摘要
Gravitational redshift,theoretically predicted by Einstein,is considered a crucial test of general relativity(GR);it constitutes a test of the local position invariance(LPI)aspect of Einstein’s equivalence principle.The weak version of the equivalence principle has been validated with high precision through the frequency comparison experiment of Gravity Probe A[1]and the Earth-Moon distance measurement of the Lunar Laser Ranging experiment[2].
