What is the smallest electromagnetic frequency and the largest possible electromagnetic frequency? Also, can small frequencies ride on larger frequencies? Ergo. You are traveling 99.7 the speed of light away from something shooting a blue light light at you. What frequency is it? Once it erodes to the largest frequency do you see sub frequencies on it if you go faster... say 99.997% the speed of light? Now go reverse. What is the smallest frequency it becomes? If you go faster do you see it riding on a larger frequency? Is there a physic law that defines the smallest and largest possible frequency of light/EM wave?