NASA - National Aeronautics and Space Administration

NASA's Gravity Probe B Confirms Two Einstein Space-Time Theories

Artist concept of Gravity Probe B spacecraft in orbit around the Earth. Image Credit: Stanford

NASA's Gravity Probe B (GP-B) mission has confirmed two key predictions derived from Albert Einstein's general theory of relativity, which the spacecraft was designed to test. The experiment, launched in 2004, used four ultra-precise gyroscopes to measure the hypothesized geodetic effect, the warping of space and time around a gravitational body, and frame-dragging, the amount a spinning object pulls space and time with it as it rotates. GP-B determined both effects with unprecedented precision by pointing at a single star, IM Pegasi, while in a polar orbit around Earth.

› Feature
› Link to Final Paper
› View NASA Fact Sheet (PDF, 2.85 MB)
› Gravity Probe B Excecutive Summary (PDF, 1.9 MB)
› Gravity Probe B in a Nutshell (PDF, 500 KB)
› Gravity Probe B Overview Presentation (PDF, 911 KB)