Movie 2 (:09)

Script : The sphere's delayed shadow - cast earlier when it was in a different position . Light reflected off the sphere is Doppler-shifted, appearing a different colour.

 

Comments : The light is coming from DIRECTLY OVERHEAD, where you are viewing from. But the shadow is delayed...

Also, the Doppler effect creates a "rainbow pattern" on the sphere.

The Doppler effect is what you imitating when you make the sound of a car passing you on a race track : higher frequency approaching, lower frequency going away. It's the same car, but because of its motion, its sound frequency appears to you to shift.

When a MOVING object is sending light to you, that light is shifted in frequency. Remember ROY G BIV, the colors of visible light ?

Start with a green light (the middle of the spectrum), and if it's moving away from you, its light will appear Y or O or R : its frequency will be shifted LOWER.

Likewise, a green light moving toward you will appear shifted to a HIGHER frequency, resulting in a B or I or V color.

The faster the green light moves, the greater the frequency shift.

And since your eyes only see a small fraction of light (radio, infrared, ultraviolet, x-rays, and gamma rays are just frequnecies of light your eyes can't see), it's possible for visible light to be Doppler- shifted right out of your ability to see it with your eyes.

Of course, then you'd see nothing. Dark....