One of the wavelengths of light emitted by hydrogen atoms under normal laboratory conditions is A = 656.3 nm, in the red portion of the electromagnetic spectrum. In the light emitted from a distant galaxy this same spectra1line is observed to be Doppler shifted to A = 953.4 nm, in the infrared portion of the spectrum. How fast are the emitting atoms moving relative to the earth? Are they approaching the earth or receding from it?