4. Relativistic Doppler Effect. One of the strongest emission lines observed from distant galaxies comes from hydrogen and has a wavelength of122 nm (in the ultraviolet region). (a) How fast must a galaxy be moving away from us in order for that line to be observed in the visible region at 366 nm? (b) What would be the wavelength of the line if that galaxy were moving toward us at the same speed?

4. Relativistic Doppler Effect. One of the strongest emission lines observed from distant galaxies comes from hydrogen and has a wavelength of122 nm (in the ultraviolet region). (a) How fast must a galaxy be moving away from us in order for that line to be observed in the visible region at 366 nm? (b) What would be the wavelength of the line if that galaxy were moving toward us at the same speed?