Why does light move on the floor when you move your body?
 

If you watch a beam of light shining on the ground (a good example of this is the overhead lights in a supermarket shining on the clean white tiles) it will move on the ground as you move your head/body. How can this be? What does the location of your head/body have to do with the location of the beam of light on the ground? What is this?

There must be something I'm missing here, because this just is making no sense.

P.S. Sorry if the post is hard to understand.

It's the reflection of the light as it hits your eyes. If you draw a line from the light from the source, to the reflection on the floor, to your eyes, you'll see that as you move your head, the reflection will also appear to move.

I've stood in supermarkets moving my head around in different directions looking at the reflections as well. :D

Well done. Now let's tackle how it looks when you move at near light speeds! Nah, just kidding. It a quarter till 3am here and my brain is fried!

It's called a "halo". It has something to do with refraction of light. I learned all about that stuff in a Meterology class. If you want a deeper explination, I suggest you look for the answer in the metorology.

Well I'll be damned. A reflection...

You feel like seeing a wicked website about optical effects and the atmosphere?

This is your website. Peruse it until all the links and crannies are exhausted. It is wonderfully fascinating. Especially the "Complex Displays" section.

http://www.sundog.clara.co.uk/atoptics/phenom.htm

Ah! That pic on the opening page reminds me of the coolest thing I saw during the plane ride to Jamaica. It was mid-afternoon, so the sun was very high in the sky, and it was a bit to the right side of the plane. I was sitting on the left. If I looked down at where the shadow of the plane was on the tops of the clouds, I saw a rainbow AROUND the shadow. It was so cool! (Guess it's not a rainbow, more of a rain-circle). Just figured I'd share that.