Gravity probe B: Final results of a space experiment to test general relativity

Abstract

Gravity Probe B, launched 20 April 2004, is a space experiment testing two fundamental predictions of Einstein's theory of general relativity (GR), the geodetic and frame-dragging effects, by means of cryogenic gyroscopes in Earth orbit. Data collection started 28 August2004 and ended 14 August2005. Analysis of the data from all four gyroscopes results in a geodetic drift rate of -6601.8±18.3mas/yr and a frame-dragging drift rate of -37.2±7.2mas/yr, to be compared with the GR predictions of -6606.1mas/yr and -39.2mas/yr, respectively ("mas" is milliarcsecond; 1mas=4.848×10-9rad). © 2011 American Physical Society.