A distant galaxy emits light that has a wavelength of 453.8 nanometer. On earth, the wavelength of this light is measured to be 455.5 nanometer.
(a) Decide whether this galaxy is approaching or receding from the earth.
(b) Evaluate the speed of the galaxy relative to the earth. (Give your answer to 4 significant digits. Use 2.998 x 108 m/s as the speed of light).