Speed of Light and Vibration

With all other factors being equal the speed of light (and in fact, the speed of ANY electromagnetic energy such as XRays) is the same regardless of color. Light travels at 186,000 miles per second through space, regardless of its color.

 

What DOES change with color, however, is the *wavelength* of the light, or how many vibrations the light goes through in a given distance.

 

What I mean by that is that a light wave has a vibration, as in the picture to the right.

 

Different colors of light either vibrate at a faster or slower rate (they have more or fewer “waves” in a given distance traveled). More vibrations  in a given distance, like violet and ultraviolet, means that color of light is more energetic (it vibrates more than red light).