# Can light speed change relative to me?

If a light-emitting object is stationary relative to me, then the wavelength of the light emitted would be normal. However, if the object is moving away from me, then the wavelength of the light would be greater, since each wave of light emitted would be farther apart from the previous wave due to the object and the light waves moving in opposite directions. My question is, does the movement of the object also affect the relative speed of the light waves? For example, if the object was moving away from me at 50% the speed of light, would that velocity transfer to the light waves and cause them to travel 50% slower relative to me?

• "does the movement of the object also affect the relative speed of the light waves?" <- no. Commented Jan 31 at 13:35
• Commented Jan 31 at 15:55

No. The speed of light is always the same value, $$c = 299\,792\,458\, \mathrm{m}/\mathrm{s}$$, in any inertial reference frame, regardless of the relative velocity between the observer and the source. This is one of the basic principles of the theory of special relativity.