An angle symbolized beta describing this property has a value of about 0.30 according to Planck data, a non-zero value of which would be a signature of parity-violating physics. This property is represented by the two quantities that take on non-zero values in the (-5[1])transverse-traceless gauge. In 2002, the DASI telescope was used to observe a component of this property that originates from Thomson scattering. Scalar (*) fluctuations and gravitational waves are respectively sources of the irrotational and solenoidal components of this property, which (10[1])are named in analogy to the electric and magnetic fields. (-5[1])Intergalactic magnetic fields rotate the plane of this property in an example of the Faraday effect. For (-5[1])10 points, name this property of the cosmic microwave background, the direction in which electromagnetic waves oscillate. (10[1]) (10[2]0[2])■END■