Gravity Probe B mission
Everitt, Francis Gravity Probe B Project, W.W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, California.
- Why perform another test of Einstein's theory?
- Experimental design
- Extraordinary technologies
- GP-B flight mission
- Data analysis and preliminary results
- The broader legacy of GP-B
- Links to Primary Literature
- Additional Readings
Gravity Probe B (GP-B) is a landmark fundamental physics experiment in space to test Einstein's 1916 general theory of relativity. GP-B uses four spherical gyroscopes and a telescope, housed in a satellite orbiting 642 km (400 mi) above the Earth, to measure, with unprecedented accuracy, two extraordinary effects predicted by the theory: the geodetic effect—the amount by which the Earth warps the local spacetime in which it resides; and the frame-dragging effect—the amount by which the rotating Earth drags spacetime around with it. GP-B tests these two effects by precisely measuring the precession (displacement angles) of the spin axes of the four gyroscopes over the course of a year relative to a distant guide star, and comparing the experimental results with the theoretical predictions. In a polar orbit, the two effects occur at right angles to one another—the geodetic effect in the plane of the spacecraft's orbit, and the frame-dragging effect in the Earth's equatorial plane (Fig. 1). Thus, each gyroscope measures both effects simultaneously.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information