Figure 1
Credit: C. W. F. Everitt et al. [2]

Figure 1: (Top) Schematic of the orbit of the Gravity Probe B satellite. Two relativistic effects—frame-dragging and the geodetic effect—were expected to cause a precession (at ninety degree angles with respect to one another) of the gyroscopes aboard the satellite. (Bottom) Predicted precessions, given in milliarcseconds (mas), are compared to those measured by GPB.