Effect of a Gravitational Field, Due to a Rotating Body, on the Plane of Polarization of an Electromagnetic Wave

It is shown that for electromagnetic waves the gravitational field of a rotating body acts as an optically active medium. Thus, the plane of polarization of the wave rotates while it passes through this field. The effect is small. The angle of rotation due to the gravitational field of the sun is about 10^-12 radian.