I cannot search the forum to check if this has been posted before, because I do not know what it is called in english... That means that i have to try to explain what i means, here it goes: When a light producer, like a star is moving, it sends out waves that is either compressed or expanded. You know what i mean? Anyway, if the star was moving half the speed of light, will the waves be compressed to a half? Example: If the sun sends out waves at a wavelength of 800 nm, and moves TOWARDS us in the speed of light\2 (a half), would the wavelenght be 400 nm? And let's say that the star stands still, but the earth is moving half the light speed, would we observe the waves as half?