Scientific illustration

Gravity Probe B satellite, computer artwork. The Earth (background) is shown warping a grid of space-time. The Gravity Probe B satellite is an experiment that was conducted by NASA and Stanford University to test some predictions of Einstein's theory of General Relativity. This theory presents gravity as a warping of space and time, and the Gravity Probe B used gyroscopes to try to detect both the Earth's warping of space-time, and also the predicted 'drag' on space-time caused by the rotation of the Earth. The satellite was launched in 2004, and the experiment finished in September 2005. The analysis of the results is expected to be completed some time in 2007.

Image available for license from Science Photo Library