Gravity Probe B, a NASA satellite that will validate two key aspects of Einstein's general theory of relativity, was launched today aboard a Boeing Delta II rocket.
The Delta II lifted off at 9:57:24 a.m. PDT from Space Launch Complex 2W at Vandenberg Air Force Base, Calif.
Gravity Probe B will test two predictions made by Albert Einstein in 1916 as part of his general theory of relativity.
The two predictions are the Geodetic effect -- the amount by which the Earth warps local space time in which it resides, and the frame-dragging effect -- the amount by which the Earth drags local space time with it as it rotates.
The spacecraft will send back data on changes in the spin axis direction of four onboard, ultra-precise gyroscopes in relation to the spacecraft's guide star, IM Pegasi, that will enable scientists to determine if space time is distorted by the Earth's presence and rotation.
Boeing Delta website