not until the dawn of the space age in the late 1950s that such tests of Einstein’s theory actually became feasible.

The idea of testing general relativity by means of orbiting gyroscopes was suggested independently in late 1959-early 1960 by MIT physicist George Pugh and Stanford physicist Leonard Schiff. Pugh’s Proposal for aSatellite Test of the Coriolis Prediction of General Relativity appeared in an unusual location for scientific papers: the U.S. Department of Defense Weapons Systems Evaluation Group (WSEG) Memo #11(November, 12, 1959). Schiff’s Possible New Experimental Test of General Relativity Theory was published in the March 1, 1960 issue of Physical Review Letters.

Schiff, then chairman of the Stanford Physics Department, discussed his developing ideas with two physics department colleagues, Professors William Little and William Fairbank, both low-temperature physicists. Fairbank, in turn, had an exchange with Professor Robert Cannon, who like Fairbank had just arrived at Stanford. Cannon had considerable experience with state-of-the-art gyroscopes, and he had come to Stanford to create a Guidance and Control Laboratory in the Department of Aeronautics & Astronautics. There followed an important half-hour meeting between Fairbank, Cannon and Schiff, from which evolved the essential collaboration between the Physics and Aero-Astro departments which has been fundamental to the success of GP-B.

Schiff subsequently published a more extended paper, entitled Motion of a Gyroscope According to Einstein’s Theory of Gravitation in the June 15, 1960 issue of the Proceedings of the National Academy of Sciences (Volume 46, Number 6, pp. 871-882). Pugh’s proposal remained relatively unknown until 2003, when it was included in the Classical Papers section of the book, Nonlinear Gravitodynamics: The Lense-Thirring Effect, ed. R. Ruffini and C. Sigismondi, Singapore, World Scientific. An important feature of Pugh’s proposal was that it described the mechanics of a drag-compensating satellite (see the Drag-Free Satellite section below), and it proposed a number of uses for such technology, including the testing of the frame-dragging effect predicted by Einstein’s general theory of relativity.