Hey guys, I don't see how light can be a wave. If it is, then that means the velocity of light would not be constant. It would have to speed up when blue shifted because the wavelength is shorter. When the wavelength is short, it would have to travel faster up and down to make up for the horizontal speed. I'm thinking of light as literally moving like a ripple. A broader question would be, what is a wave? Does light move in an up and down motion like a ripple or is it actually linear? An idea my friend and I came up with is that light isn't a wave, but a pulse. The shorter the wavelength, the faster the light pulses. Are we right, or is light just a constant stream? BTW I'm talking about the physical aspect of light moving through a vacuum (the actual lights motion).